// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include <private/qguiapplication_p.h>
#include <private/qcolortransform_p.h>
#include <private/qcolortrclut_p.h>
#include <private/qdrawhelper_p.h>
#include <private/qendian_p.h>
#include <private/qpixellayout_p.h>
#include <private/qsimd_p.h>
#include <private/qimage_p.h>

#include <qendian.h>
#include <qrgbafloat.h>
#if QT_CONFIG(thread)
#include <qsemaphore.h>
#include <qthreadpool.h>
#ifdef Q_OS_WASM
// WebAssembly has threads; however we can't block the main thread.
#else
#define QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
#endif
#endif

QT_BEGIN_NAMESPACE

struct QDefaultColorTables
{
    QDefaultColorTables()
        : gray(256), alpha(256)
    {
        for (int i = 0; i < 256; ++i) {
            gray[i] = qRgb(i, i, i);
            alpha[i] = qRgba(0, 0, 0, i);
        }
    }

    QList<QRgb> gray, alpha;
};

Q_GLOBAL_STATIC(QDefaultColorTables, defaultColorTables);

// table to flip bits
static const uchar bitflip[256] = {
    /*
        open OUT, "| fmt";
        for $i (0..255) {
            print OUT (($i >> 7) & 0x01) | (($i >> 5) & 0x02) |
                      (($i >> 3) & 0x04) | (($i >> 1) & 0x08) |
                      (($i << 7) & 0x80) | (($i << 5) & 0x40) |
                      (($i << 3) & 0x20) | (($i << 1) & 0x10), ", ";
        }
        close OUT;
    */
    0, 128, 64, 192, 32, 160, 96, 224, 16, 144, 80, 208, 48, 176, 112, 240,
    8, 136, 72, 200, 40, 168, 104, 232, 24, 152, 88, 216, 56, 184, 120, 248,
    4, 132, 68, 196, 36, 164, 100, 228, 20, 148, 84, 212, 52, 180, 116, 244,
    12, 140, 76, 204, 44, 172, 108, 236, 28, 156, 92, 220, 60, 188, 124, 252,
    2, 130, 66, 194, 34, 162, 98, 226, 18, 146, 82, 210, 50, 178, 114, 242,
    10, 138, 74, 202, 42, 170, 106, 234, 26, 154, 90, 218, 58, 186, 122, 250,
    6, 134, 70, 198, 38, 166, 102, 230, 22, 150, 86, 214, 54, 182, 118, 246,
    14, 142, 78, 206, 46, 174, 110, 238, 30, 158, 94, 222, 62, 190, 126, 254,
    1, 129, 65, 193, 33, 161, 97, 225, 17, 145, 81, 209, 49, 177, 113, 241,
    9, 137, 73, 201, 41, 169, 105, 233, 25, 153, 89, 217, 57, 185, 121, 249,
    5, 133, 69, 197, 37, 165, 101, 229, 21, 149, 85, 213, 53, 181, 117, 245,
    13, 141, 77, 205, 45, 173, 109, 237, 29, 157, 93, 221, 61, 189, 125, 253,
    3, 131, 67, 195, 35, 163, 99, 227, 19, 147, 83, 211, 51, 179, 115, 243,
    11, 139, 75, 203, 43, 171, 107, 235, 27, 155, 91, 219, 59, 187, 123, 251,
    7, 135, 71, 199, 39, 167, 103, 231, 23, 151, 87, 215, 55, 183, 119, 247,
    15, 143, 79, 207, 47, 175, 111, 239, 31, 159, 95, 223, 63, 191, 127, 255
};

const uchar *qt_get_bitflip_array()
{
    return bitflip;
}

void qGamma_correct_back_to_linear_cs(QImage *image)
{
    const QColorTrcLut *cp = QGuiApplicationPrivate::instance()->colorProfileForA32Text();
    if (!cp)
        return;
    // gamma correct the pixels back to linear color space...
    int h = image->height();
    int w = image->width();

    for (int y=0; y<h; ++y) {
        QRgb *pixels = reinterpret_cast<QRgb *>(image->scanLine(y));
        for (int x=0; x<w; ++x)
            pixels[x] = cp->toLinear(pixels[x]);
    }
}

/*****************************************************************************
  Internal routines for converting image depth.
 *****************************************************************************/

// The drawhelper conversions from/to RGB32 are passthroughs which is not always correct for general image conversion
#if !defined(__ARM_NEON__) || !(Q_BYTE_ORDER == Q_LITTLE_ENDIAN)
static void QT_FASTCALL storeRGB32FromARGB32PM(uchar *dest, const uint *src, int index, int count,
                                               const QList<QRgb> *, QDitherInfo *)
{
    uint *d = reinterpret_cast<uint *>(dest) + index;
    for (int i = 0; i < count; ++i)
        d[i] = 0xff000000 | qUnpremultiply(src[i]);
}
#endif

static void QT_FASTCALL storeRGB32FromARGB32(uchar *dest, const uint *src, int index, int count,
                                             const QList<QRgb> *, QDitherInfo *)
{
    uint *d = reinterpret_cast<uint *>(dest) + index;
    for (int i = 0; i < count; ++i)
        d[i] = 0xff000000 | src[i];
}

static const uint *QT_FASTCALL fetchRGB32ToARGB32PM(uint *buffer, const uchar *src, int index, int count,
                                                    const QList<QRgb> *, QDitherInfo *)
{
    const uint *s = reinterpret_cast<const uint *>(src) + index;
    for (int i = 0; i < count; ++i)
        buffer[i] = 0xff000000 | s[i];
    return buffer;
}

#ifdef QT_COMPILER_SUPPORTS_SSE4_1
extern void QT_FASTCALL storeRGB32FromARGB32PM_sse4(uchar *dest, const uint *src, int index, int count,
                                                    const QList<QRgb> *, QDitherInfo *);
#elif defined(__ARM_NEON__) && (Q_BYTE_ORDER == Q_LITTLE_ENDIAN)
extern void QT_FASTCALL storeRGB32FromARGB32PM_neon(uchar *dest, const uint *src, int index, int count,
                                                    const QList<QRgb> *, QDitherInfo *);
#endif

void convert_generic(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags flags)
{
    // Cannot be used with indexed formats.
    Q_ASSERT(dest->format > QImage::Format_Indexed8);
    Q_ASSERT(src->format > QImage::Format_Indexed8);
    const QPixelLayout *srcLayout = &qPixelLayouts[src->format];
    const QPixelLayout *destLayout = &qPixelLayouts[dest->format];

    FetchAndConvertPixelsFunc fetch = srcLayout->fetchToARGB32PM;
    ConvertAndStorePixelsFunc store = destLayout->storeFromARGB32PM;
    if (!srcLayout->hasAlphaChannel && destLayout->storeFromRGB32) {
        // If the source doesn't have an alpha channel, we can use the faster storeFromRGB32 method.
        store = destLayout->storeFromRGB32;
    } else {
        // The drawhelpers do not mask the alpha value in RGB32, we want to here.
        if (src->format == QImage::Format_RGB32)
            fetch = fetchRGB32ToARGB32PM;
        if (dest->format == QImage::Format_RGB32) {
#ifdef QT_COMPILER_SUPPORTS_SSE4_1
            if (qCpuHasFeature(SSE4_1))
                store = storeRGB32FromARGB32PM_sse4;
            else
                store = storeRGB32FromARGB32PM;
#elif defined(__ARM_NEON__) && (Q_BYTE_ORDER == Q_LITTLE_ENDIAN)
            store = storeRGB32FromARGB32PM_neon;
#else
            store = storeRGB32FromARGB32PM;
#endif
        }
    }
    if (srcLayout->hasAlphaChannel && !srcLayout->premultiplied &&
            !destLayout->hasAlphaChannel && destLayout->storeFromRGB32) {
        // Avoid unnecessary premultiply and unpremultiply when converting from unpremultiplied src format.
        fetch = qPixelLayouts[src->format + 1].fetchToARGB32PM;
        if (dest->format == QImage::Format_RGB32)
            store = storeRGB32FromARGB32;
        else
            store = destLayout->storeFromRGB32;
    }

    auto convertSegment = [=](int yStart, int yEnd) {
        uint buf[BufferSize];
        uint *buffer = buf;
        const uchar *srcData = src->data + src->bytes_per_line * yStart;
        uchar *destData = dest->data + dest->bytes_per_line * yStart;
        QDitherInfo dither;
        QDitherInfo *ditherPtr = nullptr;
        if ((flags & Qt::PreferDither) && (flags & Qt::Dither_Mask) != Qt::ThresholdDither)
            ditherPtr = &dither;
        for (int y = yStart; y < yEnd; ++y) {
            dither.y = y;
            int x = 0;
            while (x < src->width) {
                dither.x = x;
                int l = src->width - x;
                if (destLayout->bpp == QPixelLayout::BPP32)
                    buffer = reinterpret_cast<uint *>(destData) + x;
                else
                    l = qMin(l, BufferSize);
                const uint *ptr = fetch(buffer, srcData, x, l, nullptr, ditherPtr);
                store(destData, ptr, x, l, nullptr, ditherPtr);
                x += l;
            }
            srcData += src->bytes_per_line;
            destData += dest->bytes_per_line;
        }
    };

#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(src->width) * src->height) >> 16;
    segments = std::min(segments, src->height);

    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments <= 1 || !threadPool || threadPool->contains(QThread::currentThread()))
        return convertSegment(0, src->height);

    QSemaphore semaphore;
    int y = 0;
    for (int i = 0; i < segments; ++i) {
        int yn = (src->height - y) / (segments - i);
        threadPool->start([&, y, yn]() {
            convertSegment(y, y + yn);
            semaphore.release(1);
        });
        y += yn;
    }
    semaphore.acquire(segments);
#else
    convertSegment(0, src->height);
#endif
}

void convert_generic_over_rgb64(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format > QImage::Format_Indexed8);
    Q_ASSERT(src->format > QImage::Format_Indexed8);
    const QPixelLayout *srcLayout = &qPixelLayouts[src->format];
    const QPixelLayout *destLayout = &qPixelLayouts[dest->format];

    const FetchAndConvertPixelsFunc64 fetch = srcLayout->fetchToRGBA64PM;
    const ConvertAndStorePixelsFunc64 store = qStoreFromRGBA64PM[dest->format];

    auto convertSegment = [=](int yStart, int yEnd) {
        QRgba64 buf[BufferSize];
        QRgba64 *buffer = buf;
        const uchar *srcData = src->data + yStart * src->bytes_per_line;
        uchar *destData = dest->data + yStart * dest->bytes_per_line;
        for (int y = yStart; y < yEnd; ++y) {
            int x = 0;
            while (x < src->width) {
                int l = src->width - x;
                if (destLayout->bpp == QPixelLayout::BPP64)
                    buffer = reinterpret_cast<QRgba64 *>(destData) + x;
                else
                    l = qMin(l, BufferSize);
                const QRgba64 *ptr = fetch(buffer, srcData, x, l, nullptr, nullptr);
                store(destData, ptr, x, l, nullptr, nullptr);
                x += l;
            }
            srcData += src->bytes_per_line;
            destData += dest->bytes_per_line;
        }
    };
#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(src->width) * src->height) >> 16;
    segments = std::min(segments, src->height);

    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments <= 1 || !threadPool || threadPool->contains(QThread::currentThread()))
        return convertSegment(0, src->height);

    QSemaphore semaphore;
    int y = 0;
    for (int i = 0; i < segments; ++i) {
        int yn = (src->height - y) / (segments - i);
        threadPool->start([&, y, yn]() {
            convertSegment(y, y + yn);
            semaphore.release(1);
        });
        y += yn;
    }
    semaphore.acquire(segments);
#else
    convertSegment(0, src->height);
#endif
}

#if QT_CONFIG(raster_fp)
void convert_generic_over_rgba32f(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format >= QImage::Format_RGBX16FPx4);
    Q_ASSERT(src->format >= QImage::Format_RGBX16FPx4);

    const FetchAndConvertPixelsFuncFP fetch = qFetchToRGBA32F[src->format];
    const ConvertAndStorePixelsFuncFP store = qStoreFromRGBA32F[dest->format];

    auto convertSegment = [=](int yStart, int yEnd) {
        QRgbaFloat32 buf[BufferSize];
        QRgbaFloat32 *buffer = buf;
        const uchar *srcData = src->data + yStart * src->bytes_per_line;
        uchar *destData = dest->data + yStart * dest->bytes_per_line;
        for (int y = yStart; y < yEnd; ++y) {
            int x = 0;
            while (x < src->width) {
                int l = src->width - x;
                if (dest->depth == 128)
                    buffer = reinterpret_cast<QRgbaFloat32 *>(destData) + x;
                else
                    l = qMin(l, BufferSize);
                const QRgbaFloat32 *ptr = fetch(buffer, srcData, x, l, nullptr, nullptr);
                store(destData, ptr, x, l, nullptr, nullptr);
                x += l;
            }
            srcData += src->bytes_per_line;
            destData += dest->bytes_per_line;
        }
    };
#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(src->width) * src->height) >> 16;
    segments = std::min(segments, src->height);

