The Tor Browser: gfx/2d/DrawTargetCG.cpp@97036ab72558 (annotated)

gfx/2d/DrawTargetCG.cpp@97036ab72558 (annotated)

gfx/2d/DrawTargetCG.cpp

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* -*- Mode: C++; tab-width: 20; 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 "BorrowedContext.h"
 #include "DataSurfaceHelpers.h"
 #include "DrawTargetCG.h"
 #include "Logging.h"
 #include "SourceSurfaceCG.h"
 #include "Rect.h"
 #include "ScaledFontMac.h"
 #include "Tools.h"
 #include <vector>
 #include <algorithm>
 #include "MacIOSurface.h"
 #include "FilterNodeSoftware.h"
 #include "mozilla/Assertions.h"
 #include "mozilla/Types.h" // for decltype
 #include "mozilla/FloatingPoint.h"
 using namespace std;
 //CG_EXTERN void CGContextSetCompositeOperation (CGContextRef, PrivateCGCompositeMode);
 // A private API that Cairo has been using for a long time
 CG_EXTERN void CGContextSetCTM(CGContextRef, CGAffineTransform);
 namespace mozilla {
 namespace gfx {
 static CGRect RectToCGRect(Rect r)
 {
   return CGRectMake(r.x, r.y, r.width, r.height);
 }
 CGBlendMode ToBlendMode(CompositionOp op)
 {
   CGBlendMode mode;
   switch (op) {
     case CompositionOp::OP_OVER:
       mode = kCGBlendModeNormal;
       break;
     case CompositionOp::OP_ADD:
       mode = kCGBlendModePlusLighter;
       break;
     case CompositionOp::OP_ATOP:
       mode = kCGBlendModeSourceAtop;
       break;
     case CompositionOp::OP_OUT:
       mode = kCGBlendModeSourceOut;
       break;
     case CompositionOp::OP_IN:
       mode = kCGBlendModeSourceIn;
       break;
     case CompositionOp::OP_SOURCE:
       mode = kCGBlendModeCopy;
       break;
     case CompositionOp::OP_DEST_IN:
       mode = kCGBlendModeDestinationIn;
       break;
     case CompositionOp::OP_DEST_OUT:
       mode = kCGBlendModeDestinationOut;
       break;
     case CompositionOp::OP_DEST_OVER:
       mode = kCGBlendModeDestinationOver;
       break;
     case CompositionOp::OP_DEST_ATOP:
       mode = kCGBlendModeDestinationAtop;
       break;
     case CompositionOp::OP_XOR:
       mode = kCGBlendModeXOR;
       break;
     case CompositionOp::OP_MULTIPLY:
       mode = kCGBlendModeMultiply;
       break;
     case CompositionOp::OP_SCREEN:
       mode = kCGBlendModeScreen;
       break;
     case CompositionOp::OP_OVERLAY:
       mode = kCGBlendModeOverlay;
       break;
     case CompositionOp::OP_DARKEN:
       mode = kCGBlendModeDarken;
       break;
     case CompositionOp::OP_LIGHTEN:
       mode = kCGBlendModeLighten;
       break;
     case CompositionOp::OP_COLOR_DODGE:
       mode = kCGBlendModeColorDodge;
       break;
     case CompositionOp::OP_COLOR_BURN:
       mode = kCGBlendModeColorBurn;
       break;
     case CompositionOp::OP_HARD_LIGHT:
       mode = kCGBlendModeHardLight;
       break;
     case CompositionOp::OP_SOFT_LIGHT:
       mode = kCGBlendModeSoftLight;
       break;
     case CompositionOp::OP_DIFFERENCE:
       mode = kCGBlendModeDifference;
       break;
     case CompositionOp::OP_EXCLUSION:
       mode = kCGBlendModeExclusion;
       break;
     case CompositionOp::OP_HUE:
       mode = kCGBlendModeHue;
       break;
     case CompositionOp::OP_SATURATION:
       mode = kCGBlendModeSaturation;
       break;
     case CompositionOp::OP_COLOR:
       mode = kCGBlendModeColor;
       break;
     case CompositionOp::OP_LUMINOSITY:
       mode = kCGBlendModeLuminosity;
       break;
       /*
     case OP_CLEAR:
       mode = kCGBlendModeClear;
       break;*/
     default:
       mode = kCGBlendModeNormal;
   }
   return mode;
 }
 static CGInterpolationQuality
 InterpolationQualityFromFilter(Filter aFilter)
 {
   switch (aFilter) {
     default:
     case Filter::LINEAR:
       return kCGInterpolationLow;
     case Filter::POINT:
       return kCGInterpolationNone;
     case Filter::GOOD:
       return kCGInterpolationDefault;
   }
 }
 DrawTargetCG::DrawTargetCG() : mCg(nullptr), mSnapshot(nullptr)
 {
 }
 DrawTargetCG::~DrawTargetCG()
 {
   MarkChanged();
   // We need to conditionally release these because Init can fail without initializing these.
   if (mColorSpace)
     CGColorSpaceRelease(mColorSpace);
   if (mCg)
     CGContextRelease(mCg);
 }
 BackendType
 DrawTargetCG::GetType() const
 {
   // It may be worth spliting Bitmap and IOSurface DrawTarget
   // into seperate classes.
   if (GetContextType(mCg) == CG_CONTEXT_TYPE_IOSURFACE) {
     return BackendType::COREGRAPHICS_ACCELERATED;
   } else {
     return BackendType::COREGRAPHICS;
   }
 }
 TemporaryRef<SourceSurface>
 DrawTargetCG::Snapshot()
 {
   if (!mSnapshot) {
     if (GetContextType(mCg) == CG_CONTEXT_TYPE_IOSURFACE) {
       return new SourceSurfaceCGIOSurfaceContext(this);
     } else {
       mSnapshot = new SourceSurfaceCGBitmapContext(this);
     }
   }
   return mSnapshot;
 }
 TemporaryRef<DrawTarget>
 DrawTargetCG::CreateSimilarDrawTarget(const IntSize &aSize, SurfaceFormat aFormat) const
 {
   // XXX: in thebes we use CGLayers to do this kind of thing. It probably makes sense
   // to add that in somehow, but at a higher level
   RefPtr<DrawTargetCG> newTarget = new DrawTargetCG();
   if (newTarget->Init(GetType(), aSize, aFormat)) {
     return newTarget;
   } else {
     return nullptr;
   }
 }
 TemporaryRef<SourceSurface>
 DrawTargetCG::CreateSourceSurfaceFromData(unsigned char *aData,
                                            const IntSize &aSize,
                                            int32_t aStride,
                                            SurfaceFormat aFormat) const
 {
   RefPtr<SourceSurfaceCG> newSurf = new SourceSurfaceCG();
  if (!newSurf->InitFromData(aData, aSize, aStride, aFormat)) {
     return nullptr;
   }
   return newSurf;
 }
 // This function returns a retained CGImage that needs to be released after
 // use. The reason for this is that we want to either reuse an existing CGImage
 // or create a new one.
