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| 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 <stddef.h> |
| 9 #include <time.h> |
| 10 |
| 11 #include "base/mac/mac_util.h" |
| 12 #include "base/memory/ref_counted.h" |
| 13 #include "skia/ext/bitmap_platform_device.h" |
| 14 #include "skia/ext/platform_canvas.h" |
| 15 #include "skia/ext/skia_utils_mac.h" |
| 16 #include "third_party/skia/include/core/SkMatrix.h" |
| 17 #include "third_party/skia/include/core/SkPath.h" |
| 18 #include "third_party/skia/include/core/SkRect.h" |
| 19 #include "third_party/skia/include/core/SkTypes.h" |
| 20 |
| 21 namespace skia { |
| 22 |
| 23 namespace { |
| 24 |
| 25 // Returns true if it is unsafe to attempt to allocate an offscreen buffer |
| 26 // given these dimensions. |
| 27 bool RasterDeviceTooBigToAllocate(int width, int height) { |
| 28 |
| 29 #ifndef SKIA_EXT_RASTER_DEVICE_ALLOCATION_MAX |
| 30 #define SKIA_EXT_RASTER_DEVICE_ALLOCATION_MAX (2 * 256 * 1024 * 1024) |
| 31 #endif |
| 32 |
| 33 int bytesPerPixel = 4; |
| 34 int64_t bytes = (int64_t)width * height * bytesPerPixel; |
| 35 return bytes > SKIA_EXT_RASTER_DEVICE_ALLOCATION_MAX; |
| 36 } |
| 37 |
| 38 static CGContextRef CGContextForData(void* data, int width, int height) { |
| 39 #define HAS_ARGB_SHIFTS(a, r, g, b) \ |
| 40 (SK_A32_SHIFT == (a) && SK_R32_SHIFT == (r) \ |
| 41 && SK_G32_SHIFT == (g) && SK_B32_SHIFT == (b)) |
| 42 #if defined(SK_CPU_LENDIAN) && HAS_ARGB_SHIFTS(24, 16, 8, 0) |
| 43 // Allocate a bitmap context with 4 components per pixel (BGRA). Apple |
| 44 // recommends these flags for improved CG performance. |
| 45 |
| 46 // CGBitmapContextCreate returns NULL if width/height are 0. However, our |
| 47 // callers expect to get a canvas back (which they later resize/reallocate) |
| 48 // so we pin the dimensions here. |
| 49 width = SkMax32(1, width); |
| 50 height = SkMax32(1, height); |
| 51 CGContextRef context = |
| 52 CGBitmapContextCreate(data, width, height, 8, width * 4, |
| 53 base::mac::GetSystemColorSpace(), |
| 54 kCGImageAlphaPremultipliedFirst | |
| 55 kCGBitmapByteOrder32Host); |
| 56 #else |
| 57 #error We require that Skia's and CoreGraphics's recommended \ |
| 58 image memory layout match. |
| 59 #endif |
| 60 #undef HAS_ARGB_SHIFTS |
| 61 |
| 62 if (!context) |
| 63 return NULL; |
| 64 |
| 65 // Change the coordinate system to match WebCore's |
| 66 CGContextTranslateCTM(context, 0, height); |
| 67 CGContextScaleCTM(context, 1.0, -1.0); |
| 68 |
| 69 return context; |
| 70 } |
| 71 |
| 72 } // namespace |
| 73 |
| 74 void BitmapPlatformDevice::ReleaseBitmapContext() { |
| 75 SkASSERT(bitmap_context_); |
| 76 CGContextRelease(bitmap_context_); |
| 77 bitmap_context_ = NULL; |
| 78 } |
| 79 |
| 80 // Loads the specified Skia transform into the device context |
| 81 static void LoadTransformToCGContext(CGContextRef context, |
| 82 const SkMatrix& matrix) { |
| 83 // CoreGraphics can concatenate transforms, but not reset the current one. |
| 84 // So in order to get the required behavior here, we need to first make |
| 85 // the current transformation matrix identity and only then load the new one. |
| 86 |
| 87 // Reset matrix to identity. |
| 88 CGAffineTransform orig_cg_matrix = CGContextGetCTM(context); |
| 89 CGAffineTransform orig_cg_matrix_inv = |
| 90 CGAffineTransformInvert(orig_cg_matrix); |
| 91 CGContextConcatCTM(context, orig_cg_matrix_inv); |
| 92 |
| 93 // assert that we have indeed returned to the identity Matrix. |
| 94 SkASSERT(CGAffineTransformIsIdentity(CGContextGetCTM(context))); |
