printing/emf_win.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 "printing/emf_win.h"
   6
   7 #include "base/files/file_path.h"
   8 #include "base/logging.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/win/scoped_gdi_object.h"
  11 #include "base/win/scoped_hdc.h"
  12 #include "base/win/scoped_select_object.h"
  13 #include "skia/ext/vector_platform_device_emf_win.h"
  14 #include "third_party/skia/include/core/SkBitmap.h"
  15 #include "ui/gfx/codec/jpeg_codec.h"
  16 #include "ui/gfx/codec/png_codec.h"
  17 #include "ui/gfx/gdi_util.h"
  18 #include "ui/gfx/rect.h"
  19 #include "ui/gfx/size.h"
  20
  21 namespace {
  22
  23 const int kCustomGdiCommentSignature = 0xdeadbabe;
  24 struct PageBreakRecord {
  25   int signature;
  26   enum PageBreakType {
  27     START_PAGE,
  28     END_PAGE,
  29   } type;
  30   explicit PageBreakRecord(PageBreakType type_in)
  31       : signature(kCustomGdiCommentSignature), type(type_in) {
  32   }
  33   bool IsValid() const {
  34     return (signature == kCustomGdiCommentSignature) &&
  35            (type >= START_PAGE) && (type <= END_PAGE);
  36   }
  37 };
  38
  39 int CALLBACK IsAlphaBlendUsedEnumProc(HDC,
  40                                       HANDLETABLE*,
  41                                       const ENHMETARECORD *record,
  42                                       int,
  43                                       LPARAM data) {
  44   bool* result = reinterpret_cast<bool*>(data);
  45   if (!result)
  46     return 0;
  47   switch (record->iType) {
  48     case EMR_ALPHABLEND: {
  49       *result = true;
  50       return 0;
  51       break;
  52     }
  53   }
  54   return 1;
  55 }
  56
  57 int CALLBACK RasterizeAlphaBlendProc(HDC metafile_dc,
  58                                      HANDLETABLE* handle_table,
  59                                      const ENHMETARECORD *record,
  60                                      int num_objects,
  61                                      LPARAM data) {
  62     HDC bitmap_dc = *reinterpret_cast<HDC*>(data);
  63     // Play this command to the bitmap DC.
  64     ::PlayEnhMetaFileRecord(bitmap_dc, handle_table, record, num_objects);
  65     switch (record->iType) {
  66     case EMR_ALPHABLEND: {
  67       const EMRALPHABLEND* alpha_blend =
  68           reinterpret_cast<const EMRALPHABLEND*>(record);
  69       // Don't modify transformation here.
  70       // Old implementation did reset transformations for DC to identity matrix.
  71       // That was not correct and cause some bugs, like unexpected cropping.
  72       // EMRALPHABLEND is rendered into bitmap and metafile contexts with
  73       // current transformation. If we don't touch them here BitBlt will copy
  74       // same areas.
  75       ::BitBlt(metafile_dc,
  76                alpha_blend->xDest,
  77                alpha_blend->yDest,
  78                alpha_blend->cxDest,
  79                alpha_blend->cyDest,
  80                bitmap_dc,
  81                alpha_blend->xDest,
  82                alpha_blend->yDest,
  83                SRCCOPY);
  84       break;
  85     }
  86     case EMR_CREATEBRUSHINDIRECT:
  87     case EMR_CREATECOLORSPACE:
  88     case EMR_CREATECOLORSPACEW:
  89     case EMR_CREATEDIBPATTERNBRUSHPT:
  90     case EMR_CREATEMONOBRUSH:
  91     case EMR_CREATEPALETTE:
  92     case EMR_CREATEPEN:
  93     case EMR_DELETECOLORSPACE:
  94     case EMR_DELETEOBJECT:
  95     case EMR_EXTCREATEFONTINDIRECTW:
  96       // Play object creation command only once.
  97       break;
  98
  99     default:
 100       // Play this command to the metafile DC.
 101       ::PlayEnhMetaFileRecord(metafile_dc, handle_table, record, num_objects);
 102       break;
 103     }
 104     return 1;  // Continue enumeration
 105 }
 106
 107 // Bitmapt for rasterization.
