1 files changed, 512 insertions, 0 deletions
diff --git a/image/ClippedImage.cpp b/image/ClippedImage.cpp
new file mode 100644
index 0000000000..cad74ebdf8
--- /dev/null
+++ b/image/ClippedImage.cpp
@@ -0,0 +1,512 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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 "ClippedImage.h"
+
+#include <algorithm>
+#include <cmath>
+#include <new>  // Workaround for bug in VS10; see bug 981264.
+#include <utility>
+
+#include "ImageRegion.h"
+#include "Orientation.h"
+#include "gfxContext.h"
+#include "gfxDrawable.h"
+#include "gfxPlatform.h"
+#include "gfxUtils.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/SVGImageContext.h"
+
+#include "mozilla/gfx/2D.h"
+
+namespace mozilla {
+
+using namespace gfx;
+using std::max;
+
+namespace image {
+
+class ClippedImageCachedSurface {
+ public:
+  ClippedImageCachedSurface(already_AddRefed<SourceSurface> aSurface,
+                            const nsIntSize& aSize,
+                            const SVGImageContext& aSVGContext, float aFrame,
+                            uint32_t aFlags, ImgDrawResult aDrawResult)
+      : mSurface(aSurface),
+        mSize(aSize),
+        mSVGContext(aSVGContext),
+        mFrame(aFrame),
+        mFlags(aFlags),
+        mDrawResult(aDrawResult) {
+    MOZ_ASSERT(mSurface, "Must have a valid surface");
+  }
+
+  bool Matches(const nsIntSize& aSize, const SVGImageContext& aSVGContext,
+               float aFrame, uint32_t aFlags) const {
+    return mSize == aSize && mSVGContext == aSVGContext && mFrame == aFrame &&
+           mFlags == aFlags;
+  }
+
+  already_AddRefed<SourceSurface> Surface() const {
+    RefPtr<SourceSurface> surf(mSurface);
+    return surf.forget();
+  }
+
+  ImgDrawResult GetDrawResult() const { return mDrawResult; }
+
+  bool NeedsRedraw() const {
+    return mDrawResult != ImgDrawResult::SUCCESS &&
+           mDrawResult != ImgDrawResult::BAD_IMAGE;
+  }
+
+ private:
+  RefPtr<SourceSurface> mSurface;
+  const nsIntSize mSize;
+  SVGImageContext mSVGContext;
+  const float mFrame;
+  const uint32_t mFlags;
+  const ImgDrawResult mDrawResult;
+};
+
+class DrawSingleTileCallback : public gfxDrawingCallback {
+ public:
+  DrawSingleTileCallback(ClippedImage* aImage, const nsIntSize& aSize,
+                         const SVGImageContext& aSVGContext,
+                         uint32_t aWhichFrame, uint32_t aFlags, float aOpacity)
+      : mImage(aImage),
+        mSize(aSize),
+        mSVGContext(aSVGContext),
+        mWhichFrame(aWhichFrame),
+        mFlags(aFlags),
+        mDrawResult(ImgDrawResult::NOT_READY),
+        mOpacity(aOpacity) {
+    MOZ_ASSERT(mImage, "Must have an image to clip");
+  }
+
+  virtual bool operator()(gfxContext* aContext, const gfxRect& aFillRect,
+                          const SamplingFilter aSamplingFilter,
+                          const gfxMatrix& aTransform) override {
+    MOZ_ASSERT(aTransform.IsIdentity(),
+               "Caller is probably CreateSamplingRestrictedDrawable, "
+               "which should not happen");
+
+    // Draw the image. |gfxCallbackDrawable| always calls this function with
+    // arguments that guarantee we never tile.
