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// Copyright (c) 2009 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.
#ifndef SKIA_EXT_CANVAS_PAINT_MAC_H_
#define SKIA_EXT_CANVAS_PAINT_MAC_H_
#pragma once
#include "skia/ext/platform_canvas.h"
#import <Cocoa/Cocoa.h>
namespace skia {
// A class designed to translate skia painting into a region to the current
// graphics context. This class has been adapted from the class with the same
// name in platform_canvas_win.h. On construction, it will set up a context for
// painting into, and on destruction, it will commit it to the current context.
template <class T>
class CanvasPaintT : public T {
public:
// This constructor assumes the result is opaque.
explicit CanvasPaintT(NSRect dirtyRect)
: context_(NULL),
rectangle_(dirtyRect),
composite_alpha_(false) {
init(true);
}
CanvasPaintT(NSRect dirtyRect, bool opaque)
: context_(NULL),
rectangle_(dirtyRect),
composite_alpha_(false) {
init(opaque);
}
virtual ~CanvasPaintT() {
if (!is_empty()) {
T::restoreToCount(1);
// Blit the dirty rect to the current context.
CGImageRef image = CGBitmapContextCreateImage(context_);
CGRect destRect = NSRectToCGRect(rectangle_);
CGContextRef destinationContext =
(CGContextRef)[[NSGraphicsContext currentContext] graphicsPort];
CGContextSaveGState(destinationContext);
CGContextSetBlendMode(
destinationContext,
composite_alpha_ ? kCGBlendModeNormal : kCGBlendModeCopy);
if ([[NSGraphicsContext currentContext] isFlipped]) {
// Mirror context on the target's rect middle scanline.
CGContextTranslateCTM(destinationContext, 0.0, NSMidY(rectangle_));
CGContextScaleCTM(destinationContext, 1.0, -1.0);
CGContextTranslateCTM(destinationContext, 0.0, -NSMidY(rectangle_));
}
CGContextDrawImage(destinationContext, destRect, image);
CGContextRestoreGState(destinationContext);
CFRelease(image);
}
}
// If true, the data painted into the CanvasPaintT is blended onto the current
// context, else it is copied.
void set_composite_alpha(bool composite_alpha) {
composite_alpha_ = composite_alpha;
}
// Returns true if the invalid region is empty. The caller should call this
// function to determine if anything needs painting.
bool is_empty() const {
return rectangle_.size.width == 0 || rectangle_.size.height == 0;
}
const NSRect& rectangle() const {
return rectangle_;
}
private:
void init(bool opaque) {
if (!T::initialize(rectangle_.size.width, rectangle_.size.height,
opaque, NULL)) {
// Cause a deliberate crash;
*(char*) 0 = 0;
}
// Need to translate so that the dirty region appears at the origin of the
// surface.
T::translate(-SkIntToScalar(rectangle_.origin.x),
-SkIntToScalar(rectangle_.origin.y));
context_ = T::getTopPlatformDevice().GetBitmapContext();
}
CGContext* context_;
NSRect rectangle_;
// See description above setter.
bool composite_alpha_;
// Disallow copy and assign.
CanvasPaintT(const CanvasPaintT&);
CanvasPaintT& operator=(const CanvasPaintT&);
};
typedef CanvasPaintT<PlatformCanvas> PlatformCanvasPaint;
} // namespace skia
#endif // SKIA_EXT_CANVAS_PAINT_MAC_H_
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