 108 class RasterBitmap {
 109  public:
 110   explicit RasterBitmap(const gfx::Size& raster_size)
 111       : saved_object_(NULL) {
 112     context_.Set(::CreateCompatibleDC(NULL));
 113     if (!context_) {
 114       NOTREACHED() << "Bitmap DC creation failed";
 115       return;
 116     }
 117     ::SetGraphicsMode(context_, GM_ADVANCED);
 118     void* bits = NULL;
 119     gfx::Rect bitmap_rect(raster_size);
 120     gfx::CreateBitmapHeader(raster_size.width(), raster_size.height(),
 121                             &header_.bmiHeader);
 122     bitmap_.Set(::CreateDIBSection(context_, &header_, DIB_RGB_COLORS, &bits,
 123                                    NULL, 0));
 124     if (!bitmap_)
 125       NOTREACHED() << "Raster bitmap creation for printing failed";
 126
 127     saved_object_ = ::SelectObject(context_, bitmap_);
 128     RECT rect = bitmap_rect.ToRECT();
 129     ::FillRect(context_, &rect,
 130                static_cast<HBRUSH>(::GetStockObject(WHITE_BRUSH)));
 131
 132   }
 133
 134   ~RasterBitmap() {
 135     ::SelectObject(context_, saved_object_);
 136   }
 137
 138   HDC context() const {
 139     return context_;
 140   }
 141
 142   base::win::ScopedCreateDC context_;
 143   BITMAPINFO header_;
 144   base::win::ScopedBitmap bitmap_;
 145   HGDIOBJ saved_object_;
 146
 147  private:
 148   DISALLOW_COPY_AND_ASSIGN(RasterBitmap);
 149 };
 150
 151
 152
 153 }  // namespace
 154
 155 namespace printing {
 156
 157 bool DIBFormatNativelySupported(HDC dc, uint32 escape, const BYTE* bits,
 158                                 int size) {
 159   BOOL supported = FALSE;
 160   if (ExtEscape(dc, QUERYESCSUPPORT, sizeof(escape),
 161                 reinterpret_cast<LPCSTR>(&escape), 0, 0) > 0) {
 162     ExtEscape(dc, escape, size, reinterpret_cast<LPCSTR>(bits),
 163               sizeof(supported), reinterpret_cast<LPSTR>(&supported));
 164   }
 165   return !!supported;
 166 }
 167
 168 Emf::Emf() : emf_(NULL), hdc_(NULL), page_count_(0) {
 169 }
 170
 171 Emf::~Emf() {
 172   DCHECK(!hdc_);
 173   if (emf_)
 174     DeleteEnhMetaFile(emf_);
 175 }
 176
 177 bool Emf::InitToFile(const base::FilePath& metafile_path) {
 178   DCHECK(!emf_ && !hdc_);
 179   hdc_ = CreateEnhMetaFile(NULL, metafile_path.value().c_str(), NULL, NULL);
 180   DCHECK(hdc_);
 181   return hdc_ != NULL;
 182 }
 183
 184 bool Emf::InitFromFile(const base::FilePath& metafile_path) {
 185   DCHECK(!emf_ && !hdc_);
 186   emf_ = GetEnhMetaFile(metafile_path.value().c_str());
 187   DCHECK(emf_);
 188   return emf_ != NULL;
 189 }
 190
 191 bool Emf::Init() {
 192   DCHECK(!emf_ && !hdc_);
 193   hdc_ = CreateEnhMetaFile(NULL, NULL, NULL, NULL);
 194   DCHECK(hdc_);
 195   return hdc_ != NULL;
 196 }
 197
 198 bool Emf::InitFromData(const void* src_buffer, uint32 src_buffer_size) {
 199   DCHECK(!emf_ && !hdc_);
 200   emf_ = SetEnhMetaFileBits(src_buffer_size,
 201                             reinterpret_cast<const BYTE*>(src_buffer));
 202   return emf_ != NULL;
 203 }
 204
 205 bool Emf::FinishDocument() {
 206   DCHECK(!emf_ && hdc_);
 207   emf_ = CloseEnhMetaFile(hdc_);
 208   DCHECK(emf_);
 209   hdc_ = NULL;
 210   return emf_ != NULL;
 211 }
 212
 213 bool Emf::Playback(HDC hdc, const RECT* rect) const {
 214   DCHECK(emf_ && !hdc_);
 215   RECT bounds;
 216   if (!rect) {
 217     // Get the natural bounds of the EMF buffer.
