gecko-dev/gfx/thebes/gfxUtils.cpp

/* -*- 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/. */

#include "gfxUtils.h"

#include "cairo.h"
#include "gfxContext.h"
#include "gfxEnv.h"
#include "gfxImageSurface.h"
#include "gfxPlatform.h"
#include "gfxDrawable.h"
#include "imgIEncoder.h"
#include "libyuv.h"
#include "mozilla/Base64.h"
#include "mozilla/dom/ImageEncoder.h"
#include "mozilla/dom/WorkerPrivate.h"
#include "mozilla/dom/WorkerRunnable.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/DataSurfaceHelpers.h"
#include "mozilla/gfx/Logging.h"
#include "mozilla/gfx/PathHelpers.h"
#include "mozilla/Maybe.h"
#include "mozilla/RefPtr.h"
#include "mozilla/UniquePtrExtensions.h"
#include "mozilla/Vector.h"
#include "nsComponentManagerUtils.h"
#include "nsIClipboardHelper.h"
#include "nsIFile.h"
#include "nsIGfxInfo.h"
#include "nsIPresShell.h"
#include "nsPresContext.h"
#include "nsRegion.h"
#include "nsServiceManagerUtils.h"
#include "GeckoProfiler.h"
#include "ImageContainer.h"
#include "ImageRegion.h"
#include "gfx2DGlue.h"
#include "gfxPrefs.h"

#ifdef XP_WIN
#include "gfxWindowsPlatform.h"
#endif

using namespace mozilla;
using namespace mozilla::image;
using namespace mozilla::layers;
using namespace mozilla::gfx;

#include "DeprecatedPremultiplyTables.h"

#undef compress
#include "mozilla/Compression.h"

using namespace mozilla::Compression;
extern "C" {

/**
 * Dump a raw image to the default log.  This function is exported
 * from libxul, so it can be called from any library in addition to
 * (of course) from a debugger.
 *
 * Note: this helper currently assumes that all 2-bytepp images are
 * r5g6b5, and that all 4-bytepp images are r8g8b8a8.
 */
NS_EXPORT
void mozilla_dump_image(void* bytes, int width, int height, int bytepp,
                        int strideBytes)
{
    if (0 == strideBytes) {
        strideBytes = width * bytepp;
    }
    SurfaceFormat format;
    // TODO more flexible; parse string?
    switch (bytepp) {
    case 2:
        format = SurfaceFormat::R5G6B5_UINT16;
        break;
    case 4:
    default:
        format = SurfaceFormat::R8G8B8A8;
        break;
    }

    RefPtr<DataSourceSurface> surf =
        Factory::CreateWrappingDataSourceSurface((uint8_t*)bytes, strideBytes,
                                                 IntSize(width, height),
                                                 format);
    gfxUtils::DumpAsDataURI(surf);
}

}

static uint8_t PremultiplyValue(uint8_t a, uint8_t v) {
    return gfxUtils::sPremultiplyTable[a*256+v];
}

static uint8_t UnpremultiplyValue(uint8_t a, uint8_t v) {
    return gfxUtils::sUnpremultiplyTable[a*256+v];
}

static void
PremultiplyData(const uint8_t* srcData,
                size_t srcStride,  // row-to-row stride in bytes
                uint8_t* destData,
                size_t destStride, // row-to-row stride in bytes
                size_t pixelWidth,
                size_t rowCount)
{
    MOZ_ASSERT(srcData && destData);

    for (size_t y = 0; y < rowCount; ++y) {
        const uint8_t* src  = srcData  + y * srcStride;
        uint8_t* dest       = destData + y * destStride;

        for (size_t x = 0; x < pixelWidth; ++x) {
#ifdef IS_LITTLE_ENDIAN
            uint8_t b = *src++;
            uint8_t g = *src++;
            uint8_t r = *src++;
            uint8_t a = *src++;

            *dest++ = PremultiplyValue(a, b);
            *dest++ = PremultiplyValue(a, g);
            *dest++ = PremultiplyValue(a, r);
            *dest++ = a;
#else
            uint8_t a = *src++;
            uint8_t r = *src++;
            uint8_t g = *src++;
            uint8_t b = *src++;

            *dest++ = a;
            *dest++ = PremultiplyValue(a, r);
            *dest++ = PremultiplyValue(a, g);
            *dest++ = PremultiplyValue(a, b);
#endif
        }
    }
}
static void
UnpremultiplyData(const uint8_t* srcData,
                  size_t srcStride,  // row-to-row stride in bytes
                  uint8_t* destData,
                  size_t destStride, // row-to-row stride in bytes
                  size_t pixelWidth,
                  size_t rowCount)
{
    MOZ_ASSERT(srcData && destData);

    for (size_t y = 0; y < rowCount; ++y) {
        const uint8_t* src  = srcData  + y * srcStride;
        uint8_t* dest       = destData + y * destStride;

        for (size_t x = 0; x < pixelWidth; ++x) {
#ifdef IS_LITTLE_ENDIAN
            uint8_t b = *src++;
            uint8_t g = *src++;
            uint8_t r = *src++;
            uint8_t a = *src++;

            *dest++ = UnpremultiplyValue(a, b);
            *dest++ = UnpremultiplyValue(a, g);
            *dest++ = UnpremultiplyValue(a, r);
            *dest++ = a;
#else
            uint8_t a = *src++;
            uint8_t r = *src++;
            uint8_t g = *src++;
            uint8_t b = *src++;

            *dest++ = a;
            *dest++ = UnpremultiplyValue(a, r);
            *dest++ = UnpremultiplyValue(a, g);
            *dest++ = UnpremultiplyValue(a, b);
#endif
        }
    }
}

static bool
MapSrcDest(DataSourceSurface* srcSurf,
           DataSourceSurface* destSurf,
           DataSourceSurface::MappedSurface* out_srcMap,
           DataSourceSurface::MappedSurface* out_destMap)
{
    MOZ_ASSERT(srcSurf && destSurf);
    MOZ_ASSERT(out_srcMap && out_destMap);

    if (srcSurf->GetFormat()  != SurfaceFormat::B8G8R8A8 ||
        destSurf->GetFormat() != SurfaceFormat::B8G8R8A8)
    {
        MOZ_ASSERT(false, "Only operate on BGRA8 surfs.");
        return false;
    }

    if (srcSurf->GetSize().width  != destSurf->GetSize().width ||
        srcSurf->GetSize().height != destSurf->GetSize().height)
    {
        MOZ_ASSERT(false, "Width and height must match.");
        return false;
    }

    if (srcSurf == destSurf) {
        DataSourceSurface::MappedSurface map;
        if (!srcSurf->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
            NS_WARNING("Couldn't Map srcSurf/destSurf.");
            return false;
        }

        *out_srcMap = map;
        *out_destMap = map;
        return true;
    }

    // Map src for reading.
    DataSourceSurface::MappedSurface srcMap;
    if (!srcSurf->Map(DataSourceSurface::MapType::READ, &srcMap)) {
        NS_WARNING("Couldn't Map srcSurf.");
        return false;
    }

    // Map dest for writing.
    DataSourceSurface::MappedSurface destMap;
    if (!destSurf->Map(DataSourceSurface::MapType::WRITE, &destMap)) {
        NS_WARNING("Couldn't Map aDest.");
        srcSurf->Unmap();
        return false;
    }