    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments <= 1 || !threadPool || threadPool->contains(QThread::currentThread()))
        return convertSegment(0, src->height);

    QSemaphore semaphore;
    int y = 0;
    for (int i = 0; i < segments; ++i) {
        int yn = (src->height - y) / (segments - i);
        threadPool->start([&, y, yn]() {
            convertSegment(y, y + yn);
            semaphore.release(1);
        });
        y += yn;
    }
    semaphore.acquire(segments);
#else
    convertSegment(0, src->height);
#endif
}
#endif

bool convert_generic_inplace(QImageData *data, QImage::Format dst_format, Qt::ImageConversionFlags flags)
{
    // Cannot be used with indexed formats or between formats with different pixel depths.
    Q_ASSERT(dst_format > QImage::Format_Indexed8);
    Q_ASSERT(data->format > QImage::Format_Indexed8);
    const int destDepth = qt_depthForFormat(dst_format);
    if (data->depth < destDepth)
        return false;

    const QPixelLayout *srcLayout = &qPixelLayouts[data->format];
    const QPixelLayout *destLayout = &qPixelLayouts[dst_format];

    // The precision here is only ARGB32PM so don't convert between higher accuracy
    // formats.
    Q_ASSERT(!qt_highColorPrecision(data->format, !destLayout->hasAlphaChannel)
             || !qt_highColorPrecision(dst_format, !srcLayout->hasAlphaChannel));

    QImageData::ImageSizeParameters params = { data->bytes_per_line, data->nbytes };
    if (data->depth != destDepth) {
        params = QImageData::calculateImageParameters(data->width, data->height, destDepth);
        if (!params.isValid())
            return false;
    }

    Q_ASSERT(destLayout->bpp < QPixelLayout::BPP64);
    FetchAndConvertPixelsFunc fetch = srcLayout->fetchToARGB32PM;
    ConvertAndStorePixelsFunc store = destLayout->storeFromARGB32PM;
    if (!srcLayout->hasAlphaChannel && destLayout->storeFromRGB32) {
        // If the source doesn't have an alpha channel, we can use the faster storeFromRGB32 method.
        store = destLayout->storeFromRGB32;
    } else {
        if (data->format == QImage::Format_RGB32)
            fetch = fetchRGB32ToARGB32PM;
        if (dst_format == QImage::Format_RGB32) {
#ifdef QT_COMPILER_SUPPORTS_SSE4_1
            if (qCpuHasFeature(SSE4_1))
                store = storeRGB32FromARGB32PM_sse4;
            else
                store = storeRGB32FromARGB32PM;
#elif defined(__ARM_NEON__) && (Q_BYTE_ORDER == Q_LITTLE_ENDIAN)
            store = storeRGB32FromARGB32PM_neon;
#else
            store = storeRGB32FromARGB32PM;
#endif
        }
    }
    if (srcLayout->hasAlphaChannel && !srcLayout->premultiplied &&
            !destLayout->hasAlphaChannel && destLayout->storeFromRGB32) {
        // Avoid unnecessary premultiply and unpremultiply when converting from unpremultiplied src format.
        fetch = qPixelLayouts[data->format + 1].fetchToARGB32PM;
        if (data->format == QImage::Format_RGB32)
            store = storeRGB32FromARGB32;
        else
            store = destLayout->storeFromRGB32;
    }

    auto convertSegment = [=](int yStart, int yEnd) {
        uint buf[BufferSize];
        uint *buffer = buf;
        uchar *srcData = data->data + data->bytes_per_line * yStart;
        uchar *destData = srcData; // This can be temporarily wrong if we doing a shrinking conversion
        QDitherInfo dither;
        QDitherInfo *ditherPtr = nullptr;
        if ((flags & Qt::PreferDither) && (flags & Qt::Dither_Mask) != Qt::ThresholdDither)
            ditherPtr = &dither;
        for (int y = yStart; y < yEnd; ++y) {
            dither.y = y;
            int x = 0;
            while (x < data->width) {
                dither.x = x;
                int l = data->width - x;
                if (srcLayout->bpp == QPixelLayout::BPP32)
                    buffer = reinterpret_cast<uint *>(srcData) + x;
                else
                    l = qMin(l, BufferSize);
                const uint *ptr = fetch(buffer, srcData, x, l, nullptr, ditherPtr);
                store(destData, ptr, x, l, nullptr, ditherPtr);
                x += l;
            }
            srcData += data->bytes_per_line;
            destData += params.bytesPerLine;
        }
    };
#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(data->width) * data->height) >> 16;
    segments = std::min(segments, data->height);
    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments > 1 && threadPool && !threadPool->contains(QThread::currentThread())) {
        QSemaphore semaphore;
        int y = 0;
        for (int i = 0; i < segments; ++i) {
            int yn = (data->height - y) / (segments - i);
            threadPool->start([&, y, yn]() {
                convertSegment(y, y + yn);
                semaphore.release(1);
            });
            y += yn;
        }
        semaphore.acquire(segments);
        if (data->bytes_per_line != params.bytesPerLine) {
            // Compress segments to a continuous block
            y = 0;
            for (int i = 0; i < segments; ++i) {
                int yn = (data->height - y) / (segments - i);
                uchar *srcData = data->data + data->bytes_per_line * y;
                uchar *destData = data->data + params.bytesPerLine * y;
                if (srcData != destData)
                    memmove(destData, srcData, params.bytesPerLine * yn);
                y += yn;
            }
        }
    } else
#endif
        convertSegment(0, data->height);
    if (params.totalSize != data->nbytes) {
        Q_ASSERT(params.totalSize < data->nbytes);
        void *newData = realloc(data->data, params.totalSize);
        if (newData) {
            data->data = (uchar *)newData;
            data->nbytes = params.totalSize;
        }
        data->bytes_per_line = params.bytesPerLine;
    }
    data->depth = destDepth;
    data->format = dst_format;
    return true;
}

bool convert_generic_inplace_over_rgb64(QImageData *data, QImage::Format dst_format, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format > QImage::Format_Indexed8);
    Q_ASSERT(dst_format > QImage::Format_Indexed8);
    const int destDepth = qt_depthForFormat(dst_format);
    if (data->depth < destDepth)
        return false;

    const QPixelLayout *srcLayout = &qPixelLayouts[data->format];
    const QPixelLayout *destLayout = &qPixelLayouts[dst_format];

    QImageData::ImageSizeParameters params = { data->bytes_per_line, data->nbytes };
    if (data->depth != destDepth) {
        params = QImageData::calculateImageParameters(data->width, data->height, destDepth);
        if (!params.isValid())
            return false;
    }

    FetchAndConvertPixelsFunc64 fetch = srcLayout->fetchToRGBA64PM;
    ConvertAndStorePixelsFunc64 store = qStoreFromRGBA64PM[dst_format];
    if (srcLayout->hasAlphaChannel && !srcLayout->premultiplied &&
        destLayout->hasAlphaChannel && !destLayout->premultiplied) {
        // Avoid unnecessary premultiply and unpremultiply when converting between two unpremultiplied formats.
        // This abuses the fact unpremultiplied formats are always before their premultiplied counterparts.
        fetch = qPixelLayouts[data->format + 1].fetchToRGBA64PM;
        store = qStoreFromRGBA64PM[dst_format + 1];
    }

    auto convertSegment = [=](int yStart, int yEnd) {
        QRgba64 buf[BufferSize];
        QRgba64 *buffer = buf;
        uchar *srcData = data->data + yStart * data->bytes_per_line;
        uchar *destData = srcData;
        for (int y = yStart; y < yEnd; ++y) {
            int x = 0;
            while (x < data->width) {
                int l = data->width - x;
                if (srcLayout->bpp == QPixelLayout::BPP64)
                    buffer = reinterpret_cast<QRgba64 *>(srcData) + x;
                else
                    l = qMin(l, BufferSize);
                const QRgba64 *ptr = fetch(buffer, srcData, x, l, nullptr, nullptr);
                store(destData, ptr, x, l, nullptr, nullptr);
                x += l;
            }
            srcData += data->bytes_per_line;
            destData += params.bytesPerLine;
        }
    };
#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(data->width) * data->height) >> 16;
    segments = std::min(segments, data->height);
    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments > 1 && threadPool && !threadPool->contains(QThread::currentThread())) {
        QSemaphore semaphore;
        int y = 0;
        for (int i = 0; i < segments; ++i) {
            int yn = (data->height - y) / (segments - i);
            threadPool->start([&, y, yn]() {
                convertSegment(y, y + yn);
                semaphore.release(1);
            });
            y += yn;
        }
        semaphore.acquire(segments);
        if (data->bytes_per_line != params.bytesPerLine) {
            // Compress segments to a continuous block
            y = 0;
            for (int i = 0; i < segments; ++i) {
                int yn = (data->height - y) / (segments - i);
                uchar *srcData = data->data + data->bytes_per_line * y;
                uchar *destData = data->data + params.bytesPerLine * y;
                if (srcData != destData)
                    memmove(destData, srcData, params.bytesPerLine * yn);
                y += yn;
            }
        }
    } else
#endif
        convertSegment(0, data->height);
    if (params.totalSize != data->nbytes) {
        Q_ASSERT(params.totalSize < data->nbytes);
        void *newData = realloc(data->data, params.totalSize);
        if (newData) {
            data->data = (uchar *)newData;
            data->nbytes = params.totalSize;
        }
        data->bytes_per_line = params.bytesPerLine;
    }
    data->depth = destDepth;
    data->format = dst_format;
    return true;
}

#if QT_CONFIG(raster_fp)
bool convert_generic_inplace_over_rgba32f(QImageData *data, QImage::Format dst_format, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format >= QImage::Format_RGBX16FPx4);
    Q_ASSERT(dst_format >= QImage::Format_RGBX16FPx4);
    const int destDepth = qt_depthForFormat(dst_format);
    if (data->depth < destDepth)
        return false;

    const QPixelLayout *srcLayout = &qPixelLayouts[data->format];
    const QPixelLayout *destLayout = &qPixelLayouts[dst_format];

    QImageData::ImageSizeParameters params = { data->bytes_per_line, data->nbytes };
    if (data->depth != destDepth) {
        params = QImageData::calculateImageParameters(data->width, data->height, destDepth);
        if (!params.isValid())
            return false;
    }

    FetchAndConvertPixelsFuncFP fetch = qFetchToRGBA32F[data->format];
    ConvertAndStorePixelsFuncFP store = qStoreFromRGBA32F[dst_format];
    if (srcLayout->hasAlphaChannel && !srcLayout->premultiplied &&
        destLayout->hasAlphaChannel && !destLayout->premultiplied) {
        // Avoid unnecessary premultiply and unpremultiply when converting between two unpremultiplied formats.
        // This abuses the fact unpremultiplied formats are always before their premultiplied counterparts.
        fetch = qFetchToRGBA32F[data->format + 1];
        store = qStoreFromRGBA32F[dst_format + 1];
    }

    auto convertSegment = [=](int yStart, int yEnd) {
        QRgbaFloat32 buf[BufferSize];
        QRgbaFloat32 *buffer = buf;
        uchar *srcData = data->data + yStart * data->bytes_per_line;
        uchar *destData = srcData;
        for (int y = yStart; y < yEnd; ++y) {
            int x = 0;
            while (x < data->width) {
                int l = data->width - x;
                if (srcLayout->bpp == QPixelLayout::BPP32FPx4)
                    buffer = reinterpret_cast<QRgbaFloat32 *>(srcData) + x;
                else
                    l = qMin(l, BufferSize);
                const QRgbaFloat32 *ptr = fetch(buffer, srcData, x, l, nullptr, nullptr);
                store(destData, ptr, x, l, nullptr, nullptr);
                x += l;
            }
            srcData += data->bytes_per_line;
            destData += params.bytesPerLine;
        }
    };
#ifdef QT_USE_THREAD_PARALLEL_IMAGE_CONVERSIONS
    int segments = (qsizetype(data->width) * data->height) >> 16;
    segments = std::min(segments, data->height);
    QThreadPool *threadPool = QThreadPool::globalInstance();
    if (segments > 1 && threadPool && !threadPool->contains(QThread::currentThread())) {
        QSemaphore semaphore;
        int y = 0;
        for (int i = 0; i < segments; ++i) {
            int yn = (data->height - y) / (segments - i);
            threadPool->start([&, y, yn]() {
                convertSegment(y, y + yn);
                semaphore.release(1);
            });
            y += yn;
        }
        semaphore.acquire(segments);
        if (data->bytes_per_line != params.bytesPerLine) {
            // Compress segments to a continuous block
            y = 0;
            for (int i = 0; i < segments; ++i) {
                int yn = (data->height - y) / (segments - i);
                uchar *srcData = data->data + data->bytes_per_line * y;
                uchar *destData = data->data + params.bytesPerLine * y;
                if (srcData != destData)
                    memmove(destData, srcData, params.bytesPerLine * yn);
                y += yn;
            }
        }
    } else
#endif
        convertSegment(0, data->height);
    if (params.totalSize != data->nbytes) {
        Q_ASSERT(params.totalSize < data->nbytes);
        void *newData = realloc(data->data, params.totalSize);
        if (newData) {
            data->data = (uchar *)newData;
            data->nbytes = params.totalSize;
        }
        data->bytes_per_line = params.bytesPerLine;
    }
    data->depth = destDepth;
    data->format = dst_format;
    return true;
}
#endif

static void convert_passthrough(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_bpl = src->bytes_per_line;
    const int dest_bpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    for (int i = 0; i < src->height; ++i) {
        memcpy(dest_data, src_data, src_bpl);
        src_data += src_bpl;
        dest_data += dest_bpl;
    }
}

template<QImage::Format Format>
static bool convert_passthrough_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    data->format = Format;
    return true;
}

