/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2008, Blender Foundation
 * This is a new part of Blender
 */

/** \file
 * \ingroup bke
 */

#include <math.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "CLG_log.h"

#include "MEM_guardedalloc.h"

#include "BLI_blenlib.h"
#include "BLI_math_vector.h"
#include "BLI_string_utils.h"

#include "BLT_translation.h"

#include "IMB_imbuf.h"
#include "IMB_imbuf_types.h"

#include "DNA_gpencil_types.h"
#include "DNA_material_types.h"
#include "DNA_meshdata_types.h"
#include "DNA_space_types.h"

#include "BKE_action.h"
#include "BKE_collection.h"
#include "BKE_colortools.h"
#include "BKE_deform.h"
#include "BKE_gpencil.h"
#include "BKE_gpencil_geom.h"
#include "BKE_icons.h"
#include "BKE_idtype.h"
#include "BKE_image.h"
#include "BKE_lib_id.h"
#include "BKE_main.h"
#include "BKE_material.h"
#include "BKE_paint.h"

#include "BLI_math_color.h"

#include "DEG_depsgraph_query.h"

static CLG_LogRef LOG = {"bke.gpencil"};

static void greasepencil_copy_data(Main *UNUSED(bmain),
                                   ID *id_dst,
                                   const ID *id_src,
                                   const int UNUSED(flag))
{
  bGPdata *gpd_dst = (bGPdata *)id_dst;
  const bGPdata *gpd_src = (const bGPdata *)id_src;

  /* duplicate material array */
  if (gpd_src->mat) {
    gpd_dst->mat = MEM_dupallocN(gpd_src->mat);
  }

  /* copy layers */
  BLI_listbase_clear(&gpd_dst->layers);
  LISTBASE_FOREACH (bGPDlayer *, gpl_src, &gpd_src->layers) {
    /* make a copy of source layer and its data */

    /* TODO here too could add unused flags... */
    bGPDlayer *gpl_dst = BKE_gpencil_layer_duplicate(gpl_src);

    BLI_addtail(&gpd_dst->layers, gpl_dst);
  }
}

static void greasepencil_free_data(ID *id)
{
  /* Really not ideal, but for now will do... In theory custom behaviors like not freeing cache
   * should be handled through specific API, and not be part of the generic one. */
  BKE_gpencil_free((bGPdata *)id, true);
}

IDTypeInfo IDType_ID_GD = {
    .id_code = ID_GD,
    .id_filter = FILTER_ID_GD,
    .main_listbase_index = INDEX_ID_GD,
    .struct_size = sizeof(bGPdata),
    .name = "GPencil",
    .name_plural = "grease_pencils",
    .translation_context = BLT_I18NCONTEXT_ID_GPENCIL,
    .flags = 0,

    .init_data = NULL,
    .copy_data = greasepencil_copy_data,
    .free_data = greasepencil_free_data,
    .make_local = NULL,
};

/* ************************************************** */
/* Draw Engine */

void (*BKE_gpencil_batch_cache_dirty_tag_cb)(bGPdata *gpd) = NULL;
void (*BKE_gpencil_batch_cache_free_cb)(bGPdata *gpd) = NULL;

void BKE_gpencil_batch_cache_dirty_tag(bGPdata *gpd)
{
  if (gpd) {
    DEG_id_tag_update(&gpd->id, ID_RECALC_GEOMETRY);
    BKE_gpencil_batch_cache_dirty_tag_cb(gpd);
  }
}

void BKE_gpencil_batch_cache_free(bGPdata *gpd)
{
  if (gpd) {
    BKE_gpencil_batch_cache_free_cb(gpd);
  }
}

/* ************************************************** */
/* Memory Management */

/* clean vertex groups weights */
void BKE_gpencil_free_point_weights(MDeformVert *dvert)
{
  if (dvert == NULL) {
    return;
  }
  MEM_SAFE_FREE(dvert->dw);
}

void BKE_gpencil_free_stroke_weights(bGPDstroke *gps)
{
  if (gps == NULL) {
    return;
  }

  if (gps->dvert == NULL) {
    return;
  }

  for (int i = 0; i < gps->totpoints; i++) {
    MDeformVert *dvert = &gps->dvert[i];
    BKE_gpencil_free_point_weights(dvert);
  }
}

/* free stroke, doesn't unlink from any listbase */
void BKE_gpencil_free_stroke(bGPDstroke *gps)
{
  if (gps == NULL) {
    return;
  }
  /* free stroke memory arrays, then stroke itself */
  if (gps->points) {
    MEM_freeN(gps->points);
  }
  if (gps->dvert) {
    BKE_gpencil_free_stroke_weights(gps);
    MEM_freeN(gps->dvert);
  }
  if (gps->triangles) {
    MEM_freeN(gps->triangles);
  }

  MEM_freeN(gps);
}

/* Free strokes belonging to a gp-frame */
bool BKE_gpencil_free_strokes(bGPDframe *gpf)
{
  bool changed = (BLI_listbase_is_empty(&gpf->strokes) == false);

  /* free strokes */
  LISTBASE_FOREACH_MUTABLE (bGPDstroke *, gps, &gpf->strokes) {
    BKE_gpencil_free_stroke(gps);
  }
  BLI_listbase_clear(&gpf->strokes);

  return changed;
}

/* Free all of a gp-layer's frames */
void BKE_gpencil_free_frames(bGPDlayer *gpl)
{
  bGPDframe *gpf_next;

  /* error checking */
  if (gpl == NULL) {
    return;
  }

  /* free frames */
  for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf_next) {
    gpf_next = gpf->next;

    /* free strokes and their associated memory */
    BKE_gpencil_free_strokes(gpf);
    BLI_freelinkN(&gpl->frames, gpf);
  }
  gpl->actframe = NULL;
}

void BKE_gpencil_free_layer_masks(bGPDlayer *gpl)
{
  /* Free masks.*/
  bGPDlayer_Mask *mask_next = NULL;
  for (bGPDlayer_Mask *mask = gpl->mask_layers.first; mask; mask = mask_next) {
    mask_next = mask->next;
    BLI_freelinkN(&gpl->mask_layers, mask);
  }
}
/* Free all of the gp-layers for a viewport (list should be &gpd->layers or so) */
void BKE_gpencil_free_layers(ListBase *list)
{
  bGPDlayer *gpl_next;

  /* error checking */
  if (list == NULL) {
    return;
  }

  /* delete layers */
  for (bGPDlayer *gpl = list->first; gpl; gpl = gpl_next) {
    gpl_next = gpl->next;

    /* free layers and their data */
    BKE_gpencil_free_frames(gpl);

    /* Free masks.*/
    BKE_gpencil_free_layer_masks(gpl);

    BLI_freelinkN(list, gpl);
  }
}

/** Free (or release) any data used by this grease pencil (does not free the gpencil itself). */
void BKE_gpencil_free(bGPdata *gpd, bool free_all)
{
  /* free layers */
  BKE_gpencil_free_layers(&gpd->layers);

  /* materials */
  MEM_SAFE_FREE(gpd->mat);

  /* free all data */
  if (free_all) {
    /* clear cache */
    BKE_gpencil_batch_cache_free(gpd);
  }
}

void BKE_gpencil_eval_delete(bGPdata *gpd_eval)
{
  BKE_gpencil_free(gpd_eval, true);
  BKE_libblock_free_data(&gpd_eval->id, false);
  MEM_freeN(gpd_eval);
}

/* ************************************************** */
/* Container Creation */

/* add a new gp-frame to the given layer */
bGPDframe *BKE_gpencil_frame_addnew(bGPDlayer *gpl, int cframe)
{
  bGPDframe *gpf = NULL, *gf = NULL;
  short state = 0;

  /* error checking */
  if (gpl == NULL) {
    return NULL;
  }

  /* allocate memory for this frame */
  gpf = MEM_callocN(sizeof(bGPDframe), "bGPDframe");
  gpf->framenum = cframe;

  /* find appropriate place to add frame */
  if (gpl->frames.first) {
    for (gf = gpl->frames.first; gf; gf = gf->next) {
      /* check if frame matches one that is supposed to be added */
      if (gf->framenum == cframe) {
        state = -1;
        break;
      }

      /* if current frame has already exceeded the frame to add, add before */
      if (gf->framenum > cframe) {
        BLI_insertlinkbefore(&gpl->frames, gf, gpf);
        state = 1;
        break;
      }
    }
  }

  /* check whether frame was added successfully */
  if (state == -1) {
    CLOG_ERROR(
        &LOG, "Frame (%d) existed already for this layer_active. Using existing frame", cframe);

    /* free the newly created one, and use the old one instead */
    MEM_freeN(gpf);

    /* return existing frame instead... */
    BLI_assert(gf != NULL);
    gpf = gf;
  }
  else if (state == 0) {
    /* add to end then! */
    BLI_addtail(&gpl->frames, gpf);
  }