    *out_srcMap = srcMap;
    *out_destMap = destMap;
    return true;
}

static void
UnmapSrcDest(DataSourceSurface* srcSurf,
             DataSourceSurface* destSurf)
{
    if (srcSurf == destSurf) {
        srcSurf->Unmap();
    } else {
        srcSurf->Unmap();
        destSurf->Unmap();
    }
}

bool
gfxUtils::PremultiplyDataSurface(DataSourceSurface* srcSurf,
                                 DataSourceSurface* destSurf)
{
    MOZ_ASSERT(srcSurf && destSurf);

    DataSourceSurface::MappedSurface srcMap;
    DataSourceSurface::MappedSurface destMap;
    if (!MapSrcDest(srcSurf, destSurf, &srcMap, &destMap))
        return false;

    PremultiplyData(srcMap.mData, srcMap.mStride,
                    destMap.mData, destMap.mStride,
                    srcSurf->GetSize().width,
                    srcSurf->GetSize().height);

    UnmapSrcDest(srcSurf, destSurf);
    return true;
}

bool
gfxUtils::UnpremultiplyDataSurface(DataSourceSurface* srcSurf,
                                   DataSourceSurface* destSurf)
{
    MOZ_ASSERT(srcSurf && destSurf);

    DataSourceSurface::MappedSurface srcMap;
    DataSourceSurface::MappedSurface destMap;
    if (!MapSrcDest(srcSurf, destSurf, &srcMap, &destMap))
        return false;

    UnpremultiplyData(srcMap.mData, srcMap.mStride,
                      destMap.mData, destMap.mStride,
                      srcSurf->GetSize().width,
                      srcSurf->GetSize().height);

    UnmapSrcDest(srcSurf, destSurf);
    return true;
}

static bool
MapSrcAndCreateMappedDest(DataSourceSurface* srcSurf,
                          RefPtr<DataSourceSurface>* out_destSurf,
                          DataSourceSurface::MappedSurface* out_srcMap,
                          DataSourceSurface::MappedSurface* out_destMap)
{
    MOZ_ASSERT(srcSurf);
    MOZ_ASSERT(out_destSurf && out_srcMap && out_destMap);

    if (srcSurf->GetFormat() != SurfaceFormat::B8G8R8A8) {
        MOZ_ASSERT(false, "Only operate on BGRA8.");
        return false;
    }

    // Ok, map source for reading.
    DataSourceSurface::MappedSurface srcMap;
    if (!srcSurf->Map(DataSourceSurface::MapType::READ, &srcMap)) {
        MOZ_ASSERT(false, "Couldn't Map srcSurf.");
        return false;
    }

    // Make our dest surface based on the src.
    RefPtr<DataSourceSurface> destSurf =
        Factory::CreateDataSourceSurfaceWithStride(srcSurf->GetSize(),
                                                   srcSurf->GetFormat(),
                                                   srcMap.mStride);
    if (NS_WARN_IF(!destSurf)) {
        return false;
    }

    DataSourceSurface::MappedSurface destMap;
    if (!destSurf->Map(DataSourceSurface::MapType::WRITE, &destMap)) {
        MOZ_ASSERT(false, "Couldn't Map destSurf.");
        srcSurf->Unmap();
        return false;
    }

    *out_destSurf = destSurf;
    *out_srcMap = srcMap;
    *out_destMap = destMap;
    return true;
}

already_AddRefed<DataSourceSurface>
gfxUtils::CreatePremultipliedDataSurface(DataSourceSurface* srcSurf)
{
    RefPtr<DataSourceSurface> destSurf;
    DataSourceSurface::MappedSurface srcMap;
    DataSourceSurface::MappedSurface destMap;
    if (!MapSrcAndCreateMappedDest(srcSurf, &destSurf, &srcMap, &destMap)) {
        MOZ_ASSERT(false, "MapSrcAndCreateMappedDest failed.");
        RefPtr<DataSourceSurface> surface(srcSurf);
        return surface.forget();
    }

    PremultiplyData(srcMap.mData, srcMap.mStride,
                    destMap.mData, destMap.mStride,
                    srcSurf->GetSize().width,
                    srcSurf->GetSize().height);

    UnmapSrcDest(srcSurf, destSurf);
    return destSurf.forget();
}

already_AddRefed<DataSourceSurface>
gfxUtils::CreateUnpremultipliedDataSurface(DataSourceSurface* srcSurf)
{
    RefPtr<DataSourceSurface> destSurf;
    DataSourceSurface::MappedSurface srcMap;
    DataSourceSurface::MappedSurface destMap;
    if (!MapSrcAndCreateMappedDest(srcSurf, &destSurf, &srcMap, &destMap)) {
        MOZ_ASSERT(false, "MapSrcAndCreateMappedDest failed.");
        RefPtr<DataSourceSurface> surface(srcSurf);
        return surface.forget();
    }

    UnpremultiplyData(srcMap.mData, srcMap.mStride,
                      destMap.mData, destMap.mStride,
                      srcSurf->GetSize().width,
                      srcSurf->GetSize().height);

    UnmapSrcDest(srcSurf, destSurf);
    return destSurf.forget();
}

void
gfxUtils::ConvertBGRAtoRGBA(uint8_t* aData, uint32_t aLength)
{
    MOZ_ASSERT((aLength % 4) == 0, "Loop below will pass srcEnd!");
    libyuv::ABGRToARGB(aData, aLength, aData, aLength, aLength / 4, 1);
}

#if !defined(MOZ_GFX_OPTIMIZE_MOBILE)
/**
 * This returns the fastest operator to use for solid surfaces which have no
 * alpha channel or their alpha channel is uniformly opaque.
 * This differs per render mode.
 */
static CompositionOp
OptimalFillOp()
{
#ifdef XP_WIN
    if (gfxWindowsPlatform::GetPlatform()->IsDirect2DBackend()) {
        // D2D -really- hates operator source.
        return CompositionOp::OP_OVER;
    }
#endif
    return CompositionOp::OP_SOURCE;
}

// EXTEND_PAD won't help us here; we have to create a temporary surface to hold
// the subimage of pixels we're allowed to sample.
static already_AddRefed<gfxDrawable>
CreateSamplingRestrictedDrawable(gfxDrawable* aDrawable,
                                 gfxContext* aContext,
                                 const ImageRegion& aRegion,
                                 const SurfaceFormat aFormat)
{
    PROFILER_LABEL("gfxUtils", "CreateSamplingRestricedDrawable",
      js::ProfileEntry::Category::GRAPHICS);

    DrawTarget* destDrawTarget = aContext->GetDrawTarget();
    if (destDrawTarget->GetBackendType() == BackendType::DIRECT2D1_1) {
      return nullptr;
    }

    gfxRect clipExtents = aContext->GetClipExtents();

    // Inflate by one pixel because bilinear filtering will sample at most
    // one pixel beyond the computed image pixel coordinate.
    clipExtents.Inflate(1.0);

    gfxRect needed = aRegion.IntersectAndRestrict(clipExtents);
    needed.RoundOut();

    // if 'needed' is empty, nothing will be drawn since aFill
    // must be entirely outside the clip region, so it doesn't
    // matter what we do here, but we should avoid trying to
    // create a zero-size surface.
    if (needed.IsEmpty())
        return nullptr;