+    mDrawResult = mImage->DrawSingleTile(
+        aContext, mSize, ImageRegion::Create(aFillRect), mWhichFrame,
+        aSamplingFilter, mSVGContext, mFlags, mOpacity);
+
+    return true;
+  }
+
+  ImgDrawResult GetDrawResult() { return mDrawResult; }
+
+ private:
+  RefPtr<ClippedImage> mImage;
+  const nsIntSize mSize;
+  const SVGImageContext& mSVGContext;
+  const uint32_t mWhichFrame;
+  const uint32_t mFlags;
+  ImgDrawResult mDrawResult;
+  float mOpacity;
+};
+
+ClippedImage::ClippedImage(Image* aImage, nsIntRect aClip,
+                           const Maybe<nsSize>& aSVGViewportSize)
+    : ImageWrapper(aImage), mClip(aClip) {
+  MOZ_ASSERT(aImage != nullptr, "ClippedImage requires an existing Image");
+  MOZ_ASSERT_IF(aSVGViewportSize,
+                aImage->GetType() == imgIContainer::TYPE_VECTOR);
+  if (aSVGViewportSize) {
+    mSVGViewportSize =
+        Some(aSVGViewportSize->ToNearestPixels(AppUnitsPerCSSPixel()));
+  }
+}
+
+ClippedImage::~ClippedImage() {}
+
+bool ClippedImage::ShouldClip() {
+  // We need to evaluate the clipping region against the image's width and
+  // height once they're available to determine if it's valid and whether we
+  // actually need to do any work. We may fail if the image's width and height
+  // aren't available yet, in which case we'll try again later.
+  if (mShouldClip.isNothing()) {
+    int32_t width, height;
+    RefPtr<ProgressTracker> progressTracker =
+        InnerImage()->GetProgressTracker();
+    if (InnerImage()->HasError()) {
+      // If there's a problem with the inner image we'll let it handle
+      // everything.
+      mShouldClip.emplace(false);
+    } else if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
+      // Clamp the clipping region to the size of the SVG viewport.
+      nsIntRect svgViewportRect(nsIntPoint(0, 0), *mSVGViewportSize);
+
+      mClip = mClip.Intersect(svgViewportRect);
+
+      // If the clipping region is the same size as the SVG viewport size
+      // we don't have to do anything.
+      mShouldClip.emplace(!mClip.IsEqualInterior(svgViewportRect));
+    } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&width)) && width > 0 &&
+               NS_SUCCEEDED(InnerImage()->GetHeight(&height)) && height > 0) {
+      // Clamp the clipping region to the size of the underlying image.
+      mClip = mClip.Intersect(nsIntRect(0, 0, width, height));
+
+      // If the clipping region is the same size as the underlying image we
+      // don't have to do anything.
+      mShouldClip.emplace(
+          !mClip.IsEqualInterior(nsIntRect(0, 0, width, height)));
+    } else if (progressTracker &&
+               !(progressTracker->GetProgress() & FLAG_LOAD_COMPLETE)) {
+      // The image just hasn't finished loading yet. We don't yet know whether
+      // clipping with be needed or not for now. Just return without memorizing
+      // anything.
+      return false;
+    } else {
+      // We have a fully loaded image without a clearly defined width and
+      // height. This can happen with SVG images.
+      mShouldClip.emplace(false);
+    }
+  }
+
+  MOZ_ASSERT(mShouldClip.isSome(), "Should have computed a result");
+  return *mShouldClip;
+}
+
+NS_IMETHODIMP
+ClippedImage::GetWidth(int32_t* aWidth) {
+  if (!ShouldClip()) {
+    return InnerImage()->GetWidth(aWidth);
+  }
+
+  *aWidth = mClip.Width();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ClippedImage::GetHeight(int32_t* aHeight) {
+  if (!ShouldClip()) {
+    return InnerImage()->GetHeight(aHeight);
+  }
+
+  *aHeight = mClip.Height();
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ClippedImage::GetIntrinsicSize(nsSize* aSize) {
+  if (!ShouldClip()) {
+    return InnerImage()->GetIntrinsicSize(aSize);
+  }
+
+  *aSize = nsSize(mClip.Width(), mClip.Height());
+  return NS_OK;
+}
+
+Maybe<AspectRatio> ClippedImage::GetIntrinsicRatio() {
+  if (!ShouldClip()) {
+    return InnerImage()->GetIntrinsicRatio();
+  }
+
+  return Some(AspectRatio::FromSize(mClip.Width(), mClip.Height()));
+}
+
+NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
+ClippedImage::GetFrame(uint32_t aWhichFrame, uint32_t aFlags) {
+  RefPtr<SourceSurface> surface;
+  std::tie(std::ignore, surface) = GetFrameInternal(
+      mClip.Size(), SVGImageContext(), Nothing(), aWhichFrame, aFlags, 1.0);
+  return surface.forget();
+}
+
+NS_IMETHODIMP_(already_AddRefed<SourceSurface>)
+ClippedImage::GetFrameAtSize(const IntSize& aSize, uint32_t aWhichFrame,
+                             uint32_t aFlags) {
+  // XXX(seth): It'd be nice to support downscale-during-decode for this case,
+  // but right now we just fall back to the intrinsic size.