 static CGImageRef
 GetRetainedImageFromSourceSurface(SourceSurface *aSurface)
 {
   if (aSurface->GetType() == SurfaceType::COREGRAPHICS_IMAGE)
     return CGImageRetain(static_cast<SourceSurfaceCG*>(aSurface)->GetImage());
   else if (aSurface->GetType() == SurfaceType::COREGRAPHICS_CGCONTEXT)
     return CGImageRetain(static_cast<SourceSurfaceCGContext*>(aSurface)->GetImage());
   if (aSurface->GetType() == SurfaceType::DATA) {
     DataSourceSurface* dataSource = static_cast<DataSourceSurface*>(aSurface);
     return CreateCGImage(nullptr, dataSource->GetData(), dataSource->GetSize(),
                          dataSource->Stride(), dataSource->GetFormat());
   }
   MOZ_CRASH("unsupported source surface");
 }
 TemporaryRef<SourceSurface>
 DrawTargetCG::OptimizeSourceSurface(SourceSurface *aSurface) const
 {
   if (aSurface->GetType() == SurfaceType::COREGRAPHICS_IMAGE ||
       aSurface->GetType() == SurfaceType::COREGRAPHICS_CGCONTEXT) {
     return aSurface;
   }
   return aSurface->GetDataSurface();
 }
 class UnboundnessFixer
 {
     CGRect mClipBounds;
     CGLayerRef mLayer;
     CGContextRef mCg;
   public:
     UnboundnessFixer() : mCg(nullptr) {}
     CGContextRef Check(CGContextRef baseCg, CompositionOp blend, const Rect* maskBounds = nullptr)
     {
       if (!IsOperatorBoundByMask(blend)) {
         mClipBounds = CGContextGetClipBoundingBox(baseCg);
         // If we're entirely clipped out or if the drawing operation covers the entire clip then
         // we don't need to create a temporary surface.
         if (CGRectIsEmpty(mClipBounds) ||
             (maskBounds && maskBounds->Contains(CGRectToRect(mClipBounds)))) {
           return baseCg;
         }
         // TransparencyLayers aren't blended using the blend mode so
         // we are forced to use CGLayers
         //XXX: The size here is in default user space units, of the layer relative to the graphics context.
         // is the clip bounds still correct if, for example, we have a scale applied to the context?
         mLayer = CGLayerCreateWithContext(baseCg, mClipBounds.size, nullptr);
         mCg = CGLayerGetContext(mLayer);
         // CGContext's default to have the origin at the bottom left
         // so flip it to the top left and adjust for the origin
         // of the layer
         CGContextTranslateCTM(mCg, -mClipBounds.origin.x, mClipBounds.origin.y + mClipBounds.size.height);
         CGContextScaleCTM(mCg, 1, -1);
         return mCg;
       } else {
         return baseCg;
       }
     }
     void Fix(CGContextRef baseCg)
     {
         if (mCg) {
             CGContextTranslateCTM(baseCg, 0, mClipBounds.size.height);
             CGContextScaleCTM(baseCg, 1, -1);
             mClipBounds.origin.y *= -1;
             CGContextDrawLayerAtPoint(baseCg, mClipBounds.origin, mLayer);
             CGContextRelease(mCg);
         }
     }
 };
 void
 DrawTargetCG::DrawSurface(SourceSurface *aSurface,
                            const Rect &aDest,
                            const Rect &aSource,
                            const DrawSurfaceOptions &aSurfOptions,
                            const DrawOptions &aDrawOptions)
 {
   MarkChanged();
   CGContextSaveGState(mCg);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp, &aDest);
   CGContextSetAlpha(cg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextSetInterpolationQuality(cg, InterpolationQualityFromFilter(aSurfOptions.mFilter));
   CGImageRef image = GetRetainedImageFromSourceSurface(aSurface);
   if (aSurfOptions.mFilter == Filter::POINT) {
     CGImageRef subimage = CGImageCreateWithImageInRect(image, RectToCGRect(aSource));
     CGImageRelease(image);
     CGContextScaleCTM(cg, 1, -1);
     CGRect flippedRect = CGRectMake(aDest.x, -(aDest.y + aDest.height),
                                     aDest.width, aDest.height);
     CGContextDrawImage(cg, flippedRect, subimage);
     CGImageRelease(subimage);
   } else {
     CGRect destRect = CGRectMake(aDest.x, aDest.y, aDest.width, aDest.height);
     CGContextClipToRect(cg, destRect);
     float xScale = aSource.width / aDest.width;
     float yScale = aSource.height / aDest.height;
     CGContextTranslateCTM(cg, aDest.x - aSource.x / xScale, aDest.y - aSource.y / yScale);
     CGRect adjustedDestRect = CGRectMake(0, 0, CGImageGetWidth(image) / xScale,
                                          CGImageGetHeight(image) / yScale);
     CGContextTranslateCTM(cg, 0, CGRectGetHeight(adjustedDestRect));
     CGContextScaleCTM(cg, 1, -1);
     CGContextDrawImage(cg, adjustedDestRect, image);
     CGImageRelease(image);
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 TemporaryRef<FilterNode>
 DrawTargetCG::CreateFilter(FilterType aType)
 {
   return FilterNodeSoftware::Create(aType);
 }
 void
 DrawTargetCG::DrawFilter(FilterNode *aNode,
                          const Rect &aSourceRect,
                          const Point &aDestPoint,
                          const DrawOptions &aOptions)
 {
   FilterNodeSoftware* filter = static_cast<FilterNodeSoftware*>(aNode);
   filter->Draw(this, aSourceRect, aDestPoint, aOptions);
 }
 static CGColorRef ColorToCGColor(CGColorSpaceRef aColorSpace, const Color& aColor)
 {
   CGFloat components[4] = {aColor.r, aColor.g, aColor.b, aColor.a};
   return CGColorCreate(aColorSpace, components);
 }
 class GradientStopsCG : public GradientStops
 {
   public:
   MOZ_DECLARE_REFCOUNTED_VIRTUAL_TYPENAME(GradientStopsCG)
   //XXX: The skia backend uses a vector and passes in aNumStops. It should do better
   GradientStopsCG(GradientStop* aStops, uint32_t aNumStops, ExtendMode aExtendMode)
   {
     mExtend = aExtendMode;
     if (aExtendMode == ExtendMode::CLAMP) {
       //XXX: do the stops need to be in any particular order?
       // what should we do about the color space here? we certainly shouldn't be
       // recreating it all the time
       std::vector<CGFloat> colors;
       std::vector<CGFloat> offsets;
       colors.reserve(aNumStops*4);
       offsets.reserve(aNumStops);
       for (uint32_t i = 0; i < aNumStops; i++) {
         colors.push_back(aStops[i].color.r);
         colors.push_back(aStops[i].color.g);
         colors.push_back(aStops[i].color.b);
         colors.push_back(aStops[i].color.a);
         offsets.push_back(aStops[i].offset);
       }
       CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
       mGradient = CGGradientCreateWithColorComponents(colorSpace,
                                                       &colors.front(),
                                                       &offsets.front(),
                                                       aNumStops);
       CGColorSpaceRelease(colorSpace);
     } else {
       mGradient = nullptr;
       mStops.reserve(aNumStops);
       for (uint32_t i = 0; i < aNumStops; i++) {
         mStops.push_back(aStops[i]);
       }
     }
   }
   virtual ~GradientStopsCG() {
     if (mGradient)
         CGGradientRelease(mGradient);
   }
   // Will always report BackendType::COREGRAPHICS, but it is compatible
   // with BackendType::COREGRAPHICS_ACCELERATED
   BackendType GetBackendType() const { return BackendType::COREGRAPHICS; }
   // XXX this should be a union
   CGGradientRef mGradient;
   std::vector<GradientStop> mStops;
   ExtendMode mExtend;
 };
 TemporaryRef<GradientStops>
 DrawTargetCG::CreateGradientStops(GradientStop *aStops, uint32_t aNumStops,
                                   ExtendMode aExtendMode) const
 {
   return new GradientStopsCG(aStops, aNumStops, aExtendMode);
 }
 static void
 UpdateLinearParametersToIncludePoint(double *min_t, double *max_t,
                                      CGPoint *start,
                                      double dx, double dy,
                                      double x, double y)
 {
   MOZ_ASSERT(IsFinite(x) && IsFinite(y));
   /**
    * Compute a parameter t such that a line perpendicular to the (dx,dy)
    * vector, passing through (start->x + dx*t, start->y + dy*t), also
    * passes through (x,y).