  /* return frame */
  return gpf;
}

/* add a copy of the active gp-frame to the given layer */
bGPDframe *BKE_gpencil_frame_addcopy(bGPDlayer *gpl, int cframe)
{
  bGPDframe *new_frame;
  bool found = false;

  /* Error checking/handling */
  if (gpl == NULL) {
    /* no layer */
    return NULL;
  }
  else if (gpl->actframe == NULL) {
    /* no active frame, so just create a new one from scratch */
    return BKE_gpencil_frame_addnew(gpl, cframe);
  }

  /* Create a copy of the frame */
  new_frame = BKE_gpencil_frame_duplicate(gpl->actframe);

  /* Find frame to insert it before */
  LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
    if (gpf->framenum > cframe) {
      /* Add it here */
      BLI_insertlinkbefore(&gpl->frames, gpf, new_frame);

      found = true;
      break;
    }
    else if (gpf->framenum == cframe) {
      /* This only happens when we're editing with framelock on...
       * - Delete the new frame and don't do anything else here...
       */
      BKE_gpencil_free_strokes(new_frame);
      MEM_freeN(new_frame);
      new_frame = NULL;

      found = true;
      break;
    }
  }

  if (found == false) {
    /* Add new frame to the end */
    BLI_addtail(&gpl->frames, new_frame);
  }

  /* Ensure that frame is set up correctly, and return it */
  if (new_frame) {
    new_frame->framenum = cframe;
    gpl->actframe = new_frame;
  }

  return new_frame;
}

/* add a new gp-layer and make it the active layer */
bGPDlayer *BKE_gpencil_layer_addnew(bGPdata *gpd, const char *name, bool setactive)
{
  bGPDlayer *gpl = NULL;
  bGPDlayer *gpl_active = NULL;

  /* check that list is ok */
  if (gpd == NULL) {
    return NULL;
  }

  /* allocate memory for frame and add to end of list */
  gpl = MEM_callocN(sizeof(bGPDlayer), "bGPDlayer");

  gpl_active = BKE_gpencil_layer_active_get(gpd);

  /* add to datablock */
  if (gpl_active == NULL) {
    BLI_addtail(&gpd->layers, gpl);
  }
  else {
    /* if active layer, add after that layer */
    BLI_insertlinkafter(&gpd->layers, gpl_active, gpl);
  }

  /* annotation vs GP Object behavior is slightly different */
  if (gpd->flag & GP_DATA_ANNOTATIONS) {
    /* set default color of new strokes for this layer */
    copy_v4_v4(gpl->color, U.gpencil_new_layer_col);
    gpl->opacity = 1.0f;

    /* set default thickness of new strokes for this layer */
    gpl->thickness = 3;

    /* Onion colors */
    ARRAY_SET_ITEMS(gpl->gcolor_prev, 0.302f, 0.851f, 0.302f);
    ARRAY_SET_ITEMS(gpl->gcolor_next, 0.250f, 0.1f, 1.0f);
  }
  else {
    /* thickness parameter represents "thickness change", not absolute thickness */
    gpl->thickness = 0;
    gpl->opacity = 1.0f;
    /* default channel color */
    ARRAY_SET_ITEMS(gpl->color, 0.2f, 0.2f, 0.2f);
    /* Default vertex mix. */
    gpl->vertex_paint_opacity = 1.0f;
  }

  /* auto-name */
  BLI_strncpy(gpl->info, name, sizeof(gpl->info));
  BLI_uniquename(&gpd->layers,
                 gpl,
                 (gpd->flag & GP_DATA_ANNOTATIONS) ? DATA_("Note") : DATA_("GP_Layer"),
                 '.',
                 offsetof(bGPDlayer, info),
                 sizeof(gpl->info));

  /* Enable always affected by scene lights. */
  gpl->flag |= GP_LAYER_USE_LIGHTS;
  /* make this one the active one */
  if (setactive) {
    BKE_gpencil_layer_active_set(gpd, gpl);
  }

  /* return layer */
  return gpl;
}

/* add a new gp-datablock */
bGPdata *BKE_gpencil_data_addnew(Main *bmain, const char name[])
{
  bGPdata *gpd;

  /* allocate memory for a new block */
  gpd = BKE_libblock_alloc(bmain, ID_GD, name, 0);

  /* initial settings */
  gpd->flag = (GP_DATA_DISPINFO | GP_DATA_EXPAND);

  /* general flags */
  gpd->flag |= GP_DATA_VIEWALIGN;
  /* always enable object onion skin switch */
  gpd->flag |= GP_DATA_SHOW_ONIONSKINS;
  /* GP object specific settings */
  ARRAY_SET_ITEMS(gpd->line_color, 0.6f, 0.6f, 0.6f, 0.5f);

  gpd->pixfactor = GP_DEFAULT_PIX_FACTOR;

  gpd->zdepth_offset = 0.150f;

  /* grid settings */
  ARRAY_SET_ITEMS(gpd->grid.color, 0.5f, 0.5f, 0.5f); /* Color */
  ARRAY_SET_ITEMS(gpd->grid.scale, 1.0f, 1.0f);       /* Scale */
  gpd->grid.lines = GP_DEFAULT_GRID_LINES;            /* Number of lines */

  /* onion-skinning settings (datablock level) */
  gpd->onion_flag |= (GP_ONION_GHOST_PREVCOL | GP_ONION_GHOST_NEXTCOL);
  gpd->onion_flag |= GP_ONION_FADE;
  gpd->onion_mode = GP_ONION_MODE_RELATIVE;
  gpd->onion_factor = 0.5f;
  ARRAY_SET_ITEMS(gpd->gcolor_prev, 0.145098f, 0.419608f, 0.137255f); /* green */
  ARRAY_SET_ITEMS(gpd->gcolor_next, 0.125490f, 0.082353f, 0.529412f); /* blue */
  gpd->gstep = 1;
  gpd->gstep_next = 1;

  return gpd;
}

/* ************************************************** */
/* Primitive Creation */
/* Utilities for easier bulk-creation of geometry */

/**
 * Populate stroke with point data from data buffers
 *
 * \param array: Flat array of point data values. Each entry has GP_PRIM_DATABUF_SIZE values
 * \param mat: 4x4 transform matrix to transform points into the right coordinate space
 */
void BKE_gpencil_stroke_add_points(bGPDstroke *gps,
                                   const float *array,
                                   const int totpoints,
                                   const float mat[4][4])
{
  for (int i = 0; i < totpoints; i++) {
    bGPDspoint *pt = &gps->points[i];
    const int x = GP_PRIM_DATABUF_SIZE * i;

    pt->x = array[x];
    pt->y = array[x + 1];
    pt->z = array[x + 2];
    mul_m4_v3(mat, &pt->x);

    pt->pressure = array[x + 3];
    pt->strength = array[x + 4];
  }
}

/* Create a new stroke, with pre-allocated data buffers. */
bGPDstroke *BKE_gpencil_stroke_new(int mat_idx, int totpoints, short thickness)
{
  /* allocate memory for a new stroke */
  bGPDstroke *gps = MEM_callocN(sizeof(bGPDstroke), "gp_stroke");

  gps->thickness = thickness;
  gps->fill_opacity_fac = 1.0f;
  gps->hardeness = 1.0f;
  copy_v2_fl(gps->aspect_ratio, 1.0f);

  gps->uv_scale = 1.0f;

  gps->inittime = 0;

  gps->flag = GP_STROKE_3DSPACE;

  gps->totpoints = totpoints;
  if (gps->totpoints > 0) {
    gps->points = MEM_callocN(sizeof(bGPDspoint) * gps->totpoints, "gp_stroke_points");
  }
  else {
    gps->points = NULL;
  }

  /* initialize triangle memory to dummy data */
  gps->triangles = NULL;
  gps->tot_triangles = 0;

  gps->mat_nr = mat_idx;

  return gps;
}

/* Create a new stroke and add to frame. */
bGPDstroke *BKE_gpencil_stroke_add(
    bGPDframe *gpf, int mat_idx, int totpoints, short thickness, const bool insert_at_head)
{
  bGPDstroke *gps = BKE_gpencil_stroke_new(mat_idx, totpoints, thickness);

  /* Add to frame. */
  if ((gps != NULL) && (gpf != NULL)) {
    if (!insert_at_head) {
      BLI_addtail(&gpf->strokes, gps);
    }
    else {
      BLI_addhead(&gpf->strokes, gps);
    }
  }

  return gps;
}

/* Add a stroke and copy the temporary drawing color value from one of the existing stroke */
bGPDstroke *BKE_gpencil_stroke_add_existing_style(
    bGPDframe *gpf, bGPDstroke *existing, int mat_idx, int totpoints, short thickness)
{
  bGPDstroke *gps = BKE_gpencil_stroke_add(gpf, mat_idx, totpoints, thickness, false);
  /* Copy run-time color data so that strokes added in the modifier has the style.
   * There are depsgraph reference pointers inside,
   * change the copy function if interfere with future drawing implementation. */
  memcpy(&gps->runtime, &existing->runtime, sizeof(bGPDstroke_Runtime));
  return gps;
}