Q_GUI_EXPORT void QT_FASTCALL qt_convert_rgb888_to_rgb32(quint32 *dest_data, const uchar *src_data, int len)
{
    int pixel = 0;
    // prolog: align input to 32bit
    while ((quintptr(src_data) & 0x3) && pixel < len) {
        *dest_data = 0xff000000 | (src_data[0] << 16) | (src_data[1] << 8) | (src_data[2]);
        src_data += 3;
        ++dest_data;
        ++pixel;
    }

    // Handle 4 pixels at a time 12 bytes input to 16 bytes output.
    for (; pixel + 3 < len; pixel += 4) {
        const quint32_be *src_packed = reinterpret_cast<const quint32_be *>(src_data);
        const quint32 src1 = src_packed[0];
        const quint32 src2 = src_packed[1];
        const quint32 src3 = src_packed[2];

        dest_data[0] = 0xff000000 | (src1 >> 8);
        dest_data[1] = 0xff000000 | (src1 << 16) | (src2 >> 16);
        dest_data[2] = 0xff000000 | (src2 << 8) | (src3 >> 24);
        dest_data[3] = 0xff000000 | src3;

        src_data += 12;
        dest_data += 4;
    }

    // epilog: handle left over pixels
    for (; pixel < len; ++pixel) {
        *dest_data = 0xff000000 | (src_data[0] << 16) | (src_data[1] << 8) | (src_data[2]);
        src_data += 3;
        ++dest_data;
    }
}

Q_GUI_EXPORT void QT_FASTCALL qt_convert_rgb888_to_rgbx8888(quint32 *dest_data, const uchar *src_data, int len)
{
    int pixel = 0;
    // prolog: align input to 32bit
    while ((quintptr(src_data) & 0x3) && pixel < len) {
        *dest_data = ARGB2RGBA(0xff000000 | (src_data[0] << 16) | (src_data[1] << 8) | (src_data[2]));
        src_data += 3;
        ++dest_data;
        ++pixel;
    }

    // Handle 4 pixels at a time 12 bytes input to 16 bytes output.
    for (; pixel + 3 < len; pixel += 4) {
        const quint32 *src_packed = (const quint32 *) src_data;
        const quint32 src1 = src_packed[0];
        const quint32 src2 = src_packed[1];
        const quint32 src3 = src_packed[2];

#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
        dest_data[0] = 0xff000000 | src1;
        dest_data[1] = 0xff000000 | (src1 >> 24) | (src2 << 8);
        dest_data[2] = 0xff000000 | (src2 >> 16) | (src3 << 16);
        dest_data[3] = 0xff000000 | (src3 >> 8);
#else
        dest_data[0] = 0xff | src1;
        dest_data[1] = 0xff | (src1 << 24) | (src2 >> 8);
        dest_data[2] = 0xff | (src2 << 16) | (src3 >> 16);
        dest_data[3] = 0xff | (src3 << 8);
#endif

        src_data += 12;
        dest_data += 4;
    }

    // epilog: handle left over pixels
    for (; pixel < len; ++pixel) {
        *dest_data = ARGB2RGBA(0xff000000 | (src_data[0] << 16) | (src_data[1] << 8) | (src_data[2]));
        src_data += 3;
        ++dest_data;
    }
}

typedef void (QT_FASTCALL *Rgb888ToRgbConverter)(quint32 *dst, const uchar *src, int len);

template <bool rgbx>
static void convert_RGB888_to_RGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGB888 || src->format == QImage::Format_BGR888);
    if (rgbx ^ (src->format == QImage::Format_BGR888))
        Q_ASSERT(dest->format == QImage::Format_RGBX8888 || dest->format == QImage::Format_RGBA8888 || dest->format == QImage::Format_RGBA8888_Premultiplied);
    else
        Q_ASSERT(dest->format == QImage::Format_RGB32 || dest->format == QImage::Format_ARGB32 || dest->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const uchar *src_data = (uchar *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    Rgb888ToRgbConverter line_converter= rgbx ? qt_convert_rgb888_to_rgbx8888 : qt_convert_rgb888_to_rgb32;

    for (int i = 0; i < src->height; ++i) {
        line_converter(dest_data, src_data, src->width);
        src_data += src->bytes_per_line;
        dest_data = (quint32 *)((uchar*)dest_data + dest->bytes_per_line);
    }
}

static void convert_ARGB_to_RGBx(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_ARGB32);
    Q_ASSERT(dest->format == QImage::Format_RGBX8888);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = ARGB2RGBA(0xff000000 | *src_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

static void convert_ARGB_to_RGBA(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_ARGB32 || src->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_RGBA8888 || dest->format == QImage::Format_RGBA8888_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = ARGB2RGBA(*src_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<QImage::Format DestFormat>
static bool convert_ARGB_to_RGBA_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_ARGB32 || data->format == QImage::Format_ARGB32_Premultiplied);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    quint32 *rgb_data = (quint32 *) data->data;
    constexpr uint mask = (DestFormat == QImage::Format_RGBX8888) ? 0xff000000 : 0;

    for (int i = 0; i < data->height; ++i) {
        const quint32 *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = ARGB2RGBA(*rgb_data | mask);
            ++rgb_data;
        }
        rgb_data += pad;
    }

    data->format = DestFormat;
    return true;
}

static void convert_RGBA_to_ARGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGBX8888 || src->format == QImage::Format_RGBA8888 || src->format == QImage::Format_RGBA8888_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_ARGB32 || dest->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = RGBA2ARGB(*src_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<QImage::Format DestFormat>
static bool convert_RGBA_to_ARGB_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_RGBX8888 || data->format == QImage::Format_RGBA8888 || data->format == QImage::Format_RGBA8888_Premultiplied);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    QRgb *rgb_data = (QRgb *) data->data;
    constexpr uint mask = (DestFormat == QImage::Format_RGB32) ? 0xff000000 : 0;

    for (int i = 0; i < data->height; ++i) {
        const QRgb *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = mask | RGBA2ARGB(*rgb_data);
            ++rgb_data;
        }
        rgb_data += pad;
    }
    data->format = DestFormat;
    return true;
}

static void convert_rgbswap_generic(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const RbSwapFunc func = qPixelLayouts[src->format].rbSwap;
    Q_ASSERT(func);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    for (int i = 0; i < src->height; ++i) {
        func(dest_data, src_data, src->width);

        src_data += sbpl;
        dest_data += dbpl;
    }
}

static bool convert_rgbswap_generic_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    const RbSwapFunc func = qPixelLayouts[data->format].rbSwap;
    Q_ASSERT(func);

    const qsizetype bpl = data->bytes_per_line;
    uchar *line_data = data->data;

    for (int i = 0; i < data->height; ++i) {
        func(line_data, line_data, data->width);
        line_data += bpl;
    }

    switch (data->format) {
    case QImage::Format_RGB888:
        data->format = QImage::Format_BGR888;
        break;
    case QImage::Format_BGR888:
        data->format = QImage::Format_RGB888;
        break;
    case QImage::Format_BGR30:
        data->format = QImage::Format_RGB30;
        break;
    case QImage::Format_A2BGR30_Premultiplied:
        data->format = QImage::Format_A2RGB30_Premultiplied;
        break;
    case QImage::Format_RGB30:
        data->format = QImage::Format_BGR30;
        break;
    case QImage::Format_A2RGB30_Premultiplied:
        data->format = QImage::Format_A2BGR30_Premultiplied;
        break;
    default:
        Q_UNREACHABLE();
        data->format = QImage::Format_Invalid;
        return false;
    }
    return true;
}

template<QtPixelOrder PixelOrder, bool RGBA>
static void convert_ARGB_to_A2RGB30(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{

    Q_ASSERT(RGBA || src->format == QImage::Format_ARGB32);
    Q_ASSERT(!RGBA || src->format == QImage::Format_RGBA8888);
    Q_ASSERT(dest->format == QImage::Format_A2BGR30_Premultiplied
             || dest->format == QImage::Format_A2RGB30_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            QRgb c = *src_data;
            if (RGBA)
                c = RGBA2ARGB(c);
            const uint alpha = (qAlpha(c) >> 6) * 85;
            c = BYTE_MUL(c, alpha);
            *dest_data = (qConvertRgb32ToRgb30<PixelOrder>(c) & 0x3fffffff) | (alpha << 30);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<QtPixelOrder PixelOrder, bool RGBA>
static bool convert_ARGB_to_A2RGB30_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(RGBA || data->format == QImage::Format_ARGB32);
    Q_ASSERT(!RGBA || data->format == QImage::Format_RGBA8888);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    QRgb *rgb_data = (QRgb *) data->data;

    for (int i = 0; i < data->height; ++i) {
        const QRgb *end = rgb_data + data->width;
        while (rgb_data < end) {
            QRgb c = *rgb_data;
            if (RGBA)
                c = RGBA2ARGB(c);
            const uint alpha = (qAlpha(c) >> 6) * 85;
            c = BYTE_MUL(c, alpha);
            *rgb_data = (qConvertRgb32ToRgb30<PixelOrder>(c) & 0x3fffffff) | (alpha << 30);
            ++rgb_data;
        }
        rgb_data += pad;
    }

    data->format = (PixelOrder == PixelOrderRGB) ? QImage::Format_A2RGB30_Premultiplied
                                                 : QImage::Format_A2BGR30_Premultiplied;
    return true;
}

static inline uint qUnpremultiplyRgb30(uint rgb30)
{
    const uint a = rgb30 >> 30;
    switch (a) {
    case 0:
        return 0;
    case 1: {
        uint rgb = rgb30 & 0x3fffffff;
        rgb *= 3;
        return (a << 30) | rgb;
    }
    case 2: {
        uint rgb = rgb30 & 0x3fffffff;
        rgb += (rgb >> 1) & 0x5ff7fdff;
        return (a << 30) | rgb;
    }
    case 3:
        return rgb30;
    }
    Q_UNREACHABLE();
    return 0;
}

template<bool rgbswap>
static void convert_A2RGB30_PM_to_RGB30(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_A2RGB30_Premultiplied || src->format == QImage::Format_A2BGR30_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_RGB30 || dest->format == QImage::Format_BGR30);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            const uint p = 0xc0000000 | qUnpremultiplyRgb30(*src_data);
            *dest_data = (rgbswap) ? qRgbSwapRgb30(p) : p;
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<bool rgbswap>
static bool convert_A2RGB30_PM_to_RGB30_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_A2RGB30_Premultiplied || data->format == QImage::Format_A2BGR30_Premultiplied);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    uint *rgb_data = (uint *) data->data;

    for (int i = 0; i < data->height; ++i) {
        const uint *end = rgb_data + data->width;
        while (rgb_data < end) {
            const uint p = 0xc0000000 | qUnpremultiplyRgb30(*rgb_data);
            *rgb_data = (rgbswap) ? qRgbSwapRgb30(p) : p;
            ++rgb_data;
        }
        rgb_data += pad;
    }

    if (data->format == QImage::Format_A2RGB30_Premultiplied)
        data->format = (rgbswap) ? QImage::Format_BGR30 : QImage::Format_RGB30;
    else
        data->format = (rgbswap) ? QImage::Format_RGB30 : QImage::Format_BGR30;
    return true;
}

