1 2/* 3 * Copyright 2006 The Android Open Source Project 4 * 5 * Use of this source code is governed by a BSD-style license that can be 6 * found in the LICENSE file. 7 */ 8 9 10#include "SkBitmap.h" 11#include "SkCanvas.h" 12#include "SkColorPriv.h" 13#include "SkDescriptor.h" 14#include "SkFDot6.h" 15#include "SkFontHost.h" 16#include "SkMask.h" 17#include "SkAdvancedTypefaceMetrics.h" 18#include "SkScalerContext.h" 19#include "SkStream.h" 20#include "SkString.h" 21#include "SkTemplates.h" 22#include "SkThread.h" 23 24#include <ft2build.h> 25#include FT_FREETYPE_H 26#include FT_OUTLINE_H 27#include FT_SIZES_H 28#include FT_TRUETYPE_TABLES_H 29#include FT_TYPE1_TABLES_H 30#include FT_BITMAP_H 31// In the past, FT_GlyphSlot_Own_Bitmap was defined in this header file. 32#include FT_SYNTHESIS_H 33#include FT_XFREE86_H 34#ifdef FT_LCD_FILTER_H 35#include FT_LCD_FILTER_H 36#endif 37 38#ifdef FT_ADVANCES_H 39#include FT_ADVANCES_H 40#endif 41 42#if 0 43// Also include the files by name for build tools which require this. 44#include <freetype/freetype.h> 45#include <freetype/ftoutln.h> 46#include <freetype/ftsizes.h> 47#include <freetype/tttables.h> 48#include <freetype/ftadvanc.h> 49#include <freetype/ftlcdfil.h> 50#include <freetype/ftbitmap.h> 51#include <freetype/ftsynth.h> 52#endif 53 54//#define ENABLE_GLYPH_SPEW // for tracing calls 55//#define DUMP_STRIKE_CREATION 56 57//#define SK_GAMMA_APPLY_TO_A8 58 59#ifndef SK_GAMMA_CONTRAST 60 #define SK_GAMMA_CONTRAST 0x66 61#endif 62#ifndef SK_GAMMA_EXPONENT 63 #define SK_GAMMA_EXPONENT 2.2 64#endif 65 66#ifdef SK_DEBUG 67 #define SkASSERT_CONTINUE(pred) \ 68 do { \ 69 if (!(pred)) \ 70 SkDebugf("file %s:%d: assert failed '" #pred "'\n", __FILE__, __LINE__); \ 71 } while (false) 72#else 73 #define SkASSERT_CONTINUE(pred) 74#endif 75 76using namespace skia_advanced_typeface_metrics_utils; 77 78static bool isLCD(const SkScalerContext::Rec& rec) { 79 switch (rec.fMaskFormat) { 80 case SkMask::kLCD16_Format: 81 case SkMask::kLCD32_Format: 82 return true; 83 default: 84 return false; 85 } 86} 87 88////////////////////////////////////////////////////////////////////////// 89 90struct SkFaceRec; 91 92SK_DECLARE_STATIC_MUTEX(gFTMutex); 93static int gFTCount; 94static FT_Library gFTLibrary; 95static SkFaceRec* gFaceRecHead; 96static bool gLCDSupportValid; // true iff |gLCDSupport| has been set. 97static bool gLCDSupport; // true iff LCD is supported by the runtime. 98static int gLCDExtra; // number of extra pixels for filtering. 99 100static const uint8_t* gGammaTables[2]; 101 102///////////////////////////////////////////////////////////////////////// 103 104// See http://freetype.sourceforge.net/freetype2/docs/reference/ft2-bitmap_handling.html#FT_Bitmap_Embolden 105// This value was chosen by eyeballing the result in Firefox and trying to match it. 106static const FT_Pos kBitmapEmboldenStrength = 1 << 6; 107 108// convert from Skia's fixed (16.16) to FreeType's fixed (26.6) representation 109static inline int FixedToDot6(SkFixed x) { return x >> 10; } 110// convert from FreeType's fixed (26.6) to Skia's fixed (16.16) representation 111static inline SkFixed Dot6ToFixed(int x) { return x << 10; } 112 113static bool 114InitFreetype() { 115 FT_Error err = FT_Init_FreeType(&gFTLibrary); 116 if (err) { 117 return false; 118 } 119 120 // Setup LCD filtering. This reduces colour fringes for LCD rendered 121 // glyphs. 