 218     bounds = GetPageBounds(1).ToRECT();
 219     rect = &bounds;
 220   }
 221   return PlayEnhMetaFile(hdc, emf_, rect) != 0;
 222 }
 223
 224 bool Emf::SafePlayback(HDC context) const {
 225   DCHECK(emf_ && !hdc_);
 226   XFORM base_matrix;
 227   if (!GetWorldTransform(context, &base_matrix)) {
 228     NOTREACHED();
 229     return false;
 230   }
 231   Emf::EnumerationContext playback_context;
 232   playback_context.base_matrix = &base_matrix;
 233   RECT rect = GetPageBounds(1).ToRECT();
 234   return EnumEnhMetaFile(context,
 235                          emf_,
 236                          &Emf::SafePlaybackProc,
 237                          reinterpret_cast<void*>(&playback_context),
 238                          &rect) != 0;
 239 }
 240
 241 gfx::Rect Emf::GetPageBounds(unsigned int page_number) const {
 242   DCHECK(emf_ && !hdc_);
 243   DCHECK_EQ(1U, page_number);
 244   ENHMETAHEADER header;
 245   if (GetEnhMetaFileHeader(emf_, sizeof(header), &header) != sizeof(header)) {
 246     NOTREACHED();
 247     return gfx::Rect();
 248   }
 249   // Add 1 to right and bottom because it's inclusive rectangle.
 250   // See ENHMETAHEADER.
 251   return gfx::Rect(header.rclBounds.left,
 252                    header.rclBounds.top,
 253                    header.rclBounds.right - header.rclBounds.left + 1,
 254                    header.rclBounds.bottom - header.rclBounds.top + 1);
 255 }
 256
 257 uint32 Emf::GetDataSize() const {
 258   DCHECK(emf_ && !hdc_);
 259   return GetEnhMetaFileBits(emf_, 0, NULL);
 260 }
 261
 262 bool Emf::GetData(void* buffer, uint32 size) const {
 263   DCHECK(emf_ && !hdc_);
 264   DCHECK(buffer && size);
 265   uint32 size2 =
 266       GetEnhMetaFileBits(emf_, size, reinterpret_cast<BYTE*>(buffer));
 267   DCHECK(size2 == size);
 268   return size2 == size && size2 != 0;
 269 }
 270
 271 bool Emf::GetDataAsVector(std::vector<uint8>* buffer) const {
 272   uint32 size = GetDataSize();
 273   if (!size)
 274     return false;
 275
 276   buffer->resize(size);
 277   if (!GetData(&buffer->front(), size))
 278     return false;
 279   return true;
 280 }
 281
 282 bool Emf::SaveTo(const base::FilePath& file_path) const {
 283   HANDLE file = CreateFile(file_path.value().c_str(), GENERIC_WRITE,
 284                            FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
 285                            CREATE_ALWAYS, 0, NULL);
 286   if (file == INVALID_HANDLE_VALUE)
 287     return false;
 288
 289   bool success = false;
 290   std::vector<uint8> buffer;
 291   if (GetDataAsVector(&buffer)) {
 292     DWORD written = 0;
 293     if (WriteFile(file, &*buffer.begin(), static_cast<DWORD>(buffer.size()),
 294                   &written, NULL) &&
 295         written == buffer.size()) {
 296       success = true;
 297     }
 298   }
 299   CloseHandle(file);
 300   return success;
 301 }
 302
 303 int CALLBACK Emf::SafePlaybackProc(HDC hdc,
 304                                    HANDLETABLE* handle_table,
 305                                    const ENHMETARECORD* record,
 306                                    int objects_count,
 307                                    LPARAM param) {
 308   Emf::EnumerationContext* context =
 309       reinterpret_cast<Emf::EnumerationContext*>(param);
 310   context->handle_table = handle_table;
 311   context->objects_count = objects_count;
 312   context->hdc = hdc;
 313   Record record_instance(record);
 314   bool success = record_instance.SafePlayback(context);
 315   DCHECK(success);
 316   return 1;
 317 }
 318
 319 Emf::EnumerationContext::EnumerationContext() {
 320   memset(this, 0, sizeof(*this));
 321 }
 322
 323 Emf::Record::Record(const ENHMETARECORD* record)
 324     : record_(record) {
 325   DCHECK(record_);
 326 }
 327
 328 bool Emf::Record::Play(Emf::EnumerationContext* context) const {
 329   return 0 != PlayEnhMetaFileRecord(context->hdc,
 330                                     context->handle_table,
 331                                     record_,
 332                                     context->objects_count);
 333 }
 334
 335 bool Emf::Record::SafePlayback(Emf::EnumerationContext* context) const {
 336   // For EMF field description, see [MS-EMF] Enhanced Metafile Format
 337   // Specification.
