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| 1 // Copyright (c) 2006-2008 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 "BitmapPlatformDeviceWin.h" | |
| 6 | |
| 7 #include "base/gfx/gdi_util.h" | |
| 8 #include "base/logging.h" | |
| 9 #include "SkMatrix.h" | |
| 10 #include "SkRegion.h" | |
| 11 #include "SkUtils.h" | |
| 12 | |
| 13 namespace gfx { | |
| 14 | |
| 15 // When Windows draws text, is sets the fourth byte (which Skia uses for alpha) | |
| 16 // to zero. This means that if we try compositing with text that Windows has | |
| 17 // drawn, we get invalid color values (if the alpha is 0, the other channels | |
| 18 // should be 0 since Skia uses premultiplied colors) and strange results. | |
| 19 // | |
| 20 // HTML rendering only requires one bit of transparency. When you ask for a | |
| 21 // semitransparent div, the div itself is drawn in another layer as completely | |
| 22 // opaque, and then composited onto the lower layer with a transfer function. | |
| 23 // The only place an alpha channel is needed is to track what has been drawn | |
| 24 // and what has not been drawn. | |
| 25 // | |
| 26 // Therefore, when we allocate a new device, we fill it with this special | |
| 27 // color. Because Skia uses premultiplied colors, any color where the alpha | |
| 28 // channel is smaller than any component is impossible, so we know that no | |
| 29 // legitimate drawing will produce this color. We use 1 as the alpha value | |
| 30 // because 0 is produced when Windows draws text (even though it should be | |
| 31 // opaque). | |
| 32 // | |
| 33 // When a layer is done and we want to render it to a lower layer, we use | |
| 34 // fixupAlphaBeforeCompositing. This replaces all 0 alpha channels with | |
| 35 // opaque (to fix the text problem), and replaces this magic color value | |
| 36 // with transparency. The result is something that can be correctly | |
| 37 // composited. However, once this has been done, no more can be drawn to | |
| 38 // the layer because fixing the alphas *again* will result in incorrect | |
| 39 // values. | |
| 40 static const uint32_t kMagicTransparencyColor = 0x01FFFEFD; | |
| 41 | |
| 42 namespace { | |
| 43 | |
| 44 // Constrains position and size to fit within available_size. If |size| is -1, | |
| 45 // all the available_size is used. Returns false if the position is out of | |
| 46 // available_size. | |
| 47 bool Constrain(int available_size, int* position, int *size) { | |
| 48 if (*size < -2) | |
| 49 return false; | |
| 50 | |
| 51 if (*position < 0) { | |
| 52 if (*size != -1) | |
| 53 *size += *position; | |
| 54 *position = 0; | |
| 55 } | |
| 56 if (*size == 0 || *position >= available_size) | |
| 57 return false; | |
| 58 | |
| 59 if (*size > 0) { | |
| 60 int overflow = (*position + *size) - available_size; | |
| 61 if (overflow > 0) { | |
| 62 *size -= overflow; | |
| 63 } | |
| 64 } else { | |
| 65 // Fill up available size. | |
| 66 *size = available_size - *position; | |
| 67 } | |
| 68 return true; | |
| 69 } | |
| 70 | |
| 71 // If the pixel value is 0, it gets set to kMagicTransparencyColor. | |
| 72 void PrepareAlphaForGDI(uint32_t* pixel) { | |
| 73 if (*pixel == 0) { | |
| 74 *pixel = kMagicTransparencyColor; | |
| 75 } | |
| 76 } | |
| 77 | |
| 78 // If the pixel value is kMagicTransparencyColor, it gets set to 0. Otherwise | |
| 79 // if the alpha is 0, the alpha is set to 255. | |
| 80 void PostProcessAlphaForGDI(uint32_t* pixel) { | |
| 81 if (*pixel == kMagicTransparencyColor) { | |
