Bug 1082530, part 3 - Get rid of gfxContext::FLAG_DISABLE_SNAPPING and use DrawTarget UserData to store information on whether to disable pixel snapping. r=mattwoodrow

gfx/layers/basic/BasicLayerManager.cpp

@@ -34,6 +34,7 @@
 #include "mozilla/gfx/BasePoint.h"      // for BasePoint
 #include "mozilla/gfx/BaseRect.h"       // for BaseRect
 #include "mozilla/gfx/Matrix.h"         // for Matrix
+#include "mozilla/gfx/PathHelpers.h"
 #include "mozilla/gfx/Rect.h"           // for IntRect, Rect
 #include "mozilla/layers/LayersTypes.h"  // for BufferMode::BUFFER_NONE, etc
 #include "mozilla/mozalloc.h"           // for operator new
@@ -486,8 +487,12 @@ BasicLayerManager::EndTransactionInternal(DrawPaintedLayerCallback aCallback,
   if (mRoot) {
     // Need to do this before we call ApplyDoubleBuffering,
     // which depends on correct effective transforms
-    mSnapEffectiveTransforms =
-      mTarget ? !(mTarget->GetFlags() & gfxContext::FLAG_DISABLE_SNAPPING) : true;
+    if (mTarget) {
+      mSnapEffectiveTransforms =
+        !mTarget->GetDrawTarget()->GetUserData(&sDisablePixelSnapping);
+    } else {
+      mSnapEffectiveTransforms = true;
+    }
     mRoot->ComputeEffectiveTransforms(mTarget ? Matrix4x4::From2D(ToMatrix(mTarget->CurrentMatrix())) : Matrix4x4());
 
     ToData(mRoot)->Validate(aCallback, aCallbackData, nullptr);

gfx/src/nsDeviceContext.cpp

@@ -10,6 +10,7 @@
 #include "gfxImageSurface.h"            // for gfxImageSurface
 #include "gfxPoint.h"                   // for gfxSize
 #include "mozilla/Attributes.h"         // for MOZ_FINAL
+#include "mozilla/gfx/PathHelpers.h"
 #include "mozilla/Preferences.h"        // for Preferences
 #include "mozilla/Services.h"           // for GetObserverService
 #include "mozilla/mozalloc.h"           // for operator new
@@ -48,6 +49,7 @@
 #endif
 
 using namespace mozilla;
+using namespace mozilla::gfx;
 using mozilla::services::GetObserverService;
 
 class nsFontCache MOZ_FINAL : public nsIObserver
@@ -409,7 +411,8 @@ nsDeviceContext::CreateRenderingContext()
 #endif
 
     pContext->Init(this, dt);
-    pContext->ThebesContext()->SetFlag(gfxContext::FLAG_DISABLE_SNAPPING);
+    pContext->GetDrawTarget()->AddUserData(&sDisablePixelSnapping,
+                                           (void*)0x1, nullptr);
     pContext->ThebesContext()->SetMatrix(gfxMatrix::Scaling(mPrintingScale,
                                                             mPrintingScale));
 

gfx/thebes/gfxContext.cpp

@@ -88,7 +88,6 @@ gfxContext::gfxContext(DrawTarget *aTarget, const Point& aDeviceOffset)
   : mPathIsRect(false)
   , mTransformChanged(false)
   , mRefCairo(nullptr)
-  , mFlags(0)
   , mDT(aTarget)
   , mOriginalDT(aTarget)
 {
@@ -489,7 +488,7 @@ gfxContext::UserToDevice(const gfxRect& rect) const
 bool
 gfxContext::UserToDevicePixelSnapped(gfxRect& rect, bool ignoreScale) const
 {
-  if (GetFlags() & FLAG_DISABLE_SNAPPING)
+  if (mDT->GetUserData(&sDisablePixelSnapping))
       return false;
 
   // if we're not at 1.0 scale, don't snap, unless we're
@@ -530,7 +529,7 @@ gfxContext::UserToDevicePixelSnapped(gfxRect& rect, bool ignoreScale) const
 bool
 gfxContext::UserToDevicePixelSnapped(gfxPoint& pt, bool ignoreScale) const
 {
-  if (GetFlags() & FLAG_DISABLE_SNAPPING)
+  if (mDT->GetUserData(&sDisablePixelSnapping))
       return false;
 
   // if we're not at 1.0 scale, don't snap, unless we're

gfx/thebes/gfxContext.h

@@ -576,18 +576,6 @@ public:
 
     mozilla::gfx::Point GetDeviceOffset() const;
 
-    enum {
-         /**
-         * When this flag is set, snapping to device pixels is disabled.
-         * It simply never does anything.
-         */
-        FLAG_DISABLE_SNAPPING = (1 << 1),
-    };
-
-    void SetFlag(int32_t aFlag) { mFlags |= aFlag; }
-    void ClearFlag(int32_t aFlag) { mFlags &= ~aFlag; }
-    int32_t GetFlags() const { return mFlags; }
-
     // Work out whether cairo will snap inter-glyph spacing to pixels.
     void GetRoundOffsetsToPixels(bool *aRoundX, bool *aRoundY);
 
@@ -695,7 +683,6 @@ private:
   const AzureState &CurrentState() const { return mStateStack[mStateStack.Length() - 1]; }
 
   cairo_t *mRefCairo;
-  int32_t mFlags;
 
   mozilla::RefPtr<DrawTarget> mDT;
   mozilla::RefPtr<DrawTarget> mOriginalDT;