    *
    * Let px = x - start->x, py = y - start->y.
    * t is given by
    *   (px - dx*t)*dx + (py - dy*t)*dy = 0
    *
    * Solving for t we get
    *   numerator = dx*px + dy*py
    *   denominator = dx^2 + dy^2
    *   t = numerator/denominator
    *
    * In CalculateRepeatingGradientParams we know the length of (dx,dy)
    * is not zero. (This is checked in DrawLinearRepeatingGradient.)
    */
   double px = x - start->x;
   double py = y - start->y;
   double numerator = dx * px + dy * py;
   double denominator = dx * dx + dy * dy;
   double t = numerator / denominator;
   if (*min_t > t) {
     *min_t = t;
   }
   if (*max_t < t) {
     *max_t = t;
   }
 }
 /**
  * Repeat the gradient line such that lines extended perpendicular to the
  * gradient line at both start and end would completely enclose the drawing
  * extents.
  */
 static void
 CalculateRepeatingGradientParams(CGPoint *aStart, CGPoint *aEnd,
                                  CGRect aExtents, int *aRepeatCount)
 {
   double t_min = INFINITY;
   double t_max = -INFINITY;
   double dx = aEnd->x - aStart->x;
   double dy = aEnd->y - aStart->y;
   double bounds_x1 = aExtents.origin.x;
   double bounds_y1 = aExtents.origin.y;
   double bounds_x2 = aExtents.origin.x + aExtents.size.width;
   double bounds_y2 = aExtents.origin.y + aExtents.size.height;
   UpdateLinearParametersToIncludePoint(&t_min, &t_max, aStart, dx, dy,
                                        bounds_x1, bounds_y1);
   UpdateLinearParametersToIncludePoint(&t_min, &t_max, aStart, dx, dy,
                                        bounds_x2, bounds_y1);
   UpdateLinearParametersToIncludePoint(&t_min, &t_max, aStart, dx, dy,
                                        bounds_x2, bounds_y2);
   UpdateLinearParametersToIncludePoint(&t_min, &t_max, aStart, dx, dy,
                                        bounds_x1, bounds_y2);
   MOZ_ASSERT(!isinf(t_min) && !isinf(t_max),
              "The first call to UpdateLinearParametersToIncludePoint should have made t_min and t_max non-infinite.");
   // Move t_min and t_max to the nearest usable integer to try to avoid
   // subtle variations due to numerical instability, especially accidentally
   // cutting off a pixel. Extending the gradient repetitions is always safe.
   t_min = floor (t_min);
   t_max = ceil (t_max);
   aEnd->x = aStart->x + dx * t_max;
   aEnd->y = aStart->y + dy * t_max;
   aStart->x = aStart->x + dx * t_min;
   aStart->y = aStart->y + dy * t_min;
   *aRepeatCount = t_max - t_min;
 }
 static void
 DrawLinearRepeatingGradient(CGContextRef cg, const LinearGradientPattern &aPattern, const CGRect &aExtents)
 {
   GradientStopsCG *stops = static_cast<GradientStopsCG*>(aPattern.mStops.get());
   CGPoint startPoint = { aPattern.mBegin.x, aPattern.mBegin.y };
   CGPoint endPoint = { aPattern.mEnd.x, aPattern.mEnd.y };
   int repeatCount = 1;
   // if we don't have a line then we can't extend it
   if (aPattern.mEnd.x != aPattern.mBegin.x ||
       aPattern.mEnd.y != aPattern.mBegin.y) {
     CalculateRepeatingGradientParams(&startPoint, &endPoint, aExtents,
                                      &repeatCount);
   }
   double scale = 1./repeatCount;
   std::vector<CGFloat> colors;
   std::vector<CGFloat> offsets;
   colors.reserve(stops->mStops.size()*repeatCount*4);
   offsets.reserve(stops->mStops.size()*repeatCount);
   for (int j = 0; j < repeatCount; j++) {
     for (uint32_t i = 0; i < stops->mStops.size(); i++) {
       colors.push_back(stops->mStops[i].color.r);
       colors.push_back(stops->mStops[i].color.g);
       colors.push_back(stops->mStops[i].color.b);
       colors.push_back(stops->mStops[i].color.a);
       offsets.push_back((stops->mStops[i].offset + j)*scale);
     }
   }
   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
   CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace,
                                                                &colors.front(),
                                                                &offsets.front(),
                                                                repeatCount*stops->mStops.size());
   CGColorSpaceRelease(colorSpace);
   CGContextDrawLinearGradient(cg, gradient, startPoint, endPoint,
                               kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
   CGGradientRelease(gradient);
 }
 static CGPoint CGRectTopLeft(CGRect a)
 { return a.origin; }
 static CGPoint CGRectBottomLeft(CGRect a)
 { return CGPointMake(a.origin.x, a.origin.y + a.size.height); }
 static CGPoint CGRectTopRight(CGRect a)
 { return CGPointMake(a.origin.x + a.size.width, a.origin.y); }
 static CGPoint CGRectBottomRight(CGRect a)
 { return CGPointMake(a.origin.x + a.size.width, a.origin.y + a.size.height); }
 static CGFloat
 CGPointDistance(CGPoint a, CGPoint b)
 {
   return hypot(a.x-b.x, a.y-b.y);
 }
 static void
 DrawRadialRepeatingGradient(CGContextRef cg, const RadialGradientPattern &aPattern, const CGRect &aExtents)
 {
   GradientStopsCG *stops = static_cast<GradientStopsCG*>(aPattern.mStops.get());
   CGPoint startCenter = { aPattern.mCenter1.x, aPattern.mCenter1.y };
   CGFloat startRadius = aPattern.mRadius1;
   CGPoint endCenter   = { aPattern.mCenter2.x, aPattern.mCenter2.y };
   CGFloat endRadius   = aPattern.mRadius2;
   // find the maximum distance from endCenter to a corner of aExtents
   CGFloat minimumEndRadius = endRadius;
   minimumEndRadius = max(minimumEndRadius, CGPointDistance(endCenter, CGRectTopLeft(aExtents)));
   minimumEndRadius = max(minimumEndRadius, CGPointDistance(endCenter, CGRectBottomLeft(aExtents)));
   minimumEndRadius = max(minimumEndRadius, CGPointDistance(endCenter, CGRectTopRight(aExtents)));
   minimumEndRadius = max(minimumEndRadius, CGPointDistance(endCenter, CGRectBottomRight(aExtents)));
   CGFloat length = endRadius - startRadius;
   int repeatCount = 1;
   while (endRadius < minimumEndRadius) {
     endRadius += length;
     repeatCount++;
   }
   while (startRadius-length >= 0) {
     startRadius -= length;
     repeatCount++;
   }
   double scale = 1./repeatCount;
   std::vector<CGFloat> colors;
   std::vector<CGFloat> offsets;
   colors.reserve(stops->mStops.size()*repeatCount*4);
   offsets.reserve(stops->mStops.size()*repeatCount);
   for (int j = 0; j < repeatCount; j++) {
     for (uint32_t i = 0; i < stops->mStops.size(); i++) {
       colors.push_back(stops->mStops[i].color.r);
       colors.push_back(stops->mStops[i].color.g);
       colors.push_back(stops->mStops[i].color.b);
       colors.push_back(stops->mStops[i].color.a);
       offsets.push_back((stops->mStops[i].offset + j)*scale);
     }
   }
   CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
   CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace,
                                                                &colors.front(),
                                                                &offsets.front(),
                                                                repeatCount*stops->mStops.size());
   CGColorSpaceRelease(colorSpace);
   //XXX: are there degenerate radial gradients that we should avoid drawing?