| 95 |
| 96 // Convert xform to CG-land. |
| 97 // Our coordinate system is flipped to match WebKit's so we need to modify |
| 98 // the xform to match that. |
| 99 SkMatrix transformed_matrix = matrix; |
| 100 SkScalar sy = -matrix.getScaleY(); |
| 101 transformed_matrix.setScaleY(sy); |
| 102 size_t height = CGBitmapContextGetHeight(context); |
| 103 SkScalar ty = -matrix.getTranslateY(); // y axis is flipped. |
| 104 transformed_matrix.setTranslateY(ty + (SkScalar)height); |
| 105 |
| 106 CGAffineTransform cg_matrix = |
| 107 skia::SkMatrixToCGAffineTransform(transformed_matrix); |
| 108 |
| 109 // Load final transform into context. |
| 110 CGContextConcatCTM(context, cg_matrix); |
| 111 } |
| 112 |
| 113 static void LoadClippingRegionToCGContext(CGContextRef context, |
| 114 const SkIRect& clip_bounds, |
| 115 const SkMatrix& transformation) { |
| 116 // CoreGraphics applies the current transform to clip rects, which is |
| 117 // unwanted. Inverse-transform the rect before sending it to CG. This only |
| 118 // works for translations and scaling, but not for rotations (but the |
| 119 // viewport is never rotated anyway). |
| 120 SkMatrix t; |
| 121 bool did_invert = transformation.invert(&t); |
| 122 if (!did_invert) |
| 123 t.reset(); |
| 124 |
| 125 SkRect rect = SkRect::Make(clip_bounds); |
| 126 t.mapRect(&rect); |
| 127 SkIRect irect; |
| 128 rect.round(&irect); |
| 129 CGContextClipToRect(context, skia::SkIRectToCGRect(irect)); |
| 130 } |
| 131 |
| 132 void BitmapPlatformDevice::LoadConfig(const SkMatrix& transform, |
| 133 const SkIRect& clip_bounds) { |
| 134 if (!bitmap_context_) |
| 135 return; // Nothing to do. |
| 136 |
| 137 // We must restore and then save the state of the graphics context since the |
| 138 // calls to Load the clipping region to the context are strictly cummulative, |
| 139 // i.e., you can't replace a clip rect, other than with a save/restore. |
| 140 // But this implies that no other changes to the state are done elsewhere. |
| 141 // If we ever get to need to change this, then we must replace the clip rect |
| 142 // calls in LoadClippingRegionToCGContext() with an image mask instead. |
| 143 CGContextRestoreGState(bitmap_context_); |
| 144 CGContextSaveGState(bitmap_context_); |
| 145 LoadTransformToCGContext(bitmap_context_, transform); |
| 146 LoadClippingRegionToCGContext(bitmap_context_, clip_bounds, transform); |
| 147 } |
| 148 |
| 149 |
| 150 // We use this static factory function instead of the regular constructor so |
| 151 // that we can create the pixel data before calling the constructor. This is |
| 152 // required so that we can call the base class' constructor with the pixel |
| 153 // data. |
| 154 BitmapPlatformDevice* BitmapPlatformDevice::Create(CGContextRef context, |
| 155 int width, |
| 156 int height, |
| 157 bool is_opaque, |
| 158 bool do_clear) { |
| 159 if (RasterDeviceTooBigToAllocate(width, height)) |
| 160 return NULL; |
| 161 |
| 162 SkBitmap bitmap; |
| 163 // TODO: verify that the CG Context's pixels will have tight rowbytes or pass
in the correct |
| 164 // rowbytes for the case when context != NULL. |
| 165 bitmap.setInfo(SkImageInfo::MakeN32(width, height, is_opaque ? kOpaque_SkAlpha
Type : kPremul_SkAlphaType)); |
| 166 |
| 167 void* data; |
| 168 if (context) { |
| 169 data = CGBitmapContextGetData(context); |
| 170 bitmap.setPixels(data); |
| 171 } else { |
| 172 if (!bitmap.tryAllocPixels()) |
| 173 return NULL; |
| 174 data = bitmap.getPixels(); |
| 175 } |
| 176 if (do_clear) |