/* ************************************************** */
/* Data Duplication */

/* make a copy of a given gpencil weights */
void BKE_gpencil_stroke_weights_duplicate(bGPDstroke *gps_src, bGPDstroke *gps_dst)
{
  if (gps_src == NULL) {
    return;
  }
  BLI_assert(gps_src->totpoints == gps_dst->totpoints);

  BKE_defvert_array_copy(gps_dst->dvert, gps_src->dvert, gps_src->totpoints);
}

/* make a copy of a given gpencil stroke */
bGPDstroke *BKE_gpencil_stroke_duplicate(bGPDstroke *gps_src, const bool dup_points)
{
  bGPDstroke *gps_dst = NULL;

  gps_dst = MEM_dupallocN(gps_src);
  gps_dst->prev = gps_dst->next = NULL;
  gps_dst->triangles = MEM_dupallocN(gps_src->triangles);

  if (dup_points) {
    gps_dst->points = MEM_dupallocN(gps_src->points);

    if (gps_src->dvert != NULL) {
      gps_dst->dvert = MEM_dupallocN(gps_src->dvert);
      BKE_gpencil_stroke_weights_duplicate(gps_src, gps_dst);
    }
    else {
      gps_dst->dvert = NULL;
    }
  }

  /* return new stroke */
  return gps_dst;
}

/* make a copy of a given gpencil frame */
bGPDframe *BKE_gpencil_frame_duplicate(const bGPDframe *gpf_src)
{
  bGPDstroke *gps_dst = NULL;
  bGPDframe *gpf_dst;

  /* error checking */
  if (gpf_src == NULL) {
    return NULL;
  }

  /* make a copy of the source frame */
  gpf_dst = MEM_dupallocN(gpf_src);
  gpf_dst->prev = gpf_dst->next = NULL;

  /* copy strokes */
  BLI_listbase_clear(&gpf_dst->strokes);
  LISTBASE_FOREACH (bGPDstroke *, gps_src, &gpf_src->strokes) {
    /* make copy of source stroke */
    gps_dst = BKE_gpencil_stroke_duplicate(gps_src, true);
    BLI_addtail(&gpf_dst->strokes, gps_dst);
  }

  /* return new frame */
  return gpf_dst;
}

/* make a copy of strokes between gpencil frames */
void BKE_gpencil_frame_copy_strokes(bGPDframe *gpf_src, struct bGPDframe *gpf_dst)
{
  bGPDstroke *gps_dst = NULL;
  /* error checking */
  if ((gpf_src == NULL) || (gpf_dst == NULL)) {
    return;
  }

  /* copy strokes */
  BLI_listbase_clear(&gpf_dst->strokes);
  LISTBASE_FOREACH (bGPDstroke *, gps_src, &gpf_src->strokes) {
    /* make copy of source stroke */
    gps_dst = BKE_gpencil_stroke_duplicate(gps_src, true);
    BLI_addtail(&gpf_dst->strokes, gps_dst);
  }
}

/* make a copy of a given gpencil layer */
bGPDlayer *BKE_gpencil_layer_duplicate(const bGPDlayer *gpl_src)
{
  const bGPDframe *gpf_src;
  bGPDframe *gpf_dst;
  bGPDlayer *gpl_dst;

  /* error checking */
  if (gpl_src == NULL) {
    return NULL;
  }

  /* make a copy of source layer */
  gpl_dst = MEM_dupallocN(gpl_src);
  gpl_dst->prev = gpl_dst->next = NULL;

  /* Copy masks. */
  BLI_listbase_clear(&gpl_dst->mask_layers);
  LISTBASE_FOREACH (bGPDlayer_Mask *, mask_src, &gpl_src->mask_layers) {
    bGPDlayer_Mask *mask_dst = MEM_dupallocN(mask_src);
    mask_dst->prev = mask_dst->next = NULL;
    BLI_addtail(&gpl_dst->mask_layers, mask_dst);
  }

  /* copy frames */
  BLI_listbase_clear(&gpl_dst->frames);
  for (gpf_src = gpl_src->frames.first; gpf_src; gpf_src = gpf_src->next) {
    /* make a copy of source frame */
    gpf_dst = BKE_gpencil_frame_duplicate(gpf_src);
    BLI_addtail(&gpl_dst->frames, gpf_dst);

    /* if source frame was the current layer's 'active' frame, reassign that too */
    if (gpf_src == gpl_dst->actframe) {
      gpl_dst->actframe = gpf_dst;
    }
  }

  /* return new layer */
  return gpl_dst;
}

/* Standard API to make a copy of GP datablock, separate from copying its data */
bGPdata *BKE_gpencil_copy(Main *bmain, const bGPdata *gpd)
{
  bGPdata *gpd_copy;
  BKE_id_copy(bmain, &gpd->id, (ID **)&gpd_copy);
  return gpd_copy;
}

/* make a copy of a given gpencil datablock */
/* XXX: Should this be deprecated? */
bGPdata *BKE_gpencil_data_duplicate(Main *bmain, const bGPdata *gpd_src, bool internal_copy)
{
  bGPdata *gpd_dst;

  /* Yuck and super-uber-hyper yuck!!!
   * Should be replaceable with a no-main copy (LIB_ID_COPY_NO_MAIN etc.), but not sure about it,
   * so for now keep old code for that one. */

  /* error checking */
  if (gpd_src == NULL) {
    return NULL;
  }

  if (internal_copy) {
    /* make a straight copy for undo buffers used during stroke drawing */
    gpd_dst = MEM_dupallocN(gpd_src);
  }
  else {
    BLI_assert(bmain != NULL);
    BKE_id_copy(bmain, &gpd_src->id, (ID **)&gpd_dst);
  }

  /* Copy internal data (layers, etc.) */
  greasepencil_copy_data(bmain, &gpd_dst->id, &gpd_src->id, 0);

  /* return new */
  return gpd_dst;
}

/* ************************************************** */
/* GP Stroke API */

/* ensure selection status of stroke is in sync with its points */
void BKE_gpencil_stroke_sync_selection(bGPDstroke *gps)
{
  bGPDspoint *pt;
  int i;

  /* error checking */
  if (gps == NULL) {
    return;
  }

  /* we'll stop when we find the first selected point,
   * so initially, we must deselect
   */
  gps->flag &= ~GP_STROKE_SELECT;

  for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
    if (pt->flag & GP_SPOINT_SELECT) {
      gps->flag |= GP_STROKE_SELECT;
      break;
    }
  }
}

/* ************************************************** */
/* GP Frame API */

/* delete the last stroke of the given frame */
void BKE_gpencil_frame_delete_laststroke(bGPDlayer *gpl, bGPDframe *gpf)
{
  bGPDstroke *gps = (gpf) ? gpf->strokes.last : NULL;
  int cfra = (gpf) ? gpf->framenum : 0; /* assume that the current frame was not locked */

  /* error checking */
  if (ELEM(NULL, gpf, gps)) {
    return;
  }

  /* free the stroke and its data */
  if (gps->points) {
    MEM_freeN(gps->points);
  }
  if (gps->dvert) {
    BKE_gpencil_free_stroke_weights(gps);
    MEM_freeN(gps->dvert);
  }
  MEM_freeN(gps->triangles);
  BLI_freelinkN(&gpf->strokes, gps);

  /* if frame has no strokes after this, delete it */
  if (BLI_listbase_is_empty(&gpf->strokes)) {
    BKE_gpencil_layer_frame_delete(gpl, gpf);
    BKE_gpencil_layer_frame_get(gpl, cfra, GP_GETFRAME_USE_PREV);
  }
}

/* ************************************************** */
/* GP Layer API */

/* Check if the given layer is able to be edited or not */
bool BKE_gpencil_layer_is_editable(const bGPDlayer *gpl)
{
  /* Sanity check */
  if (gpl == NULL) {
    return false;
  }

  /* Layer must be: Visible + Editable */
  if ((gpl->flag & (GP_LAYER_HIDE | GP_LAYER_LOCKED)) == 0) {
    return true;
  }

  /* Something failed */
  return false;
}

/* Look up the gp-frame on the requested frame number, but don't add a new one */
bGPDframe *BKE_gpencil_layer_frame_find(bGPDlayer *gpl, int cframe)
{
  bGPDframe *gpf;