   CGContextDrawRadialGradient(cg, gradient, startCenter, startRadius, endCenter, endRadius,
                               kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
   CGGradientRelease(gradient);
 }
 static void
 DrawGradient(CGContextRef cg, const Pattern &aPattern, const CGRect &aExtents)
 {
   if (CGRectIsEmpty(aExtents)) {
     return;
   }
   if (aPattern.GetType() == PatternType::LINEAR_GRADIENT) {
     const LinearGradientPattern& pat = static_cast<const LinearGradientPattern&>(aPattern);
     GradientStopsCG *stops = static_cast<GradientStopsCG*>(pat.mStops.get());
     CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(pat.mMatrix));
     if (stops->mExtend == ExtendMode::CLAMP) {
       // XXX: we should take the m out of the properties of LinearGradientPatterns
       CGPoint startPoint = { pat.mBegin.x, pat.mBegin.y };
       CGPoint endPoint   = { pat.mEnd.x,   pat.mEnd.y };
       // Canvas spec states that we should avoid drawing degenerate gradients (XXX: should this be in common code?)
       //if (startPoint.x == endPoint.x && startPoint.y == endPoint.y)
       //  return;
       CGContextDrawLinearGradient(cg, stops->mGradient, startPoint, endPoint,
                                   kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
     } else if (stops->mExtend == ExtendMode::REPEAT) {
       DrawLinearRepeatingGradient(cg, pat, aExtents);
     }
   } else if (aPattern.GetType() == PatternType::RADIAL_GRADIENT) {
     const RadialGradientPattern& pat = static_cast<const RadialGradientPattern&>(aPattern);
     CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(pat.mMatrix));
     GradientStopsCG *stops = static_cast<GradientStopsCG*>(pat.mStops.get());
     if (stops->mExtend == ExtendMode::CLAMP) {
       // XXX: we should take the m out of the properties of RadialGradientPatterns
       CGPoint startCenter = { pat.mCenter1.x, pat.mCenter1.y };
       CGFloat startRadius = pat.mRadius1;
       CGPoint endCenter   = { pat.mCenter2.x, pat.mCenter2.y };
       CGFloat endRadius   = pat.mRadius2;
       //XXX: are there degenerate radial gradients that we should avoid drawing?
       CGContextDrawRadialGradient(cg, stops->mGradient, startCenter, startRadius, endCenter, endRadius,
                                   kCGGradientDrawsBeforeStartLocation | kCGGradientDrawsAfterEndLocation);
     } else if (stops->mExtend == ExtendMode::REPEAT) {
       DrawRadialRepeatingGradient(cg, pat, aExtents);
     }
   } else {
     assert(0);
   }
 }
 static void
 drawPattern(void *info, CGContextRef context)
 {
   CGImageRef image = static_cast<CGImageRef>(info);
   CGRect rect = {{0, 0},
     {static_cast<CGFloat>(CGImageGetWidth(image)),
      static_cast<CGFloat>(CGImageGetHeight(image))}};
   CGContextDrawImage(context, rect, image);
 }
 static void
 releaseInfo(void *info)
 {
   CGImageRef image = static_cast<CGImageRef>(info);
   CGImageRelease(image);
 }
 CGPatternCallbacks patternCallbacks = {
 ,
   drawPattern,
   releaseInfo
 };
 static bool
 isGradient(const Pattern &aPattern)
 {
   return aPattern.GetType() == PatternType::LINEAR_GRADIENT || aPattern.GetType() == PatternType::RADIAL_GRADIENT;
 }
 /* CoreGraphics patterns ignore the userspace transform so
  * we need to multiply it in */
 static CGPatternRef
 CreateCGPattern(const Pattern &aPattern, CGAffineTransform aUserSpace)
 {
   const SurfacePattern& pat = static_cast<const SurfacePattern&>(aPattern);
   // XXX: is .get correct here?
   CGImageRef image = GetRetainedImageFromSourceSurface(pat.mSurface.get());
   CGFloat xStep, yStep;
   switch (pat.mExtendMode) {
     case ExtendMode::CLAMP:
       // The 1 << 22 comes from Webkit see Pattern::createPlatformPattern() in PatternCG.cpp for more info
       xStep = static_cast<CGFloat>(1 << 22);
       yStep = static_cast<CGFloat>(1 << 22);
       break;
     case ExtendMode::REFLECT:
       assert(0);
     case ExtendMode::REPEAT:
       xStep = static_cast<CGFloat>(CGImageGetWidth(image));
       yStep = static_cast<CGFloat>(CGImageGetHeight(image));
       // webkit uses wkCGPatternCreateWithImageAndTransform a wrapper around CGPatternCreateWithImage2
       // this is done to avoid pixel-cracking along pattern boundaries
       // (see https://bugs.webkit.org/show_bug.cgi?id=53055)
       // typedef enum {
       //    wkPatternTilingNoDistortion,
       //    wkPatternTilingConstantSpacingMinimalDistortion,
       //    wkPatternTilingConstantSpacing
       // } wkPatternTiling;
       // extern CGPatternRef (*wkCGPatternCreateWithImageAndTransform)(CGImageRef, CGAffineTransform, int);
   }
   //XXX: We should be using CGContextDrawTiledImage when we can. Even though it
   // creates a pattern, it seems to go down a faster path than using a delegate
   // like we do below
   CGRect bounds = {
     {0, 0,},
     {static_cast<CGFloat>(CGImageGetWidth(image)), static_cast<CGFloat>(CGImageGetHeight(image))}
   };
   CGAffineTransform transform =
       CGAffineTransformConcat(CGAffineTransformConcat(CGAffineTransformMakeScale(1,
                                                                                  -1),
                                                       GfxMatrixToCGAffineTransform(pat.mMatrix)),
                               aUserSpace);
   transform = CGAffineTransformTranslate(transform, 0, -static_cast<float>(CGImageGetHeight(image)));
   return CGPatternCreate(image, bounds, transform, xStep, yStep, kCGPatternTilingConstantSpacing,
                          true, &patternCallbacks);
 }
 static void
 SetFillFromPattern(CGContextRef cg, CGColorSpaceRef aColorSpace, const Pattern &aPattern)
 {
   assert(!isGradient(aPattern));
   if (aPattern.GetType() == PatternType::COLOR) {
     const Color& color = static_cast<const ColorPattern&>(aPattern).mColor;
     //XXX: we should cache colors
     CGColorRef cgcolor = ColorToCGColor(aColorSpace, color);
     CGContextSetFillColorWithColor(cg, cgcolor);
     CGColorRelease(cgcolor);
   } else if (aPattern.GetType() == PatternType::SURFACE) {
     CGColorSpaceRef patternSpace;
     patternSpace = CGColorSpaceCreatePattern (nullptr);
     CGContextSetFillColorSpace(cg, patternSpace);
     CGColorSpaceRelease(patternSpace);
     CGPatternRef pattern = CreateCGPattern(aPattern, CGContextGetCTM(cg));
     const SurfacePattern& pat = static_cast<const SurfacePattern&>(aPattern);
     CGContextSetInterpolationQuality(cg, InterpolationQualityFromFilter(pat.mFilter));
     CGFloat alpha = 1.;
     CGContextSetFillPattern(cg, pattern, &alpha);
     CGPatternRelease(pattern);
   }
 }
 static void
 SetStrokeFromPattern(CGContextRef cg, CGColorSpaceRef aColorSpace, const Pattern &aPattern)
 {
   assert(!isGradient(aPattern));