122#ifdef FT_LCD_FILTER_H 123// err = FT_Library_SetLcdFilter(gFTLibrary, FT_LCD_FILTER_DEFAULT); 124 err = FT_Library_SetLcdFilter(gFTLibrary, FT_LCD_FILTER_LIGHT); 125 gLCDSupport = err == 0; 126 if (gLCDSupport) { 127 gLCDExtra = 2; //DEFAULT and LIGHT add one pixel to each side. 128 } 129#else 130 gLCDSupport = false; 131#endif 132 gLCDSupportValid = true; 133 134 return true; 135} 136 137class SkScalerContext_FreeType : public SkScalerContext { 138public: 139 SkScalerContext_FreeType(const SkDescriptor* desc); 140 virtual ~SkScalerContext_FreeType(); 141 142 bool success() const { 143 return fFaceRec != NULL && 144 fFTSize != NULL && 145 fFace != NULL; 146 } 147 148protected: 149 virtual unsigned generateGlyphCount(); 150 virtual uint16_t generateCharToGlyph(SkUnichar uni); 151 virtual void generateAdvance(SkGlyph* glyph); 152 virtual void generateMetrics(SkGlyph* glyph); 153 virtual void generateImage(const SkGlyph& glyph); 154 virtual void generatePath(const SkGlyph& glyph, SkPath* path); 155 virtual void generateFontMetrics(SkPaint::FontMetrics* mx, 156 SkPaint::FontMetrics* my); 157 virtual SkUnichar generateGlyphToChar(uint16_t glyph); 158 159private: 160 SkFaceRec* fFaceRec; 161 FT_Face fFace; // reference to shared face in gFaceRecHead 162 FT_Size fFTSize; // our own copy 163 SkFixed fScaleX, fScaleY; 164 FT_Matrix fMatrix22; 165 uint32_t fLoadGlyphFlags; 166 bool fDoLinearMetrics; 167 168 FT_Error setupSize(); 169 void emboldenOutline(FT_Outline* outline); 170 void getBBoxForCurrentGlyph(SkGlyph* glyph, FT_BBox* bbox, 171 bool snapToPixelBoundary = false); 172 void updateGlyphIfLCD(SkGlyph* glyph); 173}; 174 175/////////////////////////////////////////////////////////////////////////// 176/////////////////////////////////////////////////////////////////////////// 177 178#include "SkStream.h" 179 180struct SkFaceRec { 181 SkFaceRec* fNext; 182 FT_Face fFace; 183 FT_StreamRec fFTStream; 184 SkStream* fSkStream; 185 uint32_t fRefCnt; 186 uint32_t fFontID; 187 188 // assumes ownership of the stream, will call unref() when its done 189 SkFaceRec(SkStream* strm, uint32_t fontID); 190 ~SkFaceRec() { 191 fSkStream->unref(); 192 } 193}; 194 195extern "C" { 196 static unsigned long sk_stream_read(FT_Stream stream, 197 unsigned long offset, 198 unsigned char* buffer, 199 unsigned long count ) { 200 SkStream* str = (SkStream*)stream->descriptor.pointer; 201 202 if (count) { 203 if (!str->rewind()) { 204 return 0; 205 } else { 206 unsigned long ret; 207 if (offset) { 208 ret = str->read(NULL, offset); 209 if (ret != offset) { 210 return 0; 211 } 212 } 213 ret = str->read(buffer, count); 214 if (ret != count) { 215 return 0; 216 } 217 count = ret; 218 } 219 } 220 return count; 221 } 222 223 static void sk_stream_close( FT_Stream