skia/ext/bitmap_platform_device_mac.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "skia/ext/bitmap_platform_device_mac.h"
   6
   7 #import <ApplicationServices/ApplicationServices.h>
   8 #include <time.h>
   9
  10 #include "base/mac/mac_util.h"
  11 #include "base/memory/ref_counted.h"
  12 #include "skia/ext/bitmap_platform_device.h"
  13 #include "skia/ext/platform_canvas.h"
  14 #include "skia/ext/skia_utils_mac.h"
  15 #include "third_party/skia/include/core/SkMatrix.h"
  16 #include "third_party/skia/include/core/SkRegion.h"
  17 #include "third_party/skia/include/core/SkTypes.h"
  18 #include "third_party/skia/include/core/SkUtils.h"
  19
  20 namespace skia {
  21
  22 namespace {
  23
  24 static CGContextRef CGContextForData(void* data, int width, int height) {
  25 #define HAS_ARGB_SHIFTS(a, r, g, b) \
  26             (SK_A32_SHIFT == (a) && SK_R32_SHIFT == (r) \
  27              && SK_G32_SHIFT == (g) && SK_B32_SHIFT == (b))
  28 #if defined(SK_CPU_LENDIAN) && HAS_ARGB_SHIFTS(24, 16, 8, 0)
  29   // Allocate a bitmap context with 4 components per pixel (BGRA).  Apple
  30   // recommends these flags for improved CG performance.
  31
  32   // CGBitmapContextCreate returns NULL if width/height are 0. However, our
  33   // callers expect to get a canvas back (which they later resize/reallocate)
  34   // so we pin the dimensions here.
  35   width = SkMax32(1, width);
  36   height = SkMax32(1, height);
  37   CGContextRef context =
  38       CGBitmapContextCreate(data, width, height, 8, width * 4,
  39                             base::mac::GetSystemColorSpace(),
  40                             kCGImageAlphaPremultipliedFirst |
  41                                 kCGBitmapByteOrder32Host);
  42 #else
  43 #error We require that Skia's and CoreGraphics's recommended \
  44        image memory layout match.
  45 #endif
  46 #undef HAS_ARGB_SHIFTS
  47
  48   if (!context)
  49     return NULL;
  50
  51   // Change the coordinate system to match WebCore's
  52   CGContextTranslateCTM(context, 0, height);
  53   CGContextScaleCTM(context, 1.0, -1.0);
  54
  55   return context;
  56 }
  57
  58 }  // namespace
  59
  60 void BitmapPlatformDevice::ReleaseBitmapContext() {
  61   SkASSERT(bitmap_context_);
  62   CGContextRelease(bitmap_context_);
  63   bitmap_context_ = NULL;
  64 }
  65
  66 void BitmapPlatformDevice::SetMatrixClip(
  67     const SkMatrix& transform,
  68     const SkRegion& region) {
  69   transform_ = transform;
  70   clip_region_ = region;
  71   config_dirty_ = true;
  72 }
  73
  74 void BitmapPlatformDevice::LoadConfig() {
  75   if (!config_dirty_ || !bitmap_context_)
  76     return;  // Nothing to do.
  77   config_dirty_ = false;
  78
  79   // We must restore and then save the state of the graphics context since the
  80   // calls to Load the clipping region to the context are strictly cummulative,
  81   // i.e., you can't replace a clip rect, other than with a save/restore.
  82   // But this implies that no other changes to the state are done elsewhere.
  83   // If we ever get to need to change this, then we must replace the clip rect
  84   // calls in LoadClippingRegionToCGContext() with an image mask instead.
  85   CGContextRestoreGState(bitmap_context_);
  86   CGContextSaveGState(bitmap_context_);
  87   LoadTransformToCGContext(bitmap_context_, transform_);
  88   LoadClippingRegionToCGContext(bitmap_context_, clip_region_, transform_);
  89 }
  90
  91
  92 // We use this static factory function instead of the regular constructor so
  93 // that we can create the pixel data before calling the constructor. This is
  94 // required so that we can call the base class' constructor with the pixel
  95 // data.