| 82 *pixel = 0; | |
| 83 } else if ((*pixel & 0xFF000000) == 0) { | |
| 84 *pixel |= 0xFF000000; | |
| 85 } | |
| 86 } | |
| 87 | |
| 88 // Sets the opacity of the specified value to 0xFF. | |
| 89 void MakeOpaqueAlphaAdjuster(uint32_t* pixel) { | |
| 90 *pixel |= 0xFF000000; | |
| 91 } | |
| 92 | |
| 93 // See the declaration of kMagicTransparencyColor at the top of the file. | |
| 94 void FixupAlphaBeforeCompositing(uint32_t* pixel) { | |
| 95 if (*pixel == kMagicTransparencyColor) | |
| 96 *pixel = 0; | |
| 97 else | |
| 98 *pixel |= 0xFF000000; | |
| 99 } | |
| 100 | |
| 101 } // namespace | |
| 102 | |
| 103 class BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData | |
| 104 : public base::RefCounted<BitmapPlatformDeviceWinData> { | |
| 105 public: | |
| 106 explicit BitmapPlatformDeviceWinData(HBITMAP hbitmap); | |
| 107 | |
| 108 // Create/destroy hdc_, which is the memory DC for our bitmap data. | |
| 109 HDC GetBitmapDC(); | |
| 110 void ReleaseBitmapDC(); | |
| 111 bool IsBitmapDCCreated() const; | |
| 112 | |
| 113 // Sets the transform and clip operations. This will not update the DC, | |
| 114 // but will mark the config as dirty. The next call of LoadConfig will | |
| 115 // pick up these changes. | |
| 116 void SetMatrixClip(const SkMatrix& transform, const SkRegion& region); | |
| 117 | |
| 118 const SkMatrix& transform() const { | |
| 119 return transform_; | |
| 120 } | |
| 121 | |
| 122 protected: | |
| 123 // Loads the current transform and clip into the DC. Can be called even when | |
| 124 // the DC is NULL (will be a NOP). | |
| 125 void LoadConfig(); | |
| 126 | |
| 127 // Windows bitmap corresponding to our surface. | |
| 128 HBITMAP hbitmap_; | |
| 129 | |
| 130 // Lazily-created DC used to draw into the bitmap, see getBitmapDC. | |
| 131 HDC hdc_; | |
| 132 | |
| 133 // True when there is a transform or clip that has not been set to the DC. | |
| 134 // The DC is retrieved for every text operation, and the transform and clip | |
| 135 // do not change as much. We can save time by not loading the clip and | |
| 136 // transform for every one. | |
| 137 bool config_dirty_; | |
| 138 | |
| 139 // Translation assigned to the DC: we need to keep track of this separately | |
| 140 // so it can be updated even if the DC isn't created yet. | |
| 141 SkMatrix transform_; | |
| 142 | |
| 143 // The current clipping | |
| 144 SkRegion clip_region_; | |
| 145 | |
| 146 private: | |
| 147 friend class base::RefCounted<BitmapPlatformDeviceWinData>; | |
| 148 ~BitmapPlatformDeviceWinData(); | |
| 149 | |
| 150 DISALLOW_EVIL_CONSTRUCTORS(BitmapPlatformDeviceWinData); | |
| 151 }; | |
| 152 | |
| 153 BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::BitmapPlatformDeviceWinDat
a( | |
| 154 HBITMAP hbitmap) | |
| 155 : hbitmap_(hbitmap), | |
| 156 hdc_(NULL), | |
| 157 config_dirty_(true) { // Want to load the config next time. | |
| 158 // Initialize the clip region to the entire bitmap. | |
| 159 BITMAP bitmap_data; | |
| 160 if (GetObject(hbitmap_, sizeof(BITMAP), &bitmap_data)) { | |
| 161 SkIRect rect; | |
| 162 rect.set(0, 0, bitmap_data.bmWidth, bitmap_data.bmHeight); | |
| 163 clip_region_ = SkRegion(rect); | |
| 164 } | |
| 165 | |
| 166 transform_.reset(); | |
| 167 } | |
| 168 | |
| 169 BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::~BitmapPlatformDeviceWinDa
ta() { | |
| 170 if (hdc_) | |
| 171 ReleaseBitmapDC(); | |
| 172 | |
| 173 // this will free the bitmap data as well as the bitmap handle | |
