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