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#ifndef INCLUDED_SVX_IACCESSIBLEVIEWFORWARDER_HXX
#define INCLUDED_SVX_IACCESSIBLEVIEWFORWARDER_HXX

#include <sal/types.h>
#include <tools/gen.hxx>


namespace accessibility {



/** <p>This interface provides the means to transform between internal
    coordinates in 100th of mm and screen coordinates without giving direct
    access to the underlying view.  Each view forwarder represents a
    specific real or virtual window.  A call to
    <method>GetVisibleArea</method> returns the visible rectangle that
    corresponds to this window.</p>

    <p>This interface is similar to the SvxViewForwarder but
    differs in two important points: Firstly the <member>GetVisArea</member>
    method returns a rectangle in internal coordinates and secondly the
    transformation methods do not require explicit mapmodes.  These have to
    be provided implicitly by the classes that implement this
    interface.  A third, less important, difference are the additional
    transfomation methods for sizes.  The reasons for their existence are
    convenience and improved performance.</p>

    @attention
        Note, that modifications of the underlying view that lead to
        different transformations between internal and screen coordinates or
        change the validity of the forwarder have to be signaled separately.
*/
class IAccessibleViewForwarder
{
public:
    virtual ~IAccessibleViewForwarder (void){};

    /** This method informs you about the state of the forwarder.  Do not
        use it when the returned value is <false/>.

        @return
            Return <true/> if the view forwarder is valid and <false/> else.
     */
    virtual bool IsValid (void) const = 0;

    /** Returns the area of the underlying document that is visible in the
    * corresponding window.

        @return
            The rectangle of the visible part of the document. The values
            are, contrary to the base class, in internal coordinates of
            100th of mm.
     */
    virtual Rectangle GetVisibleArea() const = 0;

    /** Transform the specified point from internal coordinates in 100th of
        mm to an absolute screen position.

        @param rPoint
            Point in internal coordinates (100th of mm).

        @return
            The same point but in screen coordinates relative to the upper
            left corner of the (current) screen.
     */
    virtual Point LogicToPixel (const Point& rPoint) const = 0;

    /** Transform the specified size from internal coordinates in 100th of
        mm to a screen oriented pixel size.

        @param rSize
            Size in internal coordinates (100th of mm).

        @return
            The same size but in screen coordinates.
     */
    virtual Size LogicToPixel (const Size& rSize) const = 0;

    /** Transform the specified point from absolute screen coordinates to
        internal coordinates (100th of mm).

        @param rPoint
            Point in screen coordinates relative to the upper left corner of
            the (current) screen.

        @return
            The same point but in internal coordinates (100th of mm).
     */
    virtual Point PixelToLogic (const Point& rPoint) const = 0;

    /** Transform the specified size from screen coordinates to internal
        coordinates (100th of mm).

        @param rSize
            Size in screen coordinates.

        @return
            The same size but in internal coordinates (100th of mm).
     */
    virtual Size PixelToLogic (const Size& rSize) const = 0;
};

} // end of namespace accessibility

#endif

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