 338   //
 339   // This is the second major EMF breakage I get; the first one being
 340   // SetDCBrushColor/SetDCPenColor/DC_PEN/DC_BRUSH being silently ignored.
 341   //
 342   // This function is the guts of the fix for bug 1186598. Some printer drivers
 343   // somehow choke on certain EMF records, but calling the corresponding
 344   // function directly on the printer HDC is fine. Still, playing the EMF record
 345   // fails. Go figure.
 346   //
 347   // The main issue is that SetLayout is totally unsupported on these printers
 348   // (HP 4500/4700). I used to call SetLayout and I stopped. I found out this is
 349   // not sufficient because GDI32!PlayEnhMetaFile internally calls SetLayout(!)
 350   // Damn.
 351   //
 352   // So I resorted to manually parse the EMF records and play them one by one.
 353   // The issue with this method compared to using PlayEnhMetaFile to play back
 354   // an EMF buffer is that the later silently fixes the matrix to take in
 355   // account the matrix currently loaded at the time of the call.
 356   // The matrix magic is done transparently when using PlayEnhMetaFile but since
 357   // I'm processing one field at a time, I need to do the fixup myself. Note
 358   // that PlayEnhMetaFileRecord doesn't fix the matrix correctly even when
 359   // called inside an EnumEnhMetaFile loop. Go figure (bis).
 360   //
 361   // So when I see a EMR_SETWORLDTRANSFORM and EMR_MODIFYWORLDTRANSFORM, I need
 362   // to fix the matrix according to the matrix previously loaded before playing
 363   // back the buffer. Otherwise, the previously loaded matrix would be ignored
 364   // and the EMF buffer would always be played back at its native resolution.
 365   // Duh.
 366   //
 367   // I also use this opportunity to skip over eventual EMR_SETLAYOUT record that
 368   // could remain.
 369   //
 370   // Another tweak we make is for JPEGs/PNGs in calls to StretchDIBits.
 371   // (Our Pepper plugin code uses a JPEG). If the printer does not support
 372   // JPEGs/PNGs natively we decompress the JPEG/PNG and then set it to the
 373   // device.
 374   // TODO(sanjeevr): We should also add JPEG/PNG support for SetSIBitsToDevice
 375   //
 376   // We also process any custom EMR_GDICOMMENT records which are our
 377   // placeholders for StartPage and EndPage.
 378   // Note: I should probably care about view ports and clipping, eventually.