  /* Search in reverse order, since this is often used for playback/adding,
   * where it's less likely that we're interested in the earlier frames
   */
  for (gpf = gpl->frames.last; gpf; gpf = gpf->prev) {
    if (gpf->framenum == cframe) {
      return gpf;
    }
  }

  return NULL;
}

/* get the appropriate gp-frame from a given layer
 * - this sets the layer's actframe var (if allowed to)
 * - extension beyond range (if first gp-frame is after all frame in interest and cannot add)
 */
bGPDframe *BKE_gpencil_layer_frame_get(bGPDlayer *gpl, int cframe, eGP_GetFrame_Mode addnew)
{
  bGPDframe *gpf = NULL;
  bool found = false;

  /* error checking */
  if (gpl == NULL) {
    return NULL;
  }

  /* check if there is already an active frame */
  if (gpl->actframe) {
    gpf = gpl->actframe;

    /* do not allow any changes to layer's active frame if layer is locked from changes
     * or if the layer has been set to stay on the current frame
     */
    if (gpl->flag & GP_LAYER_FRAMELOCK) {
      return gpf;
    }
    /* do not allow any changes to actframe if frame has painting tag attached to it */
    if (gpf->flag & GP_FRAME_PAINT) {
      return gpf;
    }

    /* try to find matching frame */
    if (gpf->framenum < cframe) {
      for (; gpf; gpf = gpf->next) {
        if (gpf->framenum == cframe) {
          found = true;
          break;
        }
        else if ((gpf->next) && (gpf->next->framenum > cframe)) {
          found = true;
          break;
        }
      }

      /* set the appropriate frame */
      if (addnew) {
        if ((found) && (gpf->framenum == cframe)) {
          gpl->actframe = gpf;
        }
        else if (addnew == GP_GETFRAME_ADD_COPY) {
          gpl->actframe = BKE_gpencil_frame_addcopy(gpl, cframe);
        }
        else {
          gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
        }
      }
      else if (found) {
        gpl->actframe = gpf;
      }
      else {
        gpl->actframe = gpl->frames.last;
      }
    }
    else {
      for (; gpf; gpf = gpf->prev) {
        if (gpf->framenum <= cframe) {
          found = true;
          break;
        }
      }

      /* set the appropriate frame */
      if (addnew) {
        if ((found) && (gpf->framenum == cframe)) {
          gpl->actframe = gpf;
        }
        else if (addnew == GP_GETFRAME_ADD_COPY) {
          gpl->actframe = BKE_gpencil_frame_addcopy(gpl, cframe);
        }
        else {
          gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
        }
      }
      else if (found) {
        gpl->actframe = gpf;
      }
      else {
        gpl->actframe = gpl->frames.first;
      }
    }
  }
  else if (gpl->frames.first) {
    /* check which of the ends to start checking from */
    const int first = ((bGPDframe *)(gpl->frames.first))->framenum;
    const int last = ((bGPDframe *)(gpl->frames.last))->framenum;

    if (abs(cframe - first) > abs(cframe - last)) {
      /* find gp-frame which is less than or equal to cframe */
      for (gpf = gpl->frames.last; gpf; gpf = gpf->prev) {
        if (gpf->framenum <= cframe) {
          found = true;
          break;
        }
      }
    }
    else {
      /* find gp-frame which is less than or equal to cframe */
      for (gpf = gpl->frames.first; gpf; gpf = gpf->next) {
        if (gpf->framenum <= cframe) {
          found = true;
          break;
        }
      }
    }

    /* set the appropriate frame */
    if (addnew) {
      if ((found) && (gpf->framenum == cframe)) {
        gpl->actframe = gpf;
      }
      else {
        gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
      }
    }
    else if (found) {
      gpl->actframe = gpf;
    }
    else {
      /* If delete first frame, need to find one. */
      if (gpl->frames.first != NULL) {
        gpl->actframe = gpl->frames.first;
      }
      else {
        /* unresolved errogenous situation! */
        CLOG_STR_ERROR(&LOG, "cannot find appropriate gp-frame");
        /* gpl->actframe should still be NULL */
      }
    }
  }
  else {
    /* currently no frames (add if allowed to) */
    if (addnew) {
      gpl->actframe = BKE_gpencil_frame_addnew(gpl, cframe);
    }
    else {
      /* don't do anything... this may be when no frames yet! */
      /* gpl->actframe should still be NULL */
    }
  }

  /* return */
  return gpl->actframe;
}

/* delete the given frame from a layer */
bool BKE_gpencil_layer_frame_delete(bGPDlayer *gpl, bGPDframe *gpf)
{
  bool changed = false;

  /* error checking */
  if (ELEM(NULL, gpl, gpf)) {
    return false;
  }

  /* if this frame was active, make the previous frame active instead
   * since it's tricky to set active frame otherwise
   */
  if (gpl->actframe == gpf) {
    gpl->actframe = gpf->prev;
  }

  /* free the frame and its data */
  changed = BKE_gpencil_free_strokes(gpf);
  BLI_freelinkN(&gpl->frames, gpf);

  return changed;
}

bGPDlayer *BKE_gpencil_layer_named_get(bGPdata *gpd, const char *name)
{
  if (name[0] == '\0') {
    return NULL;
  }
  return BLI_findstring(&gpd->layers, name, offsetof(bGPDlayer, info));
}

bGPDlayer_Mask *BKE_gpencil_layer_mask_named_get(bGPDlayer *gpl, const char *name)
{
  if (name[0] == '\0') {
    return NULL;
  }
  return BLI_findstring(&gpl->mask_layers, name, offsetof(bGPDlayer_Mask, name));
}

bGPDlayer_Mask *BKE_gpencil_layer_mask_add(bGPDlayer *gpl, const char *name)
{

  bGPDlayer_Mask *mask = MEM_callocN(sizeof(bGPDlayer_Mask), "bGPDlayer_Mask");
  BLI_addtail(&gpl->mask_layers, mask);
  BLI_strncpy(mask->name, name, sizeof(mask->name));
  gpl->act_mask++;

  return mask;
}

void BKE_gpencil_layer_mask_remove(bGPDlayer *gpl, bGPDlayer_Mask *mask)
{
  BLI_freelinkN(&gpl->mask_layers, mask);
  gpl->act_mask--;
  CLAMP_MIN(gpl->act_mask, 0);
}

void BKE_gpencil_layer_mask_remove_ref(bGPdata *gpd, const char *name)
{
  bGPDlayer_Mask *mask_next;

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    for (bGPDlayer_Mask *mask = gpl->mask_layers.first; mask; mask = mask_next) {
      mask_next = mask->next;
      if (STREQ(mask->name, name)) {
        BKE_gpencil_layer_mask_remove(gpl, mask);
      }
    }
  }
}

static int gpencil_cb_sort_masks(const void *arg1, const void *arg2)
{
  /* sort is inverted as layer list. */
  const struct bGPDlayer_Mask *mask1 = arg1;
  const struct bGPDlayer_Mask *mask2 = arg2;
  int val = 0;

  if (mask1->sort_index < mask2->sort_index) {
    val = 1;
  }
  else if (mask1->sort_index > mask2->sort_index) {
    val = -1;
  }

  return val;
}

void BKE_gpencil_layer_mask_sort(bGPdata *gpd, bGPDlayer *gpl)
{
  /* Update sort index. */
  LISTBASE_FOREACH (bGPDlayer_Mask *, mask, &gpl->mask_layers) {
    bGPDlayer *gpl_mask = BKE_gpencil_layer_named_get(gpd, mask->name);
    if (gpl_mask != NULL) {
      mask->sort_index = BLI_findindex(&gpd->layers, gpl_mask);
    }
    else {
      mask->sort_index = 0;
    }
  }
  BLI_listbase_sort(&gpl->mask_layers, gpencil_cb_sort_masks);
}

void BKE_gpencil_layer_mask_sort_all(bGPdata *gpd)
{
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    BKE_gpencil_layer_mask_sort(gpd, gpl);
  }
}

static int gpencil_cb_cmp_frame(void *thunk, const void *a, const void *b)
{
  const bGPDframe *frame_a = a;
  const bGPDframe *frame_b = b;

  if (frame_a->framenum < frame_b->framenum) {
    return -1;
  }
  if (frame_a->framenum > frame_b->framenum) {
    return 1;
  }
  if (thunk != NULL) {
    *((bool *)thunk) = true;
  }
  /* Sort selected last. */
  if ((frame_a->flag & GP_FRAME_SELECT) && ((frame_b->flag & GP_FRAME_SELECT) == 0)) {
    return 1;
  }
  return 0;
}

void BKE_gpencil_layer_frames_sort(struct bGPDlayer *gpl, bool *r_has_duplicate_frames)
{
  BLI_listbase_sort_r(&gpl->frames, gpencil_cb_cmp_frame, r_has_duplicate_frames);
}

/* get the active gp-layer for editing */
bGPDlayer *BKE_gpencil_layer_active_get(bGPdata *gpd)
{
  /* error checking */
  if (ELEM(NULL, gpd, gpd->layers.first)) {
    return NULL;
  }