   if (aPattern.GetType() == PatternType::COLOR) {
     const Color& color = static_cast<const ColorPattern&>(aPattern).mColor;
     //XXX: we should cache colors
     CGColorRef cgcolor = ColorToCGColor(aColorSpace, color);
     CGContextSetStrokeColorWithColor(cg, cgcolor);
     CGColorRelease(cgcolor);
   } else if (aPattern.GetType() == PatternType::SURFACE) {
     CGColorSpaceRef patternSpace;
     patternSpace = CGColorSpaceCreatePattern (nullptr);
     CGContextSetStrokeColorSpace(cg, patternSpace);
     CGColorSpaceRelease(patternSpace);
     CGPatternRef pattern = CreateCGPattern(aPattern, CGContextGetCTM(cg));
     const SurfacePattern& pat = static_cast<const SurfacePattern&>(aPattern);
     CGContextSetInterpolationQuality(cg, InterpolationQualityFromFilter(pat.mFilter));
     CGFloat alpha = 1.;
     CGContextSetStrokePattern(cg, pattern, &alpha);
     CGPatternRelease(pattern);
   }
 }
 void
 DrawTargetCG::MaskSurface(const Pattern &aSource,
                           SourceSurface *aMask,
                           Point aOffset,
                           const DrawOptions &aDrawOptions)
 {
   MarkChanged();
   CGContextSaveGState(mCg);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(cg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   CGImageRef image = GetRetainedImageFromSourceSurface(aMask);
   // use a negative-y so that the mask image draws right ways up
   CGContextScaleCTM(cg, 1, -1);
   IntSize size = aMask->GetSize();
   CGContextClipToMask(cg, CGRectMake(aOffset.x, -(aOffset.y + size.height), size.width, size.height), image);
   CGContextScaleCTM(cg, 1, -1);
   if (isGradient(aSource)) {
     // we shouldn't need to clip to an additional rectangle
     // as the cliping to the mask should be sufficient.
     DrawGradient(cg, aSource, CGRectMake(aOffset.x, aOffset.y, size.width, size.height));
   } else {
     SetFillFromPattern(cg, mColorSpace, aSource);
     CGContextFillRect(cg, CGRectMake(aOffset.x, aOffset.y, size.width, size.height));
   }
   CGImageRelease(image);
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::FillRect(const Rect &aRect,
                         const Pattern &aPattern,
                         const DrawOptions &aDrawOptions)
 {
   MarkChanged();
   CGContextSaveGState(mCg);
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp, &aRect);
   CGContextSetAlpha(mCg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   if (isGradient(aPattern)) {
     CGContextClipToRect(cg, RectToCGRect(aRect));
     CGRect clipBounds = CGContextGetClipBoundingBox(cg);
     DrawGradient(cg, aPattern, clipBounds);
   } else {
     if (aPattern.GetType() == PatternType::SURFACE && static_cast<const SurfacePattern&>(aPattern).mExtendMode != ExtendMode::REPEAT) {
       // SetFillFromPattern can handle this case but using CGContextDrawImage
       // should give us better performance, better output, smaller PDF and
       // matches what cairo does.
       const SurfacePattern& pat = static_cast<const SurfacePattern&>(aPattern);
       CGImageRef image = GetRetainedImageFromSourceSurface(pat.mSurface.get());
       CGContextClipToRect(cg, RectToCGRect(aRect));
       CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(pat.mMatrix));
       CGContextTranslateCTM(cg, 0, CGImageGetHeight(image));
       CGContextScaleCTM(cg, 1, -1);
       CGRect imageRect = CGRectMake(0, 0, CGImageGetWidth(image), CGImageGetHeight(image));
       CGContextSetInterpolationQuality(cg, InterpolationQualityFromFilter(pat.mFilter));
       CGContextDrawImage(cg, imageRect, image);
       CGImageRelease(image);
     } else {
       SetFillFromPattern(cg, mColorSpace, aPattern);
       CGContextFillRect(cg, RectToCGRect(aRect));
     }
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::StrokeLine(const Point &p1, const Point &p2, const Pattern &aPattern, const StrokeOptions &aStrokeOptions, const DrawOptions &aDrawOptions)
 {
   if (!std::isfinite(p1.x) ||
       !std::isfinite(p1.y) ||
       !std::isfinite(p2.x) ||
       !std::isfinite(p2.y)) {
     return;
   }
   MarkChanged();
   CGContextSaveGState(mCg);
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(mCg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextBeginPath(cg);
   CGContextMoveToPoint(cg, p1.x, p1.y);
   CGContextAddLineToPoint(cg, p2.x, p2.y);
   SetStrokeOptions(cg, aStrokeOptions);
   if (isGradient(aPattern)) {
     CGContextReplacePathWithStrokedPath(cg);
     CGRect extents = CGContextGetPathBoundingBox(cg);
     //XXX: should we use EO clip here?
     CGContextClip(cg);
     DrawGradient(cg, aPattern, extents);
   } else {
     SetStrokeFromPattern(cg, mColorSpace, aPattern);
     CGContextStrokePath(cg);
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::StrokeRect(const Rect &aRect,
                          const Pattern &aPattern,
                          const StrokeOptions &aStrokeOptions,
                          const DrawOptions &aDrawOptions)
 {
   if (!aRect.IsFinite()) {
     return;
   }
   MarkChanged();
   CGContextSaveGState(mCg);
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(mCg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   SetStrokeOptions(cg, aStrokeOptions);
   if (isGradient(aPattern)) {
     // There's no CGContextClipStrokeRect so we do it by hand
     CGContextBeginPath(cg);
     CGContextAddRect(cg, RectToCGRect(aRect));
     CGContextReplacePathWithStrokedPath(cg);
     CGRect extents = CGContextGetPathBoundingBox(cg);
     //XXX: should we use EO clip here?
     CGContextClip(cg);
     DrawGradient(cg, aPattern, extents);
   } else {
     SetStrokeFromPattern(cg, mColorSpace, aPattern);
     CGContextStrokeRect(cg, RectToCGRect(aRect));
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::ClearRect(const Rect &aRect)
 {
   MarkChanged();
   CGContextSaveGState(mCg);
   CGContextConcatCTM(mCg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextClearRect(mCg, RectToCGRect(aRect));
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::Stroke(const Path *aPath, const Pattern &aPattern, const StrokeOptions &aStrokeOptions, const DrawOptions &aDrawOptions)
 {
   if (!aPath->GetBounds().IsFinite()) {
     return;
   }
   MarkChanged();
   CGContextSaveGState(mCg);
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(mCg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextBeginPath(cg);
   assert(aPath->GetBackendType() == BackendType::COREGRAPHICS);
   const PathCG *cgPath = static_cast<const PathCG*>(aPath);
   CGContextAddPath(cg, cgPath->GetPath());
   SetStrokeOptions(cg, aStrokeOptions);
   if (isGradient(aPattern)) {
     CGContextReplacePathWithStrokedPath(cg);
     CGRect extents = CGContextGetPathBoundingBox(cg);
     //XXX: should we use EO clip here?
