gecko-dev/gfx/thebes/gfxUtils.h

/* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef GFX_UTILS_H
#define GFX_UTILS_H

#include "gfxTypes.h"
#include "imgIContainer.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtr.h"
#include "nsColor.h"
#include "nsPrintfCString.h"
#include "nsRegionFwd.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/CheckedInt.h"

class gfxASurface;
class gfxDrawable;
class nsIInputStream;
class nsIGfxInfo;
class nsIPresShell;

namespace mozilla {
namespace layers {
struct PlanarYCbCrData;
} // namespace layers
namespace image {
class ImageRegion;
} // namespace image
} // namespace mozilla

class gfxUtils {
public:
    typedef mozilla::gfx::DataSourceSurface DataSourceSurface;
    typedef mozilla::gfx::DrawTarget DrawTarget;
    typedef mozilla::gfx::IntPoint IntPoint;
    typedef mozilla::gfx::Matrix Matrix;
    typedef mozilla::gfx::SourceSurface SourceSurface;
    typedef mozilla::gfx::SurfaceFormat SurfaceFormat;
    typedef mozilla::image::ImageRegion ImageRegion;

    /*
     * 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 SurfaceFormat::A8R8G8B8_UINT32, no operation is performed.  If
     * aDestSurface is given, the data is copied over.
     */
    static bool PremultiplyDataSurface(DataSourceSurface* srcSurf,
                                       DataSourceSurface* destSurf);
    static bool UnpremultiplyDataSurface(DataSourceSurface* srcSurf,
                                         DataSourceSurface* destSurf);

    static already_AddRefed<DataSourceSurface>
      CreatePremultipliedDataSurface(DataSourceSurface* srcSurf);
    static already_AddRefed<DataSourceSurface>
      CreateUnpremultipliedDataSurface(DataSourceSurface* srcSurf);

    static void ConvertBGRAtoRGBA(uint8_t* aData, uint32_t aLength);

    /**
     * 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 gfxSize&     aImageSize,
                                 const ImageRegion& aRegion,
                                 const mozilla::gfx::SurfaceFormat aFormat,
                                 mozilla::gfx::SamplingFilter aSamplingFilter,
                                 uint32_t           aImageFlags = imgIContainer::FLAG_NONE,
                                 gfxFloat           aOpacity = 1.0);

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

    /**
     * Clip aTarget to the region aRegion.
     */
    static void ClipToRegion(mozilla::gfx::DrawTarget* aTarget, const nsIntRegion& aRegion);

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

    /**
     * Return the transform matrix that maps aFrom to the rectangle defined by
     * aToTopLeft/aToTopRight/aToBottomRight. aFrom must be
     * nonempty and the destination rectangle must be axis-aligned.
     */
    static gfxMatrix TransformRectToRect(const gfxRect& aFrom,
                                         const gfxPoint& aToTopLeft,
                                         const gfxPoint& aToTopRight,
                                         const gfxPoint& aToBottomRight);

    static Matrix TransformRectToRect(const gfxRect& aFrom,
                                      const IntPoint& aToTopLeft,
                                      const IntPoint& aToTopRight,
                                      const IntPoint& aToBottomRight);

    /**
     * If aIn can be represented exactly using an gfx::IntRect (i.e.
     * integer-aligned edges and coordinates in the int32_t range) then we
     * set aOut to that rectangle, otherwise return failure.
    */
    static bool GfxRectToIntRect(const gfxRect& aIn, mozilla::gfx::IntRect* aOut);

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

    /**
     * Clears surface to aColor (which defaults to transparent black).
     */
    static void ClearThebesSurface(gfxASurface* aSurface);