  /* loop over layers until found (assume only one active) */
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    if (gpl->flag & GP_LAYER_ACTIVE) {
      return gpl;
    }
  }

  /* no active layer found */
  return NULL;
}

/* set the active gp-layer */
void BKE_gpencil_layer_active_set(bGPdata *gpd, bGPDlayer *active)
{
  /* error checking */
  if (ELEM(NULL, gpd, gpd->layers.first, active)) {
    return;
  }

  /* loop over layers deactivating all */
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    gpl->flag &= ~GP_LAYER_ACTIVE;
    if (gpd->flag & GP_DATA_AUTOLOCK_LAYERS) {
      gpl->flag |= GP_LAYER_LOCKED;
    }
  }

  /* set as active one */
  active->flag |= GP_LAYER_ACTIVE;
  if (gpd->flag & GP_DATA_AUTOLOCK_LAYERS) {
    active->flag &= ~GP_LAYER_LOCKED;
  }
}

/* Set locked layers for autolock mode. */
void BKE_gpencil_layer_autolock_set(bGPdata *gpd, const bool unlock)
{
  BLI_assert(gpd != NULL);

  if (gpd->flag & GP_DATA_AUTOLOCK_LAYERS) {
    bGPDlayer *layer_active = BKE_gpencil_layer_active_get(gpd);

    /* Lock all other layers */
    LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
      /* unlock active layer */
      if (gpl == layer_active) {
        gpl->flag &= ~GP_LAYER_LOCKED;
      }
      else {
        gpl->flag |= GP_LAYER_LOCKED;
      }
    }
  }
  else {
    /* If disable is better unlock all layers by default or it looks there is
     * a problem in the UI because the user expects all layers will be unlocked
     */
    if (unlock) {
      LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
        gpl->flag &= ~GP_LAYER_LOCKED;
      }
    }
  }
}

/* delete the active gp-layer */
void BKE_gpencil_layer_delete(bGPdata *gpd, bGPDlayer *gpl)
{
  /* error checking */
  if (ELEM(NULL, gpd, gpl)) {
    return;
  }

  /* free layer */
  BKE_gpencil_free_frames(gpl);

  /* Free Masks. */
  BKE_gpencil_free_layer_masks(gpl);

  /* Remove any reference to that layer in masking lists. */
  BKE_gpencil_layer_mask_remove_ref(gpd, gpl->info);

  /* free icon providing preview of icon color */
  BKE_icon_delete(gpl->runtime.icon_id);

  BLI_freelinkN(&gpd->layers, gpl);
}

Material *BKE_gpencil_brush_material_get(Brush *brush)
{
  Material *ma = NULL;

  if ((brush != NULL) && (brush->gpencil_settings != NULL) &&
      (brush->gpencil_settings->material != NULL)) {
    ma = brush->gpencil_settings->material;
  }

  return ma;
}

void BKE_gpencil_brush_material_set(Brush *brush, Material *ma)
{
  BLI_assert(brush);
  BLI_assert(brush->gpencil_settings);
  if (brush->gpencil_settings->material != ma) {
    if (brush->gpencil_settings->material) {
      id_us_min(&brush->gpencil_settings->material->id);
    }
    if (ma) {
      id_us_plus(&ma->id);
    }
    brush->gpencil_settings->material = ma;
  }
}

/* Adds the pinned material to the object if necessary. */
Material *BKE_gpencil_object_material_ensure_from_brush(Main *bmain, Object *ob, Brush *brush)
{
  if (brush->gpencil_settings->flag & GP_BRUSH_MATERIAL_PINNED) {
    Material *ma = BKE_gpencil_brush_material_get(brush);

    /* check if the material is already on object material slots and add it if missing */
    if (ma && BKE_gpencil_object_material_index_get(ob, ma) < 0) {
      BKE_object_material_slot_add(bmain, ob);
      BKE_object_material_assign(bmain, ob, ma, ob->totcol, BKE_MAT_ASSIGN_USERPREF);
    }

    return ma;
  }
  else {
    /* using active material instead */
    return BKE_object_material_get(ob, ob->actcol);
  }
}

/* Assigns the material to object (if not already present) and returns its index (mat_nr). */
int BKE_gpencil_object_material_ensure(Main *bmain, Object *ob, Material *material)
{
  if (!material) {
    return -1;
  }
  int index = BKE_gpencil_object_material_index_get(ob, material);
  if (index < 0) {
    BKE_object_material_slot_add(bmain, ob);
    BKE_object_material_assign(bmain, ob, material, ob->totcol, BKE_MAT_ASSIGN_USERPREF);
    return ob->totcol - 1;
  }
  return index;
}

/**
 * Creates a new gpencil material and assigns it to object.
 *
 * \param *r_index: value is set to zero based index of the new material if r_index is not NULL
 */
Material *BKE_gpencil_object_material_new(Main *bmain, Object *ob, const char *name, int *r_index)
{
  Material *ma = BKE_gpencil_material_add(bmain, name);
  id_us_min(&ma->id); /* no users yet */

  BKE_object_material_slot_add(bmain, ob);
  BKE_object_material_assign(bmain, ob, ma, ob->totcol, BKE_MAT_ASSIGN_USERPREF);

  if (r_index) {
    *r_index = ob->actcol - 1;
  }
  return ma;
}

/* Returns the material for a brush with respect to its pinned state. */
Material *BKE_gpencil_object_material_from_brush_get(Object *ob, Brush *brush)
{
  if ((brush) && (brush->gpencil_settings) &&
      (brush->gpencil_settings->flag & GP_BRUSH_MATERIAL_PINNED)) {
    Material *ma = BKE_gpencil_brush_material_get(brush);
    return ma;
  }
  else {
    return BKE_object_material_get(ob, ob->actcol);
  }
}

/* Returns the material index for a brush with respect to its pinned state. */
int BKE_gpencil_object_material_get_index_from_brush(Object *ob, Brush *brush)
{
  if ((brush) && (brush->gpencil_settings->flag & GP_BRUSH_MATERIAL_PINNED)) {
    return BKE_gpencil_object_material_index_get(ob, brush->gpencil_settings->material);
  }
  else {
    return ob->actcol - 1;
  }
}

/* Guaranteed to return a material assigned to object. Returns never NULL. */
Material *BKE_gpencil_object_material_ensure_from_active_input_toolsettings(Main *bmain,
                                                                            Object *ob,
                                                                            ToolSettings *ts)
{
  if (ts && ts->gp_paint && ts->gp_paint->paint.brush) {
    return BKE_gpencil_object_material_ensure_from_active_input_brush(
        bmain, ob, ts->gp_paint->paint.brush);
  }
  else {
    return BKE_gpencil_object_material_ensure_from_active_input_brush(bmain, ob, NULL);
  }
}

/* Guaranteed to return a material assigned to object. Returns never NULL. */
Material *BKE_gpencil_object_material_ensure_from_active_input_brush(Main *bmain,
                                                                     Object *ob,
                                                                     Brush *brush)
{
  if (brush) {
    Material *ma = BKE_gpencil_object_material_ensure_from_brush(bmain, ob, brush);
    if (ma) {
      return ma;
    }
    else if (brush->gpencil_settings->flag & GP_BRUSH_MATERIAL_PINNED) {
      /* it is easier to just unpin a NULL material, instead of setting a new one */
      brush->gpencil_settings->flag &= ~GP_BRUSH_MATERIAL_PINNED;
    }
  }
  return BKE_gpencil_object_material_ensure_from_active_input_material(ob);
}

/**
 * Guaranteed to return a material assigned to object. Returns never NULL.
 * Only use this for materials unrelated to user input.
 */
Material *BKE_gpencil_object_material_ensure_from_active_input_material(Object *ob)
{
  Material *ma = BKE_object_material_get(ob, ob->actcol);
  if (ma) {
    return ma;
  }

  return BKE_material_default_gpencil();
}

/* Get active color, and add all default settings if we don't find anything */
Material *BKE_gpencil_object_material_ensure_active(Object *ob)
{
  Material *ma = NULL;

  /* sanity checks */
  if (ob == NULL) {
    return NULL;
  }

  ma = BKE_gpencil_object_material_ensure_from_active_input_material(ob);
  if (ma->gp_style == NULL) {
    BKE_gpencil_material_attr_init(ma);
  }

  return ma;
}

/* ************************************************** */
bool BKE_gpencil_stroke_select_check(const bGPDstroke *gps)
{
  const bGPDspoint *pt;
  int i;
  for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
    if (pt->flag & GP_SPOINT_SELECT) {
      return true;
    }
  }
  return false;
}

/* ************************************************** */
/* GP Object - Vertex Groups */