     CGContextClip(cg);
     DrawGradient(cg, aPattern, extents);
   } else {
     // XXX: we could put fill mode into the path fill rule if we wanted
     SetStrokeFromPattern(cg, mColorSpace, aPattern);
     CGContextStrokePath(cg);
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::Fill(const Path *aPath, const Pattern &aPattern, const DrawOptions &aDrawOptions)
 {
   MarkChanged();
   assert(aPath->GetBackendType() == BackendType::COREGRAPHICS);
   CGContextSaveGState(mCg);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(cg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextBeginPath(cg);
   // XXX: we could put fill mode into the path fill rule if we wanted
   const PathCG *cgPath = static_cast<const PathCG*>(aPath);
   if (isGradient(aPattern)) {
     // setup a clip to draw the gradient through
     CGRect extents;
     if (CGPathIsEmpty(cgPath->GetPath())) {
       // Adding an empty path will cause us not to clip
       // so clip everything explicitly
       CGContextClipToRect(mCg, CGRectZero);
       extents = CGRectZero;
     } else {
       CGContextAddPath(cg, cgPath->GetPath());
       extents = CGContextGetPathBoundingBox(cg);
       if (cgPath->GetFillRule() == FillRule::FILL_EVEN_ODD)
         CGContextEOClip(mCg);
       else
         CGContextClip(mCg);
     }
     DrawGradient(cg, aPattern, extents);
   } else {
     CGContextAddPath(cg, cgPath->GetPath());
     SetFillFromPattern(cg, mColorSpace, aPattern);
     if (cgPath->GetFillRule() == FillRule::FILL_EVEN_ODD)
       CGContextEOFillPath(cg);
     else
       CGContextFillPath(cg);
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(mCg);
 }
 CGRect ComputeGlyphsExtents(CGRect *bboxes, CGPoint *positions, CFIndex count, float scale)
 {
   CGFloat x1, x2, y1, y2;
   if (count < 1)
     return CGRectZero;
   x1 = bboxes[0].origin.x + positions[0].x;
   x2 = bboxes[0].origin.x + positions[0].x + scale*bboxes[0].size.width;
   y1 = bboxes[0].origin.y + positions[0].y;
   y2 = bboxes[0].origin.y + positions[0].y + scale*bboxes[0].size.height;
   // accumulate max and minimum coordinates
   for (int i = 1; i < count; i++) {
     x1 = min(x1, bboxes[i].origin.x + positions[i].x);
     y1 = min(y1, bboxes[i].origin.y + positions[i].y);
     x2 = max(x2, bboxes[i].origin.x + positions[i].x + scale*bboxes[i].size.width);
     y2 = max(y2, bboxes[i].origin.y + positions[i].y + scale*bboxes[i].size.height);
   }
   CGRect extents = {{x1, y1}, {x2-x1, y2-y1}};
   return extents;
 }
 void
 DrawTargetCG::FillGlyphs(ScaledFont *aFont, const GlyphBuffer &aBuffer, const Pattern &aPattern, const DrawOptions &aDrawOptions,
                          const GlyphRenderingOptions*)
 {
   MarkChanged();
   assert(aBuffer.mNumGlyphs);
   CGContextSaveGState(mCg);
   CGContextSetBlendMode(mCg, ToBlendMode(aDrawOptions.mCompositionOp));
   UnboundnessFixer fixer;
   CGContextRef cg = fixer.Check(mCg, aDrawOptions.mCompositionOp);
   CGContextSetAlpha(cg, aDrawOptions.mAlpha);
   CGContextSetShouldAntialias(cg, aDrawOptions.mAntialiasMode != AntialiasMode::NONE);
   if (aDrawOptions.mAntialiasMode != AntialiasMode::DEFAULT) {
     CGContextSetShouldSmoothFonts(cg, aDrawOptions.mAntialiasMode == AntialiasMode::SUBPIXEL);
   }
   CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(mTransform));
   ScaledFontMac* macFont = static_cast<ScaledFontMac*>(aFont);
   //XXX: we should use a stack vector here when we have a class like that
   std::vector<CGGlyph> glyphs;
   std::vector<CGPoint> positions;
   glyphs.resize(aBuffer.mNumGlyphs);
   positions.resize(aBuffer.mNumGlyphs);
   // Handle the flip
   CGContextScaleCTM(cg, 1, -1);
   // CGContextSetTextMatrix works differently with kCGTextClip && kCGTextFill
   // It seems that it transforms the positions with TextFill and not with TextClip
   // Therefore we'll avoid it. See also:
   // http://cgit.freedesktop.org/cairo/commit/?id=9c0d761bfcdd28d52c83d74f46dd3c709ae0fa69
   for (unsigned int i = 0; i < aBuffer.mNumGlyphs; i++) {
     glyphs[i] = aBuffer.mGlyphs[i].mIndex;
     // XXX: CGPointMake might not be inlined
     positions[i] = CGPointMake(aBuffer.mGlyphs[i].mPosition.x,
                               -aBuffer.mGlyphs[i].mPosition.y);
   }
   //XXX: CGContextShowGlyphsAtPositions is 10.5+ for older versions use CGContextShowGlyphsWithAdvances
   if (isGradient(aPattern)) {
     CGContextSetTextDrawingMode(cg, kCGTextClip);
     CGRect extents;
     if (ScaledFontMac::CTFontDrawGlyphsPtr != nullptr) {
       CGRect *bboxes = new CGRect[aBuffer.mNumGlyphs];
       CTFontGetBoundingRectsForGlyphs(macFont->mCTFont, kCTFontDefaultOrientation,
                                       &glyphs.front(), bboxes, aBuffer.mNumGlyphs);
       extents = ComputeGlyphsExtents(bboxes, &positions.front(), aBuffer.mNumGlyphs, 1.0f);
       ScaledFontMac::CTFontDrawGlyphsPtr(macFont->mCTFont, &glyphs.front(),
                                          &positions.front(), aBuffer.mNumGlyphs, cg);
       delete bboxes;
     } else {
       CGRect *bboxes = new CGRect[aBuffer.mNumGlyphs];
       CGFontGetGlyphBBoxes(macFont->mFont, &glyphs.front(), aBuffer.mNumGlyphs, bboxes);
       extents = ComputeGlyphsExtents(bboxes, &positions.front(), aBuffer.mNumGlyphs, macFont->mSize);
       CGContextSetFont(cg, macFont->mFont);
       CGContextSetFontSize(cg, macFont->mSize);
       CGContextShowGlyphsAtPositions(cg, &glyphs.front(), &positions.front(),
                                      aBuffer.mNumGlyphs);
       delete bboxes;
     }
     CGContextScaleCTM(cg, 1, -1);
     DrawGradient(cg, aPattern, extents);
   } else {
     //XXX: with CoreGraphics we can stroke text directly instead of going
     // through GetPath. It would be nice to add support for using that
     CGContextSetTextDrawingMode(cg, kCGTextFill);
     SetFillFromPattern(cg, mColorSpace, aPattern);
     if (ScaledFontMac::CTFontDrawGlyphsPtr != nullptr) {
       ScaledFontMac::CTFontDrawGlyphsPtr(macFont->mCTFont, &glyphs.front(),
                                          &positions.front(),
                                          aBuffer.mNumGlyphs, cg);
     } else {
       CGContextSetFont(cg, macFont->mFont);
       CGContextSetFontSize(cg, macFont->mSize);
       CGContextShowGlyphsAtPositions(cg, &glyphs.front(), &positions.front(),
                                      aBuffer.mNumGlyphs);
     }
   }
   fixer.Fix(mCg);
   CGContextRestoreGState(cg);
 }
 extern "C" {
 void
 CGContextResetClip(CGContextRef);
 };
 void
 DrawTargetCG::CopySurface(SourceSurface *aSurface,
                           const IntRect& aSourceRect,
                           const IntPoint &aDestination)
 {
   MarkChanged();
   if (aSurface->GetType() == SurfaceType::COREGRAPHICS_IMAGE ||
       aSurface->GetType() == SurfaceType::COREGRAPHICS_CGCONTEXT ||
       aSurface->GetType() == SurfaceType::DATA) {
     CGImageRef image = GetRetainedImageFromSourceSurface(aSurface);
     // XXX: it might be more efficient for us to do the copy directly if we have access to the bits
     CGContextSaveGState(mCg);
     // CopySurface ignores the clip, so we need to use private API to temporarily reset it
     CGContextResetClip(mCg);
     CGRect destRect = CGRectMake(aDestination.x, aDestination.y,
                                  aSourceRect.width, aSourceRect.height);
     CGContextClipToRect(mCg, destRect);
     CGContextSetBlendMode(mCg, kCGBlendModeCopy);
     CGContextScaleCTM(mCg, 1, -1);
     CGRect flippedRect = CGRectMake(aDestination.x - aSourceRect.x, -(aDestination.y - aSourceRect.y + double(CGImageGetHeight(image))),
                                     CGImageGetWidth(image), CGImageGetHeight(image));
     // Quartz seems to copy A8 surfaces incorrectly if we don't initialize them
     // to transparent first.