  96 BitmapPlatformDevice* BitmapPlatformDevice::Create(CGContextRef context,
  97                                                    int width,
  98                                                    int height,
  99                                                    bool is_opaque) {
 100   if (RasterDeviceTooBigToAllocate(width, height))
 101     return NULL;
 102
 103   SkBitmap bitmap;
 104   // TODO: verify that the CG Context's pixels will have tight rowbytes or pass in the correct
 105   // rowbytes for the case when context != NULL.
 106   bitmap.setInfo(SkImageInfo::MakeN32(width, height, is_opaque ? kOpaque_SkAlphaType : kPremul_SkAlphaType));
 107
 108   void* data;
 109   if (context) {
 110     data = CGBitmapContextGetData(context);
 111     bitmap.setPixels(data);
 112   } else {
 113     if (!bitmap.tryAllocPixels())
 114       return NULL;
 115     data = bitmap.getPixels();
 116   }
 117
 118   // If we were given data, then don't clobber it!
 119 #ifndef NDEBUG
 120   if (!context && is_opaque) {
 121     // To aid in finding bugs, we set the background color to something
 122     // obviously wrong so it will be noticable when it is not cleared
 123     bitmap.eraseARGB(255, 0, 255, 128);  // bright bluish green
 124   }
 125 #endif
 126
 127   if (!context) {
 128     context = CGContextForData(data, width, height);
 129     if (!context)
 130       return NULL;
 131   } else
 132     CGContextRetain(context);
 133
 134   BitmapPlatformDevice* rv = new BitmapPlatformDevice(context, bitmap);
 135
 136   // The device object took ownership of the graphics context with its own
 137   // CGContextRetain call.
 138   CGContextRelease(context);
 139
 140   return rv;
 141 }
 142
 143 BitmapPlatformDevice* BitmapPlatformDevice::CreateAndClear(int width,
 144                                                            int height,
 145                                                            bool is_opaque) {
 146   BitmapPlatformDevice* device = Create(NULL, width, height, is_opaque);
 147   if (!is_opaque)
 148     device->clear(0);
 149   return device;
 150 }
 151
 152 BitmapPlatformDevice* BitmapPlatformDevice::CreateWithData(uint8_t* data,
 153                                                            int width,
 154                                                            int height,
 155                                                            bool is_opaque) {
 156   CGContextRef context = NULL;
 157   if (data)
 158     context = CGContextForData(data, width, height);
 159
 160   BitmapPlatformDevice* rv = Create(context, width, height, is_opaque);
 161
 162   // The device object took ownership of the graphics context with its own
 163   // CGContextRetain call.
 164   if (context)
 165     CGContextRelease(context);
 166
 167   return rv;
 168 }
 169
 170 // The device will own the bitmap, which corresponds to also owning the pixel
 171 // data. Therefore, we do not transfer ownership to the SkBitmapDevice's bitmap.
 172 BitmapPlatformDevice::BitmapPlatformDevice(
 173     CGContextRef context, const SkBitmap& bitmap)
 174     : SkBitmapDevice(bitmap),
 175       bitmap_context_(context),
 176       config_dirty_(true),  // Want to load the config next time.
 177       transform_(SkMatrix::I()) {
 178   SetPlatformDevice(this, this);
 179   SkASSERT(bitmap_context_);
 180   // Initialize the clip region to the entire bitmap.
 181
 182   SkIRect rect;
 183   rect.set(0, 0,
 184            CGBitmapContextGetWidth(bitmap_context_),
 185            CGBitmapContextGetHeight(bitmap_context_));
 186   clip_region_ = SkRegion(rect);
 187   CGContextRetain(bitmap_context_);
 188   // We must save the state once so that we can use the restore/save trick
 189   // in LoadConfig().