/* remove a vertex group */
void BKE_gpencil_vgroup_remove(Object *ob, bDeformGroup *defgroup)
{
  bGPdata *gpd = ob->data;
  MDeformVert *dvert = NULL;
  const int def_nr = BLI_findindex(&ob->defbase, defgroup);
  const int totgrp = BLI_listbase_count(&ob->defbase);

  /* Remove points data */
  if (gpd) {
    LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
      LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
        LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
          if (gps->dvert != NULL) {
            for (int i = 0; i < gps->totpoints; i++) {
              dvert = &gps->dvert[i];
              MDeformWeight *dw = BKE_defvert_find_index(dvert, def_nr);
              if (dw != NULL) {
                BKE_defvert_remove_group(dvert, dw);
              }
              else {
                /* Reorganize weights for other groups after deleted one. */
                for (int g = 0; g < totgrp; g++) {
                  dw = BKE_defvert_find_index(dvert, g);
                  if ((dw != NULL) && (dw->def_nr > def_nr)) {
                    dw->def_nr--;
                  }
                }
              }
            }
          }
        }
      }
    }
  }

  /* Remove the group */
  BLI_freelinkN(&ob->defbase, defgroup);
  DEG_id_tag_update(&gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY);
}

void BKE_gpencil_dvert_ensure(bGPDstroke *gps)
{
  if (gps->dvert == NULL) {
    gps->dvert = MEM_callocN(sizeof(MDeformVert) * gps->totpoints, "gp_stroke_weights");
  }
}

/* ************************************************** */

/**
 * Get range of selected frames in layer.
 * Always the active frame is considered as selected, so if no more selected the range
 * will be equal to the current active frame.
 * \param gpl: Layer
 * \param r_initframe: Number of first selected frame
 * \param r_endframe: Number of last selected frame
 */
void BKE_gpencil_frame_range_selected(bGPDlayer *gpl, int *r_initframe, int *r_endframe)
{
  *r_initframe = gpl->actframe->framenum;
  *r_endframe = gpl->actframe->framenum;

  LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
    if (gpf->flag & GP_FRAME_SELECT) {
      if (gpf->framenum < *r_initframe) {
        *r_initframe = gpf->framenum;
      }
      if (gpf->framenum > *r_endframe) {
        *r_endframe = gpf->framenum;
      }
    }
  }
}

/**
 * Get Falloff factor base on frame range
 * \param gpf: Frame
 * \param actnum: Number of active frame in layer
 * \param f_init: Number of first selected frame
 * \param f_end: Number of last selected frame
 * \param cur_falloff: Curve with falloff factors
 */
float BKE_gpencil_multiframe_falloff_calc(
    bGPDframe *gpf, int actnum, int f_init, int f_end, CurveMapping *cur_falloff)
{
  float fnum = 0.5f; /* default mid curve */
  float value;

  /* check curve is available */
  if (cur_falloff == NULL) {
    return 1.0f;
  }

  /* frames to the right of the active frame */
  if (gpf->framenum < actnum) {
    fnum = (float)(gpf->framenum - f_init) / (actnum - f_init);
    fnum *= 0.5f;
    value = BKE_curvemapping_evaluateF(cur_falloff, 0, fnum);
  }
  /* frames to the left of the active frame */
  else if (gpf->framenum > actnum) {
    fnum = (float)(gpf->framenum - actnum) / (f_end - actnum);
    fnum *= 0.5f;
    value = BKE_curvemapping_evaluateF(cur_falloff, 0, fnum + 0.5f);
  }
  else {
    value = 1.0f;
  }

  return value;
}

/* reassign strokes using a material */
void BKE_gpencil_material_index_reassign(bGPdata *gpd, int totcol, int index)
{
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        /* reassign strokes */
        if ((gps->mat_nr > index) || (gps->mat_nr > totcol - 1)) {
          gps->mat_nr--;
          CLAMP_MIN(gps->mat_nr, 0);
        }
      }
    }
  }
}

/* remove strokes using a material */
bool BKE_gpencil_material_index_used(bGPdata *gpd, int index)
{
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        if (gps->mat_nr == index) {
          return true;
        }
      }
    }
  }

  return false;
}

void BKE_gpencil_material_remap(struct bGPdata *gpd,
                                const unsigned int *remap,
                                unsigned int remap_len)
{
  const short remap_len_short = (short)remap_len;

#define MAT_NR_REMAP(n) \
  if (n < remap_len_short) { \
    BLI_assert(n >= 0 && remap[n] < remap_len_short); \
    n = remap[n]; \
  } \
  ((void)0)

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        /* reassign strokes */
        MAT_NR_REMAP(gps->mat_nr);
      }
    }
  }

#undef MAT_NR_REMAP
}

/* Load a table with material conversion index for merged materials. */
bool BKE_gpencil_merge_materials_table_get(Object *ob,
                                           const float hue_threshold,
                                           const float sat_threshold,
                                           const float val_threshold,
                                           GHash *r_mat_table)
{
  bool changed = false;

  Material *ma_primary = NULL;
  Material *ma_secondary = NULL;
  MaterialGPencilStyle *gp_style_primary = NULL;
  MaterialGPencilStyle *gp_style_secondary = NULL;

  short *totcol = BKE_object_material_len_p(ob);
  if (totcol == 0) {
    return changed;
  }

  for (int idx_primary = 0; idx_primary < *totcol; idx_primary++) {
    /* Read primary material to compare. */
    ma_primary = BKE_gpencil_material(ob, idx_primary + 1);
    if (ma_primary == NULL) {
      continue;
    }

    for (int idx_secondary = idx_primary + 1; idx_secondary < *totcol; idx_secondary++) {
      /* Read secondary material to compare with primary material. */
      ma_secondary = BKE_gpencil_material(ob, idx_secondary + 1);
      if ((ma_secondary == NULL) ||
          (BLI_ghash_haskey(r_mat_table, POINTER_FROM_INT(idx_secondary)))) {
        continue;
      }
      gp_style_primary = ma_primary->gp_style;
      gp_style_secondary = ma_secondary->gp_style;

      if ((gp_style_primary == NULL) || (gp_style_secondary == NULL) ||
          (gp_style_secondary->flag & GP_MATERIAL_LOCKED)) {
        continue;
      }

      /* Check materials have the same mode. */
      if (gp_style_primary->mode != gp_style_secondary->mode) {
        continue;
      }

      /* Check materials have same stroke and fill attributes. */
      if ((gp_style_primary->flag & GP_MATERIAL_STROKE_SHOW) !=
          (gp_style_secondary->flag & GP_MATERIAL_STROKE_SHOW)) {
        continue;
      }

      if ((gp_style_primary->flag & GP_MATERIAL_FILL_SHOW) !=
          (gp_style_secondary->flag & GP_MATERIAL_FILL_SHOW)) {
        continue;
      }

      /* Check materials have the same type. */
      if ((gp_style_primary->stroke_style != gp_style_secondary->stroke_style) ||
          (gp_style_primary->fill_style != gp_style_secondary->fill_style)) {
        continue;
      }

      float s_hsv_a[3], s_hsv_b[3], f_hsv_a[3], f_hsv_b[3], col[3];
      copy_v3_v3(col, gp_style_primary->stroke_rgba);
      rgb_to_hsv_compat_v(col, s_hsv_a);
      copy_v3_v3(col, gp_style_secondary->stroke_rgba);
      rgb_to_hsv_compat_v(col, s_hsv_b);

      copy_v3_v3(col, gp_style_primary->fill_rgba);
      rgb_to_hsv_compat_v(col, f_hsv_a);
      copy_v3_v3(col, gp_style_secondary->fill_rgba);
      rgb_to_hsv_compat_v(col, f_hsv_b);

      /* Check stroke and fill color (only Hue and Saturation). */
      if ((!compare_ff(s_hsv_a[0], s_hsv_b[0], hue_threshold)) ||
          (!compare_ff(s_hsv_a[1], s_hsv_b[1], sat_threshold)) ||
          (!compare_ff(f_hsv_a[0], f_hsv_b[0], hue_threshold)) ||
          (!compare_ff(f_hsv_a[1], f_hsv_b[1], sat_threshold)) ||
          (!compare_ff(s_hsv_a[2], s_hsv_b[2], val_threshold)) ||
          (!compare_ff(s_hsv_a[2], s_hsv_b[2], val_threshold)) ||
          (!compare_ff(s_hsv_a[2], s_hsv_b[2], val_threshold)) ||
          (!compare_ff(s_hsv_a[2], s_hsv_b[2], val_threshold))) {
        continue;
      }

      /* Save conversion indexes. */
      BLI_ghash_insert(
          r_mat_table, POINTER_FROM_INT(idx_secondary), POINTER_FROM_INT(idx_primary));
      changed = true;
    }
  }

  return changed;
}

/* statistics functions */
void BKE_gpencil_stats_update(bGPdata *gpd)
{
  gpd->totlayer = 0;
  gpd->totframe = 0;
  gpd->totstroke = 0;
  gpd->totpoint = 0;