static bool convert_BGR30_to_A2RGB30_inplace(QImageData *data, Qt::ImageConversionFlags flags)
{
    Q_ASSERT(data->format == QImage::Format_RGB30 || data->format == QImage::Format_BGR30);
    if (!convert_rgbswap_generic_inplace(data, flags))
        return false;

    if (data->format == QImage::Format_RGB30)
        data->format = QImage::Format_A2RGB30_Premultiplied;
    else
        data->format = QImage::Format_A2BGR30_Premultiplied;
    return true;
}

template<QtPixelOrder PixelOrder, bool RGBA>
static void convert_A2RGB30_PM_to_ARGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_A2RGB30_Premultiplied || src->format == QImage::Format_A2BGR30_Premultiplied);
    Q_ASSERT(RGBA ? dest->format == QImage::Format_RGBA8888 : dest->format == QImage::Format_ARGB32);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const quint32 *src_data = (quint32 *) src->data;
    quint32 *dest_data = (quint32 *) dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint32 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = qConvertA2rgb30ToArgb32<PixelOrder>(qUnpremultiplyRgb30(*src_data));
            if (RGBA)
                *dest_data = ARGB2RGBA(*dest_data);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<QtPixelOrder PixelOrder, bool RGBA>
static bool convert_A2RGB30_PM_to_ARGB_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_A2RGB30_Premultiplied || data->format == QImage::Format_A2BGR30_Premultiplied);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    uint *rgb_data = (uint *) data->data;

    for (int i = 0; i < data->height; ++i) {
        const uint *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = qConvertA2rgb30ToArgb32<PixelOrder>(qUnpremultiplyRgb30(*rgb_data));
            if (RGBA)
                *rgb_data = ARGB2RGBA(*rgb_data);
            ++rgb_data;
        }
        rgb_data += pad;
    }
    if (RGBA)
        data->format = QImage::Format_RGBA8888;
    else
        data->format = QImage::Format_ARGB32;
    return true;
}

static void convert_RGBA_to_RGB(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGBA8888 || src->format == QImage::Format_RGBX8888);
    Q_ASSERT(dest->format == QImage::Format_RGB32);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const uint *src_data = (const uint *)src->data;
    uint *dest_data = (uint *)dest->data;

    for (int i = 0; i < src->height; ++i) {
        const uint *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = RGBA2ARGB(*src_data) | 0xff000000;
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

static void swap_bit_order(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Mono || src->format == QImage::Format_MonoLSB);
    Q_ASSERT(dest->format == QImage::Format_Mono || dest->format == QImage::Format_MonoLSB);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);
    Q_ASSERT(src->nbytes == dest->nbytes);
    Q_ASSERT(src->bytes_per_line == dest->bytes_per_line);

    dest->colortable = src->colortable;

    const uchar *src_data = src->data;
    const uchar *end = src->data + src->nbytes;
    uchar *dest_data = dest->data;
    while (src_data < end) {
        *dest_data = bitflip[*src_data];
        ++src_data;
        ++dest_data;
    }
}

static void mask_alpha_converter(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const uint *src_data = (const uint *)src->data;
    uint *dest_data = (uint *)dest->data;

    for (int i = 0; i < src->height; ++i) {
        const uint *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = *src_data | 0xff000000;
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<QImage::Format DestFormat>
static bool mask_alpha_converter_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_RGB32
            || DestFormat == QImage::Format_RGB32
            || DestFormat == QImage::Format_RGBX8888);
    const int pad = (data->bytes_per_line >> 2) - data->width;
    QRgb *rgb_data = (QRgb *) data->data;

    for (int i = 0; i < data->height; ++i) {
        const QRgb *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = *rgb_data | 0xff000000;
            ++rgb_data;
        }
        rgb_data += pad;
    }
    data->format = DestFormat;
    return true;
}

static void mask_alpha_converter_RGBx(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags flags)
{
#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
    return mask_alpha_converter(dest, src, flags);
#else
    Q_UNUSED(flags);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 2) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 2) - dest->width;
    const uint *src_data = (const uint *)src->data;
    uint *dest_data = (uint *)dest->data;

    for (int i = 0; i < src->height; ++i) {
        const uint *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = *src_data | 0x000000ff;
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
#endif
}

static bool mask_alpha_converter_rgbx_inplace(QImageData *data, Qt::ImageConversionFlags flags)
{
#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
    return mask_alpha_converter_inplace<QImage::Format_RGBX8888>(data, flags);
#else
    Q_UNUSED(flags);

    const int pad = (data->bytes_per_line >> 2) - data->width;
    QRgb *rgb_data = (QRgb *) data->data;

    for (int i = 0; i < data->height; ++i) {
        const QRgb *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = *rgb_data | 0x000000fff;
            ++rgb_data;
        }
        rgb_data += pad;
    }
    data->format = QImage::Format_RGBX8888;
    return true;
#endif
}

template<bool RGBA>
static void convert_RGBA64_to_ARGB32(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGBA64);
    Q_ASSERT(RGBA || dest->format == QImage::Format_ARGB32);
    Q_ASSERT(!RGBA || dest->format == QImage::Format_RGBA8888);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const uchar *srcData = src->data;
    uchar *destData = dest->data;

    for (int i = 0; i < src->height; ++i) {
        uint *d = reinterpret_cast<uint *>(destData);
        const QRgba64 *s = reinterpret_cast<const QRgba64 *>(srcData);
        qt_convertRGBA64ToARGB32<RGBA>(d, s, src->width);
        srcData += src->bytes_per_line;
        destData += dest->bytes_per_line;
    }
}

template<bool RGBA>
static void convert_ARGB32_to_RGBA64(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(RGBA || src->format == QImage::Format_ARGB32);
    Q_ASSERT(!RGBA || src->format == QImage::Format_RGBA8888);
    Q_ASSERT(dest->format == QImage::Format_RGBA64);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;
    const FetchAndConvertPixelsFunc64 fetch = qPixelLayouts[src->format + 1].fetchToRGBA64PM;

    for (int i = 0; i < src->height; ++i) {
        fetch(reinterpret_cast<QRgba64 *>(dest_data), src_data, 0, src->width, nullptr, nullptr);
        src_data += src->bytes_per_line;;
        dest_data += dest->bytes_per_line;
    }
}

static void convert_RGBA64_to_RGBx64(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGBA64);
    Q_ASSERT(dest->format == QImage::Format_RGBX64);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 3) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 3) - dest->width;
    const QRgba64 *src_data = reinterpret_cast<const QRgba64 *>(src->data);
    QRgba64 *dest_data = reinterpret_cast<QRgba64 *>(dest->data);

    for (int i = 0; i < src->height; ++i) {
        const QRgba64 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = *src_data;
            dest_data->setAlpha(65535);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

static bool convert_RGBA64_to_RGBx64_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_RGBA64);

    const int pad = (data->bytes_per_line >> 3) - data->width;
    QRgba64 *rgb_data = reinterpret_cast<QRgba64 *>(data->data);

    for (int i = 0; i < data->height; ++i) {
        const QRgba64 *end = rgb_data + data->width;
        while (rgb_data < end) {
            rgb_data->setAlpha(65535);
            ++rgb_data;
        }
        rgb_data += pad;
    }
    data->format = QImage::Format_RGBX64;
    return true;
}

static void convert_gray16_to_RGBA64(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Grayscale16);
    Q_ASSERT(dest->format == QImage::Format_RGBA64 || dest->format == QImage::Format_RGBX64 ||
             dest->format == QImage::Format_RGBA64_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    for (int i = 0; i < src->height; ++i) {
        const quint16 *src_line = reinterpret_cast<const quint16 *>(src_data);
        QRgba64 *dest_line = reinterpret_cast<QRgba64 *>(dest_data);
        for (int j = 0; j < src->width; ++j) {
            quint16 s = src_line[j];
            dest_line[j] = qRgba64(s, s, s, 0xFFFF);
        }
        src_data += sbpl;
        dest_data += dbpl;
    }
}

template<bool Premultiplied>
static void convert_ARGB_to_gray8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format == QImage::Format_Grayscale8);
    Q_ASSERT(src->format == QImage::Format_RGB32 ||
             src->format == QImage::Format_ARGB32 ||
             src->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    QColorSpace fromCS = src->colorSpace.isValid() ? src->colorSpace : QColorSpace::SRgb;
    QColorTransform tf = QColorSpacePrivate::get(fromCS)->transformationToXYZ();
    const QColorTransformPrivate *tfd = QColorTransformPrivate::get(tf);
    QColorTransformPrivate::TransformFlags flags = Premultiplied
            ? QColorTransformPrivate::InputPremultiplied
            : QColorTransformPrivate::Unpremultiplied;

    for (int i = 0; i < src->height; ++i) {
        const QRgb *src_line = reinterpret_cast<const QRgb *>(src_data);
        tfd->apply(dest_data, src_line, src->width, flags);
        src_data += sbpl;
        dest_data += dbpl;
    }
}

template<bool Premultiplied>
static void convert_ARGB_to_gray16(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format == QImage::Format_Grayscale16);
    Q_ASSERT(src->format == QImage::Format_RGB32 ||
             src->format == QImage::Format_ARGB32 ||
             src->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    QColorSpace fromCS = src->colorSpace.isValid() ? src->colorSpace : QColorSpace::SRgb;
    QColorTransform tf = QColorSpacePrivate::get(fromCS)->transformationToXYZ();
    const QColorTransformPrivate *tfd = QColorTransformPrivate::get(tf);
    QColorTransformPrivate::TransformFlags flags = Premultiplied
            ? QColorTransformPrivate::InputPremultiplied
            : QColorTransformPrivate::Unpremultiplied;

    QRgba64 tmp_line[BufferSize];
    for (int i = 0; i < src->height; ++i) {
        const QRgb *src_line = reinterpret_cast<const QRgb *>(src_data);
        quint16 *dest_line = reinterpret_cast<quint16 *>(dest_data);
        int j = 0;
        while (j < src->width) {
            const int len = std::min(src->width - j, BufferSize);
            for (int k = 0; k < len; ++k)
                tmp_line[k] = QRgba64::fromArgb32(src_line[j + k]);
            tfd->apply(dest_line + j, tmp_line, len, flags);
            j += len;
        }
        src_data += sbpl;
        dest_data += dbpl;
    }
}

template<bool Premultiplied>
static void convert_RGBA64_to_gray8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format == QImage::Format_Grayscale8);
    Q_ASSERT(src->format == QImage::Format_RGBX64 ||
             src->format == QImage::Format_RGBA64 ||
             src->format == QImage::Format_RGBA64_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    QColorSpace fromCS = src->colorSpace.isValid() ? src->colorSpace : QColorSpace::SRgb;
    QColorTransform tf = QColorSpacePrivate::get(fromCS)->transformationToXYZ();
    const QColorTransformPrivate *tfd = QColorTransformPrivate::get(tf);
    QColorTransformPrivate::TransformFlags flags = Premultiplied
            ? QColorTransformPrivate::InputPremultiplied
            : QColorTransformPrivate::Unpremultiplied;

    quint16 gray_line[BufferSize];
    for (int i = 0; i < src->height; ++i) {
        const QRgba64 *src_line = reinterpret_cast<const QRgba64 *>(src_data);
        uchar *dest_line = dest_data;
        int j = 0;
        while (j < src->width) {
            const int len = std::min(src->width - j, BufferSize);
            tfd->apply(gray_line, src_line + j, len, flags);
            for (int k = 0; k < len; ++k)
                dest_line[j + k] = qt_div_257(gray_line[k]);
            j += len;
        }
        src_data += sbpl;
        dest_data += dbpl;
    }
}

template<bool Premultiplied>
static void convert_RGBA64_to_gray16(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(dest->format == QImage::Format_Grayscale16);
    Q_ASSERT(src->format == QImage::Format_RGBX64 ||
             src->format == QImage::Format_RGBA64 ||
             src->format == QImage::Format_RGBA64_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const qsizetype sbpl = src->bytes_per_line;
    const qsizetype dbpl = dest->bytes_per_line;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;

