blob: cc4f3ef8e8932a31ba9255231594ced80b6cf596 [file] [log] [blame]
// 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/bitmap_platform_device_mac.h"
#import <ApplicationServices/ApplicationServices.h>
#include <time.h>
#include "base/mac/mac_util.h"
#include "base/memory/ref_counted.h"
#include "skia/ext/bitmap_platform_device.h"
#include "skia/ext/platform_canvas.h"
#include "skia/ext/skia_utils_mac.h"
#include "third_party/skia/include/core/SkMatrix.h"
#include "third_party/skia/include/core/SkPath.h"
#include "third_party/skia/include/core/SkRegion.h"
#include "third_party/skia/include/core/SkTypes.h"
#include "third_party/skia/include/core/SkUtils.h"
namespace skia {
namespace {
static CGContextRef CGContextForData(void* data, int width, int height) {
#define HAS_ARGB_SHIFTS(a, r, g, b) \
(SK_A32_SHIFT == (a) && SK_R32_SHIFT == (r) \
&& SK_G32_SHIFT == (g) && SK_B32_SHIFT == (b))
#if defined(SK_CPU_LENDIAN) && HAS_ARGB_SHIFTS(24, 16, 8, 0)
// Allocate a bitmap context with 4 components per pixel (BGRA). Apple
// recommends these flags for improved CG performance.
// CGBitmapContextCreate returns NULL if width/height are 0. However, our
// callers expect to get a canvas back (which they later resize/reallocate)
// so we pin the dimensions here.
width = SkMax32(1, width);
height = SkMax32(1, height);
CGContextRef context =
CGBitmapContextCreate(data, width, height, 8, width * 4,
kCGImageAlphaPremultipliedFirst |
#error We require that Skia's and CoreGraphics's recommended \
image memory layout match.
if (!context)
return NULL;
// Change the coordinate system to match WebCore's
CGContextTranslateCTM(context, 0, height);
CGContextScaleCTM(context, 1.0, -1.0);
return context;
} // namespace
void BitmapPlatformDevice::ReleaseBitmapContext() {
bitmap_context_ = NULL;
void BitmapPlatformDevice::SetMatrixClip(
const SkMatrix& transform,
const SkRegion& region) {
transform_ = transform;
clip_region_ = region;
config_dirty_ = true;
// Loads the specified Skia transform into the device context
static void LoadTransformToCGContext(CGContextRef context,
const SkMatrix& matrix) {
// CoreGraphics can concatenate transforms, but not reset the current one.
// So in order to get the required behavior here, we need to first make
// the current transformation matrix identity and only then load the new one.
// Reset matrix to identity.
CGAffineTransform orig_cg_matrix = CGContextGetCTM(context);
CGAffineTransform orig_cg_matrix_inv =
CGContextConcatCTM(context, orig_cg_matrix_inv);
// assert that we have indeed returned to the identity Matrix.
// Convert xform to CG-land.
// Our coordinate system is flipped to match WebKit's so we need to modify
// the xform to match that.
SkMatrix transformed_matrix = matrix;
SkScalar sy = -matrix.getScaleY();
size_t height = CGBitmapContextGetHeight(context);
SkScalar ty = -matrix.getTranslateY(); // y axis is flipped.
transformed_matrix.setTranslateY(ty + (SkScalar)height);
CGAffineTransform cg_matrix =
// Load final transform into context.
CGContextConcatCTM(context, cg_matrix);
// Loads a SkRegion into the CG context.
static void LoadClippingRegionToCGContext(CGContextRef context,
const SkRegion& region,
const SkMatrix& transformation) {
if (region.isEmpty()) {
// region can be empty, in which case everything will be clipped.
SkRect rect;
CGContextClipToRect(context, gfx::SkRectToCGRect(rect));
} else if (region.isRect()) {
// CoreGraphics applies the current transform to clip rects, which is
// unwanted. Inverse-transform the rect before sending it to CG. This only
// works for translations and scaling, but not for rotations (but the
// viewport is never rotated anyway).
SkMatrix t;
bool did_invert = transformation.invert(&t);
if (!did_invert)
// Do the transformation.
SkRect rect;
SkIRect irect;
CGContextClipToRect(context, gfx::SkIRectToCGRect(irect));
} else {
// It is complex.
SkPath path;
// Clip. Note that windows clipping regions are not affected by the
// transform so apply it manually.
// TODO(playmobil): Implement.