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    gpd->totlayer++;
    LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
      gpd->totframe++;
      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        gpd->totstroke++;
        gpd->totpoint += gps->totpoints;
      }
    }
  }
}

/* get material index (0-based like mat_nr not actcol) */
int BKE_gpencil_object_material_index_get(Object *ob, Material *ma)
{
  short *totcol = BKE_object_material_len_p(ob);
  Material *read_ma = NULL;
  for (short i = 0; i < *totcol; i++) {
    read_ma = BKE_object_material_get(ob, i + 1);
    if (ma == read_ma) {
      return i;
    }
  }

  return -1;
}

/* Create a default palette */
void BKE_gpencil_palette_ensure(Main *bmain, Scene *scene)
{
  const int totcol = 120;
  const char *hexcol[] = {
      "FFFFFF", "F2F2F2", "E6E6E6", "D9D9D9", "CCCCCC", "BFBFBF", "B2B2B2", "A6A6A6", "999999",
      "8C8C8C", "808080", "737373", "666666", "595959", "4C4C4C", "404040", "333333", "262626",
      "1A1A1A", "000000", "F2FC24", "FFEA00", "FEA711", "FE8B68", "FB3B02", "FE3521", "D00000",
      "A81F3D", "780422", "2B0000", "F1E2C5", "FEE4B3", "FEDABB", "FEC28E", "D88F57", "BD6340",
      "A2402B", "63352D", "6B2833", "34120C", "E7CB8F", "D1B38B", "C1B17F", "D7980B", "FFB100",
      "FE8B00", "FF6A00", "B74100", "5F3E1D", "3B2300", "FECADA", "FE65CB", "FE1392", "DD3062",
      "C04A6D", "891688", "4D2689", "441521", "2C1139", "241422", "FFFF7D", "FFFF00", "FF7F00",
      "FF7D7D", "FF7DFF", "FF00FE", "FF007F", "FF0000", "7F0000", "0A0A00", "F6FDFF", "E9F7FF",
      "CFE6FE", "AAC7FE", "77B3FE", "1E74FD", "0046AA", "2F4476", "003052", "0E0E25", "EEF5F0",
      "D6E5DE", "ACD8B9", "6CADC6", "42A9AF", "007F7F", "49675C", "2E4E4E", "1D3239", "0F1C21",
      "D8FFF4", "B8F4F5", "AECCB5", "76C578", "358757", "409B68", "468768", "1F512B", "2A3C37",
      "122E1D", "EFFFC9", "E6F385", "BCF51C", "D4DC18", "82D322", "5C7F00", "59932B", "297F00",
      "004320", "1C3322", "00FF7F", "00FF00", "7DFF7D", "7DFFFF", "00FFFF", "7D7DFF", "7F00FF",
      "0000FF", "3F007F", "00007F"};

  ToolSettings *ts = scene->toolsettings;
  GpPaint *gp_paint = ts->gp_paint;
  Paint *paint = &gp_paint->paint;

  if (paint->palette != NULL) {
    return;
  }

  paint->palette = BLI_findstring(&bmain->palettes, "Palette", offsetof(ID, name) + 2);
  /* Try with first palette. */
  if (bmain->palettes.first != NULL) {
    paint->palette = bmain->palettes.first;
    ts->gp_vertexpaint->paint.palette = paint->palette;
    return;
  }

  if (paint->palette == NULL) {
    paint->palette = BKE_palette_add(bmain, "Palette");
    ts->gp_vertexpaint->paint.palette = paint->palette;

    /* Create Colors. */
    for (int i = 0; i < totcol; i++) {
      PaletteColor *palcol = BKE_palette_color_add(paint->palette);
      if (palcol) {
        hex_to_rgb((char *)hexcol[i], palcol->rgb, palcol->rgb + 1, palcol->rgb + 2);
      }
    }
  }
}

bool BKE_gpencil_from_image(SpaceImage *sima, bGPDframe *gpf, const float size, const bool mask)
{
  Image *image = sima->image;
  bool done = false;

  if (image == NULL) {
    return false;
  }

  ImageUser iuser = sima->iuser;
  void *lock;
  ImBuf *ibuf;

  ibuf = BKE_image_acquire_ibuf(image, &iuser, &lock);

  if (ibuf->rect) {
    int img_x = ibuf->x;
    int img_y = ibuf->y;

    float color[4];
    bGPDspoint *pt;
    for (int row = 0; row < img_y; row++) {
      /* Create new stroke */
      bGPDstroke *gps = BKE_gpencil_stroke_add(gpf, 0, img_x, size * 1000, false);
      done = true;
      for (int col = 0; col < img_x; col++) {
        IMB_sampleImageAtLocation(ibuf, col, row, true, color);
        pt = &gps->points[col];
        pt->pressure = 1.0f;
        pt->x = col * size;
        pt->z = row * size;
        if (!mask) {
          copy_v3_v3(pt->vert_color, color);
          pt->vert_color[3] = 1.0f;
          pt->strength = color[3];
        }
        else {
          zero_v3(pt->vert_color);
          pt->vert_color[3] = 1.0f;
          pt->strength = 1.0f - color[3];
        }

        /* Selet Alpha points. */
        if (pt->strength < 0.03f) {
          gps->flag |= GP_STROKE_SELECT;
          pt->flag |= GP_SPOINT_SELECT;
        }
      }
      BKE_gpencil_stroke_geometry_update(gps);
    }
  }

  /* Free memory. */
  BKE_image_release_ibuf(image, ibuf, lock);

  return done;
}

/**
 * Helper to check if a layers is used as mask
 * \param gpd Grease pencil datablock
 * \param gpl_mask Actual Layer
 * \return True if the layer is a mask
 */
static bool gpencil_is_layer_mask(ViewLayer *view_layer, bGPdata *gpd, bGPDlayer *gpl_mask)
{
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    if ((gpl->viewlayername[0] != '\0') && (!STREQ(view_layer->name, gpl->viewlayername))) {
      continue;
    }

    LISTBASE_FOREACH (bGPDlayer_Mask *, mask, &gpl->mask_layers) {
      if (STREQ(gpl_mask->info, mask->name)) {
        return true;
      }
    }
  }

  return false;
}

/* -------------------------------------------------------------------- */
/** \name Iterators
 *
 * Iterate over all visible stroke of all visible layers inside a gpObject.
 * Also take into account onion skining.
 *
 * \{ */

void BKE_gpencil_visible_stroke_iter(ViewLayer *view_layer,
                                     Object *ob,
                                     gpIterCb layer_cb,
                                     gpIterCb stroke_cb,
                                     void *thunk,
                                     bool do_onion,
                                     int cfra)
{
  bGPdata *gpd = (bGPdata *)ob->data;
  const bool is_multiedit = GPENCIL_MULTIEDIT_SESSIONS_ON(gpd);
  const bool is_onion = do_onion && ((gpd->flag & GP_DATA_STROKE_WEIGHTMODE) == 0);

  /* Onion skinning. */
  const bool onion_mode_abs = (gpd->onion_mode == GP_ONION_MODE_ABSOLUTE);
  const bool onion_mode_sel = (gpd->onion_mode == GP_ONION_MODE_SELECTED);
  const bool onion_loop = (gpd->onion_flag & GP_ONION_LOOP) != 0;
  const short onion_keytype = gpd->onion_keytype;

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {

    bGPDframe *act_gpf = gpl->actframe;
    bGPDframe *sta_gpf = act_gpf;
    bGPDframe *end_gpf = act_gpf ? act_gpf->next : NULL;

    if (gpl->flag & GP_LAYER_HIDE) {
      continue;
    }

    /* Hide the layer if it's defined a view layer filter. This is used to
     * generate renders, putting only selected GP layers for each View Layer.
     * This is used only in final render and never in Viewport. */
    if ((view_layer != NULL) && (gpl->viewlayername[0] != '\0') &&
        (!STREQ(view_layer->name, gpl->viewlayername))) {
      /* If the layer is used as mask, cannot be filtered or the masking system
       * will crash because needs the mask layer in the draw pipeline. */
      if (!gpencil_is_layer_mask(view_layer, gpd, gpl)) {
        continue;
      }
    }

    if (is_multiedit) {
      sta_gpf = end_gpf = NULL;
      /* Check the whole range and tag the editable frames. */
      LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
        if (gpf == act_gpf || (gpf->flag & GP_FRAME_SELECT)) {
          gpf->runtime.onion_id = 0;
          if (sta_gpf == NULL) {
            sta_gpf = gpf;
          }
          end_gpf = gpf->next;
        }
        else {
          gpf->runtime.onion_id = INT_MAX;
        }
      }
    }
    else if (is_onion && (gpl->onion_flag & GP_LAYER_ONIONSKIN)) {
      if (act_gpf) {
        bGPDframe *last_gpf = gpl->frames.last;

        int frame_len = 0;
        LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
          gpf->runtime.frameid = frame_len++;
        }