    QColorSpace fromCS = src->colorSpace.isValid() ? src->colorSpace : QColorSpace::SRgb;
    QColorTransform tf = QColorSpacePrivate::get(fromCS)->transformationToXYZ();
    const QColorTransformPrivate *tfd = QColorTransformPrivate::get(tf);
    QColorTransformPrivate::TransformFlags flags = Premultiplied
            ? QColorTransformPrivate::InputPremultiplied
            : QColorTransformPrivate::Unpremultiplied;

    for (int i = 0; i < src->height; ++i) {
        const QRgba64 *src_line = reinterpret_cast<const QRgba64 *>(src_data);
        quint16 *dest_line = reinterpret_cast<quint16 *>(dest_data);
        tfd->apply(dest_line, src_line, src->width, flags);
        src_data += sbpl;
        dest_data += dbpl;
    }
}

template<bool MaskAlpha>
static void convert_RGBA16FPM_to_RGBA16F(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_RGBA16FPx4_Premultiplied);
    Q_ASSERT(dest->format == QImage::Format_RGBA16FPx4 || dest->format == QImage::Format_RGBX16FPx4);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    const int src_pad = (src->bytes_per_line >> 3) - src->width;
    const int dest_pad = (dest->bytes_per_line >> 3) - dest->width;
    const QRgbaFloat16 *src_data = reinterpret_cast<const QRgbaFloat16 *>(src->data);
    QRgbaFloat16 *dest_data = reinterpret_cast<QRgbaFloat16 *>(dest->data);

    for (int i = 0; i < src->height; ++i) {
        const QRgbaFloat16 *end = src_data + src->width;
        while (src_data < end) {
            *dest_data = src_data->unpremultiplied();
            if (MaskAlpha)
                dest_data->setAlpha(1.0f);
            ++src_data;
            ++dest_data;
        }
        src_data += src_pad;
        dest_data += dest_pad;
    }
}

template<bool MaskAlpha>
static bool convert_RGBA16FPM_to_RGBA16F_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_RGBA16FPx4_Premultiplied);

    const int pad = (data->bytes_per_line >> 3) - data->width;
    QRgbaFloat16 *rgb_data = reinterpret_cast<QRgbaFloat16 *>(data->data);

    for (int i = 0; i < data->height; ++i) {
        const QRgbaFloat16 *end = rgb_data + data->width;
        while (rgb_data < end) {
            *rgb_data = rgb_data->unpremultiplied();
            if (MaskAlpha)
                rgb_data->setAlpha(1.0f);
            ++rgb_data;
        }
        rgb_data += pad;
    }
    data->format = MaskAlpha ? QImage::Format_RGBX16FPx4 : QImage::Format_RGBA16FPx4;
    return true;
}

static QList<QRgb> fix_color_table(const QList<QRgb> &ctbl, QImage::Format format)
{
    QList<QRgb> colorTable = ctbl;
    if (format == QImage::Format_RGB32) {
        // check if the color table has alpha
        for (int i = 0; i < colorTable.size(); ++i)
            if (qAlpha(colorTable.at(i)) != 0xff)
                colorTable[i] = colorTable.at(i) | 0xff000000;
    } else if (format == QImage::Format_ARGB32_Premultiplied) {
        // check if the color table has alpha
        for (int i = 0; i < colorTable.size(); ++i)
            colorTable[i] = qPremultiply(colorTable.at(i));
    }
    return colorTable;
}

//
// dither_to_1:  Uses selected dithering algorithm.
//

void dither_to_Mono(QImageData *dst, const QImageData *src,
                           Qt::ImageConversionFlags flags, bool fromalpha)
{
    Q_ASSERT(src->width == dst->width);
    Q_ASSERT(src->height == dst->height);
    Q_ASSERT(dst->format == QImage::Format_Mono || dst->format == QImage::Format_MonoLSB);

    dst->colortable.clear();
    dst->colortable.append(0xffffffff);
    dst->colortable.append(0xff000000);

    enum { Threshold, Ordered, Diffuse } dithermode;

    if (fromalpha) {
        if ((flags & Qt::AlphaDither_Mask) == Qt::DiffuseAlphaDither)
            dithermode = Diffuse;
        else if ((flags & Qt::AlphaDither_Mask) == Qt::OrderedAlphaDither)
            dithermode = Ordered;
        else
            dithermode = Threshold;
    } else {
        if ((flags & Qt::Dither_Mask) == Qt::ThresholdDither)
            dithermode = Threshold;
        else if ((flags & Qt::Dither_Mask) == Qt::OrderedDither)
            dithermode = Ordered;
        else
            dithermode = Diffuse;
    }

    int          w = src->width;
    int          h = src->height;
    int          d = src->depth;
    uchar gray[256];                                // gray map for 8 bit images
    bool  use_gray = (d == 8);
    if (use_gray) {                                // make gray map
        if (fromalpha) {
            // Alpha 0x00 -> 0 pixels (white)
            // Alpha 0xFF -> 1 pixels (black)
            for (int i = 0; i < src->colortable.size(); i++)
                gray[i] = (255 - (src->colortable.at(i) >> 24));
        } else {
            // Pixel 0x00 -> 1 pixels (black)
            // Pixel 0xFF -> 0 pixels (white)
            for (int i = 0; i < src->colortable.size(); i++)
                gray[i] = qGray(src->colortable.at(i));
        }
    }

    uchar *dst_data = dst->data;
    qsizetype dst_bpl = dst->bytes_per_line;
    const uchar *src_data = src->data;
    qsizetype src_bpl = src->bytes_per_line;

    switch (dithermode) {
    case Diffuse: {
        QScopedArrayPointer<int> lineBuffer(new int[w * 2]);
        int *line1 = lineBuffer.data();
        int *line2 = lineBuffer.data() + w;
        int bmwidth = (w+7)/8;

        int *b1, *b2;
        int wbytes = w * (d/8);
        const uchar *p = src->data;
        const uchar *end = p + wbytes;
        b2 = line2;
        if (use_gray) {                        // 8 bit image
            while (p < end)
                *b2++ = gray[*p++];
        } else {                                // 32 bit image
            if (fromalpha) {
                while (p < end) {
                    *b2++ = 255 - (*(const uint*)p >> 24);
                    p += 4;
                }
            } else {
                while (p < end) {
                    *b2++ = qGray(*(const uint*)p);
                    p += 4;
                }
            }
        }
        for (int y=0; y<h; y++) {                        // for each scan line...
            int *tmp = line1; line1 = line2; line2 = tmp;
            bool not_last_line = y < h - 1;
            if (not_last_line) {                // calc. grayvals for next line
                p = src->data + (y+1)*src->bytes_per_line;
                end = p + wbytes;
                b2 = line2;
                if (use_gray) {                // 8 bit image
                    while (p < end)
                        *b2++ = gray[*p++];
                } else {                        // 24 bit image
                    if (fromalpha) {
                        while (p < end) {
                            *b2++ = 255 - (*(const uint*)p >> 24);
                            p += 4;
                        }
                    } else {
                        while (p < end) {
                            *b2++ = qGray(*(const uint*)p);
                            p += 4;
                        }
                    }
                }
            }

            int err;
            uchar *p = dst->data + y*dst->bytes_per_line;
            memset(p, 0, bmwidth);
            b1 = line1;
            b2 = line2;
            int bit = 7;
            for (int x=1; x<=w; x++) {
                if (*b1 < 128) {                // black pixel
                    err = *b1++;
                    *p |= 1 << bit;
                } else {                        // white pixel
                    err = *b1++ - 255;
                }
                if (bit == 0) {
                    p++;
                    bit = 7;
                } else {
                    bit--;
                }
                const int e7 = ((err * 7) + 8) >> 4;
                const int e5 = ((err * 5) + 8) >> 4;
                const int e3 = ((err * 3) + 8) >> 4;
                const int e1 = err - (e7 + e5 + e3);
                if (x < w)
                    *b1 += e7;                  // spread error to right pixel
                if (not_last_line) {
                    b2[0] += e5;                // pixel below
                    if (x > 1)
                        b2[-1] += e3;           // pixel below left
                    if (x < w)
                        b2[1] += e1;            // pixel below right
                }
                b2++;
            }
        }
    } break;
    case Ordered: {

        memset(dst->data, 0, dst->nbytes);
        if (d == 32) {
            for (int i=0; i<h; i++) {
                const uint *p = (const uint *)src_data;
                const uint *end = p + w;
                uchar *m = dst_data;
                int bit = 7;
                int j = 0;
                if (fromalpha) {
                    while (p < end) {
                        if ((*p++ >> 24) >= qt_bayer_matrix[j++&15][i&15])
                            *m |= 1 << bit;
                        if (bit == 0) {
                            m++;
                            bit = 7;
                        } else {
                            bit--;
                        }
                    }
                } else {
                    while (p < end) {
                        if ((uint)qGray(*p++) < qt_bayer_matrix[j++&15][i&15])
                            *m |= 1 << bit;
                        if (bit == 0) {
                            m++;
                            bit = 7;
                        } else {
                            bit--;
                        }
                    }
                }
                dst_data += dst_bpl;
                src_data += src_bpl;
            }
        } else if (d == 8) {
            for (int i=0; i<h; i++) {
                const uchar *p = src_data;
                const uchar *end = p + w;
                uchar *m = dst_data;
                int bit = 7;
                int j = 0;
                while (p < end) {
                    if ((uint)gray[*p++] < qt_bayer_matrix[j++&15][i&15])
                        *m |= 1 << bit;
                    if (bit == 0) {
                        m++;
                        bit = 7;
                    } else {
                        bit--;
                    }
                }
                dst_data += dst_bpl;
                src_data += src_bpl;
            }
        }
    } break;
    default: { // Threshold:
        memset(dst->data, 0, dst->nbytes);
        if (d == 32) {
            for (int i=0; i<h; i++) {
                const uint *p = (const uint *)src_data;
                const uint *end = p + w;
                uchar *m = dst_data;
                int bit = 7;
                if (fromalpha) {
                    while (p < end) {
                        if ((*p++ >> 24) >= 128)
                            *m |= 1 << bit;        // Set mask "on"
                        if (bit == 0) {
                            m++;
                            bit = 7;
                        } else {
                            bit--;
                        }
                    }
                } else {
                    while (p < end) {
                        if (qGray(*p++) < 128)
                            *m |= 1 << bit;        // Set pixel "black"
                        if (bit == 0) {
                            m++;
                            bit = 7;
                        } else {
                            bit--;
                        }
                    }
                }
                dst_data += dst_bpl;
                src_data += src_bpl;
            }
        } else
            if (d == 8) {
                for (int i=0; i<h; i++) {
                    const uchar *p = src_data;
                    const uchar *end = p + w;
                    uchar *m = dst_data;
                    int bit = 7;
                    while (p < end) {
                        if (gray[*p++] < 128)
                            *m |= 1 << bit;                // Set mask "on"/ pixel "black"
                        if (bit == 0) {
                            m++;
                            bit = 7;
                        } else {
                            bit--;
                        }
                    }
                    dst_data += dst_bpl;
                    src_data += src_bpl;
                }
            }
        }
    }

    if (dst->format == QImage::Format_MonoLSB) {
        // need to swap bit order
        uchar *sl = dst->data;
        int bpl = (dst->width + 7) * dst->depth / 8;
        int pad = dst->bytes_per_line - bpl;
        for (int y=0; y<dst->height; ++y) {
            for (int x=0; x<bpl; ++x) {
                *sl = bitflip[*sl];
                ++sl;
            }
            sl += pad;
        }
    }
}

static void convert_X_to_Mono(QImageData *dst, const QImageData *src, Qt::ImageConversionFlags flags)
{
    dither_to_Mono(dst, src, flags, false);
}

static void convert_ARGB_PM_to_Mono(QImageData *dst, const QImageData *src, Qt::ImageConversionFlags flags)
{
    QScopedPointer<QImageData> tmp(QImageData::create(QSize(src->width, src->height), QImage::Format_ARGB32));
    convert_generic(tmp.data(), src, Qt::AutoColor);
    dither_to_Mono(dst, tmp.data(), flags, false);
}