+  return GetFrame(aWhichFrame, aFlags);
+}
+
+std::pair<ImgDrawResult, RefPtr<SourceSurface>> ClippedImage::GetFrameInternal(
+    const nsIntSize& aSize, const SVGImageContext& aSVGContext,
+    const Maybe<ImageIntRegion>& aRegion, uint32_t aWhichFrame, uint32_t aFlags,
+    float aOpacity) {
+  if (!ShouldClip()) {
+    RefPtr<SourceSurface> surface = InnerImage()->GetFrame(aWhichFrame, aFlags);
+    return std::make_pair(
+        surface ? ImgDrawResult::SUCCESS : ImgDrawResult::NOT_READY,
+        std::move(surface));
+  }
+
+  float frameToDraw = InnerImage()->GetFrameIndex(aWhichFrame);
+  if (!mCachedSurface ||
+      !mCachedSurface->Matches(aSize, aSVGContext, frameToDraw, aFlags) ||
+      mCachedSurface->NeedsRedraw()) {
+    // Create a surface to draw into.
+    RefPtr<DrawTarget> target =
+        gfxPlatform::GetPlatform()->CreateOffscreenContentDrawTarget(
+            IntSize(aSize.width, aSize.height), SurfaceFormat::OS_RGBA);
+    if (!target || !target->IsValid()) {
+      NS_ERROR("Could not create a DrawTarget");
+      return std::make_pair(ImgDrawResult::TEMPORARY_ERROR,
+                            RefPtr<SourceSurface>());
+    }
+
+    gfxContext ctx(target);
+
+    // Create our callback.
+    RefPtr<DrawSingleTileCallback> drawTileCallback =
+        new DrawSingleTileCallback(this, aSize, aSVGContext, aWhichFrame,
+                                   aFlags, aOpacity);
+    RefPtr<gfxDrawable> drawable =
+        new gfxCallbackDrawable(drawTileCallback, aSize);
+
+    // Actually draw. The callback will end up invoking DrawSingleTile.
+    gfxUtils::DrawPixelSnapped(&ctx, drawable, SizeDouble(aSize),
+                               ImageRegion::Create(aSize),
+                               SurfaceFormat::OS_RGBA, SamplingFilter::LINEAR,
+                               imgIContainer::FLAG_CLAMP);
+
+    // Cache the resulting surface.
+    mCachedSurface = MakeUnique<ClippedImageCachedSurface>(
+        target->Snapshot(), aSize, aSVGContext, frameToDraw, aFlags,
+        drawTileCallback->GetDrawResult());
+  }
+
+  MOZ_ASSERT(mCachedSurface, "Should have a cached surface now");
+  RefPtr<SourceSurface> surface = mCachedSurface->Surface();
+  return std::make_pair(mCachedSurface->GetDrawResult(), std::move(surface));
+}
+
+NS_IMETHODIMP_(bool)
+ClippedImage::IsImageContainerAvailable(WindowRenderer* aRenderer,
+                                        uint32_t aFlags) {
+  if (!ShouldClip()) {
+    return InnerImage()->IsImageContainerAvailable(aRenderer, aFlags);
+  }
+  return false;
+}
+
+NS_IMETHODIMP_(ImgDrawResult)
+ClippedImage::GetImageProvider(WindowRenderer* aRenderer,
+                               const gfx::IntSize& aSize,
+                               const SVGImageContext& aSVGContext,
+                               const Maybe<ImageIntRegion>& aRegion,
+                               uint32_t aFlags,
+                               WebRenderImageProvider** aProvider) {
+  // XXX(seth): We currently don't have a way of clipping the result of
+  // GetImageContainer. We work around this by always returning null, but if it
+  // ever turns out that ClippedImage is widely used on codepaths that can
+  // actually benefit from GetImageContainer, it would be a good idea to fix
+  // that method for performance reasons.