| 177 memset(data, 0, bitmap.getSafeSize()); |
| 178 |
| 179 // If we were given data, then don't clobber it! |
| 180 #ifndef NDEBUG |
| 181 if (!context && is_opaque) { |
| 182 // To aid in finding bugs, we set the background color to something |
| 183 // obviously wrong so it will be noticable when it is not cleared |
| 184 bitmap.eraseARGB(255, 0, 255, 128); // bright bluish green |
| 185 } |
| 186 #endif |
| 187 |
| 188 if (!context) { |
| 189 context = CGContextForData(data, width, height); |
| 190 if (!context) |
| 191 return NULL; |
| 192 } else |
| 193 CGContextRetain(context); |
| 194 |
| 195 BitmapPlatformDevice* rv = new BitmapPlatformDevice(context, bitmap); |
| 196 |
| 197 // The device object took ownership of the graphics context with its own |
| 198 // CGContextRetain call. |
| 199 CGContextRelease(context); |
| 200 |
| 201 return rv; |
| 202 } |
| 203 |
| 204 BitmapPlatformDevice* BitmapPlatformDevice::CreateWithData(uint8_t* data, |
| 205 int width, |
| 206 int height, |
| 207 bool is_opaque) { |
| 208 CGContextRef context = NULL; |
| 209 if (data) |
| 210 context = CGContextForData(data, width, height); |
| 211 |
| 212 BitmapPlatformDevice* rv = Create(context, width, height, is_opaque, false); |
| 213 |
| 214 // The device object took ownership of the graphics context with its own |
| 215 // CGContextRetain call. |
| 216 if (context) |
| 217 CGContextRelease(context); |
| 218 |
| 219 return rv; |
| 220 } |
| 221 |
| 222 // The device will own the bitmap, which corresponds to also owning the pixel |
| 223 // data. Therefore, we do not transfer ownership to the SkBitmapDevice's bitmap. |
| 224 BitmapPlatformDevice::BitmapPlatformDevice( |
| 225 CGContextRef context, const SkBitmap& bitmap) |
| 226 : SkBitmapDevice(bitmap), |
| 227 bitmap_context_(context) { |
| 228 SetPlatformDevice(this, this); |
| 229 SkASSERT(bitmap_context_); |
| 230 // Initialize the clip region to the entire bitmap. |
| 231 |
| 232 SkIRect rect; |
| 233 rect.set(0, 0, |
| 234 CGBitmapContextGetWidth(bitmap_context_), |
| 235 CGBitmapContextGetHeight(bitmap_context_)); |
| 236 CGContextRetain(bitmap_context_); |
| 237 // We must save the state once so that we can use the restore/save trick |
| 238 // in LoadConfig(). |
| 239 CGContextSaveGState(bitmap_context_); |
| 240 } |
| 241 |
| 242 BitmapPlatformDevice::~BitmapPlatformDevice() { |
| 243 if (bitmap_context_) |
| 244 CGContextRelease(bitmap_context_); |
| 245 } |
| 246 |
| 247 NativeDrawingContext BitmapPlatformDevice::BeginPlatformPaint( |
| 248 const SkMatrix& transform, |
| 249 const SkIRect& clip_bounds) { |
| 250 LoadConfig(transform, clip_bounds); |
| 251 return bitmap_context_; |
| 252 } |
| 253 |
| 254 SkBaseDevice* BitmapPlatformDevice::onCreateDevice(const CreateInfo& cinfo, |
| 255 const SkPaint*) { |
| 256 const SkImageInfo& info = cinfo.fInfo; |
| 257 const bool do_clear = !info.isOpaque(); |
| 258 SkASSERT(info.colorType() == kN32_SkColorType); |
| 259 return Create(NULL, info.width(), info.height(), info.isOpaque(), do_clear); |
| 260 } |
| 261 |
| 262 // PlatformCanvas impl |
| 263 |
| 264 std::unique_ptr<SkCanvas> CreatePlatformCanvasWithPixels( |
| 265 int width, |
| 266 int height, |
| 267 bool is_opaque, |
| 268 uint8_t* data, |
| 269 OnFailureType failureType) { |
| 270 sk_sp<SkBaseDevice> dev( |
| 271 BitmapPlatformDevice::CreateWithData(data, width, height, is_opaque)); |
| 272 return CreateCanvas(dev, failureType); |
| 273 } |
| 274 |
| 275 } // namespace skia |
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