//
// convert_32_to_8:  Converts a 32 bits depth (true color) to an 8 bit
// image with a colormap. If the 32 bit image has more than 256 colors,
// we convert the red,green and blue bytes into a single byte encoded
// as 6 shades of each of red, green and blue.
//
// if dithering is needed, only 1 color at most is available for alpha.
//
struct QRgbMap {
    inline QRgbMap() : used(0) { }
    uchar  pix;
    uchar used;
    QRgb  rgb;
};

static void convert_RGB_to_Indexed8(QImageData *dst, const QImageData *src, Qt::ImageConversionFlags flags)
{
    Q_ASSERT(src->format == QImage::Format_RGB32 || src->format == QImage::Format_ARGB32);
    Q_ASSERT(dst->format == QImage::Format_Indexed8);
    Q_ASSERT(src->width == dst->width);
    Q_ASSERT(src->height == dst->height);

    bool    do_quant = (flags & Qt::DitherMode_Mask) == Qt::PreferDither
                       || src->format == QImage::Format_ARGB32;
    uint alpha_mask = src->format == QImage::Format_RGB32 ? 0xff000000 : 0;

    const int tablesize = 997; // prime
    QRgbMap table[tablesize];
    int   pix=0;

    if (!dst->colortable.isEmpty()) {
        QList<QRgb> ctbl = dst->colortable;
        dst->colortable.resize(256);
        // Preload palette into table.
        // Almost same code as pixel insertion below
        for (int i = 0; i < dst->colortable.size(); ++i) {
            // Find in table...
            QRgb p = ctbl.at(i) | alpha_mask;
            int hash = p % tablesize;
            for (;;) {
                if (table[hash].used) {
                    if (table[hash].rgb == p) {
                        // Found previous insertion - use it
                        break;
                    } else {
                        // Keep searching...
                        if (++hash == tablesize) hash = 0;
                    }
                } else {
                    // Cannot be in table
                    Q_ASSERT (pix != 256);        // too many colors
                    // Insert into table at this unused position
                    dst->colortable[pix] = p;
                    table[hash].pix = pix++;
                    table[hash].rgb = p;
                    table[hash].used = 1;
                    break;
                }
            }
        }
    }

    if ((flags & Qt::DitherMode_Mask) != Qt::PreferDither) {
        dst->colortable.resize(256);
        const uchar *src_data = src->data;
        uchar *dest_data = dst->data;
        for (int y = 0; y < src->height; y++) {        // check if <= 256 colors
            const QRgb *s = (const QRgb *)src_data;
            uchar *b = dest_data;
            for (int x = 0; x < src->width; ++x) {
                QRgb p = s[x] | alpha_mask;
                int hash = p % tablesize;
                for (;;) {
                    if (table[hash].used) {
                        if (table[hash].rgb == (p)) {
                            // Found previous insertion - use it
                            break;
                        } else {
                            // Keep searching...
                            if (++hash == tablesize) hash = 0;
                        }
                    } else {
                        // Cannot be in table
                        if (pix == 256) {        // too many colors
                            do_quant = true;
                            // Break right out
                            x = src->width;
                            y = src->height;
                        } else {
                            // Insert into table at this unused position
                            dst->colortable[pix] = p;
                            table[hash].pix = pix++;
                            table[hash].rgb = p;
                            table[hash].used = 1;
                        }
                        break;
                    }
                }
                *b++ = table[hash].pix;                // May occur once incorrectly
            }
            src_data += src->bytes_per_line;
            dest_data += dst->bytes_per_line;
        }
    }
    int numColors = do_quant ? 256 : pix;

    dst->colortable.resize(numColors);

    if (do_quant) {                                // quantization needed

#define MAX_R 5
#define MAX_G 5
#define MAX_B 5
#define INDEXOF(r,g,b) (((r)*(MAX_G+1)+(g))*(MAX_B+1)+(b))

        for (int rc=0; rc<=MAX_R; rc++)                // build 6x6x6 color cube
            for (int gc=0; gc<=MAX_G; gc++)
                for (int bc=0; bc<=MAX_B; bc++)
                    dst->colortable[INDEXOF(rc,gc,bc)] = 0xff000000 | qRgb(rc*255/MAX_R, gc*255/MAX_G, bc*255/MAX_B);

        const uchar *src_data = src->data;
        uchar *dest_data = dst->data;
        if ((flags & Qt::Dither_Mask) == Qt::ThresholdDither) {
            for (int y = 0; y < src->height; y++) {
                const QRgb *p = (const QRgb *)src_data;
                const QRgb *end = p + src->width;
                uchar *b = dest_data;

                while (p < end) {
#define DITHER(p,m) ((uchar) ((p * (m) + 127) / 255))
                    *b++ =
                        INDEXOF(
                            DITHER(qRed(*p), MAX_R),
                            DITHER(qGreen(*p), MAX_G),
                            DITHER(qBlue(*p), MAX_B)
                            );
#undef DITHER
                    p++;
                }
                src_data += src->bytes_per_line;
                dest_data += dst->bytes_per_line;
            }
        } else if ((flags & Qt::Dither_Mask) == Qt::DiffuseDither) {
            int* line1[3];
            int* line2[3];
            int* pv[3];
            QScopedArrayPointer<int> lineBuffer(new int[src->width * 9]);
            line1[0] = lineBuffer.data();
            line2[0] = lineBuffer.data() + src->width;
            line1[1] = lineBuffer.data() + src->width * 2;
            line2[1] = lineBuffer.data() + src->width * 3;
            line1[2] = lineBuffer.data() + src->width * 4;
            line2[2] = lineBuffer.data() + src->width * 5;
            pv[0] = lineBuffer.data() + src->width * 6;
            pv[1] = lineBuffer.data() + src->width * 7;
            pv[2] = lineBuffer.data() + src->width * 8;

            int endian = (QSysInfo::ByteOrder == QSysInfo::BigEndian);
            for (int y = 0; y < src->height; y++) {
                const uchar* q = src_data;
                const uchar* q2 = y < src->height - 1 ? q + src->bytes_per_line : src->data;
                uchar *b = dest_data;
                for (int chan = 0; chan < 3; chan++) {
                    int *l1 = (y&1) ? line2[chan] : line1[chan];
                    int *l2 = (y&1) ? line1[chan] : line2[chan];
                    if (y == 0) {
                        for (int i = 0; i < src->width; i++)
                            l1[i] = q[i*4+chan+endian];
                    }
                    if (y+1 < src->height) {
                        for (int i = 0; i < src->width; i++)
                            l2[i] = q2[i*4+chan+endian];
                    }
                    // Bi-directional error diffusion
                    if (y&1) {
                        for (int x = 0; x < src->width; x++) {
                            int pix = qMax(qMin(5, (l1[x] * 5 + 128)/ 255), 0);
                            int err = l1[x] - pix * 255 / 5;
                            pv[chan][x] = pix;

                            // Spread the error around...
                            if (x + 1< src->width) {
                                l1[x+1] += (err*7)>>4;
                                l2[x+1] += err>>4;
                            }
                            l2[x]+=(err*5)>>4;
                            if (x>1)
                                l2[x-1]+=(err*3)>>4;
                        }
                    } else {
                        for (int x = src->width; x-- > 0;) {
                            int pix = qMax(qMin(5, (l1[x] * 5 + 128)/ 255), 0);
                            int err = l1[x] - pix * 255 / 5;
                            pv[chan][x] = pix;

                            // Spread the error around...
                            if (x > 0) {
                                l1[x-1] += (err*7)>>4;
                                l2[x-1] += err>>4;
                            }
                            l2[x]+=(err*5)>>4;
                            if (x + 1 < src->width)
                                l2[x+1]+=(err*3)>>4;
                        }
                    }
                }
                if (endian) {
                    for (int x = 0; x < src->width; x++) {
                        *b++ = INDEXOF(pv[0][x],pv[1][x],pv[2][x]);
                    }
                } else {
                    for (int x = 0; x < src->width; x++) {
                        *b++ = INDEXOF(pv[2][x],pv[1][x],pv[0][x]);
                    }
                }
                src_data += src->bytes_per_line;
                dest_data += dst->bytes_per_line;
            }
        } else { // OrderedDither
            for (int y = 0; y < src->height; y++) {
                const QRgb *p = (const QRgb *)src_data;
                const QRgb *end = p + src->width;
                uchar *b = dest_data;

                int x = 0;
                while (p < end) {
                    uint d = qt_bayer_matrix[y & 15][x & 15] << 8;

#define DITHER(p, d, m) ((uchar) ((((256 * (m) + (m) + 1)) * (p) + (d)) >> 16))
                    *b++ =
                        INDEXOF(
                            DITHER(qRed(*p), d, MAX_R),
                            DITHER(qGreen(*p), d, MAX_G),
                            DITHER(qBlue(*p), d, MAX_B)
                            );
#undef DITHER

                    p++;
                    x++;
                }
                src_data += src->bytes_per_line;
                dest_data += dst->bytes_per_line;
            }
        }

        if (src->format != QImage::Format_RGB32
            && src->format != QImage::Format_RGB16) {
            const int trans = 216;
            Q_ASSERT(dst->colortable.size() > trans);
            dst->colortable[trans] = 0;
            QScopedPointer<QImageData> mask(QImageData::create(QSize(src->width, src->height), QImage::Format_Mono));
            dither_to_Mono(mask.data(), src, flags, true);
            uchar *dst_data = dst->data;
            const uchar *mask_data = mask->data;
            for (int y = 0; y < src->height; y++) {
                for (int x = 0; x < src->width ; x++) {
                    if (!(mask_data[x>>3] & (0x80 >> (x & 7))))
                        dst_data[x] = trans;
                }
                mask_data += mask->bytes_per_line;
                dst_data += dst->bytes_per_line;
            }
            dst->has_alpha_clut = true;
        }

#undef MAX_R
#undef MAX_G
#undef MAX_B
#undef INDEXOF

    }
}

static void convert_ARGB_PM_to_Indexed8(QImageData *dst, const QImageData *src, Qt::ImageConversionFlags flags)
{
    QScopedPointer<QImageData> tmp(QImageData::create(QSize(src->width, src->height), QImage::Format_ARGB32));
    convert_generic(tmp.data(), src, Qt::AutoColor);
    convert_RGB_to_Indexed8(dst, tmp.data(), flags);
}

static void convert_ARGB_to_Indexed8(QImageData *dst, const QImageData *src, Qt::ImageConversionFlags flags)
{
    convert_RGB_to_Indexed8(dst, src, flags);
}

static void convert_Indexed8_to_X32(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Indexed8);
    Q_ASSERT(dest->format == QImage::Format_RGB32
             || dest->format == QImage::Format_ARGB32
             || dest->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    QList<QRgb> colorTable = src->has_alpha_clut ? fix_color_table(src->colortable, dest->format) : src->colortable;
    if (colorTable.size() == 0) {
        colorTable.resize(256);
        for (int i=0; i<256; ++i)
            colorTable[i] = qRgb(i, i, i);
    }
    if (colorTable.size() < 256) {
        int tableSize = colorTable.size();
        colorTable.resize(256);
        QRgb fallbackColor = (dest->format == QImage::Format_RGB32) ? 0xff000000 : 0;
        for (int i=tableSize; i<256; ++i)
            colorTable[i] = fallbackColor;
    }

    int w = src->width;
    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;
    const QRgb *colorTablePtr = colorTable.constData();
    for (int y = 0; y < src->height; y++) {
        uint *p = reinterpret_cast<uint *>(dest_data);
        const uchar *b = src_data;
        uint *end = p + w;

        while (p < end)
            *p++ = colorTablePtr[*b++];

        src_data += src->bytes_per_line;
        dest_data += dest->bytes_per_line;
    }
}

static void convert_Mono_to_X32(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Mono || src->format == QImage::Format_MonoLSB);
    Q_ASSERT(dest->format == QImage::Format_RGB32
             || dest->format == QImage::Format_ARGB32
             || dest->format == QImage::Format_ARGB32_Premultiplied);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    QList<QRgb> colorTable = fix_color_table(src->colortable, dest->format);

    // Default to black / white colors
    if (colorTable.size() < 2) {
        if (colorTable.size() == 0)
            colorTable << 0xff000000;
        colorTable << 0xffffffff;
    }

    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;
    if (src->format == QImage::Format_Mono) {
        for (int y = 0; y < dest->height; y++) {
            uint *p = (uint *)dest_data;
            for (int x = 0; x < dest->width; x++)
                *p++ = colorTable.at((src_data[x>>3] >> (7 - (x & 7))) & 1);

            src_data += src->bytes_per_line;
            dest_data += dest->bytes_per_line;
        }
    } else {
        for (int y = 0; y < dest->height; y++) {
            uint *p = (uint *)dest_data;
            for (int x = 0; x < dest->width; x++)
                *p++ = colorTable.at((src_data[x>>3] >> (x & 7)) & 1);

            src_data += src->bytes_per_line;
            dest_data += dest->bytes_per_line;
        }
    }
}


static void convert_Mono_to_Indexed8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Mono || src->format == QImage::Format_MonoLSB);
    Q_ASSERT(dest->format == QImage::Format_Indexed8);
    Q_ASSERT(src->width == dest->width);
    Q_ASSERT(src->height == dest->height);