    IntSize size(int32_t(needed.Width()), int32_t(needed.Height()));

    RefPtr<DrawTarget> target =
      gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(size, aFormat);
    if (!target || !target->IsValid()) {
      return nullptr;
    }

    RefPtr<gfxContext> tmpCtx = gfxContext::CreateOrNull(target);
    MOZ_ASSERT(tmpCtx); // already checked the target above

    tmpCtx->SetOp(OptimalFillOp());
    aDrawable->Draw(tmpCtx, needed - needed.TopLeft(), ExtendMode::REPEAT,
                    SamplingFilter::LINEAR,
                    1.0, gfxMatrix::Translation(needed.TopLeft()));
    RefPtr<SourceSurface> surface = target->Snapshot();

    RefPtr<gfxDrawable> drawable = new gfxSurfaceDrawable(surface, size, gfxMatrix::Translation(-needed.TopLeft()));
    return drawable.forget();
}
#endif // !MOZ_GFX_OPTIMIZE_MOBILE

/* These heuristics are based on Source/WebCore/platform/graphics/skia/ImageSkia.cpp:computeResamplingMode() */
#ifdef MOZ_GFX_OPTIMIZE_MOBILE
static SamplingFilter ReduceResamplingFilter(SamplingFilter aSamplingFilter,
                                             int aImgWidth, int aImgHeight,
                                             float aSourceWidth, float aSourceHeight)
{
    // Images smaller than this in either direction are considered "small" and
    // are not resampled ever (see below).
    const int kSmallImageSizeThreshold = 8;

    // The amount an image can be stretched in a single direction before we
    // say that it is being stretched so much that it must be a line or
    // background that doesn't need resampling.
    const float kLargeStretch = 3.0f;

    if (aImgWidth <= kSmallImageSizeThreshold
        || aImgHeight <= kSmallImageSizeThreshold) {
        // Never resample small images. These are often used for borders and
        // rules (think 1x1 images used to make lines).
        return SamplingFilter::POINT;
    }

    if (aImgHeight * kLargeStretch <= aSourceHeight || aImgWidth * kLargeStretch <= aSourceWidth) {
        // Large image tiling detected.

        // Don't resample if it is being tiled a lot in only one direction.
        // This is trying to catch cases where somebody has created a border
        // (which might be large) and then is stretching it to fill some part
        // of the page.
        if (fabs(aSourceWidth - aImgWidth)/aImgWidth < 0.5 || fabs(aSourceHeight - aImgHeight)/aImgHeight < 0.5)
            return SamplingFilter::POINT;

        // The image is growing a lot and in more than one direction. Resampling
        // is slow and doesn't give us very much when growing a lot.
        return aSamplingFilter;
    }

    /* Some notes on other heuristics:
       The Skia backend also uses nearest for backgrounds that are stretched by
       a large amount. I'm not sure this is common enough for us to worry about
       now. It also uses nearest for backgrounds/avoids high quality for images
       that are very slightly scaled.  I'm also not sure that very slightly
       scaled backgrounds are common enough us to worry about.

       We don't currently have much support for doing high quality interpolation.
       The only place this currently happens is on Quartz and we don't have as
       much control over it as would be needed. Webkit avoids using high quality
       resampling during load. It also avoids high quality if the transformation
       is not just a scale and translation

       WebKit bug #40045 added code to avoid resampling different parts
       of an image with different methods by using a resampling hint size.
       It currently looks unused in WebKit but it's something to watch out for.
    */

    return aSamplingFilter;
}
#else
static SamplingFilter ReduceResamplingFilter(SamplingFilter aSamplingFilter,
                                             int aImgWidth, int aImgHeight,
                                             int aSourceWidth, int aSourceHeight)
{
    // Just pass the filter through unchanged
    return aSamplingFilter;
}
#endif

#ifdef MOZ_WIDGET_COCOA
// Only prescale a temporary surface if we're going to repeat it often.
// Scaling is expensive on OS X and without prescaling, we'd scale
// every tile of the repeated rect. However, using a temp surface also potentially uses
// more memory if the scaled image is large. So only prescale on a temp
// surface if we know we're going to repeat the image in either the X or Y axis
// multiple times.
static bool
ShouldUseTempSurface(Rect aImageRect, Rect aNeededRect)
{
  int repeatX = aNeededRect.width / aImageRect.width;
  int repeatY = aNeededRect.height / aImageRect.height;
  return (repeatX >= 5) || (repeatY >= 5);
}

static bool
PrescaleAndTileDrawable(gfxDrawable* aDrawable,
                        gfxContext* aContext,
                        const ImageRegion& aRegion,
                        Rect aImageRect,
                        const SamplingFilter aSamplingFilter,
                        const SurfaceFormat aFormat,
                        gfxFloat aOpacity,
                        ExtendMode aExtendMode)
{
  gfxSize scaleFactor = aContext->CurrentMatrix().ScaleFactors(true);
  gfxMatrix scaleMatrix = gfxMatrix::Scaling(scaleFactor.width, scaleFactor.height);
  const float fuzzFactor = 0.01;

  // If we aren't scaling or translating, don't go down this path
  if ((FuzzyEqual(scaleFactor.width, 1.0, fuzzFactor) &&
      FuzzyEqual(scaleFactor.width, 1.0, fuzzFactor)) ||
      aContext->CurrentMatrix().HasNonAxisAlignedTransform()) {
    return false;
  }

  gfxRect clipExtents = aContext->GetClipExtents();

  // Inflate by one pixel because bilinear filtering will sample at most
  // one pixel beyond the computed image pixel coordinate.
  clipExtents.Inflate(1.0);

  gfxRect needed = aRegion.IntersectAndRestrict(clipExtents);
  Rect scaledNeededRect = ToMatrix(scaleMatrix).TransformBounds(ToRect(needed));
  scaledNeededRect.RoundOut();
  if (scaledNeededRect.IsEmpty()) {
    return false;
  }

  Rect scaledImageRect = ToMatrix(scaleMatrix).TransformBounds(aImageRect);
  if (!ShouldUseTempSurface(scaledImageRect, scaledNeededRect)) {
    return false;
  }

  IntSize scaledImageSize((int32_t)scaledImageRect.width,
                          (int32_t)scaledImageRect.height);
  if (scaledImageSize.width != scaledImageRect.width ||
      scaledImageSize.height != scaledImageRect.height) {
    // If the scaled image isn't pixel aligned, we'll get artifacts
    // so we have to take the slow path.
    return false;
  }

  RefPtr<DrawTarget> scaledDT =
    gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(scaledImageSize, aFormat);
  if (!scaledDT || !scaledDT->IsValid()) {
    return false;
  }

  RefPtr<gfxContext> tmpCtx = gfxContext::CreateOrNull(scaledDT);
  MOZ_ASSERT(tmpCtx); // already checked the target above

  scaledDT->SetTransform(ToMatrix(scaleMatrix));
  gfxRect gfxImageRect(aImageRect.x, aImageRect.y, aImageRect.width, aImageRect.height);

  // Since this is just the scaled image, we don't want to repeat anything yet.
  aDrawable->Draw(tmpCtx, gfxImageRect, ExtendMode::CLAMP, aSamplingFilter, 1.0, gfxMatrix());