+
+  if (!ShouldClip()) {
+    return InnerImage()->GetImageProvider(aRenderer, aSize, aSVGContext,
+                                          aRegion, aFlags, aProvider);
+  }
+
+  return ImgDrawResult::NOT_SUPPORTED;
+}
+
+static bool MustCreateSurface(gfxContext* aContext, const nsIntSize& aSize,
+                              const ImageRegion& aRegion,
+                              const uint32_t aFlags) {
+  gfxRect imageRect(0, 0, aSize.width, aSize.height);
+  bool willTile = !imageRect.Contains(aRegion.Rect()) &&
+                  !(aFlags & imgIContainer::FLAG_CLAMP);
+  bool willResample = aContext->CurrentMatrix().HasNonIntegerTranslation() &&
+                      (willTile || !aRegion.RestrictionContains(imageRect));
+  return willTile || willResample;
+}
+
+NS_IMETHODIMP_(ImgDrawResult)
+ClippedImage::Draw(gfxContext* aContext, const nsIntSize& aSize,
+                   const ImageRegion& aRegion, uint32_t aWhichFrame,
+                   SamplingFilter aSamplingFilter,
+                   const SVGImageContext& aSVGContext, uint32_t aFlags,
+                   float aOpacity) {
+  if (!ShouldClip()) {
+    return InnerImage()->Draw(aContext, aSize, aRegion, aWhichFrame,
+                              aSamplingFilter, aSVGContext, aFlags, aOpacity);
+  }
+
+  // Check for tiling. If we need to tile then we need to create a
+  // gfxCallbackDrawable to handle drawing for us.
+  if (MustCreateSurface(aContext, aSize, aRegion, aFlags)) {
+    // Create a temporary surface containing a single tile of this image.
+    // GetFrame will call DrawSingleTile internally.
+    auto [result, surface] = GetFrameInternal(aSize, aSVGContext, Nothing(),
+                                              aWhichFrame, aFlags, aOpacity);
+    if (!surface) {
+      MOZ_ASSERT(result != ImgDrawResult::SUCCESS);
+      return result;
+    }
+
+    // Create a drawable from that surface.
+    RefPtr<gfxSurfaceDrawable> drawable =
+        new gfxSurfaceDrawable(surface, aSize);
+
+    // Draw.
+    gfxUtils::DrawPixelSnapped(aContext, drawable, SizeDouble(aSize), aRegion,
+                               SurfaceFormat::OS_RGBA, aSamplingFilter,
+                               aOpacity);
+
+    return result;
+  }
+
+  return DrawSingleTile(aContext, aSize, aRegion, aWhichFrame, aSamplingFilter,
+                        aSVGContext, aFlags, aOpacity);
+}
+
+ImgDrawResult ClippedImage::DrawSingleTile(
+    gfxContext* aContext, const nsIntSize& aSize, const ImageRegion& aRegion,
+    uint32_t aWhichFrame, SamplingFilter aSamplingFilter,
+    const SVGImageContext& aSVGContext, uint32_t aFlags, float aOpacity) {
+  MOZ_ASSERT(!MustCreateSurface(aContext, aSize, aRegion, aFlags),
+             "Shouldn't need to create a surface");
+
+  gfxRect clip(mClip.X(), mClip.Y(), mClip.Width(), mClip.Height());
+  nsIntSize size(aSize), innerSize(aSize);
+  bool needScale = false;
+  if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
+    innerSize = *mSVGViewportSize;
+    needScale = true;
+  } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&innerSize.width)) &&
+             NS_SUCCEEDED(InnerImage()->GetHeight(&innerSize.height))) {
+    needScale = true;
+  } else {
+    MOZ_ASSERT_UNREACHABLE(
+        "If ShouldClip() led us to draw then we should never get here");
+  }
+
+  if (needScale) {
+    double scaleX = aSize.width / clip.Width();
+    double scaleY = aSize.height / clip.Height();
+
+    // Map the clip and size to the scale requested by the caller.
+    clip.Scale(scaleX, scaleY);
+    size = innerSize;
+    size.Scale(scaleX, scaleY);
+  }
+
+  // We restrict our drawing to only the clipping region, and translate so that
+  // the clipping region is placed at the position the caller expects.
+  ImageRegion region(aRegion);
+  region.MoveBy(clip.X(), clip.Y());
+  region = region.Intersect(clip);
+
+  gfxContextMatrixAutoSaveRestore saveMatrix(aContext);
+  aContext->Multiply(gfxMatrix::Translation(-clip.X(), -clip.Y()));
+
+  auto unclipViewport = [&](const SVGImageContext& aOldContext) {
+    // Map the viewport to the inner image. Note that we don't take the aSize
+    // parameter of imgIContainer::Draw into account, just the clipping region.
+    // The size in pixels at which the output will ultimately be drawn is
+    // irrelevant here since the purpose of the SVG viewport size is to
+    // determine what *region* of the SVG document will be drawn.