 379   bool res = false;
 380   const XFORM* base_matrix = context->base_matrix;
 381   switch (record()->iType) {
 382     case EMR_STRETCHDIBITS: {
 383       const EMRSTRETCHDIBITS * sdib_record =
 384           reinterpret_cast<const EMRSTRETCHDIBITS*>(record());
 385       const BYTE* record_start = reinterpret_cast<const BYTE *>(record());
 386       const BITMAPINFOHEADER *bmih =
 387           reinterpret_cast<const BITMAPINFOHEADER *>(record_start +
 388                                                      sdib_record->offBmiSrc);
 389       const BYTE* bits = record_start + sdib_record->offBitsSrc;
 390       bool play_normally = true;
 391       res = false;
 392       HDC hdc = context->hdc;
 393       scoped_ptr<SkBitmap> bitmap;
 394       if (bmih->biCompression == BI_JPEG) {
 395         if (!DIBFormatNativelySupported(hdc, CHECKJPEGFORMAT, bits,
 396                                         bmih->biSizeImage)) {
 397           play_normally = false;
 398           bitmap.reset(gfx::JPEGCodec::Decode(bits, bmih->biSizeImage));
 399         }
 400       } else if (bmih->biCompression == BI_PNG) {
 401         if (!DIBFormatNativelySupported(hdc, CHECKPNGFORMAT, bits,
 402                                         bmih->biSizeImage)) {
 403           play_normally = false;
 404           bitmap.reset(new SkBitmap());
 405           gfx::PNGCodec::Decode(bits, bmih->biSizeImage, bitmap.get());
 406         }
 407       }
 408       if (!play_normally) {
 409         DCHECK(bitmap.get());
 410         if (bitmap.get()) {
 411           SkAutoLockPixels lock(*bitmap.get());
 412           DCHECK_EQ(bitmap->config(), SkBitmap::kARGB_8888_Config);
 413           const uint32_t* pixels =
 414               static_cast<const uint32_t*>(bitmap->getPixels());
 415           if (pixels == NULL) {
 416             NOTREACHED();
 417             return false;
 418           }
 419           BITMAPINFOHEADER bmi = {0};
 420           gfx::CreateBitmapHeader(bitmap->width(), bitmap->height(), &bmi);
 421           res = (0 != StretchDIBits(hdc, sdib_record->xDest, sdib_record->yDest,
 422                                     sdib_record->cxDest,
 423                                     sdib_record->cyDest, sdib_record->xSrc,
 424                                     sdib_record->ySrc,
 425                                     sdib_record->cxSrc, sdib_record->cySrc,
 426                                     pixels,
 427                                     reinterpret_cast<const BITMAPINFO *>(&bmi),
 428                                     sdib_record->iUsageSrc,
 429                                     sdib_record->dwRop));
 430         }
 431       } else {
 432         res = Play(context);
 433       }
 434       break;
 435     }
 436     case EMR_SETWORLDTRANSFORM: {
 437       DCHECK_EQ(record()->nSize, sizeof(DWORD) * 2 + sizeof(XFORM));
 438       const XFORM* xform = reinterpret_cast<const XFORM*>(record()->dParm);
 439       HDC hdc = context->hdc;
 440       if (base_matrix) {
 441         res = 0 != SetWorldTransform(hdc, base_matrix) &&
 442                    ModifyWorldTransform(hdc, xform, MWT_LEFTMULTIPLY);
 443       } else {
 444         res = 0 != SetWorldTransform(hdc, xform);
 445       }
 446       break;
 447     }
 448     case EMR_MODIFYWORLDTRANSFORM: {
 449       DCHECK_EQ(record()->nSize,
 450                 sizeof(DWORD) * 2 + sizeof(XFORM) + sizeof(DWORD));
 451       const XFORM* xform = reinterpret_cast<const XFORM*>(record()->dParm);
 452       const DWORD* option = reinterpret_cast<const DWORD*>(xform + 1);
 453       HDC hdc = context->hdc;
 454       switch (*option) {
 455         case MWT_IDENTITY:
 456           if (base_matrix) {
 457             res = 0 != SetWorldTransform(hdc, base_matrix);
 458           } else {
 459             res = 0 != ModifyWorldTransform(hdc, xform, MWT_IDENTITY);
 460           }
 461           break;
 462         case MWT_LEFTMULTIPLY:
 463         case MWT_RIGHTMULTIPLY:
 464           res = 0 != ModifyWorldTransform(hdc, xform, *option);
 465           break;
 466         case 4:  // MWT_SET
 467           if (base_matrix) {
 468             res = 0 != SetWorldTransform(hdc, base_matrix) &&
 469                        ModifyWorldTransform(hdc, xform, MWT_LEFTMULTIPLY);
 470           } else {
 471             res = 0 != SetWorldTransform(hdc, xform);
 472           }
 473           break;
 474         default:
 475           res = false;
 476           break;
 477       }
 478       break;
 479     }
 480     case EMR_SETLAYOUT:
 481       // Ignore it.