  RefPtr<SourceSurface> scaledImage = scaledDT->Snapshot();

  {
    gfxContextMatrixAutoSaveRestore autoSR(aContext);
    Matrix withoutScale = ToMatrix(aContext->CurrentMatrix());
    DrawTarget* destDrawTarget = aContext->GetDrawTarget();

    // The translation still is in scaled units
    withoutScale.PreScale(1.0 / scaleFactor.width, 1.0 / scaleFactor.height);
    aContext->SetMatrix(ThebesMatrix(withoutScale));

    DrawOptions drawOptions(aOpacity, aContext->CurrentOp(),
                            aContext->CurrentAntialiasMode());

    SurfacePattern scaledImagePattern(scaledImage, aExtendMode,
                                      Matrix(), aSamplingFilter);
    destDrawTarget->FillRect(scaledNeededRect, scaledImagePattern, drawOptions);
  }
  return true;
}
#endif // MOZ_WIDGET_COCOA

/* static */ void
gfxUtils::DrawPixelSnapped(gfxContext*         aContext,
                           gfxDrawable*        aDrawable,
                           const gfxSize&      aImageSize,
                           const ImageRegion&  aRegion,
                           const SurfaceFormat aFormat,
                           SamplingFilter      aSamplingFilter,
                           uint32_t            aImageFlags,
                           gfxFloat            aOpacity)
{
    PROFILER_LABEL("gfxUtils", "DrawPixelSnapped",
      js::ProfileEntry::Category::GRAPHICS);

    gfxRect imageRect(gfxPoint(0, 0), aImageSize);
    gfxRect region(aRegion.Rect());
    ExtendMode extendMode = aRegion.GetExtendMode();

    RefPtr<gfxDrawable> drawable = aDrawable;

    aSamplingFilter =
      ReduceResamplingFilter(aSamplingFilter,
                             imageRect.Width(), imageRect.Height(),
                             region.Width(), region.Height());

    // OK now, the hard part left is to account for the subimage sampling
    // restriction. If all the transforms involved are just integer
    // translations, then we assume no resampling will occur so there's
    // nothing to do.
    // XXX if only we had source-clipping in cairo!

    if (aContext->CurrentMatrix().HasNonIntegerTranslation()) {
        if ((extendMode != ExtendMode::CLAMP) || !aRegion.RestrictionContains(imageRect)) {
            if (drawable->DrawWithSamplingRect(aContext->GetDrawTarget(),
                                               aContext->CurrentOp(),
                                               aContext->CurrentAntialiasMode(),
                                               aRegion.Rect(),
                                               aRegion.Restriction(),
                                               extendMode, aSamplingFilter,
                                               aOpacity)) {
              return;
            }

#ifdef MOZ_WIDGET_COCOA
            if (PrescaleAndTileDrawable(aDrawable, aContext, aRegion,
                                        ToRect(imageRect), aSamplingFilter,
                                        aFormat, aOpacity, extendMode)) {
              return;
            }
#endif

            // On Mobile, we don't ever want to do this; it has the potential for
            // allocating very large temporary surfaces, especially since we'll
            // do full-page snapshots often (see bug 749426).
#if !defined(MOZ_GFX_OPTIMIZE_MOBILE)
            RefPtr<gfxDrawable> restrictedDrawable =
              CreateSamplingRestrictedDrawable(aDrawable, aContext,
                                               aRegion, aFormat);
            if (restrictedDrawable) {
              drawable.swap(restrictedDrawable);

              // We no longer need to tile: Either we never needed to, or we already
              // filled a surface with the tiled pattern; this surface can now be
              // drawn without tiling.
              extendMode = ExtendMode::CLAMP;
            }
#endif
        }
    }

    drawable->Draw(aContext, aRegion.Rect(), extendMode, aSamplingFilter,
                   aOpacity, gfxMatrix());
}

/* static */ int
gfxUtils::ImageFormatToDepth(gfxImageFormat aFormat)
{
    switch (aFormat) {
        case SurfaceFormat::A8R8G8B8_UINT32:
            return 32;
        case SurfaceFormat::X8R8G8B8_UINT32:
            return 24;
        case SurfaceFormat::R5G6B5_UINT16:
            return 16;
        default:
            break;
    }
    return 0;
}

/*static*/ void
gfxUtils::ClipToRegion(gfxContext* aContext, const nsIntRegion& aRegion)
{
  aContext->NewPath();
  for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
    const IntRect& r = iter.Get();
    aContext->Rectangle(gfxRect(r.x, r.y, r.width, r.height));
  }
  aContext->Clip();
}

/*static*/ void
gfxUtils::ClipToRegion(DrawTarget* aTarget, const nsIntRegion& aRegion)
{
  uint32_t numRects = aRegion.GetNumRects();
  // If there is only one rect, then the region bounds are equivalent to the
  // contents. So just use push a single clip rect with the bounds.
  if (numRects == 1) {
    aTarget->PushClipRect(Rect(aRegion.GetBounds()));
    return;
  }

  // Check if the target's transform will preserve axis-alignment and
  // pixel-alignment for each rect. For now, just handle the common case
  // of integer translations.
  Matrix transform = aTarget->GetTransform();
  if (transform.IsIntegerTranslation()) {
    IntPoint translation = RoundedToInt(transform.GetTranslation());
    AutoTArray<IntRect, 16> rects;
    rects.SetLength(numRects);
    uint32_t i = 0;
    // Build the list of transformed rects by adding in the translation.
    for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
      IntRect rect = iter.Get();
      rect.MoveBy(translation);
      rects[i++] = rect;
    }
    aTarget->PushDeviceSpaceClipRects(rects.Elements(), rects.Length());
  } else {
    // The transform does not produce axis-aligned rects or a rect was not
    // pixel-aligned. So just build a path with all the rects and clip to it
    // instead.
    RefPtr<PathBuilder> pathBuilder = aTarget->CreatePathBuilder();
    for (auto iter = aRegion.RectIter(); !iter.Done(); iter.Next()) {
      AppendRectToPath(pathBuilder, Rect(iter.Get()));
    }
    RefPtr<Path> path = pathBuilder->Finish();
    aTarget->PushClip(path);
  }
}

/*static*/ gfxFloat
gfxUtils::ClampToScaleFactor(gfxFloat aVal)
{
  // Arbitary scale factor limitation. We can increase this
  // for better scaling performance at the cost of worse
  // quality.
  static const gfxFloat kScaleResolution = 2;

  // Negative scaling is just a flip and irrelevant to
  // our resolution calculation.
  if (aVal < 0.0) {
    aVal = -aVal;
  }

  bool inverse = false;
  if (aVal < 1.0) {
    inverse = true;
    aVal = 1 / aVal;
  }

  gfxFloat power = log(aVal)/log(kScaleResolution);

