palemoon-dev/platform/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);
}

/**
 * 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();
}

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

#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

            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;
            }
        }
    }

    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(dom::workers::Terminating, 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::IsFeatureBlacklisted(nsCOMPtr<nsIGfxInfo> gfxInfo, int32_t feature,
                               nsACString* const out_blacklistId)
{
  if (!gfxInfo) {
    gfxInfo = services::GetGfxInfo();
  }

  int32_t status;
  if (!NS_SUCCEEDED(gfxUtils::ThreadSafeGetFeatureStatus(gfxInfo, feature,
                                                         *out_blacklistId, &status)))
  {
    out_blacklistId->AssignLiteral("");
    return true;
  }

  return status != nsIGfxInfo::FEATURE_STATUS_OK;
}

/* 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