 190   CGContextSaveGState(bitmap_context_);
 191 }
 192
 193 BitmapPlatformDevice::~BitmapPlatformDevice() {
 194   if (bitmap_context_)
 195     CGContextRelease(bitmap_context_);
 196 }
 197
 198 CGContextRef BitmapPlatformDevice::GetBitmapContext() {
 199   LoadConfig();
 200   return bitmap_context_;
 201 }
 202
 203 void BitmapPlatformDevice::setMatrixClip(const SkMatrix& transform,
 204                                          const SkRegion& region,
 205                                          const SkClipStack&) {
 206   SetMatrixClip(transform, region);
 207 }
 208
 209 void BitmapPlatformDevice::DrawToNativeContext(CGContextRef context, int x,
 210                                                int y, const CGRect* src_rect) {
 211   bool created_dc = false;
 212   if (!bitmap_context_) {
 213     created_dc = true;
 214     GetBitmapContext();
 215   }
 216
 217   // this should not make a copy of the bits, since we're not doing
 218   // anything to trigger copy on write
 219   CGImageRef image = CGBitmapContextCreateImage(bitmap_context_);
 220   CGRect bounds;
 221   bounds.origin.x = x;
 222   bounds.origin.y = y;
 223   if (src_rect) {
 224     bounds.size.width = src_rect->size.width;
 225     bounds.size.height = src_rect->size.height;
 226     CGImageRef sub_image = CGImageCreateWithImageInRect(image, *src_rect);
 227     CGContextDrawImage(context, bounds, sub_image);
 228     CGImageRelease(sub_image);
 229   } else {
 230     bounds.size.width = width();
 231     bounds.size.height = height();
 232     CGContextDrawImage(context, bounds, image);
 233   }
 234   CGImageRelease(image);
 235
 236   if (created_dc)
 237     ReleaseBitmapContext();
 238 }
 239
 240 SkBaseDevice* BitmapPlatformDevice::onCreateDevice(const SkImageInfo& info,
 241                                                    Usage /*usage*/) {
 242   SkASSERT(info.colorType() == kN32_SkColorType);
 243   return BitmapPlatformDevice::CreateAndClear(info.width(), info.height(),
 244                                                 info.isOpaque());
 245 }
 246
 247 // PlatformCanvas impl
 248
 249 SkCanvas* CreatePlatformCanvas(CGContextRef ctx, int width, int height,
 250                                bool is_opaque, OnFailureType failureType) {
 251   skia::RefPtr<SkBaseDevice> dev = skia::AdoptRef(
 252       BitmapPlatformDevice::Create(ctx, width, height, is_opaque));
 253   return CreateCanvas(dev, failureType);
 254 }
 255
 256 SkCanvas* CreatePlatformCanvas(int width, int height, bool is_opaque,
 257                                uint8_t* data, OnFailureType failureType) {
 258   skia::RefPtr<SkBaseDevice> dev = skia::AdoptRef(
 259       BitmapPlatformDevice::CreateWithData(data, width, height, is_opaque));
 260   return CreateCanvas(dev, failureType);
 261 }
 262
 263 // Port of PlatformBitmap to mac
 264
 265 PlatformBitmap::~PlatformBitmap() {
 266   if (surface_)
 267     CGContextRelease(surface_);
 268 }
 269
 270 bool PlatformBitmap::Allocate(int width, int height, bool is_opaque) {
 271   if (RasterDeviceTooBigToAllocate(width, height))
 272     return false;
 273
 274   if (!bitmap_.tryAllocN32Pixels(width, height, is_opaque))
 275     return false;
 276
 277   if (!is_opaque)
 278     bitmap_.eraseColor(0);
 279
 280   surface_ = CGContextForData(bitmap_.getPixels(), bitmap_.width(),
 281                               bitmap_.height());
 282   return true;
 283 }
 284
 285 }  // namespace skia