  // If power is within 1e-5 of an integer, round to nearest to
  // prevent floating point errors, otherwise round up to the
  // next integer value.
  if (fabs(power - NS_round(power)) < 1e-5) {
    power = NS_round(power);
  } else if (inverse) {
    power = floor(power);
  } else {
    power = ceil(power);
  }

  gfxFloat scale = pow(kScaleResolution, power);

  if (inverse) {
    scale = 1 / scale;
  }

  return scale;
}

gfxMatrix
gfxUtils::TransformRectToRect(const gfxRect& aFrom, const gfxPoint& aToTopLeft,
                              const gfxPoint& aToTopRight, const gfxPoint& aToBottomRight)
{
  gfxMatrix m;
  if (aToTopRight.y == aToTopLeft.y && aToTopRight.x == aToBottomRight.x) {
    // Not a rotation, so xy and yx are zero
    m._21 = m._12 = 0.0;
    m._11 = (aToBottomRight.x - aToTopLeft.x)/aFrom.width;
    m._22 = (aToBottomRight.y - aToTopLeft.y)/aFrom.height;
    m._31 = aToTopLeft.x - m._11*aFrom.x;
    m._32 = aToTopLeft.y - m._22*aFrom.y;
  } else {
    NS_ASSERTION(aToTopRight.y == aToBottomRight.y && aToTopRight.x == aToTopLeft.x,
                 "Destination rectangle not axis-aligned");
    m._11 = m._22 = 0.0;
    m._21 = (aToBottomRight.x - aToTopLeft.x)/aFrom.height;
    m._12 = (aToBottomRight.y - aToTopLeft.y)/aFrom.width;
    m._31 = aToTopLeft.x - m._21*aFrom.y;
    m._32 = aToTopLeft.y - m._12*aFrom.x;
  }
  return m;
}

Matrix
gfxUtils::TransformRectToRect(const gfxRect& aFrom, const IntPoint& aToTopLeft,
                              const IntPoint& aToTopRight, const IntPoint& aToBottomRight)
{
  Matrix m;
  if (aToTopRight.y == aToTopLeft.y && aToTopRight.x == aToBottomRight.x) {
    // Not a rotation, so xy and yx are zero
    m._12 = m._21 = 0.0;
    m._11 = (aToBottomRight.x - aToTopLeft.x)/aFrom.width;
    m._22 = (aToBottomRight.y - aToTopLeft.y)/aFrom.height;
    m._31 = aToTopLeft.x - m._11*aFrom.x;
    m._32 = aToTopLeft.y - m._22*aFrom.y;
  } else {
    NS_ASSERTION(aToTopRight.y == aToBottomRight.y && aToTopRight.x == aToTopLeft.x,
                 "Destination rectangle not axis-aligned");
    m._11 = m._22 = 0.0;
    m._21 = (aToBottomRight.x - aToTopLeft.x)/aFrom.height;
    m._12 = (aToBottomRight.y - aToTopLeft.y)/aFrom.width;
    m._31 = aToTopLeft.x - m._21*aFrom.y;
    m._32 = aToTopLeft.y - m._12*aFrom.x;
  }
  return m;
}

/* This function is sort of shitty. We truncate doubles
 * to ints then convert those ints back to doubles to make sure that
 * they equal the doubles that we got in. */
bool
gfxUtils::GfxRectToIntRect(const gfxRect& aIn, IntRect* aOut)
{
  *aOut = IntRect(int32_t(aIn.X()), int32_t(aIn.Y()),
  int32_t(aIn.Width()), int32_t(aIn.Height()));
  return gfxRect(aOut->x, aOut->y, aOut->width, aOut->height).IsEqualEdges(aIn);
}

/* static */ void gfxUtils::ClearThebesSurface(gfxASurface* aSurface)
{
  if (aSurface->CairoStatus()) {
    return;
  }
  cairo_surface_t* surf = aSurface->CairoSurface();
  if (cairo_surface_status(surf)) {
    return;
  }
  cairo_t* ctx = cairo_create(surf);
  cairo_set_source_rgba(ctx, 0.0, 0.0, 0.0, 0.0);
  cairo_set_operator(ctx, CAIRO_OPERATOR_SOURCE);
  IntRect bounds(nsIntPoint(0, 0), aSurface->GetSize());
  cairo_rectangle(ctx, bounds.x, bounds.y, bounds.width, bounds.height);
  cairo_fill(ctx);
  cairo_destroy(ctx);
}

/* static */ already_AddRefed<DataSourceSurface>
gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat(SourceSurface* aSurface,
                                                   SurfaceFormat aFormat)
{
  MOZ_ASSERT(aFormat != aSurface->GetFormat(),
             "Unnecessary - and very expersive - surface format conversion");

  Rect bounds(0, 0, aSurface->GetSize().width, aSurface->GetSize().height);

  if (aSurface->GetType() != SurfaceType::DATA) {
    // If the surface is NOT of type DATA then its data is not mapped into main
    // memory. Format conversion is probably faster on the GPU, and by doing it
    // there we can avoid any expensive uploads/readbacks except for (possibly)
    // a single readback due to the unavoidable GetDataSurface() call. Using
    // CreateOffscreenContentDrawTarget ensures the conversion happens on the
    // GPU.
    RefPtr<DrawTarget> dt = gfxPlatform::GetPlatform()->
      CreateOffscreenContentDrawTarget(aSurface->GetSize(), aFormat);
    if (!dt) {
      gfxWarning() << "gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat failed in CreateOffscreenContentDrawTarget";
      return nullptr;
    }

    // Using DrawSurface() here rather than CopySurface() because CopySurface
    // is optimized for memcpy and therefore isn't good for format conversion.
    // Using OP_OVER since in our case it's equivalent to OP_SOURCE and
    // generally more optimized.
    dt->DrawSurface(aSurface, bounds, bounds, DrawSurfaceOptions(),
                    DrawOptions(1.0f, CompositionOp::OP_OVER));
    RefPtr<SourceSurface> surface = dt->Snapshot();
    return surface->GetDataSurface();
  }

  // If the surface IS of type DATA then it may or may not be in main memory
  // depending on whether or not it has been mapped yet. We have no way of
  // knowing, so we can't be sure if it's best to create a data wrapping
  // DrawTarget for the conversion or an offscreen content DrawTarget. We could
  // guess it's not mapped and create an offscreen content DrawTarget, but if
  // it is then we'll end up uploading the surface data, and most likely the
  // caller is going to be accessing the resulting surface data, resulting in a
  // readback (both very expensive operations). Alternatively we could guess
  // the data is mapped and create a data wrapping DrawTarget and, if the
  // surface is not in main memory, then we will incure a readback. The latter
  // of these two "wrong choices" is the least costly (a readback, vs an
  // upload and a readback), and more than likely the DATA surface that we've
  // been passed actually IS in main memory anyway. For these reasons it's most
  // likely best to create a data wrapping DrawTarget here to do the format
  // conversion.
  RefPtr<DataSourceSurface> dataSurface =
    Factory::CreateDataSourceSurface(aSurface->GetSize(), aFormat);
  DataSourceSurface::MappedSurface map;
  if (!dataSurface ||
      !dataSurface->Map(DataSourceSurface::MapType::READ_WRITE, &map)) {
    return nullptr;
  }
  RefPtr<DrawTarget> dt =
    Factory::CreateDrawTargetForData(BackendType::CAIRO,
                                     map.mData,
                                     dataSurface->GetSize(),
                                     map.mStride,
                                     aFormat);
  if (!dt) {
    dataSurface->Unmap();
    return nullptr;
  }
  // Using DrawSurface() here rather than CopySurface() because CopySurface
  // is optimized for memcpy and therefore isn't good for format conversion.
  // Using OP_OVER since in our case it's equivalent to OP_SOURCE and
  // generally more optimized.
  dt->DrawSurface(aSurface, bounds, bounds, DrawSurfaceOptions(),
                  DrawOptions(1.0f, CompositionOp::OP_OVER));
  dataSurface->Unmap();
  return dataSurface.forget();
}

const uint32_t gfxUtils::sNumFrameColors = 8;