    QList<QRgb> ctbl = src->colortable;
    if (ctbl.size() > 2) {
        ctbl.resize(2);
    } else if (ctbl.size() < 2) {
        if (ctbl.size() == 0)
            ctbl << 0xff000000;
        ctbl << 0xffffffff;
    }
    dest->colortable = ctbl;
    dest->has_alpha_clut = src->has_alpha_clut;


    const uchar *src_data = src->data;
    uchar *dest_data = dest->data;
    if (src->format == QImage::Format_Mono) {
        for (int y = 0; y < dest->height; y++) {
            uchar *p = dest_data;
            for (int x = 0; x < dest->width; x++)
                *p++ = (src_data[x>>3] >> (7 - (x & 7))) & 1;
            src_data += src->bytes_per_line;
            dest_data += dest->bytes_per_line;
        }
    } else {
        for (int y = 0; y < dest->height; y++) {
            uchar *p = dest_data;
            for (int x = 0; x < dest->width; x++)
                *p++ = (src_data[x>>3] >> (x & 7)) & 1;
            src_data += src->bytes_per_line;
            dest_data += dest->bytes_per_line;
        }
    }
}

static void copy_8bit_pixels(QImageData *dest, const QImageData *src)
{
    if (src->bytes_per_line == dest->bytes_per_line) {
        memcpy(dest->data, src->data, src->bytes_per_line * src->height);
    } else {
        const uchar *sdata = src->data;
        uchar *ddata = dest->data;
        for (int y = 0; y < src->height; ++y) {
            memcpy(ddata, sdata, src->width);
            sdata += src->bytes_per_line;
            ddata += dest->bytes_per_line;
        }
    }
}

static void convert_Indexed8_to_Alpha8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Indexed8);
    Q_ASSERT(dest->format == QImage::Format_Alpha8);

    uchar translate[256];
    const QList<QRgb> &colors = src->colortable;
    bool simpleCase = (colors.size() == 256);
    for (int i = 0; i < colors.size(); ++i) {
        uchar alpha = qAlpha(colors[i]);
        translate[i] = alpha;
        simpleCase = simpleCase && (alpha == i);
    }

    if (simpleCase)
        copy_8bit_pixels(dest, src);
    else {
        const uchar *sdata = src->data;
        uchar *ddata = dest->data;
        for (int y = 0; y < src->height; ++y) {
            for (int x = 0; x < src->width; ++x)
                ddata[x] = translate[sdata[x]];
            sdata += src->bytes_per_line;
            ddata += dest->bytes_per_line;
        }
    }
}

static void convert_Indexed8_to_Grayscale8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Indexed8);
    Q_ASSERT(dest->format == QImage::Format_Grayscale8);

    uchar translate[256];
    const QList<QRgb> &colors = src->colortable;
    bool simpleCase = (colors.size() == 256);
    for (int i = 0; i < colors.size() && simpleCase; ++i) {
        if (colors[i] != qRgb(i, i, i))
            simpleCase = false;
    }
    if (simpleCase) {
        copy_8bit_pixels(dest, src);
        return;
    }

    QColorSpace fromCS = src->colorSpace.isValid() ? src->colorSpace : QColorSpace::SRgb;
    QColorTransform tf = QColorSpacePrivate::get(fromCS)->transformationToXYZ();
    for (int i = 0; i < colors.size(); ++i) {
        QRgba64 c16 = tf.map(QRgba64::fromArgb32(colors[i]));
        translate[i] = c16.green8(); // Y from XYZ ends up in the G channel
    }

    const uchar *sdata = src->data;
    uchar *ddata = dest->data;
    for (int y = 0; y < src->height; ++y) {
        for (int x = 0; x < src->width; ++x)
            ddata[x] = translate[sdata[x]];
        sdata += src->bytes_per_line;
        ddata += dest->bytes_per_line;
    }
}

static bool convert_Indexed8_to_Alpha8_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_Indexed8);

    // Just check if this is an Alpha8 in Indexed8 disguise.
    const QList<QRgb> &colors = data->colortable;
    if (colors.size() != 256)
        return false;
    for (int i = 0; i < colors.size(); ++i) {
        if (i != qAlpha(colors[i]))
            return false;
    }

    data->colortable.clear();
    data->format = QImage::Format_Alpha8;

    return true;
}

static bool convert_Indexed8_to_Grayscale8_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_Indexed8);

    // Just check if this is a Grayscale8 in Indexed8 disguise.
    const QList<QRgb> &colors = data->colortable;
    if (colors.size() != 256)
        return false;
    for (int i = 0; i < colors.size(); ++i) {
        if (colors[i] != qRgb(i, i, i))
            return false;
    }

    data->colortable.clear();
    data->format = QImage::Format_Grayscale8;

    return true;
}

static void convert_Alpha8_to_Indexed8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Alpha8);
    Q_ASSERT(dest->format == QImage::Format_Indexed8);

    copy_8bit_pixels(dest, src);

    dest->colortable = defaultColorTables->alpha;
}

static void convert_Grayscale8_to_Indexed8(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags)
{
    Q_ASSERT(src->format == QImage::Format_Grayscale8);
    Q_ASSERT(dest->format == QImage::Format_Indexed8);

    copy_8bit_pixels(dest, src);

    dest->colortable = defaultColorTables->gray;
}

static bool convert_Alpha8_to_Indexed8_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_Alpha8);

    data->colortable = defaultColorTables->alpha;
    data->format = QImage::Format_Indexed8;

    return true;
}

static bool convert_Grayscale8_to_Indexed8_inplace(QImageData *data, Qt::ImageConversionFlags)
{
    Q_ASSERT(data->format == QImage::Format_Grayscale8);

    data->colortable = defaultColorTables->gray;
    data->format = QImage::Format_Indexed8;

    return true;
}


// first index source, second dest
Image_Converter qimage_converter_map[QImage::NImageFormats][QImage::NImageFormats] = {};
InPlace_Image_Converter qimage_inplace_converter_map[QImage::NImageFormats][QImage::NImageFormats] = {};

static void qInitImageConversions()
{
    // Some conversions can not be generic, other are just hard to make as fast in the generic converter.

    // All conversions to and from indexed formats can not be generic and needs to go over RGB32 or ARGB32
    qimage_converter_map[QImage::Format_Mono][QImage::Format_MonoLSB] = swap_bit_order;
    qimage_converter_map[QImage::Format_Mono][QImage::Format_Indexed8] = convert_Mono_to_Indexed8;
    qimage_converter_map[QImage::Format_Mono][QImage::Format_RGB32] = convert_Mono_to_X32;
    qimage_converter_map[QImage::Format_Mono][QImage::Format_ARGB32] = convert_Mono_to_X32;
    qimage_converter_map[QImage::Format_Mono][QImage::Format_ARGB32_Premultiplied] = convert_Mono_to_X32;

    qimage_converter_map[QImage::Format_MonoLSB][QImage::Format_Mono] = swap_bit_order;
    qimage_converter_map[QImage::Format_MonoLSB][QImage::Format_Indexed8] = convert_Mono_to_Indexed8;
    qimage_converter_map[QImage::Format_MonoLSB][QImage::Format_RGB32] = convert_Mono_to_X32;
    qimage_converter_map[QImage::Format_MonoLSB][QImage::Format_ARGB32] = convert_Mono_to_X32;
    qimage_converter_map[QImage::Format_MonoLSB][QImage::Format_ARGB32_Premultiplied] = convert_Mono_to_X32;

    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_Mono] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_MonoLSB] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_RGB32] = convert_Indexed8_to_X32;
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_ARGB32] = convert_Indexed8_to_X32;
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_ARGB32_Premultiplied] = convert_Indexed8_to_X32;
    // Indexed8, Alpha8 and Grayscale8 have a special relationship that can be short-cut.
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_Grayscale8] = convert_Indexed8_to_Grayscale8;
    qimage_converter_map[QImage::Format_Indexed8][QImage::Format_Alpha8] = convert_Indexed8_to_Alpha8;

    qimage_converter_map[QImage::Format_RGB32][QImage::Format_Mono] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_MonoLSB] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_Indexed8] = convert_RGB_to_Indexed8;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_ARGB32] = mask_alpha_converter;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_ARGB32_Premultiplied] = mask_alpha_converter;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_Grayscale8] = convert_ARGB_to_gray8<false>;
    qimage_converter_map[QImage::Format_RGB32][QImage::Format_Grayscale16] = convert_ARGB_to_gray16<false>;

    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_Mono] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_MonoLSB] = convert_X_to_Mono;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_Indexed8] = convert_ARGB_to_Indexed8;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_RGB32] = mask_alpha_converter;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_RGBX8888] = convert_ARGB_to_RGBx;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_RGBA8888] = convert_ARGB_to_RGBA;
    // ARGB32 has higher precision than ARGB32PM and needs explicit conversions to other higher color-precision formats with alpha
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_A2BGR30_Premultiplied] = convert_ARGB_to_A2RGB30<PixelOrderBGR, false>;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_A2RGB30_Premultiplied] = convert_ARGB_to_A2RGB30<PixelOrderRGB, false>;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_RGBA64] = convert_ARGB32_to_RGBA64<false>;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_Grayscale8] = convert_ARGB_to_gray8<false>;
    qimage_converter_map[QImage::Format_ARGB32][QImage::Format_Grayscale16] = convert_ARGB_to_gray16<false>;

    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_Mono] = convert_ARGB_PM_to_Mono;
    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_MonoLSB] = convert_ARGB_PM_to_Mono;
    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_Indexed8] = convert_ARGB_PM_to_Indexed8;
    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_RGBA8888_Premultiplied] = convert_ARGB_to_RGBA;
    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_Grayscale8] = convert_ARGB_to_gray8<true>;
    qimage_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_Grayscale16] = convert_ARGB_to_gray16<true>;

    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGB32] = convert_RGB888_to_RGB<false>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32] = convert_RGB888_to_RGB<false>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32_Premultiplied] = convert_RGB888_to_RGB<false>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGBX8888] = convert_RGB888_to_RGB<true>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGBA8888] = convert_RGB888_to_RGB<true>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGBA8888_Premultiplied] = convert_RGB888_to_RGB<true>;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_BGR888] = convert_rgbswap_generic;

    qimage_converter_map[QImage::Format_RGBX8888][QImage::Format_RGB32] = convert_RGBA_to_RGB;
    qimage_converter_map[QImage::Format_RGBX8888][QImage::Format_ARGB32] = convert_RGBA_to_ARGB;
    qimage_converter_map[QImage::Format_RGBX8888][QImage::Format_ARGB32_Premultiplied] = convert_RGBA_to_ARGB;
    qimage_converter_map[QImage::Format_RGBX8888][QImage::Format_RGBA8888] = convert_passthrough;
    qimage_converter_map[QImage::Format_RGBX8888][QImage::Format_RGBA8888_Premultiplied] = convert_passthrough;

    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_RGB32] = convert_RGBA_to_RGB;
    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_ARGB32] = convert_RGBA_to_ARGB;
    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_RGBX8888] = mask_alpha_converter_RGBx;
    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_A2BGR30_Premultiplied] = convert_ARGB_to_A2RGB30<PixelOrderBGR, true>;
    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_A2RGB30_Premultiplied] = convert_ARGB_to_A2RGB30<PixelOrderRGB, true>;
    qimage_converter_map[QImage::Format_RGBA8888][QImage::Format_RGBA64] = convert_ARGB32_to_RGBA64<true>;

    qimage_converter_map[QImage::Format_RGBA8888_Premultiplied][QImage::Format_ARGB32_Premultiplied] = convert_RGBA_to_ARGB;

    qimage_converter_map[QImage::Format_BGR30][QImage::Format_A2BGR30_Premultiplied] = convert_passthrough;
    qimage_converter_map[QImage::Format_BGR30][QImage::Format_RGB30] = convert_rgbswap_generic;
    qimage_converter_map[QImage::Format_BGR30][QImage::Format_A2RGB30_Premultiplied] = convert_rgbswap_generic;

    qimage_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_ARGB32] = convert_A2RGB30_PM_to_ARGB<PixelOrderBGR, false>;
    qimage_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_RGBA8888] = convert_A2RGB30_PM_to_ARGB<PixelOrderBGR, true>;
    qimage_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_BGR30] = convert_A2RGB30_PM_to_RGB30<false>;
    qimage_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_RGB30] = convert_A2RGB30_PM_to_RGB30<true>;
    qimage_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_A2RGB30_Premultiplied] = convert_rgbswap_generic;

    qimage_converter_map[QImage::Format_RGB30][QImage::Format_BGR30] = convert_rgbswap_generic;
    qimage_converter_map[QImage::Format_RGB30][QImage::Format_A2BGR30_Premultiplied] = convert_rgbswap_generic;
    qimage_converter_map[QImage::Format_RGB30][QImage::Format_A2RGB30_Premultiplied] = convert_passthrough;

    qimage_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_ARGB32] = convert_A2RGB30_PM_to_ARGB<PixelOrderRGB, false>;
    qimage_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_RGBA8888] = convert_A2RGB30_PM_to_ARGB<PixelOrderRGB, true>;
    qimage_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_BGR30] = convert_A2RGB30_PM_to_RGB30<true>;
    qimage_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_A2BGR30_Premultiplied] = convert_rgbswap_generic;
    qimage_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_RGB30] = convert_A2RGB30_PM_to_RGB30<false>;