// LoadPathToDC(context, path);
// hrgn = PathToRegion(context);
void BitmapPlatformDevice::LoadConfig() {
if (!config_dirty_ || !bitmap_context_)
return; // Nothing to do.
config_dirty_ = false;
// We must restore and then save the state of the graphics context since the
// calls to Load the clipping region to the context are strictly cummulative,
// i.e., you can't replace a clip rect, other than with a save/restore.
// But this implies that no other changes to the state are done elsewhere.
// If we ever get to need to change this, then we must replace the clip rect
// calls in LoadClippingRegionToCGContext() with an image mask instead.
LoadTransformToCGContext(bitmap_context_, transform_);
LoadClippingRegionToCGContext(bitmap_context_, clip_region_, transform_);
// We use this static factory function instead of the regular constructor so
// that we can create the pixel data before calling the constructor. This is
// required so that we can call the base class' constructor with the pixel
// data.
BitmapPlatformDevice* BitmapPlatformDevice::Create(CGContextRef context,
int width,
int height,
bool is_opaque,
bool do_clear) {
if (RasterDeviceTooBigToAllocate(width, height))
return NULL;
SkBitmap bitmap;
// TODO: verify that the CG Context's pixels will have tight rowbytes or pass in the correct
// rowbytes for the case when context != NULL.
bitmap.setInfo(SkImageInfo::MakeN32(width, height, is_opaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType));
void* data;
if (context) {
data = CGBitmapContextGetData(context);
} else {
if (!bitmap.tryAllocPixels())
return NULL;
data = bitmap.getPixels();
if (do_clear)
memset(data, 0, bitmap.getSafeSize());
// If we were given data, then don't clobber it!
#ifndef NDEBUG
if (!context && is_opaque) {
// To aid in finding bugs, we set the background color to something
// obviously wrong so it will be noticable when it is not cleared
bitmap.eraseARGB(255, 0, 255, 128); // bright bluish green
if (!context) {
context = CGContextForData(data, width, height);
if (!context)
return NULL;
} else
BitmapPlatformDevice* rv = new BitmapPlatformDevice(context, bitmap);
// The device object took ownership of the graphics context with its own
// CGContextRetain call.
return rv;
BitmapPlatformDevice* BitmapPlatformDevice::CreateWithData(uint8_t* data,
int width,
int height,
bool is_opaque) {
CGContextRef context = NULL;
if (data)
context = CGContextForData(data, width, height);
BitmapPlatformDevice* rv = Create(context, width, height, is_opaque, false);
// The device object took ownership of the graphics context with its own
// CGContextRetain call.
if (context)
return rv;
// The device will own the bitmap, which corresponds to also owning the pixel
// data. Therefore, we do not transfer ownership to the SkBitmapDevice's bitmap.
CGContextRef context, const SkBitmap& bitmap)
: SkBitmapDevice(bitmap),
config_dirty_(true), // Want to load the config next time.
transform_(SkMatrix::I()) {
SetPlatformDevice(this, this);
// Initialize the clip region to the entire bitmap.
SkIRect rect;
rect.set(0, 0,
clip_region_ = SkRegion(rect);
// We must save the state once so that we can use the restore/save trick
// in LoadConfig().
BitmapPlatformDevice::~BitmapPlatformDevice() {
if (bitmap_context_)
CGContextRef BitmapPlatformDevice::GetBitmapContext() {
return bitmap_context_;
void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
const SkRegion& region,
const SkClipStack&) {
SetMatrixClip(transform, region);
SkBaseDevice* BitmapPlatformDevice::onCreateDevice(const CreateInfo& cinfo,
const SkPaint*) {
const SkImageInfo& info = cinfo.fInfo;
const bool do_clear = !info.isOpaque();
SkASSERT(info.colorType() == kN32_SkColorType);
return Create(NULL, info.width(), info.height(), info.isOpaque(), do_clear);
// PlatformCanvas impl
SkCanvas* CreatePlatformCanvas(CGContextRef ctx, int width, int height,
bool is_opaque, OnFailureType failureType) {
const bool do_clear = false;
skia::RefPtr<SkBaseDevice> dev = skia::AdoptRef(
BitmapPlatformDevice::Create(ctx, width, height, is_opaque, do_clear));
return CreateCanvas(dev, failureType);
SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
uint8_t* data, OnFailureType failureType) {
skia::RefPtr<SkBaseDevice> dev = skia::AdoptRef(
BitmapPlatformDevice::CreateWithData(data, width, height, is_opaque));
return CreateCanvas(dev, failureType);
} // namespace skia