/* static */ const gfx::Color&
gfxUtils::GetColorForFrameNumber(uint64_t aFrameNumber)
{
    static bool initialized = false;
    static gfx::Color colors[sNumFrameColors];

    if (!initialized) {
        uint32_t i = 0;
        colors[i++] = gfx::Color::FromABGR(0xffff0000);
        colors[i++] = gfx::Color::FromABGR(0xffcc00ff);
        colors[i++] = gfx::Color::FromABGR(0xff0066cc);
        colors[i++] = gfx::Color::FromABGR(0xff00ff00);
        colors[i++] = gfx::Color::FromABGR(0xff33ffff);
        colors[i++] = gfx::Color::FromABGR(0xffff0099);
        colors[i++] = gfx::Color::FromABGR(0xff0000ff);
        colors[i++] = gfx::Color::FromABGR(0xff999999);
        MOZ_ASSERT(i == sNumFrameColors);
        initialized = true;
    }

    return colors[aFrameNumber % sNumFrameColors];
}

static nsresult
EncodeSourceSurfaceInternal(SourceSurface* aSurface,
                           const nsACString& aMimeType,
                           const nsAString& aOutputOptions,
                           gfxUtils::BinaryOrData aBinaryOrData,
                           FILE* aFile,
                           nsCString* aStrOut)
{
  MOZ_ASSERT(aBinaryOrData == gfxUtils::eDataURIEncode || aFile || aStrOut,
             "Copying binary encoding to clipboard not currently supported");

  const IntSize size = aSurface->GetSize();
  if (size.IsEmpty()) {
    return NS_ERROR_INVALID_ARG;
  }
  const Size floatSize(size.width, size.height);

  RefPtr<DataSourceSurface> dataSurface;
  if (aSurface->GetFormat() != SurfaceFormat::B8G8R8A8) {
    // FIXME bug 995807 (B8G8R8X8), bug 831898 (R5G6B5)
    dataSurface =
      gfxUtils::CopySurfaceToDataSourceSurfaceWithFormat(aSurface,
                                                         SurfaceFormat::B8G8R8A8);
  } else {
    dataSurface = aSurface->GetDataSurface();
  }
  if (!dataSurface) {
    return NS_ERROR_FAILURE;
  }

  DataSourceSurface::MappedSurface map;
  if (!dataSurface->Map(DataSourceSurface::MapType::READ, &map)) {
    return NS_ERROR_FAILURE;
  }

  nsAutoCString encoderCID(
    NS_LITERAL_CSTRING("@mozilla.org/image/encoder;2?type=") + aMimeType);
  nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(encoderCID.get());
  if (!encoder) {
#ifdef DEBUG
    int32_t w = std::min(size.width, 8);
    int32_t h = std::min(size.height, 8);
    printf("Could not create encoder. Top-left %dx%d pixels contain:\n", w, h);
    for (int32_t y = 0; y < h; ++y) {
      for (int32_t x = 0; x < w; ++x) {
        printf("%x ", reinterpret_cast<uint32_t*>(map.mData)[y*map.mStride+x]);
      }
    }
#endif
    dataSurface->Unmap();
    return NS_ERROR_FAILURE;
  }

  nsresult rv = encoder->InitFromData(map.mData,
                                      BufferSizeFromStrideAndHeight(map.mStride, size.height),
                                      size.width,
                                      size.height,
                                      map.mStride,
                                      imgIEncoder::INPUT_FORMAT_HOSTARGB,
                                      aOutputOptions);
  dataSurface->Unmap();
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsIInputStream> imgStream;
  CallQueryInterface(encoder.get(), getter_AddRefs(imgStream));
  if (!imgStream) {
    return NS_ERROR_FAILURE;
  }

  uint64_t bufSize64;
  rv = imgStream->Available(&bufSize64);
  NS_ENSURE_SUCCESS(rv, rv);

  NS_ENSURE_TRUE(bufSize64 < UINT32_MAX - 16, NS_ERROR_FAILURE);

  uint32_t bufSize = (uint32_t)bufSize64;

  // ...leave a little extra room so we can call read again and make sure we
  // got everything. 16 bytes for better padding (maybe)
  bufSize += 16;
  uint32_t imgSize = 0;
  Vector<char> imgData;
  if (!imgData.initCapacity(bufSize)) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  uint32_t numReadThisTime = 0;
  while ((rv = imgStream->Read(imgData.begin() + imgSize,
                               bufSize - imgSize,
                               &numReadThisTime)) == NS_OK && numReadThisTime > 0)
  {
    // Update the length of the vector without overwriting the new data.
    if (!imgData.growByUninitialized(numReadThisTime)) {
      return NS_ERROR_OUT_OF_MEMORY;
    }

    imgSize += numReadThisTime;
    if (imgSize == bufSize) {
      // need a bigger buffer, just double
      bufSize *= 2;
      if (!imgData.resizeUninitialized(bufSize)) {
        return NS_ERROR_OUT_OF_MEMORY;
      }
    }
  }
  NS_ENSURE_SUCCESS(rv, rv);
  NS_ENSURE_TRUE(!imgData.empty(), NS_ERROR_FAILURE);

  if (aBinaryOrData == gfxUtils::eBinaryEncode) {
    if (aFile) {
      fwrite(imgData.begin(), 1, imgSize, aFile);
    }
    return NS_OK;
  }

  // base 64, result will be null-terminated
  nsCString encodedImg;
  rv = Base64Encode(Substring(imgData.begin(), imgSize), encodedImg);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCString string("data:");
  string.Append(aMimeType);
  string.Append(";base64,");
  string.Append(encodedImg);

  if (aFile) {
#ifdef ANDROID
    if (aFile == stdout || aFile == stderr) {
      // ADB logcat cuts off long strings so we will break it down
      const char* cStr = string.BeginReading();
      size_t len = strlen(cStr);
      while (true) {
        printf_stderr("IMG: %.140s\n", cStr);
        if (len <= 140)
          break;
        len -= 140;
        cStr += 140;
      }
    }
#endif
    fprintf(aFile, "%s", string.BeginReading());
  } else if (aStrOut) {
    *aStrOut = string;
  } else {
    nsCOMPtr<nsIClipboardHelper> clipboard(do_GetService("@mozilla.org/widget/clipboardhelper;1", &rv));
    if (clipboard) {
      clipboard->CopyString(NS_ConvertASCIItoUTF16(string));
    }
  }
  return NS_OK;
}

static nsCString
EncodeSourceSurfaceAsPNGURI(SourceSurface* aSurface)
{
  nsCString string;
  EncodeSourceSurfaceInternal(aSurface, NS_LITERAL_CSTRING("image/png"),
                              EmptyString(), gfxUtils::eDataURIEncode,
                              nullptr, &string);
  return string;
}

/* static */ nsresult
gfxUtils::EncodeSourceSurface(SourceSurface* aSurface,
                              const nsACString& aMimeType,
                              const nsAString& aOutputOptions,
                              BinaryOrData aBinaryOrData,
                              FILE* aFile)
{
  return EncodeSourceSurfaceInternal(aSurface, aMimeType, aOutputOptions,
                                     aBinaryOrData, aFile, nullptr);
}