stream) {} 224} 225 226SkFaceRec::SkFaceRec(SkStream* strm, uint32_t fontID) 227 : fSkStream(strm), fFontID(fontID) { 228// SkDEBUGF(("SkFaceRec: opening %s (%p)\n", key.c_str(), strm)); 229 230 sk_bzero(&fFTStream, sizeof(fFTStream)); 231 fFTStream.size = fSkStream->getLength(); 232 fFTStream.descriptor.pointer = fSkStream; 233 fFTStream.read = sk_stream_read; 234 fFTStream.close = sk_stream_close; 235} 236 237// Will return 0 on failure 238static SkFaceRec* ref_ft_face(uint32_t fontID) { 239 SkFaceRec* rec = gFaceRecHead; 240 while (rec) { 241 if (rec->fFontID == fontID) { 242 SkASSERT(rec->fFace); 243 rec->fRefCnt += 1; 244 return rec; 245 } 246 rec = rec->fNext; 247 } 248 249 SkStream* strm = SkFontHost::OpenStream(fontID); 250 if (NULL == strm) { 251 SkDEBUGF(("SkFontHost::OpenStream failed opening %x\n", fontID)); 252 return 0; 253 } 254 255 // this passes ownership of strm to the rec 256 rec = SkNEW_ARGS(SkFaceRec, (strm, fontID)); 257 258 FT_Open_Args args; 259 memset(&args, 0, sizeof(args)); 260 const void* memoryBase = strm->getMemoryBase(); 261 262 if (NULL != memoryBase) { 263//printf("mmap(%s)\n", keyString.c_str()); 264 args.flags = FT_OPEN_MEMORY; 265 args.memory_base = (const FT_Byte*)memoryBase; 266 args.memory_size = strm->getLength(); 267 } else { 268//printf("fopen(%s)\n", keyString.c_str()); 269 args.flags = FT_OPEN_STREAM; 270 args.stream = &rec->fFTStream; 271 } 272 273 int face_index; 274 int length = SkFontHost::GetFileName(fontID, NULL, 0, &face_index); 275 FT_Error err = FT_Open_Face(gFTLibrary, &args, length ? face_index : 0, 276 &rec->fFace); 277 278 if (err) { // bad filename, try the default font 279 fprintf(stderr, "ERROR: unable to open font '%x'\n", fontID); 280 SkDELETE(rec); 281 return 0; 282 } else { 283 SkASSERT(rec->fFace); 284 //fprintf(stderr, "Opened font '%s'\n", filename.c_str()); 285 rec->fNext = gFaceRecHead; 286 gFaceRecHead = rec; 287 rec->fRefCnt = 1; 288 return rec; 289 } 290} 291 292static void unref_ft_face(FT_Face face) { 293 SkFaceRec* rec = gFaceRecHead; 294 SkFaceRec* prev = NULL; 295 while (rec) { 296 SkFaceRec* next = rec->fNext; 297 if (rec->fFace == face) { 298 if (--rec->fRefCnt == 0) { 299 if (prev) { 300 prev->fNext = next; 301 } else { 302 gFaceRecHead = next; 303 } 304 FT_Done_Face(face); 305 SkDELETE(rec); 306 } 307 return; 308 } 309 prev = rec; 310 rec = next; 311 } 312 SkDEBUGFAIL("shouldn't get here, face not in list"); 313} 314 315/////////////////////////////////////////////////////////////////////////// 316 317// Work around for old versions of freetype. 318static FT_Error getAdvances(FT_Face face, FT_UInt start, FT_UInt count, 319 FT_Int32 loadFlags, FT_Fixed* advances) { 320#ifdef FT_ADVANCES_H 321 return FT_Get_Advances(face, start, count, loadFlags, advances); 322#else 323 if (!face || start >= face->num_glyphs || 324 start + count > face->num_glyphs || loadFlags != FT_LOAD_NO_SCALE) { 325 return 6; // "Invalid argument." 