| 174 DeleteObject(hbitmap_); | |
| 175 } | |
| 176 | |
| 177 HDC BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::GetBitmapDC() { | |
| 178 if (!hdc_) { | |
| 179 hdc_ = CreateCompatibleDC(NULL); | |
| 180 InitializeDC(hdc_); | |
| 181 HGDIOBJ old_bitmap = SelectObject(hdc_, hbitmap_); | |
| 182 // When the memory DC is created, its display surface is exactly one | |
| 183 // monochrome pixel wide and one monochrome pixel high. Since we select our | |
| 184 // own bitmap, we must delete the previous one. | |
| 185 DeleteObject(old_bitmap); | |
| 186 } | |
| 187 | |
| 188 LoadConfig(); | |
| 189 return hdc_; | |
| 190 } | |
| 191 | |
| 192 void BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::ReleaseBitmapDC() { | |
| 193 DCHECK(hdc_); | |
| 194 DeleteDC(hdc_); | |
| 195 hdc_ = NULL; | |
| 196 } | |
| 197 | |
| 198 bool BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::IsBitmapDCCreated() | |
| 199 const { | |
| 200 return hdc_ != NULL; | |
| 201 } | |
| 202 | |
| 203 | |
| 204 void BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::SetMatrixClip( | |
| 205 const SkMatrix& transform, | |
| 206 const SkRegion& region) { | |
| 207 transform_ = transform; | |
| 208 clip_region_ = region; | |
| 209 config_dirty_ = true; | |
| 210 } | |
| 211 | |
| 212 void BitmapPlatformDeviceWin::BitmapPlatformDeviceWinData::LoadConfig() { | |
| 213 if (!config_dirty_ || !hdc_) | |
| 214 return; // Nothing to do. | |
| 215 config_dirty_ = false; | |
| 216 | |
| 217 // Transform. | |
| 218 SkMatrix t(transform_); | |
| 219 LoadTransformToDC(hdc_, t); | |
| 220 // We don't use transform_ for the clipping region since the translation is | |
| 221 // already applied to offset_x_ and offset_y_. | |
| 222 t.reset(); | |
| 223 LoadClippingRegionToDC(hdc_, clip_region_, t); | |
| 224 } | |
| 225 | |
| 226 // We use this static factory function instead of the regular constructor so | |
| 227 // that we can create the pixel data before calling the constructor. This is | |
| 228 // required so that we can call the base class' constructor with the pixel | |
| 229 // data. | |
| 230 BitmapPlatformDeviceWin* BitmapPlatformDeviceWin::create(HDC screen_dc, | |
| 231 int width, | |
| 232 int height, | |
| 233 bool is_opaque, | |
| 234 HANDLE shared_section) { | |
| 235 SkBitmap bitmap; | |
| 236 | |
| 237 // CreateDIBSection appears to get unhappy if we create an empty bitmap, so | |
| 238 // just create a minimal bitmap | |
| 239 if ((width == 0) || (height == 0)) { | |
| 240 width = 1; | |
| 241 height = 1; | |
| 242 } | |
| 243 | |
| 244 BITMAPINFOHEADER hdr = {0}; | |
| 245 CreateBitmapHeader(width, height, &hdr); | |
| 246 | |
| 247 void* data = NULL; | |
| 248 HBITMAP hbitmap = CreateDIBSection(screen_dc, | |
| 249 reinterpret_cast<BITMAPINFO*>(&hdr), 0, | |
| 250 &data, | |
| 251 shared_section, 0); | |
| 252 | |
| 253 // If we run out of GDI objects or some other error occurs, we won't get a | |
| 254 // bitmap here. This will cause us to crash later because the data pointer is | |
| 255 // NULL. To make sure that we can assign blame for those crashes to this code, | |
| 256 // we deliberately crash here, even in release mode. | |
| 257 if (!hbitmap) { | |
| 258 DWORD error = GetLastError(); | |
| 259 LOG(ERROR) << "CreateDIBSection Failed. Error: " << error << "\n"; | |
| 260 return NULL; | |
| 261 } | |
| 262 | |
| 263 bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height); | |
| 264 bitmap.setPixels(data); | |
| 265 bitmap.setIsOpaque(is_opaque); | |
| 266 | |
