gecko-dev/gfx/thebes/gfxUtils.h

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 * 1.1 (the "License"); you may not use this file except in compliance with
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 * The Original Code is Mozilla Corporation code.
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 * The Initial Developer of the Original Code is Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2008
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 * Contributor(s):
 *   Robert O'Callahan <robert@ocallahan.org>
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#ifndef GFX_UTILS_H
#define GFX_UTILS_H

#include "gfxTypes.h"
#include "gfxPattern.h"
#include "gfxImageSurface.h"
#include "ImageLayers.h"

class gfxDrawable;
class nsIntRegion;
struct nsIntRect;

class THEBES_API gfxUtils {
public:
    /*
     * Premultiply or Unpremultiply aSourceSurface, writing the result
     * to aDestSurface or back into aSourceSurface if aDestSurface is null.
     *
     * If aDestSurface is given, it must have identical format, dimensions, and
     * stride as the source.
     *
     * If the source is not ImageFormatARGB32, no operation is performed.  If
     * aDestSurface is given, the data is copied over.
     */
    static void PremultiplyImageSurface(gfxImageSurface *aSourceSurface,
                                        gfxImageSurface *aDestSurface = nsnull);
    static void UnpremultiplyImageSurface(gfxImageSurface *aSurface,
                                          gfxImageSurface *aDestSurface = nsnull);

    /**
     * Draw something drawable while working around limitations like bad support
     * for EXTEND_PAD, lack of source-clipping, or cairo / pixman bugs with
     * extreme user-space-to-image-space transforms.
     *
     * The input parameters here usually come from the output of our image
     * snapping algorithm in nsLayoutUtils.cpp.
     * This method is split from nsLayoutUtils::DrawPixelSnapped to allow for
     * adjusting the parameters. For example, certain images with transparent
     * margins only have a drawable subimage. For those images, imgFrame::Draw
     * will tweak the rects and transforms that it gets from the pixel snapping
     * algorithm before passing them on to this method.
     */
    static void DrawPixelSnapped(gfxContext*      aContext,
                                 gfxDrawable*     aDrawable,
                                 const gfxMatrix& aUserSpaceToImageSpace,
                                 const gfxRect&   aSubimage,
                                 const gfxRect&   aSourceRect,
                                 const gfxRect&   aImageRect,
                                 const gfxRect&   aFill,
                                 const gfxImageSurface::gfxImageFormat aFormat,
                                 const gfxPattern::GraphicsFilter& aFilter);

    /**
     * Clip aContext to the region aRegion.
     */
    static void ClipToRegion(gfxContext* aContext, const nsIntRegion& aRegion);

    /**
     * Clip aContext to the region aRegion, snapping the rectangles.
     */
    static void ClipToRegionSnapped(gfxContext* aContext, const nsIntRegion& aRegion);

    /**
     * Create a path consisting of rectangles in |aRegion|.
     */
    static void PathFromRegion(gfxContext* aContext, const nsIntRegion& aRegion);

    /**
     * Create a path consisting of rectangles in |aRegion|, snapping the rectangles.
     */
    static void PathFromRegionSnapped(gfxContext* aContext, const nsIntRegion& aRegion);

    /*
     * Convert image format to depth value
     */
    static int ImageFormatToDepth(gfxASurface::gfxImageFormat aFormat);

    /**
     * If aIn can be represented exactly using an nsIntRect (i.e.
     * integer-aligned edges and coordinates in the PRInt32 range) then we
     * set aOut to that rectangle, otherwise return failure.
    */
    static bool GfxRectToIntRect(const gfxRect& aIn, nsIntRect* aOut);

    /**
     * Return the smallest power of kScaleResolution (2) greater than or equal to
     * aVal.
     */
    static gfxFloat ClampToScaleFactor(gfxFloat aVal);

    /**
     * Helper function for ConvertYCbCrToRGB that finds the
     * RGB buffer size and format for given YCbCrImage.
     * @param aSuggestedFormat will be set to ImageFormatRGB24
     *   if the desired format is not supported.
     * @param aSuggestedSize will be set to the picture size from aData
     *   if either the suggested size was {0,0}
     *   or simultaneous scaling and conversion is not supported.
     */
    static void
    GetYCbCrToRGBDestFormatAndSize(const mozilla::layers::PlanarYCbCrImage::Data& aData,
                                   gfxASurface::gfxImageFormat& aSuggestedFormat,
                                   gfxIntSize& aSuggestedSize);

    /**
     * Convert YCbCrImage into RGB aDestBuffer
     * Format and Size parameters must have
     *   been passed to GetYCbCrToRGBDestFormatAndSize
     */
    static void
    ConvertYCbCrToRGB(const mozilla::layers::PlanarYCbCrImage::Data& aData,
                      const gfxASurface::gfxImageFormat& aDestFormat,
                      const gfxIntSize& aDestSize,
                      unsigned char* aDestBuffer,
                      PRInt32 aStride);
};

#endif