        LISTBASE_FOREACH (bGPDframe *, gpf, &gpl->frames) {
          bool is_wrong_keytype = (onion_keytype > -1) && (gpf->key_type != onion_keytype);
          bool is_in_range;
          int delta = (onion_mode_abs) ? (gpf->framenum - cfra) :
                                         (gpf->runtime.frameid - act_gpf->runtime.frameid);

          if (onion_mode_sel) {
            is_in_range = (gpf->flag & GP_FRAME_SELECT) != 0;
          }
          else {
            is_in_range = (-delta <= gpd->gstep) && (delta <= gpd->gstep_next);

            if (onion_loop && !is_in_range) {
              /* We wrap the value using the last frame and 0 as reference. */
              /* FIXME: This might not be good for animations not starting at 0. */
              int shift = (onion_mode_abs) ? last_gpf->framenum : last_gpf->runtime.frameid;
              delta += (delta < 0) ? (shift + 1) : -(shift + 1);
              /* Test again with wrapped value. */
              is_in_range = (-delta <= gpd->gstep) && (delta <= gpd->gstep_next);
            }
          }
          /* Mask frames that have wrong keytype of are not in range. */
          gpf->runtime.onion_id = (is_wrong_keytype || !is_in_range) ? INT_MAX : delta;
        }
        /* Active frame is always shown. */
        act_gpf->runtime.onion_id = 0;
      }

      sta_gpf = gpl->frames.first;
      end_gpf = NULL;
    }
    else {
      /* Bypass multiedit/onion skinning. */
      end_gpf = sta_gpf = NULL;
    }

    if (sta_gpf == NULL && act_gpf == NULL) {
      if (layer_cb) {
        layer_cb(gpl, act_gpf, NULL, thunk);
      }
      continue;
    }

    /* Draw multiedit/onion skinning first */
    for (bGPDframe *gpf = sta_gpf; gpf && gpf != end_gpf; gpf = gpf->next) {
      if (gpf->runtime.onion_id == INT_MAX || gpf == act_gpf) {
        continue;
      }

      if (layer_cb) {
        layer_cb(gpl, gpf, NULL, thunk);
      }

      LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
        if (gps->totpoints == 0) {
          continue;
        }
        stroke_cb(gpl, gpf, gps, thunk);
      }
    }
    /* Draw Active frame on top. */
    /* Use evaluated frame (with modifiers for active stroke)/ */
    act_gpf = gpl->actframe;
    act_gpf->runtime.onion_id = 0;
    if (act_gpf) {
      if (layer_cb) {
        layer_cb(gpl, act_gpf, NULL, thunk);
      }

      LISTBASE_FOREACH (bGPDstroke *, gps, &act_gpf->strokes) {
        if (gps->totpoints == 0) {
          continue;
        }
        stroke_cb(gpl, act_gpf, gps, thunk);
      }
    }
  }
}

void BKE_gpencil_frame_original_pointers_update(const struct bGPDframe *gpf_orig,
                                                const struct bGPDframe *gpf_eval)
{
  bGPDstroke *gps_eval = gpf_eval->strokes.first;
  LISTBASE_FOREACH (bGPDstroke *, gps_orig, &gpf_orig->strokes) {

    /* Assign original stroke pointer. */
    if (gps_eval != NULL) {
      gps_eval->runtime.gps_orig = gps_orig;

      /* Assign original point pointer. */
      for (int i = 0; i < gps_orig->totpoints; i++) {
        if (i > gps_eval->totpoints - 1) {
          break;
        }
        bGPDspoint *pt_orig = &gps_orig->points[i];
        bGPDspoint *pt_eval = &gps_eval->points[i];
        pt_orig->runtime.pt_orig = NULL;
        pt_orig->runtime.idx_orig = i;
        pt_eval->runtime.pt_orig = pt_orig;
        pt_eval->runtime.idx_orig = i;
      }
      /* Increase pointer. */
      gps_eval = gps_eval->next;
    }
  }
}

void BKE_gpencil_update_orig_pointers(const Object *ob_orig, const Object *ob_eval)
{
  bGPdata *gpd_eval = (bGPdata *)ob_eval->data;
  bGPdata *gpd_orig = (bGPdata *)ob_orig->data;

  /* Assign pointers to the original stroke and points to the evaluated data. This must
   * be done before applying any modifier because at this moment the structure is equals,
   * so we can assume the layer index is the same in both datablocks.
   * This data will be used by operators. */

  bGPDlayer *gpl_eval = gpd_eval->layers.first;
  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd_orig->layers) {
    if (gpl_eval != NULL) {
      /* Update layer reference pointers. */
      gpl_eval->runtime.gpl_orig = (bGPDlayer *)gpl;

      bGPDframe *gpf_eval = gpl_eval->frames.first;
      LISTBASE_FOREACH (bGPDframe *, gpf_orig, &gpl->frames) {
        if (gpf_eval != NULL) {
          /* Update frame reference pointers. */
          gpf_eval->runtime.gpf_orig = (bGPDframe *)gpf_orig;
          BKE_gpencil_frame_original_pointers_update(gpf_orig, gpf_eval);
          gpf_eval = gpf_eval->next;
        }
      }
      gpl_eval = gpl_eval->next;
    }
  }
}

void BKE_gpencil_parent_matrix_get(const Depsgraph *depsgraph,
                                   Object *obact,
                                   bGPDlayer *gpl,
                                   float diff_mat[4][4])
{
  Object *ob_eval = depsgraph != NULL ? DEG_get_evaluated_object(depsgraph, obact) : obact;
  Object *obparent = gpl->parent;
  Object *obparent_eval = depsgraph != NULL ? DEG_get_evaluated_object(depsgraph, obparent) :
                                              obparent;

  /* if not layer parented, try with object parented */
  if (obparent_eval == NULL) {
    if (ob_eval != NULL) {
      if (ob_eval->type == OB_GPENCIL) {
        copy_m4_m4(diff_mat, ob_eval->obmat);
        return;
      }
    }
    /* not gpencil object */
    unit_m4(diff_mat);
    return;
  }
  else {
    if ((gpl->partype == PAROBJECT) || (gpl->partype == PARSKEL)) {
      mul_m4_m4m4(diff_mat, obparent_eval->obmat, gpl->inverse);
      add_v3_v3(diff_mat[3], ob_eval->obmat[3]);
      return;
    }
    else if (gpl->partype == PARBONE) {
      bPoseChannel *pchan = BKE_pose_channel_find_name(obparent_eval->pose, gpl->parsubstr);
      if (pchan) {
        float tmp_mat[4][4];
        mul_m4_m4m4(tmp_mat, obparent_eval->obmat, pchan->pose_mat);
        mul_m4_m4m4(diff_mat, tmp_mat, gpl->inverse);
        add_v3_v3(diff_mat[3], ob_eval->obmat[3]);
      }
      else {
        /* if bone not found use object (armature) */
        mul_m4_m4m4(diff_mat, obparent_eval->obmat, gpl->inverse);
        add_v3_v3(diff_mat[3], ob_eval->obmat[3]);
      }
      return;
    }
    else {
      unit_m4(diff_mat); /* not defined type */
    }
  }
}

void BKE_gpencil_update_layer_parent(const Depsgraph *depsgraph, Object *ob)
{
  if (ob->type != OB_GPENCIL) {
    return;
  }

  bGPdata *gpd = (bGPdata *)ob->data;
  float cur_mat[4][4];

  LISTBASE_FOREACH (bGPDlayer *, gpl, &gpd->layers) {
    if ((gpl->parent != NULL) && (gpl->actframe != NULL)) {
      Object *ob_parent = DEG_get_evaluated_object(depsgraph, gpl->parent);
      /* calculate new matrix */
      if ((gpl->partype == PAROBJECT) || (gpl->partype == PARSKEL)) {
        copy_m4_m4(cur_mat, ob_parent->obmat);
      }
      else if (gpl->partype == PARBONE) {
        bPoseChannel *pchan = BKE_pose_channel_find_name(ob_parent->pose, gpl->parsubstr);
        if (pchan != NULL) {
          copy_m4_m4(cur_mat, ob->imat);
          mul_m4_m4m4(cur_mat, ob_parent->obmat, pchan->pose_mat);
        }
        else {
          unit_m4(cur_mat);
        }
      }
      /* only redo if any change */
      if (!equals_m4m4(gpl->inverse, cur_mat)) {
        LISTBASE_FOREACH (bGPDstroke *, gps, &gpl->actframe->strokes) {
          bGPDspoint *pt;
          int i;
          for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
            mul_m4_v3(gpl->inverse, &pt->x);
            mul_m4_v3(cur_mat, &pt->x);
          }
        }
      }
    }
  }
}
/** \} */