326 } 327 if (count == 0) 328 return 0; 329 330 for (int i = 0; i < count; i++) { 331 FT_Error err = FT_Load_Glyph(face, start + i, FT_LOAD_NO_SCALE); 332 if (err) 333 return err; 334 advances[i] = face->glyph->advance.x; 335 } 336 337 return 0; 338#endif 339} 340 341static bool canEmbed(FT_Face face) { 342#ifdef FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING 343 FT_UShort fsType = FT_Get_FSType_Flags(face); 344 return (fsType & (FT_FSTYPE_RESTRICTED_LICENSE_EMBEDDING | 345 FT_FSTYPE_BITMAP_EMBEDDING_ONLY)) == 0; 346#else 347 // No embedding is 0x2 and bitmap embedding only is 0x200. 348 TT_OS2* os2_table; 349 if ((os2_table = (TT_OS2*)FT_Get_Sfnt_Table(face, ft_sfnt_os2)) != NULL) { 350 return (os2_table->fsType & 0x202) == 0; 351 } 352 return false; // We tried, fail safe. 353#endif 354} 355 356static bool GetLetterCBox(FT_Face face, char letter, FT_BBox* bbox) { 357 const FT_UInt glyph_id = FT_Get_Char_Index(face, letter); 358 if (!glyph_id) 359 return false; 360 FT_Load_Glyph(face, glyph_id, FT_LOAD_NO_SCALE); 361 FT_Outline_Get_CBox(&face->glyph->outline, bbox); 362 return true; 363} 364 365static bool getWidthAdvance(FT_Face face, int gId, int16_t* data) { 366 FT_Fixed advance = 0; 367 if (getAdvances(face, gId, 1, FT_LOAD_NO_SCALE, &advance)) { 368 return false; 369 } 370 SkASSERT(data); 371 *data = advance; 372 return true; 373} 374 375static void populate_glyph_to_unicode(FT_Face& face, 376 SkTDArray<SkUnichar>* glyphToUnicode) { 377 // Check and see if we have Unicode cmaps. 378 for (int i = 0; i < face->num_charmaps; ++i) { 379 // CMaps known to support Unicode: 380 // Platform ID Encoding ID Name 381 // ----------- ----------- ----------------------------------- 382 // 0 0,1 Apple Unicode 383 // 0 3 Apple Unicode 2.0 (preferred) 384 // 3 1 Microsoft Unicode UCS-2 385 // 3 10 Microsoft Unicode UCS-4 (preferred) 386 // 387 // See Apple TrueType Reference Manual 388 // http://developer.apple.com/fonts/TTRefMan/RM06/Chap6cmap.html 389 // http://developer.apple.com/fonts/TTRefMan/RM06/Chap6name.html#ID 390 // Microsoft OpenType Specification 391 // http://www.microsoft.com/typography/otspec/cmap.htm 392 393 FT_UShort platformId = face->charmaps[i]->platform_id; 394 FT_UShort encodingId = face->charmaps[i]->encoding_id; 395 396 if (platformId != 0 && platformId != 3) { 397 continue; 398 } 399 if (platformId == 3 && encodingId != 1 && encodingId != 10) { 400 continue; 401 } 402 bool preferredMap = ((platformId == 3 && encodingId == 10) || 403 (platformId == 0 && encodingId == 3)); 404 405 FT_Set_Charmap(face, face->charmaps[i]); 406 if (glyphToUnicode->isEmpty()) { 407 glyphToUnicode->setCount(face->num_glyphs); 408 memset(glyphToUnicode->begin(), 0, 409 sizeof(SkUnichar) * face->num_glyphs); 410 } 411 412 // Iterate through each cmap entry. 