     if (mFormat == SurfaceFormat::A8) {
       CGContextClearRect(mCg, flippedRect);
     }
     CGContextDrawImage(mCg, flippedRect, image);
     CGContextRestoreGState(mCg);
     CGImageRelease(image);
   }
 }
 void
 DrawTargetCG::DrawSurfaceWithShadow(SourceSurface *aSurface, const Point &aDest, const Color &aColor, const Point &aOffset, Float aSigma, CompositionOp aOperator)
 {
   MarkChanged();
   CGImageRef image = GetRetainedImageFromSourceSurface(aSurface);
   IntSize size = aSurface->GetSize();
   CGContextSaveGState(mCg);
   //XXX do we need to do the fixup here?
   CGContextSetBlendMode(mCg, ToBlendMode(aOperator));
   CGContextScaleCTM(mCg, 1, -1);
   CGRect flippedRect = CGRectMake(aDest.x, -(aDest.y + size.height),
                                   size.width, size.height);
   CGColorRef color = ColorToCGColor(mColorSpace, aColor);
   CGSize offset = {aOffset.x, -aOffset.y};
   // CoreGraphics needs twice sigma as it's amount of blur
   CGContextSetShadowWithColor(mCg, offset, 2*aSigma, color);
   CGColorRelease(color);
   CGContextDrawImage(mCg, flippedRect, image);
   CGImageRelease(image);
   CGContextRestoreGState(mCg);
 }
 bool
 DrawTargetCG::Init(BackendType aType,
                    unsigned char* aData,
                    const IntSize &aSize,
                    int32_t aStride,
                    SurfaceFormat aFormat)
 {
   // XXX: we should come up with some consistent semantics for dealing
   // with zero area drawtargets
   if (aSize.width <= 0 || aSize.height <= 0 ||
       // 32767 is the maximum size supported by cairo
       // we clamp to that to make it easier to interoperate
       aSize.width > 32767 || aSize.height > 32767) {
     gfxWarning() << "Failed to Init() DrawTargetCG because of bad size.";
     mColorSpace = nullptr;
     mCg = nullptr;
     return false;
   }
   //XXX: handle SurfaceFormat
   //XXX: we'd be better off reusing the Colorspace across draw targets
   mColorSpace = CGColorSpaceCreateDeviceRGB();
   if (aData == nullptr && aType != BackendType::COREGRAPHICS_ACCELERATED) {
     // XXX: Currently, Init implicitly clears, that can often be a waste of time
     size_t bufLen = BufferSizeFromStrideAndHeight(aStride, aSize.height);
     if (bufLen == 0) {
       mColorSpace = nullptr;
       mCg = nullptr;
       return false;
     }
     static_assert(sizeof(decltype(mData[0])) == 1,
                   "mData.Realloc() takes an object count, so its objects must be 1-byte sized if we use bufLen");
     mData.Realloc(/* actually an object count */ bufLen);
     aData = static_cast<unsigned char*>(mData);
     memset(aData, 0, bufLen);
   }
   mSize = aSize;
   if (aType == BackendType::COREGRAPHICS_ACCELERATED) {
     RefPtr<MacIOSurface> ioSurface = MacIOSurface::CreateIOSurface(aSize.width, aSize.height);
     mCg = ioSurface->CreateIOSurfaceContext();
     // If we don't have the symbol for 'CreateIOSurfaceContext' mCg will be null
     // and we will fallback to software below
   }
   mFormat = SurfaceFormat::B8G8R8A8;
   if (!mCg || aType == BackendType::COREGRAPHICS) {
     int bitsPerComponent = 8;
     CGBitmapInfo bitinfo;
     if (aFormat == SurfaceFormat::A8) {
       if (mColorSpace)
         CGColorSpaceRelease(mColorSpace);
       mColorSpace = nullptr;
       bitinfo = kCGImageAlphaOnly;
       mFormat = SurfaceFormat::A8;
     } else {
       bitinfo = kCGBitmapByteOrder32Host;
       if (aFormat == SurfaceFormat::B8G8R8X8) {
         bitinfo |= kCGImageAlphaNoneSkipFirst;
         mFormat = aFormat;
       } else {
         bitinfo |= kCGImageAlphaPremultipliedFirst;
       }
     }
     // XXX: what should we do if this fails?
     mCg = CGBitmapContextCreate (aData,
                                  mSize.width,
                                  mSize.height,
                                  bitsPerComponent,
                                  aStride,
                                  mColorSpace,
                                  bitinfo);
   }
   assert(mCg);
   // CGContext's default to have the origin at the bottom left
   // so flip it to the top left
   CGContextTranslateCTM(mCg, 0, mSize.height);
   CGContextScaleCTM(mCg, 1, -1);
   // See Bug 722164 for performance details
   // Medium or higher quality lead to expensive interpolation
   // for canvas we want to use low quality interpolation
   // to have competitive performance with other canvas
   // implementation.
   // XXX: Create input parameter to control interpolation and
   //      use the default for content.
   CGContextSetInterpolationQuality(mCg, kCGInterpolationLow);
   if (aType == BackendType::COREGRAPHICS_ACCELERATED) {
     // The bitmap backend uses callac to clear, we can't do that without
     // reading back the surface. This should trigger something equivilent
     // to glClear.
