Fix pixeldated HiDPI Mac widgets with impl-side painting

skia/ext/skia_utils_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "skia/ext/skia_utils_mac.h"
 
 #import <AppKit/AppKit.h>
 
 #include "base/logging.h"
 #include "base/mac/scoped_cftyperef.h"
@@ skipping 251 matching lines @@
 NSImage* SkBitmapToNSImage(const SkBitmap& skiaBitmap) {
   base::ScopedCFTypeRef<CGColorSpaceRef> colorSpace(
       CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB));
   return SkBitmapToNSImageWithColorSpace(skiaBitmap, colorSpace.get());
 }
 
 SkiaBitLocker::SkiaBitLocker(SkCanvas* canvas)
     : canvas_(canvas),
       userClipRectSpecified_(false),
       cgContext_(0),
+      bitmapScaleFactor_(1),
       useDeviceBits_(false),
       bitmapIsDummy_(false) {
 }
 
-SkiaBitLocker::SkiaBitLocker(SkCanvas* canvas, const SkIRect& userClipRect)
+SkiaBitLocker::SkiaBitLocker(SkCanvas* canvas,
+                             const SkIRect& userClipRect,
+                             SkScalar bitmapScaleFactor)
     : canvas_(canvas),
       userClipRectSpecified_(true),
       cgContext_(0),
+      bitmapScaleFactor_(bitmapScaleFactor),
       useDeviceBits_(false),
       bitmapIsDummy_(false) {
   canvas_->save();
   canvas_->clipRect(SkRect::MakeFromIRect(userClipRect));
 }
 
 SkiaBitLocker::~SkiaBitLocker() {
   releaseIfNeeded();
   if (userClipRectSpecified_)
     canvas_->restore();
@@ skipping 85 matching lines @@
     // Neutralize the global matrix by concatenating the inverse. In the
     // future, Skia may provide some mechanism to set the device portion of
     // the matrix to identity without clobbering any hosting matrix (e.g., the
     // picture's matrix).
     const SkMatrix& skMatrix = canvas_->getTotalMatrix();
     SkMatrix inverse;
     if (!skMatrix.invert(&inverse))
       return;
     canvas_->save();
     canvas_->concat(inverse);
-    canvas_->drawBitmap(subset, bounds.x() + bitmapOffset_.x(),
-                                bounds.y() + bitmapOffset_.y());
+    canvas_->translate(bounds.x() + bitmapOffset_.x(),
+                       bounds.y() + bitmapOffset_.y());
+    canvas_->scale(1.f / bitmapScaleFactor_, 1.f / bitmapScaleFactor_);
+    canvas_->drawBitmap(subset, 0, 0);
     canvas_->restore();
   }
   CGContextRelease(cgContext_);
   cgContext_ = 0;
   useDeviceBits_ = false;
   bitmapIsDummy_ = false;
 }
 
 CGContextRef SkiaBitLocker::cgContext() {
   SkIRect clip_bounds;
@@ skipping 27 matching lines @@
                    canvas_->isClipRect() &&
                    !bitmapIsDummy_;
   if (useDeviceBits_) {
     bool result = deviceBits.extractSubset(&bitmap_, clip_bounds);
     DCHECK(result);
     if (!result)
       return 0;
     bitmap_.lockPixels();
   } else {
     bool result = bitmap_.tryAllocN32Pixels(
-        clip_bounds.width(), clip_bounds.height());
+        SkScalarCeilToInt(bitmapScaleFactor_ * clip_bounds.width()),
+        SkScalarCeilToInt(bitmapScaleFactor_ * clip_bounds.height()));
     DCHECK(result);
     if (!result)
       return 0;
     bitmap_.eraseColor(0);
   }
   base::ScopedCFTypeRef<CGColorSpaceRef> colorSpace(
       CGColorSpaceCreateDeviceRGB());
   cgContext_ = CGBitmapContextCreate(bitmap_.getPixels(), bitmap_.width(),
     bitmap_.height(), 8, bitmap_.rowBytes(), colorSpace, 
     kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst);
   DCHECK(cgContext_);
 
   SkMatrix matrix = canvas_->getTotalMatrix();
   matrix.postTranslate(-SkIntToScalar(bitmapOffset_.x()),
                        -SkIntToScalar(bitmapOffset_.y()));
   matrix.postScale(1, -1);
+  matrix.postScale(bitmapScaleFactor_, bitmapScaleFactor_);

[reed1, 2014/09/30 18:57:24]

nit : seems like we can combine these two postScale calls

postScale( scale, -scale );

[ccameron, 2014/09/30 19:01:46]

Done.

   matrix.postTranslate(0, SkIntToScalar(bitmap_.height()));
 
   CGContextConcatCTM(cgContext_, SkMatrixToCGAffineTransform(matrix));
   
   return cgContext_;
 }
 
 bool SkiaBitLocker::hasEmptyClipRegion() const {
   return canvas_->isClipEmpty();
 }
 
 }  // namespace gfx