413 FT_UInt glyphIndex; 414 for (SkUnichar charCode = FT_Get_First_Char(face, &glyphIndex); 415 glyphIndex != 0; 416 charCode = FT_Get_Next_Char(face, charCode, &glyphIndex)) { 417 if (charCode && 418 ((*glyphToUnicode)[glyphIndex] == 0 || preferredMap)) { 419 (*glyphToUnicode)[glyphIndex] = charCode; 420 } 421 } 422 } 423} 424 425// static 426SkAdvancedTypefaceMetrics* SkFontHost::GetAdvancedTypefaceMetrics( 427 uint32_t fontID, 428 SkAdvancedTypefaceMetrics::PerGlyphInfo perGlyphInfo, 429 const uint32_t* glyphIDs, 430 uint32_t glyphIDsCount) { 431#if defined(SK_BUILD_FOR_MAC) 432 return NULL; 433#else 434 SkAutoMutexAcquire ac(gFTMutex); 435 FT_Library libInit = NULL; 436 if (gFTCount == 0) { 437 if (!InitFreetype()) 438 sk_throw(); 439 libInit = gFTLibrary; 440 } 441 SkAutoTCallIProc<struct FT_LibraryRec_, FT_Done_FreeType> ftLib(libInit); 442 SkFaceRec* rec = ref_ft_face(fontID); 443 if (NULL == rec) 444 return NULL; 445 FT_Face face = rec->fFace; 446 447 SkAdvancedTypefaceMetrics* info = new SkAdvancedTypefaceMetrics; 448 info->fFontName.set(FT_Get_Postscript_Name(face)); 449 info->fMultiMaster = FT_HAS_MULTIPLE_MASTERS(face); 450 info->fLastGlyphID = face->num_glyphs - 1; 451 info->fEmSize = 1000; 452 453 bool cid = false; 454 const char* fontType = FT_Get_X11_Font_Format(face); 455 if (strcmp(fontType, "Type 1") == 0) { 456 info->fType = SkAdvancedTypefaceMetrics::kType1_Font; 457 } else if (strcmp(fontType, "CID Type 1") == 0) { 458 info->fType = SkAdvancedTypefaceMetrics::kType1CID_Font; 459 cid = true; 460 } else if (strcmp(fontType, "CFF") == 0) { 461 info->fType = SkAdvancedTypefaceMetrics::kCFF_Font; 462 } else if (strcmp(fontType, "TrueType") == 0) { 463 info->fType = SkAdvancedTypefaceMetrics::kTrueType_Font; 464 cid = true; 465 TT_Header* ttHeader; 466 if ((ttHeader = (TT_Header*)FT_Get_Sfnt_Table(face, 467 ft_sfnt_head)) != NULL) { 468 info->fEmSize = ttHeader->Units_Per_EM; 469 } 470 } 471 472 info->fStyle = 0; 473 if (FT_IS_FIXED_WIDTH(face)) 474 info->fStyle |= SkAdvancedTypefaceMetrics::kFixedPitch_Style; 475 if (face->style_flags & FT_STYLE_FLAG_ITALIC) 476 info->fStyle |= SkAdvancedTypefaceMetrics::kItalic_Style; 477 // We should set either Symbolic or Nonsymbolic; Nonsymbolic if the font's 478 // character set is a subset of 'Adobe standard Latin.' 479 info->fStyle |= SkAdvancedTypefaceMetrics::kSymbolic_Style; 480 481 PS_FontInfoRec ps_info; 482 TT_Postscript* tt_info; 483 if (FT_Get_PS_Font_Info(face, &ps_info) == 0) { 484 info->fItalicAngle = ps_info.italic_angle; 485 } else if ((tt_info = 486 (TT_Postscript*)FT_Get_Sfnt_Table(face, 487 ft_sfnt_post)) != NULL) { 488 info->fItalicAngle = SkFixedToScalar(tt_info->italicAngle); 489 } else { 490 info->fItalicAngle = 0; 491 } 492 493 info->fAscent = face->ascender; 494 info->fDescent = face->descender; 495 496 // Figure out a good guess for StemV - Min width of i, I, !, 1. 497 // This probably isn't very good with an italic font. 498 int16_t min_width = SHRT_MAX; 499 info->fStemV = 0; 500 char stem_chars[] = {'i', 'I', '!', '1'}; 501 for (size_t i = 0; i < SK_ARRAY_COUNT(stem_chars); i++) { 502 FT_BBox bbox; 503 if (GetLetterCBox(face, stem_chars[i], &bbox)) { 504 int16_t width = bbox.xMax - bbox.xMin; 505 if (width > 0 && width < min_width) { 506 min_width = width; 507 info->fStemV = min_width; 508 } 509 } 510 } 511 512 TT_PCLT* pclt_info; 513 TT_OS2* os2_table; 514 if ((pclt_info = (TT_PCLT*)FT_Get_Sfnt_Table(face, ft_sfnt_pclt)) != NULL) { 515 info->fCapHeight = pclt_info->CapHeight; 516 