 482       res = true;
 483       break;
 484     case EMR_GDICOMMENT: {
 485       const EMRGDICOMMENT* comment_record =
 486           reinterpret_cast<const EMRGDICOMMENT*>(record());
 487       if (comment_record->cbData == sizeof(PageBreakRecord)) {
 488         const PageBreakRecord* page_break_record =
 489             reinterpret_cast<const PageBreakRecord*>(comment_record->Data);
 490         if (page_break_record && page_break_record->IsValid()) {
 491           if (page_break_record->type == PageBreakRecord::START_PAGE) {
 492             res = !!::StartPage(context->hdc);
 493             DCHECK_EQ(0, context->dc_on_page_start);
 494             context->dc_on_page_start = ::SaveDC(context->hdc);
 495           } else if (page_break_record->type == PageBreakRecord::END_PAGE) {
 496             DCHECK_NE(0, context->dc_on_page_start);
 497             ::RestoreDC(context->hdc, context->dc_on_page_start);
 498             context->dc_on_page_start = 0;
 499             res = !!::EndPage(context->hdc);
 500           } else {
 501             res = false;
 502             NOTREACHED();
 503           }
 504         } else {
 505           res = Play(context);
 506         }
 507       } else {
 508         res = true;
 509       }
 510       break;
 511     }
 512     default: {
 513       res = Play(context);
 514       break;
 515     }
 516   }
 517   return res;
 518 }
 519
 520 SkBaseDevice* Emf::StartPageForVectorCanvas(
 521     const gfx::Size& page_size, const gfx::Rect& content_area,
 522     const float& scale_factor) {
 523   if (!StartPage(page_size, content_area, scale_factor))
 524     return NULL;
 525
 526   return skia::VectorPlatformDeviceEmf::CreateDevice(page_size.width(),
 527                                                      page_size.height(),
 528                                                      true, hdc_);
 529 }
 530
 531 bool Emf::StartPage(const gfx::Size& /*page_size*/,
 532                     const gfx::Rect& /*content_area*/,
 533                     const float& /*scale_factor*/) {
 534   DCHECK(hdc_);
 535   if (!hdc_)
 536     return false;
 537   page_count_++;
 538   PageBreakRecord record(PageBreakRecord::START_PAGE);
 539   return !!GdiComment(hdc_, sizeof(record),
 540                       reinterpret_cast<const BYTE *>(&record));
 541 }
 542
 543 bool Emf::FinishPage() {
 544   DCHECK(hdc_);
 545   if (!hdc_)
 546     return false;
 547   PageBreakRecord record(PageBreakRecord::END_PAGE);
 548   return !!GdiComment(hdc_, sizeof(record),
 549                       reinterpret_cast<const BYTE *>(&record));
 550 }
 551
 552 Emf::Enumerator::Enumerator(const Emf& emf, HDC context, const RECT* rect) {
 553   items_.clear();
 554   if (!EnumEnhMetaFile(context,
 555                        emf.emf(),
 556                        &Emf::Enumerator::EnhMetaFileProc,
 557                        reinterpret_cast<void*>(this),
 558                        rect)) {
 559     NOTREACHED();
 560     items_.clear();
 561   }
 562   DCHECK_EQ(context_.hdc, context);
 563 }
 564
 565 Emf::Enumerator::const_iterator Emf::Enumerator::begin() const {
 566   return items_.begin();
 567 }
 568
 569 Emf::Enumerator::const_iterator Emf::Enumerator::end() const {
 570   return items_.end();
 571 }
 572
 573 int CALLBACK Emf::Enumerator::EnhMetaFileProc(HDC hdc,
 574                                               HANDLETABLE* handle_table,
 575                                               const ENHMETARECORD* record,