/* From Rec601:
[R]   [1.1643835616438356,  0.0,                 1.5960267857142858]      [ Y -  16]
[G] = [1.1643835616438358, -0.3917622900949137, -0.8129676472377708]    x [Cb - 128]
[B]   [1.1643835616438356,  2.017232142857143,   8.862867620416422e-17]   [Cr - 128]

For [0,1] instead of [0,255], and to 5 places:
[R]   [1.16438,  0.00000,  1.59603]   [ Y - 0.06275]
[G] = [1.16438, -0.39176, -0.81297] x [Cb - 0.50196]
[B]   [1.16438,  2.01723,  0.00000]   [Cr - 0.50196]

From Rec709:
[R]   [1.1643835616438356,  4.2781193979771426e-17, 1.7927410714285714]     [ Y -  16]
[G] = [1.1643835616438358, -0.21324861427372963,   -0.532909328559444]    x [Cb - 128]
[B]   [1.1643835616438356,  2.1124017857142854,     0.0]                    [Cr - 128]

For [0,1] instead of [0,255], and to 5 places:
[R]   [1.16438,  0.00000,  1.79274]   [ Y - 0.06275]
[G] = [1.16438, -0.21325, -0.53291] x [Cb - 0.50196]
[B]   [1.16438,  2.11240,  0.00000]   [Cr - 0.50196]
*/

/* static */ float*
gfxUtils::Get4x3YuvColorMatrix(YUVColorSpace aYUVColorSpace)
{
  static const float yuv_to_rgb_rec601[12] = { 1.16438f,  0.0f,      1.59603f, 0.0f,
                                               1.16438f, -0.39176f, -0.81297f, 0.0f,
                                               1.16438f,  2.01723f,  0.0f,     0.0f,
                                             };

  static const float yuv_to_rgb_rec709[12] = { 1.16438f,  0.0f,      1.79274f, 0.0f,
                                               1.16438f, -0.21325f, -0.53291f, 0.0f,
                                               1.16438f,  2.11240f,  0.0f,     0.0f,
                                             };

  if (aYUVColorSpace == YUVColorSpace::BT709) {
    return const_cast<float*>(yuv_to_rgb_rec709);
  } else {
    return const_cast<float*>(yuv_to_rgb_rec601);
  }
}

/* static */ float*
gfxUtils::Get3x3YuvColorMatrix(YUVColorSpace aYUVColorSpace)
{
  static const float yuv_to_rgb_rec601[9] = {
    1.16438f, 1.16438f, 1.16438f, 0.0f, -0.39176f, 2.01723f, 1.59603f, -0.81297f, 0.0f,
  };
  static const float yuv_to_rgb_rec709[9] = {
    1.16438f, 1.16438f, 1.16438f, 0.0f, -0.21325f, 2.11240f, 1.79274f, -0.53291f, 0.0f,
  };

  if (aYUVColorSpace == YUVColorSpace::BT709) {
    return const_cast<float*>(yuv_to_rgb_rec709);
  } else {
    return const_cast<float*>(yuv_to_rgb_rec601);
  }
}

/* static */ void
gfxUtils::WriteAsPNG(SourceSurface* aSurface, const nsAString& aFile)
{
  WriteAsPNG(aSurface, NS_ConvertUTF16toUTF8(aFile).get());
}

/* static */ void
gfxUtils::WriteAsPNG(SourceSurface* aSurface, const char* aFile)
{
  FILE* file = fopen(aFile, "wb");

  if (!file) {
    // Maybe the directory doesn't exist; try creating it, then fopen again.
    nsresult rv = NS_ERROR_FAILURE;
    nsCOMPtr<nsIFile> comFile = do_CreateInstance("@mozilla.org/file/local;1");
    if (comFile) {
      NS_ConvertUTF8toUTF16 utf16path((nsDependentCString(aFile)));
      rv = comFile->InitWithPath(utf16path);
      if (NS_SUCCEEDED(rv)) {
        nsCOMPtr<nsIFile> dirPath;
        comFile->GetParent(getter_AddRefs(dirPath));
        if (dirPath) {
          rv = dirPath->Create(nsIFile::DIRECTORY_TYPE, 0777);
          if (NS_SUCCEEDED(rv) || rv == NS_ERROR_FILE_ALREADY_EXISTS) {
            file = fopen(aFile, "wb");
          }
        }
      }
    }
    if (!file) {
      NS_WARNING("Failed to open file to create PNG!");
      return;
    }
  }

  EncodeSourceSurface(aSurface, NS_LITERAL_CSTRING("image/png"),
                      EmptyString(), eBinaryEncode, file);
  fclose(file);
}

/* static */ void
gfxUtils::WriteAsPNG(DrawTarget* aDT, const nsAString& aFile)
{
  WriteAsPNG(aDT, NS_ConvertUTF16toUTF8(aFile).get());
}

/* static */ void
gfxUtils::WriteAsPNG(DrawTarget* aDT, const char* aFile)
{
  RefPtr<SourceSurface> surface = aDT->Snapshot();
  if (surface) {
    WriteAsPNG(surface, aFile);
  } else {
    NS_WARNING("Failed to get surface!");
  }
}

/* static */ void
gfxUtils::WriteAsPNG(nsIPresShell* aShell, const char* aFile)
{
  int32_t width = 1000, height = 1000;
  nsRect r(0, 0, aShell->GetPresContext()->DevPixelsToAppUnits(width),
           aShell->GetPresContext()->DevPixelsToAppUnits(height));

  RefPtr<mozilla::gfx::DrawTarget> dt = gfxPlatform::GetPlatform()->
    CreateOffscreenContentDrawTarget(IntSize(width, height),
                                     SurfaceFormat::B8G8R8A8);
  NS_ENSURE_TRUE(dt && dt->IsValid(), /*void*/);

  RefPtr<gfxContext> context = gfxContext::CreateOrNull(dt);
  MOZ_ASSERT(context); // already checked the draw target above
  aShell->RenderDocument(r, 0, NS_RGB(255, 255, 0), context);
  WriteAsPNG(dt.get(), aFile);
}

/* static */ void
gfxUtils::DumpAsDataURI(SourceSurface* aSurface, FILE* aFile)
{
  EncodeSourceSurface(aSurface, NS_LITERAL_CSTRING("image/png"),
                      EmptyString(), eDataURIEncode, aFile);
}

/* static */ nsCString
gfxUtils::GetAsDataURI(SourceSurface* aSurface)
{
  return EncodeSourceSurfaceAsPNGURI(aSurface);
}

/* static */ void
gfxUtils::DumpAsDataURI(DrawTarget* aDT, FILE* aFile)
{
  RefPtr<SourceSurface> surface = aDT->Snapshot();
  if (surface) {
    DumpAsDataURI(surface, aFile);
  } else {
    NS_WARNING("Failed to get surface!");
  }
}