+    SVGImageContext context(aOldContext);
+    auto oldViewport = aOldContext.GetViewportSize();
+    if (oldViewport) {
+      CSSIntSize newViewport;
+      newViewport.width =
+          ceil(oldViewport->width * double(innerSize.width) / mClip.Width());
+      newViewport.height =
+          ceil(oldViewport->height * double(innerSize.height) / mClip.Height());
+      context.SetViewportSize(Some(newViewport));
+    }
+    return context;
+  };
+
+  return InnerImage()->Draw(aContext, size, region, aWhichFrame,
+                            aSamplingFilter, unclipViewport(aSVGContext),
+                            aFlags, aOpacity);
+}
+
+NS_IMETHODIMP
+ClippedImage::RequestDiscard() {
+  // We're very aggressive about discarding.
+  mCachedSurface = nullptr;
+
+  return InnerImage()->RequestDiscard();
+}
+
+NS_IMETHODIMP_(Orientation)
+ClippedImage::GetOrientation() {
+  // XXX(seth): This should not actually be here; this is just to work around a
+  // what appears to be a bug in MSVC's linker.
+  return InnerImage()->GetOrientation();
+}
+
+nsIntSize ClippedImage::OptimalImageSizeForDest(const gfxSize& aDest,
+                                                uint32_t aWhichFrame,
+                                                SamplingFilter aSamplingFilter,
+                                                uint32_t aFlags) {
+  if (!ShouldClip()) {
+    return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame,
+                                                 aSamplingFilter, aFlags);
+  }
+
+  int32_t imgWidth, imgHeight;
+  bool needScale = false;
+  bool forceUniformScaling = false;
+  if (mSVGViewportSize && !mSVGViewportSize->IsEmpty()) {
+    imgWidth = mSVGViewportSize->width;
+    imgHeight = mSVGViewportSize->height;
+    needScale = true;
+    forceUniformScaling = (aFlags & imgIContainer::FLAG_FORCE_UNIFORM_SCALING);
+  } else if (NS_SUCCEEDED(InnerImage()->GetWidth(&imgWidth)) &&
+             NS_SUCCEEDED(InnerImage()->GetHeight(&imgHeight))) {
+    needScale = true;
+  }
+
+  if (needScale) {
+    // To avoid ugly sampling artifacts, ClippedImage needs the image size to
+    // be chosen such that the clipping region lies on pixel boundaries.
+
+    // First, we select a scale that's good for ClippedImage. An integer
+    // multiple of the size of the clipping region is always fine.
+    IntSize scale = IntSize::Ceil(aDest.width / mClip.Width(),
+                                  aDest.height / mClip.Height());
+
+    if (forceUniformScaling) {
+      scale.width = scale.height = max(scale.height, scale.width);
+    }
+
+    // Determine the size we'd prefer to render the inner image at, and ask the
+    // inner image what size we should actually use.
+    gfxSize desiredSize(double(imgWidth) * scale.width,
+                        double(imgHeight) * scale.height);
+    nsIntSize innerDesiredSize = InnerImage()->OptimalImageSizeForDest(
+        desiredSize, aWhichFrame, aSamplingFilter, aFlags);
+
+    // To get our final result, we take the inner image's desired size and
+    // determine how large the clipped region would be at that scale. (Again, we
+    // ensure an integer multiple of the size of the clipping region.)
+    IntSize finalScale =
+        IntSize::Ceil(double(innerDesiredSize.width) / imgWidth,
+                      double(innerDesiredSize.height) / imgHeight);
+    return mClip.Size() * finalScale;
+  }
+
+  MOZ_ASSERT(false,
+             "If ShouldClip() led us to draw then we should never get here");
+  return InnerImage()->OptimalImageSizeForDest(aDest, aWhichFrame,
+                                               aSamplingFilter, aFlags);
+}
+
+NS_IMETHODIMP_(nsIntRect)
+ClippedImage::GetImageSpaceInvalidationRect(const nsIntRect& aRect) {
+  if (!ShouldClip()) {
+    return InnerImage()->GetImageSpaceInvalidationRect(aRect);
+  }
+
+  nsIntRect rect(InnerImage()->GetImageSpaceInvalidationRect(aRect));
+  rect = rect.Intersect(mClip);
+  rect.MoveBy(-mClip.X(), -mClip.Y());
+  return rect;
+}
+
+}  // namespace image
+}  // namespace mozilla