uint8_t serif_style = pclt_info->SerifStyle & 0x3F; 517 if (serif_style >= 2 && serif_style <= 6) 518 info->fStyle |= SkAdvancedTypefaceMetrics::kSerif_Style; 519 else if (serif_style >= 9 && serif_style <= 12) 520 info->fStyle |= SkAdvancedTypefaceMetrics::kScript_Style; 521 } else if ((os2_table = 522 (TT_OS2*)FT_Get_Sfnt_Table(face, ft_sfnt_os2)) != NULL) { 523 info->fCapHeight = os2_table->sCapHeight; 524 } else { 525 // Figure out a good guess for CapHeight: average the height of M and X. 526 FT_BBox m_bbox, x_bbox; 527 bool got_m, got_x; 528 got_m = GetLetterCBox(face, 'M', &m_bbox); 529 got_x = GetLetterCBox(face, 'X', &x_bbox); 530 if (got_m && got_x) { 531 info->fCapHeight = (m_bbox.yMax - m_bbox.yMin + x_bbox.yMax - 532 x_bbox.yMin) / 2; 533 } else if (got_m && !got_x) { 534 info->fCapHeight = m_bbox.yMax - m_bbox.yMin; 535 } else if (!got_m && got_x) { 536 info->fCapHeight = x_bbox.yMax - x_bbox.yMin; 537 } 538 } 539 540 info->fBBox = SkIRect::MakeLTRB(face->bbox.xMin, face->bbox.yMax, 541 face->bbox.xMax, face->bbox.yMin); 542 543 if (!canEmbed(face) || !FT_IS_SCALABLE(face) || 544 info->fType == SkAdvancedTypefaceMetrics::kOther_Font) { 545 perGlyphInfo = SkAdvancedTypefaceMetrics::kNo_PerGlyphInfo; 546 } 547 548 if (perGlyphInfo & SkAdvancedTypefaceMetrics::kHAdvance_PerGlyphInfo) { 549 if (FT_IS_FIXED_WIDTH(face)) { 550 appendRange(&info->fGlyphWidths, 0); 551 int16_t advance = face->max_advance_width; 552 info->fGlyphWidths->fAdvance.append(1, &advance); 553 finishRange(info->fGlyphWidths.get(), 0, 554 SkAdvancedTypefaceMetrics::WidthRange::kDefault); 555 } else if (!cid) { 556 appendRange(&info->fGlyphWidths, 0); 557 // So as to not blow out the stack, get advances in batches. 558 for (int gID = 0; gID < face->num_glyphs; gID += 128) { 559 FT_Fixed advances[128]; 560 int advanceCount = 128; 561 if (gID + advanceCount > face->num_glyphs) 562 advanceCount = face->num_glyphs - gID + 1; 563 getAdvances(face, gID, advanceCount, FT_LOAD_NO_SCALE, 564 advances); 565 for (int i = 0; i < advanceCount; i++) { 566 int16_t advance = advances[gID + i]; 567 info->fGlyphWidths->fAdvance.append(1, &advance); 568 } 569 } 570 finishRange(info->fGlyphWidths.get(), face->num_glyphs - 1, 571 SkAdvancedTypefaceMetrics::WidthRange::kRange); 572 } else { 573 info->fGlyphWidths.reset( 574 getAdvanceData(face, 575 face->num_glyphs, 576 glyphIDs, 577 glyphIDsCount, 578 &getWidthAdvance)); 579 } 580 } 581 582 if (perGlyphInfo & SkAdvancedTypefaceMetrics::kVAdvance_PerGlyphInfo && 583 FT_HAS_VERTICAL(face)) { 584 SkASSERT(false); // Not implemented yet. 585 } 586 587 if (perGlyphInfo & SkAdvancedTypefaceMetrics::kGlyphNames_PerGlyphInfo && 588 info->fType == SkAdvancedTypefaceMetrics::kType1_Font) { 589 // Postscript fonts may contain more than 255 glyphs, so we end up 590 // using multiple font descriptions with a glyph ordering. Record 591 // the name of each glyph. 592 info->fGlyphNames.reset( 593 new SkAutoTArray<SkString>(face->num_glyphs)); 594 for (int gID = 0; gID < face->num_glyphs; gID++) { 595 char glyphName[128]; // PS limit for names is 127 bytes. 