    qimage_converter_map[QImage::Format_Grayscale8][QImage::Format_Indexed8] = convert_Grayscale8_to_Indexed8;
    qimage_converter_map[QImage::Format_Alpha8][QImage::Format_Indexed8] = convert_Alpha8_to_Indexed8;

    qimage_converter_map[QImage::Format_RGBX64][QImage::Format_RGBA64] = convert_passthrough;
    qimage_converter_map[QImage::Format_RGBX64][QImage::Format_RGBA64_Premultiplied] = convert_passthrough;
    qimage_converter_map[QImage::Format_RGBX64][QImage::Format_Grayscale8] = convert_RGBA64_to_gray8<false>;
    qimage_converter_map[QImage::Format_RGBX64][QImage::Format_Grayscale16] = convert_RGBA64_to_gray16<false>;

    qimage_converter_map[QImage::Format_RGBA64][QImage::Format_ARGB32] = convert_RGBA64_to_ARGB32<false>;
    qimage_converter_map[QImage::Format_RGBA64][QImage::Format_RGBA8888] = convert_RGBA64_to_ARGB32<true>;
    qimage_converter_map[QImage::Format_RGBA64][QImage::Format_RGBX64] = convert_RGBA64_to_RGBx64;
    qimage_converter_map[QImage::Format_RGBA64][QImage::Format_Grayscale8] = convert_RGBA64_to_gray8<false>;
    qimage_converter_map[QImage::Format_RGBA64][QImage::Format_Grayscale16] = convert_RGBA64_to_gray16<false>;

    qimage_converter_map[QImage::Format_RGBA64_Premultiplied][QImage::Format_Grayscale8] = convert_RGBA64_to_gray8<true>;
    qimage_converter_map[QImage::Format_RGBA64_Premultiplied][QImage::Format_Grayscale16] = convert_RGBA64_to_gray16<true>;

    qimage_converter_map[QImage::Format_Grayscale16][QImage::Format_RGBX64] = convert_gray16_to_RGBA64;
    qimage_converter_map[QImage::Format_Grayscale16][QImage::Format_RGBA64] = convert_gray16_to_RGBA64;
    qimage_converter_map[QImage::Format_Grayscale16][QImage::Format_RGBA64_Premultiplied] = convert_gray16_to_RGBA64;

    qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGB888] = convert_rgbswap_generic;
#if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
    qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBX8888] = convert_RGB888_to_RGB<false>;
    qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBA8888] = convert_RGB888_to_RGB<false>;
    qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBA8888_Premultiplied] = convert_RGB888_to_RGB<false>;
#endif

    qimage_converter_map[QImage::Format_RGBX16FPx4][QImage::Format_RGBA16FPx4] = convert_passthrough;
    qimage_converter_map[QImage::Format_RGBX16FPx4][QImage::Format_RGBA16FPx4_Premultiplied] = convert_passthrough;

    qimage_converter_map[QImage::Format_RGBX32FPx4][QImage::Format_RGBA32FPx4] = convert_passthrough;
    qimage_converter_map[QImage::Format_RGBX32FPx4][QImage::Format_RGBA32FPx4_Premultiplied] = convert_passthrough;

    // Inline converters:
    qimage_inplace_converter_map[QImage::Format_Indexed8][QImage::Format_Grayscale8] =
            convert_Indexed8_to_Grayscale8_inplace;
    qimage_inplace_converter_map[QImage::Format_Indexed8][QImage::Format_Alpha8] =
            convert_Indexed8_to_Alpha8_inplace;

    qimage_inplace_converter_map[QImage::Format_RGB32][QImage::Format_ARGB32] =
            mask_alpha_converter_inplace<QImage::Format_ARGB32>;
    qimage_inplace_converter_map[QImage::Format_RGB32][QImage::Format_ARGB32_Premultiplied] =
            mask_alpha_converter_inplace<QImage::Format_ARGB32_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_RGB32] =
            mask_alpha_converter_inplace<QImage::Format_RGB32>;
    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_RGBX8888] =
            convert_ARGB_to_RGBA_inplace<QImage::Format_RGBX8888>;
    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_RGBA8888] =
            convert_ARGB_to_RGBA_inplace<QImage::Format_RGBA8888>;
    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_A2BGR30_Premultiplied] =
            convert_ARGB_to_A2RGB30_inplace<PixelOrderBGR, false>;
    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_A2RGB30_Premultiplied] =
            convert_ARGB_to_A2RGB30_inplace<PixelOrderRGB, false>;

    qimage_inplace_converter_map[QImage::Format_ARGB32_Premultiplied][QImage::Format_RGBA8888_Premultiplied] =
            convert_ARGB_to_RGBA_inplace<QImage::Format_RGBA8888_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_RGB888][QImage::Format_BGR888] =
            convert_rgbswap_generic_inplace;

    qimage_inplace_converter_map[QImage::Format_RGBX8888][QImage::Format_RGB32] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_RGB32>;
    qimage_inplace_converter_map[QImage::Format_RGBX8888][QImage::Format_ARGB32] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_ARGB32>;
    qimage_inplace_converter_map[QImage::Format_RGBX8888][QImage::Format_ARGB32_Premultiplied] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_ARGB32_Premultiplied>;
    qimage_inplace_converter_map[QImage::Format_RGBX8888][QImage::Format_RGBA8888] =
            convert_passthrough_inplace<QImage::Format_RGBA8888>;
    qimage_inplace_converter_map[QImage::Format_RGBX8888][QImage::Format_RGBA8888_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_RGBA8888_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_RGBA8888][QImage::Format_RGB32] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_RGB32>;
    qimage_inplace_converter_map[QImage::Format_RGBA8888][QImage::Format_ARGB32] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_ARGB32>;
    qimage_inplace_converter_map[QImage::Format_RGBA8888][QImage::Format_RGBX8888] =
            mask_alpha_converter_rgbx_inplace;
    qimage_inplace_converter_map[QImage::Format_RGBA8888][QImage::Format_A2BGR30_Premultiplied] =
            convert_ARGB_to_A2RGB30_inplace<PixelOrderBGR, true>;
    qimage_inplace_converter_map[QImage::Format_RGBA8888][QImage::Format_A2RGB30_Premultiplied] =
            convert_ARGB_to_A2RGB30_inplace<PixelOrderRGB, true>;

    qimage_inplace_converter_map[QImage::Format_RGBA8888_Premultiplied][QImage::Format_ARGB32_Premultiplied] =
            convert_RGBA_to_ARGB_inplace<QImage::Format_ARGB32_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_BGR30][QImage::Format_A2BGR30_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_A2BGR30_Premultiplied>;
    qimage_inplace_converter_map[QImage::Format_BGR30][QImage::Format_RGB30] =
            convert_rgbswap_generic_inplace;
    qimage_inplace_converter_map[QImage::Format_BGR30][QImage::Format_A2RGB30_Premultiplied] =
            convert_BGR30_to_A2RGB30_inplace;

    qimage_inplace_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_ARGB32] =
            convert_A2RGB30_PM_to_ARGB_inplace<PixelOrderBGR, false>;
    qimage_inplace_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_RGBA8888] =
            convert_A2RGB30_PM_to_ARGB_inplace<PixelOrderBGR, true>;
    qimage_inplace_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_BGR30] =
            convert_A2RGB30_PM_to_RGB30_inplace<false>;
    qimage_inplace_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_RGB30] =
            convert_A2RGB30_PM_to_RGB30_inplace<true>;
    qimage_inplace_converter_map[QImage::Format_A2BGR30_Premultiplied][QImage::Format_A2RGB30_Premultiplied] =
            convert_rgbswap_generic_inplace;

    qimage_inplace_converter_map[QImage::Format_RGB30][QImage::Format_BGR30] =
            convert_rgbswap_generic_inplace;
    qimage_inplace_converter_map[QImage::Format_RGB30][QImage::Format_A2BGR30_Premultiplied] =
            convert_BGR30_to_A2RGB30_inplace;
    qimage_inplace_converter_map[QImage::Format_RGB30][QImage::Format_A2RGB30_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_A2RGB30_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_ARGB32] =
            convert_A2RGB30_PM_to_ARGB_inplace<PixelOrderRGB, false>;
    qimage_inplace_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_RGBA8888] =
            convert_A2RGB30_PM_to_ARGB_inplace<PixelOrderRGB, true>;
    qimage_inplace_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_BGR30] =
            convert_A2RGB30_PM_to_RGB30_inplace<true>;
    qimage_inplace_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_A2BGR30_Premultiplied] =
            convert_rgbswap_generic_inplace;
    qimage_inplace_converter_map[QImage::Format_A2RGB30_Premultiplied][QImage::Format_RGB30] =
            convert_A2RGB30_PM_to_RGB30_inplace<false>;

    qimage_inplace_converter_map[QImage::Format_Grayscale8][QImage::Format_Indexed8] =
            convert_Grayscale8_to_Indexed8_inplace;
    qimage_inplace_converter_map[QImage::Format_Alpha8][QImage::Format_Indexed8] =
            convert_Alpha8_to_Indexed8_inplace;

    qimage_inplace_converter_map[QImage::Format_RGBX64][QImage::Format_RGBA64] =
            convert_passthrough_inplace<QImage::Format_RGBA64>;
    qimage_inplace_converter_map[QImage::Format_RGBX64][QImage::Format_RGBA64_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_RGBA64_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_RGBA64][QImage::Format_RGBX64] =
            convert_RGBA64_to_RGBx64_inplace;

    qimage_inplace_converter_map[QImage::Format_BGR888][QImage::Format_RGB888] =
            convert_rgbswap_generic_inplace;

    qimage_inplace_converter_map[QImage::Format_RGBX16FPx4][QImage::Format_RGBA16FPx4] =
            convert_passthrough_inplace<QImage::Format_RGBA16FPx4>;
    qimage_inplace_converter_map[QImage::Format_RGBX16FPx4][QImage::Format_RGBA16FPx4_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_RGBA16FPx4_Premultiplied>;

    qimage_inplace_converter_map[QImage::Format_RGBX32FPx4][QImage::Format_RGBA32FPx4] =
            convert_passthrough_inplace<QImage::Format_RGBA32FPx4>;
    qimage_inplace_converter_map[QImage::Format_RGBX32FPx4][QImage::Format_RGBA32FPx4_Premultiplied] =
            convert_passthrough_inplace<QImage::Format_RGBA32FPx4_Premultiplied>;

    // Now architecture specific conversions:
#if defined(__SSE2__) && defined(QT_COMPILER_SUPPORTS_SSSE3)
    if (qCpuHasFeature(SSSE3)) {
        extern void convert_RGB888_to_RGB32_ssse3(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags);
        qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGB32] = convert_RGB888_to_RGB32_ssse3;
        qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32] = convert_RGB888_to_RGB32_ssse3;
        qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32_Premultiplied] = convert_RGB888_to_RGB32_ssse3;
        qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBX8888] = convert_RGB888_to_RGB32_ssse3;
        qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBA8888] = convert_RGB888_to_RGB32_ssse3;
        qimage_converter_map[QImage::Format_BGR888][QImage::Format_RGBA8888_Premultiplied] = convert_RGB888_to_RGB32_ssse3;
    }
#endif

#if defined(__ARM_NEON__)
    extern void convert_RGB888_to_RGB32_neon(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags);
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGB32] = convert_RGB888_to_RGB32_neon;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32] = convert_RGB888_to_RGB32_neon;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32_Premultiplied] = convert_RGB888_to_RGB32_neon;
#endif

#if defined(__MIPS_DSPR2__)
    extern bool convert_ARGB_to_ARGB_PM_inplace_mips_dspr2(QImageData *data, Qt::ImageConversionFlags);
    qimage_inplace_converter_map[QImage::Format_ARGB32][QImage::Format_ARGB32_Premultiplied] = convert_ARGB_to_ARGB_PM_inplace_mips_dspr2;

    extern void convert_RGB888_to_RGB32_mips_dspr2(QImageData *dest, const QImageData *src, Qt::ImageConversionFlags);
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_RGB32] = convert_RGB888_to_RGB32_mips_dspr2;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32] = convert_RGB888_to_RGB32_mips_dspr2;
    qimage_converter_map[QImage::Format_RGB888][QImage::Format_ARGB32_Premultiplied] = convert_RGB888_to_RGB32_mips_dspr2;
#endif
}

Q_CONSTRUCTOR_FUNCTION(qInitImageConversions);

QT_END_NAMESPACE