    /**
     * Creates a copy of aSurface, but having the SurfaceFormat aFormat.
     *
     * This function always creates a new surface. Do not call it if aSurface's
     * format is the same as aFormat. Such a non-conversion would just be an
     * unnecessary and wasteful copy (this function asserts to prevent that).
     *
     * This function is intended to be called by code that needs to access the
     * pixel data of the surface, but doesn't want to have lots of branches
     * to handle different pixel data formats (code which would become out of
     * date if and when new formats are added). Callers can use this function
     * to copy the surface to a specified format so that they only have to
     * handle pixel data in that one format.
     *
     * WARNING: There are format conversions that will not be supported by this
     * function. It very much depends on what the Moz2D backends support. If
     * the temporary B8G8R8A8 DrawTarget that this function creates has a
     * backend that supports DrawSurface() calls passing a surface with
     * aSurface's format it will work. Otherwise it will not.
     *
     *                      *** IMPORTANT PERF NOTE ***
     *
     * This function exists partly because format conversion is fraught with
     * non-obvious performance hazards, so we don't want Moz2D consumers to be
     * doing their own format conversion. Do not try to do so, or at least read
     * the comments in this functions implemtation. That said, the copy that
     * this function carries out has a cost and, although this function tries
     * to avoid perf hazards such as expensive uploads to/readbacks from the
     * GPU, it can't guarantee that it always successfully does so. Perf
     * critical code that can directly handle the common formats that it
     * encounters in a way that is cheaper than a copy-with-format-conversion
     * should consider doing so, and only use this function as a fallback to
     * handle other formats.
     *
     * XXXjwatt it would be nice if SourceSurface::GetDataSurface took a
     * SurfaceFormat argument (with a default argument meaning "use the
     * existing surface's format") and returned a DataSourceSurface in that
     * format. (There would then be an issue of callers maybe failing to
     * realize format conversion may involve expensive copying/uploading/
     * readback.)
     */
    static already_AddRefed<DataSourceSurface>
    CopySurfaceToDataSourceSurfaceWithFormat(SourceSurface* aSurface,
                                             SurfaceFormat aFormat);

    static const uint8_t sUnpremultiplyTable[256*256];
    static const uint8_t sPremultiplyTable[256*256];

    /**
     * Return a color that can be used to identify a frame with a given frame number.
     * The colors will cycle after sNumFrameColors.  You can query colors 0 .. sNumFrameColors-1
     * to get all the colors back.
     */
    static const mozilla::gfx::Color& GetColorForFrameNumber(uint64_t aFrameNumber);
    static const uint32_t sNumFrameColors;


    enum BinaryOrData {
        eBinaryEncode,
        eDataURIEncode
    };

    /**
     * Encodes the given surface to PNG/JPEG/BMP/etc. using imgIEncoder.
     *
     * @param aMimeType The MIME-type of the image type that the surface is to
     *   be encoded to. Used to create an appropriate imgIEncoder instance to
     *   do the encoding.
     *
     * @param aOutputOptions Passed directly to imgIEncoder::InitFromData as
     *   the value of the |outputOptions| parameter. Callers are responsible
     *   for making sure that this is a sane value for the passed MIME-type
     *   (i.e. for the type of encoder that will be created).
     *
     * @aBinaryOrData Flag used to determine if the surface is simply encoded
     *   to the requested binary image format, or if the binary image is
     *   further converted to base-64 and written out as a 'data:' URI.
     *
     * @aFile If specified, the encoded data is written out to aFile, otherwise
     *   it is copied to the clipboard.
     *
     * TODO: Copying to the clipboard as a binary file is not currently
     * supported.
     */
    static nsresult
    EncodeSourceSurface(SourceSurface* aSurface,
                        const nsACString& aMimeType,
                        const nsAString& aOutputOptions,
                        BinaryOrData aBinaryOrData,
                        FILE* aFile);

    /**
     * Write as a PNG file to the path aFile.
     */
    static void WriteAsPNG(SourceSurface* aSurface, const nsAString& aFile);
    static void WriteAsPNG(SourceSurface* aSurface, const char* aFile);
    static void WriteAsPNG(DrawTarget* aDT, const nsAString& aFile);
    static void WriteAsPNG(DrawTarget* aDT, const char* aFile);
    static void WriteAsPNG(nsIPresShell* aShell, const char* aFile);