     ClearRect(Rect(0, 0, mSize.width, mSize.height));
   }
   return true;
 }
 void
 DrawTargetCG::Flush()
 {
   if (GetContextType(mCg) == CG_CONTEXT_TYPE_IOSURFACE) {
     CGContextFlush(mCg);
   }
 }
 bool
 DrawTargetCG::Init(CGContextRef cgContext, const IntSize &aSize)
 {
   // XXX: we should come up with some consistent semantics for dealing
   // with zero area drawtargets
   if (aSize.width == 0 || aSize.height == 0) {
     mColorSpace = nullptr;
     mCg = nullptr;
     return false;
   }
   //XXX: handle SurfaceFormat
   //XXX: we'd be better off reusing the Colorspace across draw targets
   mColorSpace = CGColorSpaceCreateDeviceRGB();
   mSize = aSize;
   mCg = cgContext;
   CGContextRetain(mCg);
   assert(mCg);
   // CGContext's default to have the origin at the bottom left.
   // However, currently the only use of this function is to construct a
   // DrawTargetCG around a CGContextRef from a cairo quartz surface which
   // already has it's origin adjusted.
   //
   // CGContextTranslateCTM(mCg, 0, mSize.height);
   // CGContextScaleCTM(mCg, 1, -1);
   mFormat = SurfaceFormat::B8G8R8A8;
   if (GetContextType(mCg) == CG_CONTEXT_TYPE_BITMAP) {
     CGColorSpaceRef colorspace;
     CGBitmapInfo bitinfo = CGBitmapContextGetBitmapInfo(mCg);
     colorspace = CGBitmapContextGetColorSpace (mCg);
     if (CGColorSpaceGetNumberOfComponents(colorspace) == 1) {
       mFormat = SurfaceFormat::A8;
     } else if ((bitinfo & kCGBitmapAlphaInfoMask) == kCGImageAlphaNoneSkipFirst) {
       mFormat = SurfaceFormat::B8G8R8X8;
     }
   }
   return true;
 }
 bool
 DrawTargetCG::Init(BackendType aType, const IntSize &aSize, SurfaceFormat &aFormat)
 {
   int32_t stride = GetAlignedStride<16>(aSize.width * BytesPerPixel(aFormat));
   // Calling Init with aData == nullptr will allocate.
   return Init(aType, nullptr, aSize, stride, aFormat);
 }
 TemporaryRef<PathBuilder>
 DrawTargetCG::CreatePathBuilder(FillRule aFillRule) const
 {
   RefPtr<PathBuilderCG> pb = new PathBuilderCG(aFillRule);
   return pb;
 }
 void*
 DrawTargetCG::GetNativeSurface(NativeSurfaceType aType)
 {
   if ((aType == NativeSurfaceType::CGCONTEXT && GetContextType(mCg) == CG_CONTEXT_TYPE_BITMAP) ||
       (aType == NativeSurfaceType::CGCONTEXT_ACCELERATED && GetContextType(mCg) == CG_CONTEXT_TYPE_IOSURFACE)) {
     return mCg;
   } else {
     return nullptr;
   }
 }
 void
 DrawTargetCG::Mask(const Pattern &aSource,
                    const Pattern &aMask,
                    const DrawOptions &aDrawOptions)
 {
   MarkChanged();
   CGContextSaveGState(mCg);
   if (isGradient(aMask)) {
     assert(0);
   } else {
     if (aMask.GetType() == PatternType::COLOR) {
       DrawOptions drawOptions(aDrawOptions);
       const Color& color = static_cast<const ColorPattern&>(aMask).mColor;
       drawOptions.mAlpha *= color.a;
       assert(0);
       // XXX: we need to get a rect that when transformed covers the entire surface
       //Rect
       //FillRect(rect, aSource, drawOptions);
     } else if (aMask.GetType() == PatternType::SURFACE) {
       const SurfacePattern& pat = static_cast<const SurfacePattern&>(aMask);
       CGImageRef mask = GetRetainedImageFromSourceSurface(pat.mSurface.get());
       Rect rect(0,0, CGImageGetWidth(mask), CGImageGetHeight(mask));
       // XXX: probably we need to do some flipping of the image or something
       CGContextClipToMask(mCg, RectToCGRect(rect), mask);
       FillRect(rect, aSource, aDrawOptions);
       CGImageRelease(mask);
     }
   }
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::PushClipRect(const Rect &aRect)
 {
   CGContextSaveGState(mCg);
   /* We go through a bit of trouble to temporarilly set the transform
    * while we add the path */
   CGAffineTransform previousTransform = CGContextGetCTM(mCg);
   CGContextConcatCTM(mCg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextClipToRect(mCg, RectToCGRect(aRect));
   CGContextSetCTM(mCg, previousTransform);
 }
 void
 DrawTargetCG::PushClip(const Path *aPath)
 {
   CGContextSaveGState(mCg);
   CGContextBeginPath(mCg);
   assert(aPath->GetBackendType() == BackendType::COREGRAPHICS);
   const PathCG *cgPath = static_cast<const PathCG*>(aPath);
   // Weirdly, CoreGraphics clips empty paths as all shown
   // but emtpy rects as all clipped.  We detect this situation and
   // workaround it appropriately
   if (CGPathIsEmpty(cgPath->GetPath())) {
     // XXX: should we return here?
     CGContextClipToRect(mCg, CGRectZero);
   }
   /* We go through a bit of trouble to temporarilly set the transform
    * while we add the path. XXX: this could be improved if we keep
    * the CTM as resident state on the DrawTarget. */
   CGContextSaveGState(mCg);
   CGContextConcatCTM(mCg, GfxMatrixToCGAffineTransform(mTransform));
   CGContextAddPath(mCg, cgPath->GetPath());
   CGContextRestoreGState(mCg);
   if (cgPath->GetFillRule() == FillRule::FILL_EVEN_ODD)
     CGContextEOClip(mCg);
   else
     CGContextClip(mCg);
 }
 void
 DrawTargetCG::PopClip()
 {
   CGContextRestoreGState(mCg);
 }
 void
 DrawTargetCG::MarkChanged()
 {
   if (mSnapshot) {
     if (mSnapshot->refCount() > 1) {
       // We only need to worry about snapshots that someone else knows about
       mSnapshot->DrawTargetWillChange();
     }
     mSnapshot = nullptr;
   }
 }
 CGContextRef
 BorrowedCGContext::BorrowCGContextFromDrawTarget(DrawTarget *aDT)
 {
   if (aDT->GetType() == BackendType::COREGRAPHICS || aDT->GetType() == BackendType::COREGRAPHICS_ACCELERATED) {
     DrawTargetCG* cgDT = static_cast<DrawTargetCG*>(aDT);
     cgDT->MarkChanged();
     // swap out the context
     CGContextRef cg = cgDT->mCg;
     cgDT->mCg = nullptr;
     // save the state to make it easier for callers to avoid mucking with things
     CGContextSaveGState(cg);
     CGContextConcatCTM(cg, GfxMatrixToCGAffineTransform(cgDT->mTransform));
     return cg;
   }
   return nullptr;
 }
 void
 BorrowedCGContext::ReturnCGContextToDrawTarget(DrawTarget *aDT, CGContextRef cg)
 {
   DrawTargetCG* cgDT = static_cast<DrawTargetCG*>(aDT);
   CGContextRestoreGState(cg);
   cgDT->mCg = cg;
 }
 }
 }

The Tor Browser / annotate

gfx/2d/DrawTargetCG.cpp@97036ab72558 (annotated)

gfx/2d/DrawTargetCG.cpp