596 FT_Get_Glyph_Name(face, gID, glyphName, 128); 597 info->fGlyphNames->get()[gID].set(glyphName); 598 } 599 } 600 601 if (perGlyphInfo & SkAdvancedTypefaceMetrics::kToUnicode_PerGlyphInfo && 602 info->fType != SkAdvancedTypefaceMetrics::kType1_Font && 603 face->num_charmaps) { 604 populate_glyph_to_unicode(face, &(info->fGlyphToUnicode)); 605 } 606 607 if (!canEmbed(face)) 608 info->fType = SkAdvancedTypefaceMetrics::kNotEmbeddable_Font; 609 610 unref_ft_face(face); 611 return info; 612#endif 613} 614 615/////////////////////////////////////////////////////////////////////////// 616 617#define BLACK_LUMINANCE_LIMIT 0x40 618#define WHITE_LUMINANCE_LIMIT 0xA0 619 620static bool bothZero(SkScalar a, SkScalar b) { 621 return 0 == a && 0 == b; 622} 623 624// returns false if there is any non-90-rotation or skew 625static bool isAxisAligned(const SkScalerContext::Rec& rec) { 626 return 0 == rec.fPreSkewX && 627 (bothZero(rec.fPost2x2[0][1], rec.fPost2x2[1][0]) || 628 bothZero(rec.fPost2x2[0][0], rec.fPost2x2[1][1])); 629} 630 631void SkFontHost::FilterRec(SkScalerContext::Rec* rec) { 632 if (!gLCDSupportValid) { 633 InitFreetype(); 634 FT_Done_FreeType(gFTLibrary); 635 } 636 637 if (!gLCDSupport && isLCD(*rec)) { 638 // If the runtime Freetype library doesn't support LCD mode, we disable 639 // it here. 640 rec->fMaskFormat = SkMask::kA8_Format; 641 } 642 643 SkPaint::Hinting h = rec->getHinting(); 644 if (SkPaint::kFull_Hinting == h && !isLCD(*rec)) { 645 // collapse full->normal hinting if we're not doing LCD 646 h = SkPaint::kNormal_Hinting; 647 } 648 if ((rec->fFlags & SkScalerContext::kSubpixelPositioning_Flag) || isLCD(*rec)) { 649 if (SkPaint::kNo_Hinting != h) { 650 h = SkPaint::kSlight_Hinting; 651 } 652 } 653 654#ifndef SK_IGNORE_ROTATED_FREETYPE_FIX 655 // rotated text looks bad with hinting, so we disable it as needed 656 if (!isAxisAligned(*rec)) { 657 h = SkPaint::kNo_Hinting; 658 } 659#endif 660 rec->setHinting(h); 661 662#ifndef SK_USE_COLOR_LUMINANCE 663 // for compatibility at the moment, discretize luminance to 3 settings 664 // black, white, gray. This helps with fontcache utilization, since we 665 // won't create multiple entries that in the end map to the same results. 666 { 667 unsigned lum = rec->getLuminanceByte(); 668 if (gGammaTables[0] || gGammaTables[1]) { 669 if (lum <= BLACK_LUMINANCE_LIMIT) { 670 lum = 0; 671 } else if (lum >= WHITE_LUMINANCE_LIMIT) { 672 lum = SkScalerContext::kLuminance_Max; 673 } else { 674 lum = SkScalerContext::kLuminance_Max >> 1; 675 } 676 } else { 677 lum = 0; // no gamma correct, so use 0 since SkPaint uses that 678 // when measuring text w/o regard for luminance 679 } 680 rec->setLuminanceBits(lum); 681 } 682#endif 683} 684 685#ifdef SK_BUILD_FOR_ANDROID 686uint32_t SkFontHost::GetUnitsPerEm(SkFontID fontID) { 687 SkAutoMutexAcquire ac(gFTMutex); 688 SkFaceRec *rec = ref_ft_face(fontID); 689 uint16_t unitsPerEm = 0; 690 691 if (rec != NULL && rec->fFace != NULL) { 692 unitsPerEm = rec->fFace->units_per_EM; 693 unref_ft_face(rec->fFace); 694 } 695 696 return (uint32_t)unitsPerEm; 