/* static */ nsCString
gfxUtils::GetAsLZ4Base64Str(DataSourceSurface* aSourceSurface)
{
  int32_t dataSize = aSourceSurface->GetSize().height * aSourceSurface->Stride();
  auto compressedData = MakeUnique<char[]>(LZ4::maxCompressedSize(dataSize));
  if (compressedData) {
    int nDataSize = LZ4::compress((char*)aSourceSurface->GetData(),
                                  dataSize,
                                  compressedData.get());
    if (nDataSize > 0) {
      nsCString encodedImg;
      nsresult rv = Base64Encode(Substring(compressedData.get(), nDataSize), encodedImg);
      if (rv == NS_OK) {
        nsCString string("");
        string.AppendPrintf("data:image/lz4bgra;base64,%i,%i,%i,",
                             aSourceSurface->GetSize().width,
                             aSourceSurface->Stride(),
                             aSourceSurface->GetSize().height);
        string.Append(encodedImg);
        return string;
      }
    }
  }
  return nsCString("");
}

/* static */ nsCString
gfxUtils::GetAsDataURI(DrawTarget* aDT)
{
  RefPtr<SourceSurface> surface = aDT->Snapshot();
  if (surface) {
    return EncodeSourceSurfaceAsPNGURI(surface);
  } else {
    NS_WARNING("Failed to get surface!");
    return nsCString("");
  }
}

/* static */ void
gfxUtils::CopyAsDataURI(SourceSurface* aSurface)
{
  EncodeSourceSurface(aSurface, NS_LITERAL_CSTRING("image/png"),
                      EmptyString(), eDataURIEncode, nullptr);
}

/* static */ void
gfxUtils::CopyAsDataURI(DrawTarget* aDT)
{
  RefPtr<SourceSurface> surface = aDT->Snapshot();
  if (surface) {
    CopyAsDataURI(surface);
  } else {
    NS_WARNING("Failed to get surface!");
  }
}

/* static */ UniquePtr<uint8_t[]>
gfxUtils::GetImageBuffer(gfx::DataSourceSurface* aSurface,
                         bool aIsAlphaPremultiplied,
                         int32_t* outFormat)
{
    *outFormat = 0;

    DataSourceSurface::MappedSurface map;
    if (!aSurface->Map(DataSourceSurface::MapType::READ, &map))
        return nullptr;

    uint32_t bufferSize = aSurface->GetSize().width * aSurface->GetSize().height * 4;
    auto imageBuffer = MakeUniqueFallible<uint8_t[]>(bufferSize);
    if (!imageBuffer) {
        aSurface->Unmap();
        return nullptr;
    }
    memcpy(imageBuffer.get(), map.mData, bufferSize);

    aSurface->Unmap();

    int32_t format = imgIEncoder::INPUT_FORMAT_HOSTARGB;
    if (!aIsAlphaPremultiplied) {
        // We need to convert to INPUT_FORMAT_RGBA, otherwise
        // we are automatically considered premult, and unpremult'd.
        // Yes, it is THAT silly.
        // Except for different lossy conversions by color,
        // we could probably just change the label, and not change the data.
        gfxUtils::ConvertBGRAtoRGBA(imageBuffer.get(), bufferSize);
        format = imgIEncoder::INPUT_FORMAT_RGBA;
    }

    *outFormat = format;
    return imageBuffer;
}

/* static */ nsresult
gfxUtils::GetInputStream(gfx::DataSourceSurface* aSurface,
                         bool aIsAlphaPremultiplied,
                         const char* aMimeType,
                         const char16_t* aEncoderOptions,
                         nsIInputStream** outStream)
{
    nsCString enccid("@mozilla.org/image/encoder;2?type=");
    enccid += aMimeType;
    nsCOMPtr<imgIEncoder> encoder = do_CreateInstance(enccid.get());
    if (!encoder)
        return NS_ERROR_FAILURE;

    int32_t format = 0;
    UniquePtr<uint8_t[]> imageBuffer = GetImageBuffer(aSurface, aIsAlphaPremultiplied, &format);
    if (!imageBuffer)
        return NS_ERROR_FAILURE;

    return dom::ImageEncoder::GetInputStream(aSurface->GetSize().width,
                                             aSurface->GetSize().height,
                                             imageBuffer.get(), format,
                                             encoder, aEncoderOptions, outStream);
}

class GetFeatureStatusRunnable final : public dom::workers::WorkerMainThreadRunnable
{
public:
    GetFeatureStatusRunnable(dom::workers::WorkerPrivate* workerPrivate,
                             const nsCOMPtr<nsIGfxInfo>& gfxInfo,
                             int32_t feature,
                             nsACString& failureId,
                             int32_t* status)
      : WorkerMainThreadRunnable(workerPrivate,
                                 NS_LITERAL_CSTRING("GFX :: GetFeatureStatus"))
      , mGfxInfo(gfxInfo)
      , mFeature(feature)
      , mStatus(status)
      , mFailureId(failureId)
      , mNSResult(NS_OK)
    {
    }

    bool MainThreadRun() override
    {
      if (mGfxInfo) {
        mNSResult = mGfxInfo->GetFeatureStatus(mFeature, mFailureId, mStatus);
      }
      return true;
    }

    nsresult GetNSResult() const
    {
      return mNSResult;
    }

protected:
    ~GetFeatureStatusRunnable() {}

private:
    nsCOMPtr<nsIGfxInfo> mGfxInfo;
    int32_t mFeature;
    int32_t* mStatus;
    nsACString& mFailureId;
    nsresult mNSResult;
};

/* static */ nsresult
gfxUtils::ThreadSafeGetFeatureStatus(const nsCOMPtr<nsIGfxInfo>& gfxInfo,
                                     int32_t feature, nsACString& failureId,
                                     int32_t* status)
{
  if (!NS_IsMainThread()) {
    dom::workers::WorkerPrivate* workerPrivate =
      dom::workers::GetCurrentThreadWorkerPrivate();

    RefPtr<GetFeatureStatusRunnable> runnable =
      new GetFeatureStatusRunnable(workerPrivate, gfxInfo, feature, failureId,
                                   status);

    ErrorResult rv;
    runnable->Dispatch(rv);
    if (rv.Failed()) {
        // XXXbz This is totally broken, since we're supposed to just abort
        // everything up the callstack but the callers basically eat the
        // exception.  Ah, well.
        return rv.StealNSResult();
    }

    return runnable->GetNSResult();
  }

  return gfxInfo->GetFeatureStatus(feature, failureId, status);
}

/* static */ bool
gfxUtils::DumpDisplayList() {
  return gfxPrefs::LayoutDumpDisplayList() ||
         (gfxPrefs::LayoutDumpDisplayListContent() && XRE_IsContentProcess());
}

FILE *gfxUtils::sDumpPaintFile = stderr;

namespace mozilla {
namespace gfx {

Color ToDeviceColor(Color aColor)
{
  // aColor is pass-by-value since to get return value optimization goodness we
  // need to return the same object from all return points in this function. We
  // could declare a local Color variable and use that, but we might as well
  // just use aColor.
  if (gfxPlatform::GetCMSMode() == eCMSMode_All) {
    qcms_transform *transform = gfxPlatform::GetCMSRGBTransform();
    if (transform) {
      gfxPlatform::TransformPixel(aColor, aColor, transform);
      // Use the original alpha to avoid unnecessary float->byte->float
      // conversion errors
    }
  }
  return aColor;
}

Color ToDeviceColor(nscolor aColor)
{
  return ToDeviceColor(Color::FromABGR(aColor));
}

} // namespace gfx
} // namespace mozilla