| 267 if (is_opaque) { | |
| 268 #ifndef NDEBUG | |
| 269 // To aid in finding bugs, we set the background color to something | |
| 270 // obviously wrong so it will be noticable when it is not cleared | |
| 271 bitmap.eraseARGB(255, 0, 255, 128); // bright bluish green | |
| 272 #endif | |
| 273 } else { | |
| 274 // A transparent layer is requested: fill with our magic "transparent" | |
| 275 // color, see the declaration of kMagicTransparencyColor above | |
| 276 sk_memset32(static_cast<uint32_t*>(data), kMagicTransparencyColor, | |
| 277 width * height); | |
| 278 } | |
| 279 | |
| 280 // The device object will take ownership of the HBITMAP. | |
| 281 return new BitmapPlatformDeviceWin(new BitmapPlatformDeviceWinData(hbitmap), | |
| 282 bitmap); | |
| 283 } | |
| 284 | |
| 285 // The device will own the HBITMAP, which corresponds to also owning the pixel | |
| 286 // data. Therefore, we do not transfer ownership to the SkDevice's bitmap. | |
| 287 BitmapPlatformDeviceWin::BitmapPlatformDeviceWin( | |
| 288 BitmapPlatformDeviceWinData* data, | |
| 289 const SkBitmap& bitmap) : PlatformDeviceWin(bitmap), data_(data) { | |
| 290 } | |
| 291 | |
| 292 // The copy constructor just adds another reference to the underlying data. | |
| 293 // We use a const cast since the default Skia definitions don't define the | |
| 294 // proper constedness that we expect (accessBitmap should really be const). | |
| 295 BitmapPlatformDeviceWin::BitmapPlatformDeviceWin( | |
| 296 const BitmapPlatformDeviceWin& other) | |
| 297 : PlatformDeviceWin( | |
| 298 const_cast<BitmapPlatformDeviceWin&>(other).accessBitmap(true)), | |
| 299 data_(other.data_) { | |
| 300 } | |
| 301 | |
| 302 BitmapPlatformDeviceWin::~BitmapPlatformDeviceWin() { | |
| 303 } | |
| 304 | |
| 305 BitmapPlatformDeviceWin& BitmapPlatformDeviceWin::operator=( | |
| 306 const BitmapPlatformDeviceWin& other) { | |
| 307 data_ = other.data_; | |
| 308 return *this; | |
| 309 } | |
| 310 | |
| 311 HDC BitmapPlatformDeviceWin::getBitmapDC() { | |
| 312 return data_->GetBitmapDC(); | |
| 313 } | |
| 314 | |
| 315 void BitmapPlatformDeviceWin::setMatrixClip(const SkMatrix& transform, | |
| 316 const SkRegion& region) { | |
| 317 data_->SetMatrixClip(transform, region); | |
| 318 } | |
| 319 | |
| 320 void BitmapPlatformDeviceWin::drawToHDC(HDC dc, int x, int y, | |
| 321 const RECT* src_rect) { | |
| 322 bool created_dc = !data_->IsBitmapDCCreated(); | |
| 323 HDC source_dc = getBitmapDC(); | |
| 324 | |
| 325 RECT temp_rect; | |
| 326 if (!src_rect) { | |
| 327 temp_rect.left = 0; | |
| 328 temp_rect.right = width(); | |
| 329 temp_rect.top = 0; | |
| 330 temp_rect.bottom = height(); | |
| 331 src_rect = &temp_rect; | |
| 332 } | |
| 333 | |
| 334 int copy_width = src_rect->right - src_rect->left; | |
| 335 int copy_height = src_rect->bottom - src_rect->top; | |
| 336 | |
| 337 // We need to reset the translation for our bitmap or (0,0) won't be in the | |
| 338 // upper left anymore | |
| 339 SkMatrix identity; | |
| 340 identity.reset(); | |
| 341 | |
| 342 LoadTransformToDC(source_dc, identity); | |
| 343 if (isOpaque()) { | |
| 344 BitBlt(dc, | |
| 345 x, | |
| 346 y, | |
| 347 copy_width, | |
| 348 copy_height, | |
| 349 source_dc, | |
| 350 src_rect->left, | |
| 351 src_rect->top, | |
| 352 SRCCOPY); | |
| 353 } else { | |
| 354 DCHECK(copy_width != 0 && copy_height != 0); | |
| 355 BLENDFUNCTION blend_function = {AC_SRC_OVER, 0, 255, AC_SRC_ALPHA}; | |
| 356 GdiAlphaBlend(dc, | |
| 357 x, | |
| 358 y, | |