    /**
     * Dump as a PNG encoded Data URL to a FILE stream (using stdout by
     * default).
     *
     * Rather than giving aFile a default argument we have separate functions
     * to make them easier to use from a debugger.
     */
    static void DumpAsDataURI(SourceSurface* aSourceSurface, FILE* aFile);
    static inline void DumpAsDataURI(SourceSurface* aSourceSurface) {
        DumpAsDataURI(aSourceSurface, stdout);
    }
    static void DumpAsDataURI(DrawTarget* aDT, FILE* aFile);
    static inline void DumpAsDataURI(DrawTarget* aDT) {
        DumpAsDataURI(aDT, stdout);
    }
    static nsCString GetAsDataURI(SourceSurface* aSourceSurface);
    static nsCString GetAsDataURI(DrawTarget* aDT);
    static nsCString GetAsLZ4Base64Str(DataSourceSurface* aSourceSurface);

    static mozilla::UniquePtr<uint8_t[]> GetImageBuffer(DataSourceSurface* aSurface,
                                                        bool aIsAlphaPremultiplied,
                                                        int32_t* outFormat);

    static nsresult GetInputStream(DataSourceSurface* aSurface,
                                   bool aIsAlphaPremultiplied,
                                   const char* aMimeType,
                                   const char16_t* aEncoderOptions,
                                   nsIInputStream** outStream);

    static nsresult ThreadSafeGetFeatureStatus(const nsCOMPtr<nsIGfxInfo>& gfxInfo,
                                               int32_t feature,
                                               nsACString& failureId,
                                               int32_t* status);

    /**
     * Copy to the clipboard as a PNG encoded Data URL.
     */
    static void CopyAsDataURI(SourceSurface* aSourceSurface);
    static void CopyAsDataURI(DrawTarget* aDT);

    static bool DumpDisplayList();

    static FILE* sDumpPaintFile;
};

namespace mozilla {
namespace gfx {

/**
 * If the CMS mode is eCMSMode_All, these functions transform the passed
 * color to a device color using the transform returened by gfxPlatform::
 * GetCMSRGBTransform().  If the CMS mode is some other value, the color is
 * returned unchanged (other than a type change to Moz2D Color, if
 * applicable).
 */
Color ToDeviceColor(Color aColor);
Color ToDeviceColor(nscolor aColor);

/* These techniques are suggested by "Bit Twiddling Hacks"
 */

/**
 * Returns true if |aNumber| is a power of two
 * 0 is incorreclty considered a power of two
 */
static inline bool
IsPowerOfTwo(int aNumber)
{
    return (aNumber & (aNumber - 1)) == 0;
}

/**
 * Returns the first integer greater than or equal to |aNumber| which is a
 * power of two. Undefined for |aNumber| < 0.
 */
static inline int
NextPowerOfTwo(int aNumber)
{
#if defined(__arm__)
    return 1 << (32 - __builtin_clz(aNumber - 1));
#else
    --aNumber;
    aNumber |= aNumber >> 1;
    aNumber |= aNumber >> 2;
    aNumber |= aNumber >> 4;
    aNumber |= aNumber >> 8;
    aNumber |= aNumber >> 16;
    return ++aNumber;
#endif
}

/**
 * Performs a checked multiply of the given width, height, and bytes-per-pixel
 * values.
 */
static inline CheckedInt<uint32_t>
SafeBytesForBitmap(uint32_t aWidth, uint32_t aHeight, unsigned aBytesPerPixel)
{
  MOZ_ASSERT(aBytesPerPixel > 0);
  CheckedInt<uint32_t> width = uint32_t(aWidth);
  CheckedInt<uint32_t> height = uint32_t(aHeight);
  return width * height * aBytesPerPixel;
}

} // namespace gfx
} // namespace mozilla

#endif