Convert SkiaBitLocker to use PaintCanvas

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 <stdint.h>
 
 #include <memory>
@@ skipping 223 matching lines @@
   [image setSize:NSMakeSize(skiaBitmap.width(), skiaBitmap.height())];
   return [image.release() autorelease];
 }
 
 NSImage* SkBitmapToNSImage(const SkBitmap& skiaBitmap) {
   base::ScopedCFTypeRef<CGColorSpaceRef> colorSpace(
       CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB));
   return SkBitmapToNSImageWithColorSpace(skiaBitmap, colorSpace.get());
 }
 
-SkiaBitLocker::SkiaBitLocker(SkCanvas* canvas,
-                             const SkIRect& userClipRect,
-                             SkScalar bitmapScaleFactor)
-    : canvas_(canvas),
-      cgContext_(0),
-      bitmapScaleFactor_(bitmapScaleFactor),
-      useDeviceBits_(false),
-      bitmapIsDummy_(false) {
-  canvas_->save();
-  canvas_->clipRect(SkRect::MakeFromIRect(userClipRect));
-}
-
-SkiaBitLocker::~SkiaBitLocker() {
-  releaseIfNeeded();
-  canvas_->restore();
-}
-
-SkIRect SkiaBitLocker::computeDirtyRect() {
-  // If the user specified a clip region, assume that it was tight and that the
-  // dirty rect is approximately the whole bitmap.
-  return SkIRect::MakeWH(offscreen_.width(), offscreen_.height());
-}
-
-// This must be called to balance calls to cgContext
-void SkiaBitLocker::releaseIfNeeded() {
-  if (!cgContext_)
-    return;
-  if (!useDeviceBits_ && !bitmapIsDummy_) {
-    // Find the bits that were drawn to.
-    SkIRect bounds = computeDirtyRect();
-    SkBitmap subset;
-    if (!offscreen_.extractSubset(&subset, bounds)) {
-        return;
-    }
-    subset.setImmutable();  // Prevents a defensive copy inside Skia.
-    canvas_->save();
-    canvas_->setMatrix(SkMatrix::I());  // Reset back to device space.
-    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() {
-  releaseIfNeeded(); // This flushes any prior bitmap use
-
-  SkIRect clip_bounds;
-  if (!canvas_->getDeviceClipBounds(&clip_bounds)) {
-    // If the clip is empty, then there is nothing to draw. The caller may
-    // attempt to draw (to-be-clipped) results, so ensure there is a dummy
-    // non-NULL CGContext to use.
-    bitmapIsDummy_ = true;
-    clip_bounds = SkIRect::MakeXYWH(0, 0, 1, 1);
-  }
-
-  // remember the top/left, in case we need to compose this later
-  bitmapOffset_.set(clip_bounds.x(), clip_bounds.y());
-
-  // Now make clip_bounds be relative to the current layer/device
-  if (!bitmapIsDummy_) {
-    canvas_->temporary_internal_describeTopLayer(nullptr, &clip_bounds);
-  }
-
-  SkPixmap devicePixels;
-  skia::GetWritablePixels(canvas_, &devicePixels);
-
-  // Only draw directly if we have pixels, and we're only rect-clipped.
-  // If not, we allocate an offscreen and draw into that, relying on the
-  // compositing step to apply skia's clip.
-  useDeviceBits_ = devicePixels.addr() &&
-                   canvas_->isClipRect() &&
-                   !bitmapIsDummy_;
-  base::ScopedCFTypeRef<CGColorSpaceRef> colorSpace(
-      CGColorSpaceCreateDeviceRGB());
-
-  int displayHeight;
-  if (useDeviceBits_) {
-    SkPixmap subset;
-    bool result = devicePixels.extractSubset(&subset, clip_bounds);
-    DCHECK(result);
-    if (!result)
-      return 0;
-    displayHeight = subset.height();
-    cgContext_ = CGBitmapContextCreate(subset.writable_addr(), subset.width(),
-      subset.height(), 8, subset.rowBytes(), colorSpace, 
-      kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst);
-  } else {
-    bool result = offscreen_.tryAllocN32Pixels(
-        SkScalarCeilToInt(bitmapScaleFactor_ * clip_bounds.width()),
-        SkScalarCeilToInt(bitmapScaleFactor_ * clip_bounds.height()));
-    DCHECK(result);
-    if (!result)
-      return 0;
-    offscreen_.eraseColor(0);
-    displayHeight = offscreen_.height();
-    cgContext_ = CGBitmapContextCreate(offscreen_.getPixels(),
-      offscreen_.width(), offscreen_.height(), 8, offscreen_.rowBytes(),
-      colorSpace, kCGBitmapByteOrder32Host | kCGImageAlphaPremultipliedFirst);
-  }
-  DCHECK(cgContext_);
-
-  SkMatrix matrix = canvas_->getTotalMatrix();
-  matrix.postTranslate(-SkIntToScalar(bitmapOffset_.x()),
-                       -SkIntToScalar(bitmapOffset_.y()));
-  matrix.postScale(bitmapScaleFactor_, -bitmapScaleFactor_);
-  matrix.postTranslate(0, SkIntToScalar(displayHeight));
-
-  CGContextConcatCTM(cgContext_, SkMatrixToCGAffineTransform(matrix));
-  
-  return cgContext_;
-}
-
-bool SkiaBitLocker::hasEmptyClipRegion() const {
-  return canvas_->isClipEmpty();
-}
-
 }  // namespace skia