 576                                               int objects_count,
 577                                               LPARAM param) {
 578   Enumerator& emf = *reinterpret_cast<Enumerator*>(param);
 579   if (!emf.context_.handle_table) {
 580     DCHECK(!emf.context_.handle_table);
 581     DCHECK(!emf.context_.objects_count);
 582     emf.context_.handle_table = handle_table;
 583     emf.context_.objects_count = objects_count;
 584     emf.context_.hdc = hdc;
 585   } else {
 586     DCHECK_EQ(emf.context_.handle_table, handle_table);
 587     DCHECK_EQ(emf.context_.objects_count, objects_count);
 588     DCHECK_EQ(emf.context_.hdc, hdc);
 589   }
 590   emf.items_.push_back(Record(record));
 591   return 1;
 592 }
 593
 594 bool Emf::IsAlphaBlendUsed() const {
 595   bool result = false;
 596   ::EnumEnhMetaFile(NULL,
 597                     emf(),
 598                     &IsAlphaBlendUsedEnumProc,
 599                     &result,
 600                     NULL);
 601   return result;
 602 }
 603
 604 Emf* Emf::RasterizeMetafile(int raster_area_in_pixels) const {
 605   gfx::Rect page_bounds = GetPageBounds(1);
 606   gfx::Size page_size(page_bounds.size());
 607   if (page_size.GetArea() <= 0) {
 608     NOTREACHED() << "Metafile is empty";
 609     page_bounds = gfx::Rect(1, 1);
 610   }
 611
 612   float scale = sqrt(float(raster_area_in_pixels) / page_size.GetArea());
 613   page_size.set_width(std::max<int>(1, page_size.width() * scale));
 614   page_size.set_height(std::max<int>(1, page_size.height() * scale));
 615
 616
 617   RasterBitmap bitmap(page_size);
 618
 619   gfx::Rect bitmap_rect(page_size);
 620   RECT rect = bitmap_rect.ToRECT();
 621   Playback(bitmap.context(), &rect);
 622
 623   scoped_ptr<Emf> result(new Emf);
 624   result->Init();
 625   HDC hdc = result->context();
 626   DCHECK(hdc);
 627   skia::InitializeDC(hdc);
 628
 629   // Params are ignored.
 630   result->StartPage(page_bounds.size(), page_bounds, 1);
 631
 632   ::ModifyWorldTransform(hdc, NULL, MWT_IDENTITY);
 633   XFORM xform = {
 634     float(page_bounds.width()) / bitmap_rect.width(), 0,
 635     0, float(page_bounds.height()) / bitmap_rect.height(),
 636     page_bounds.x(),
 637     page_bounds.y(),
 638   };
 639   ::SetWorldTransform(hdc, &xform);
 640   ::BitBlt(hdc, 0, 0, bitmap_rect.width(), bitmap_rect.height(),
 641            bitmap.context(), bitmap_rect.x(), bitmap_rect.y(), SRCCOPY);
 642
 643   result->FinishPage();
 644   result->FinishDocument();
 645
 646   return result.release();
 647 }
 648
 649 Emf* Emf::RasterizeAlphaBlend() const {
 650   gfx::Rect page_bounds = GetPageBounds(1);
 651   if (page_bounds.size().GetArea() <= 0) {
 652     NOTREACHED() << "Metafile is empty";
 653     page_bounds = gfx::Rect(1, 1);
 654   }
 655
 656   RasterBitmap bitmap(page_bounds.size());
 657
 658   // Map metafile page_bounds.x(), page_bounds.y() to bitmap 0, 0.
 659   XFORM xform = { 1, 0, 0, 1, -page_bounds.x(), -page_bounds.y()};
 660   ::SetWorldTransform(bitmap.context(), &xform);
 661
 662   scoped_ptr<Emf> result(new Emf);
 663   result->Init();
 664   HDC hdc = result->context();
 665   DCHECK(hdc);
 666   skia::InitializeDC(hdc);
 667
 668   HDC bitmap_dc = bitmap.context();
 669   RECT rect = page_bounds.ToRECT();
 670   ::EnumEnhMetaFile(hdc, emf(), &RasterizeAlphaBlendProc, &bitmap_dc, &rect);
 671
 672   result->FinishDocument();
 673
 674   return result.release();
 675 }
 676
 677
 678 }  // namespace printing