| 359 copy_width, | |
| 360 copy_height, | |
| 361 source_dc, | |
| 362 src_rect->left, | |
| 363 src_rect->top, | |
| 364 copy_width, | |
| 365 copy_height, | |
| 366 blend_function); | |
| 367 } | |
| 368 LoadTransformToDC(source_dc, data_->transform()); | |
| 369 | |
| 370 if (created_dc) | |
| 371 data_->ReleaseBitmapDC(); | |
| 372 } | |
| 373 | |
| 374 void BitmapPlatformDeviceWin::prepareForGDI(int x, int y, int width, | |
| 375 int height) { | |
| 376 processPixels<PrepareAlphaForGDI>(x, y, width, height); | |
| 377 } | |
| 378 | |
| 379 void BitmapPlatformDeviceWin::postProcessGDI(int x, int y, int width, | |
| 380 int height) { | |
| 381 processPixels<PostProcessAlphaForGDI>(x, y, width, height); | |
| 382 } | |
| 383 | |
| 384 void BitmapPlatformDeviceWin::makeOpaque(int x, int y, int width, int height) { | |
| 385 processPixels<MakeOpaqueAlphaAdjuster>(x, y, width, height); | |
| 386 } | |
| 387 | |
| 388 void BitmapPlatformDeviceWin::fixupAlphaBeforeCompositing() { | |
| 389 const SkBitmap& bitmap = accessBitmap(true); | |
| 390 SkAutoLockPixels lock(bitmap); | |
| 391 uint32_t* data = bitmap.getAddr32(0, 0); | |
| 392 | |
| 393 size_t words = bitmap.rowBytes() / sizeof(uint32_t) * bitmap.height(); | |
| 394 for (size_t i = 0; i < words; i++) { | |
| 395 if (data[i] == kMagicTransparencyColor) | |
| 396 data[i] = 0; | |
| 397 else | |
| 398 data[i] |= 0xFF000000; | |
| 399 } | |
| 400 } | |
| 401 | |
| 402 // Returns the color value at the specified location. | |
| 403 SkColor BitmapPlatformDeviceWin::getColorAt(int x, int y) { | |
| 404 const SkBitmap& bitmap = accessBitmap(false); | |
| 405 SkAutoLockPixels lock(bitmap); | |
| 406 uint32_t* data = bitmap.getAddr32(0, 0); | |
| 407 return static_cast<SkColor>(data[x + y * width()]); | |
| 408 } | |
| 409 | |
| 410 void BitmapPlatformDeviceWin::onAccessBitmap(SkBitmap* bitmap) { | |
| 411 // FIXME(brettw) OPTIMIZATION: We should only flush if we know a GDI | |
| 412 // operation has occurred on our DC. | |
| 413 if (data_->IsBitmapDCCreated()) | |
| 414 GdiFlush(); | |
| 415 } | |
| 416 | |
| 417 template<BitmapPlatformDeviceWin::adjustAlpha adjustor> | |
| 418 void BitmapPlatformDeviceWin::processPixels(int x, | |
| 419 int y, | |
| 420 int width, | |
| 421 int height) { | |
| 422 const SkBitmap& bitmap = accessBitmap(true); | |
| 423 DCHECK_EQ(bitmap.config(), SkBitmap::kARGB_8888_Config); | |
| 424 const SkMatrix& matrix = data_->transform(); | |
| 425 int bitmap_start_x = SkScalarRound(matrix.getTranslateX()) + x; | |
| 426 int bitmap_start_y = SkScalarRound(matrix.getTranslateY()) + y; | |
| 427 | |
| 428 if (Constrain(bitmap.width(), &bitmap_start_x, &width) && | |
| 429 Constrain(bitmap.height(), &bitmap_start_y, &height)) { | |
| 430 SkAutoLockPixels lock(bitmap); | |
| 431 DCHECK_EQ(bitmap.rowBytes() % sizeof(uint32_t), 0u); | |
| 432 size_t row_words = bitmap.rowBytes() / sizeof(uint32_t); | |
| 433 // Set data to the first pixel to be modified. | |
| 434 uint32_t* data = bitmap.getAddr32(0, 0) + (bitmap_start_y * row_words) + | |
| 435 bitmap_start_x; | |
| 436 for (int i = 0; i < height; i++) { | |
| 437 for (int j = 0; j < width; j++) { | |
| 438 adjustor(data + j); | |
| 439 } | |
| 440 data += row_words; | |
| 441 } | |
| 442 } | |
| 443 } | |
| 444 | |
| 445 } // namespace gfx | |
| 446 | |
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Chromium Code Reviews
Issue 11568:
Move skia extensions from the port to skia/ext. (Closed)
Base URL: svn://chrome-svn/chrome/trunk/src/