697} 698#endif 699 700SkScalerContext_FreeType::SkScalerContext_FreeType(const SkDescriptor* desc) 701 : SkScalerContext(desc) { 702 SkAutoMutexAcquire ac(gFTMutex); 703 704 if (gFTCount == 0) { 705 if (!InitFreetype()) { 706 sk_throw(); 707 } 708 SkFontHost::GetGammaTables(gGammaTables); 709 } 710 ++gFTCount; 711 712 // load the font file 713 fFTSize = NULL; 714 fFace = NULL; 715 fFaceRec = ref_ft_face(fRec.fFontID); 716 if (NULL == fFaceRec) { 717 return; 718 } 719 fFace = fFaceRec->fFace; 720 721 // compute our factors from the record 722 723 SkMatrix m; 724 725 fRec.getSingleMatrix(&m); 726 727#ifdef DUMP_STRIKE_CREATION 728 SkString keyString; 729 SkFontHost::GetDescriptorKeyString(desc, &keyString); 730 printf("========== strike [%g %g %g] [%g %g %g %g] hints %d format %d %s\n", SkScalarToFloat(fRec.fTextSize), 731 SkScalarToFloat(fRec.fPreScaleX), SkScalarToFloat(fRec.fPreSkewX), 732 SkScalarToFloat(fRec.fPost2x2[0][0]), SkScalarToFloat(fRec.fPost2x2[0][1]), 733 SkScalarToFloat(fRec.fPost2x2[1][0]), SkScalarToFloat(fRec.fPost2x2[1][1]), 734 fRec.getHinting(), fRec.fMaskFormat, keyString.c_str()); 735#endif 736 737 // now compute our scale factors 738 SkScalar sx = m.getScaleX(); 739 SkScalar sy = m.getScaleY(); 740 741 if (m.getSkewX() || m.getSkewY() || sx < 0 || sy < 0) { 742 // sort of give up on hinting 743 sx = SkMaxScalar(SkScalarAbs(sx), SkScalarAbs(m.getSkewX())); 744 sy = SkMaxScalar(SkScalarAbs(m.getSkewY()), SkScalarAbs(sy)); 745 sx = sy = SkScalarAve(sx, sy); 746 747 SkScalar inv = SkScalarInvert(sx); 748 749 // flip the skew elements to go from our Y-down system to FreeType's 750 fMatrix22.xx = SkScalarToFixed(SkScalarMul(m.getScaleX(), inv)); 751 fMatrix22.xy = -SkScalarToFixed(SkScalarMul(m.getSkewX(), inv)); 752 fMatrix22.yx = -SkScalarToFixed(SkScalarMul(m.getSkewY(), inv)); 753 fMatrix22.yy = SkScalarToFixed(SkScalarMul(m.getScaleY(), inv)); 754 } else { 755 fMatrix22.xx = fMatrix22.yy = SK_Fixed1; 756 fMatrix22.xy = fMatrix22.yx = 0; 757 } 758 759 fScaleX = SkScalarToFixed(sx); 760 fScaleY = SkScalarToFixed(sy); 761 762 // compute the flags we send to Load_Glyph 763 { 764 FT_Int32 loadFlags = FT_LOAD_DEFAULT; 765 bool linearMetrics = false; 766 767 if (SkMask::kBW_Format == fRec.fMaskFormat) { 768 // See http://code.google.com/p/chromium/issues/detail?id=43252#c24 769 loadFlags = FT_LOAD_TARGET_MONO; 770 if (fRec.getHinting() == SkPaint::kNo_Hinting) { 771 loadFlags = FT_LOAD_NO_HINTING; 772 linearMetrics = true; 773 } 774 } else { 775 switch (fRec.getHinting()) { 776 case SkPaint::kNo_Hinting: 777 loadFlags = FT_LOAD_NO_HINTING; 778 linearMetrics = true; 779 break; 780 case SkPaint::kSlight_Hinting: 781 loadFlags = FT_LOAD_TARGET_LIGHT; // This implies FORCE_AUTOHINT 782 linearMetrics = true; 783 break; 784 case SkPaint::kNormal_Hinting: 785 if (fRec.fFlags & SkScalerContext::kAutohinting_Flag) 786 loadFlags = FT_LOAD_FORCE_AUTOHINT; 787 else 788 loadFlags = FT_LOAD_NO_AUTOHINT; 789 break; 790 case SkPaint::kFull_Hinting: 791 if (fRec.fFlags & SkScalerContext::kAutohinting_Flag) { 792 loadFlags = FT_LOAD_FORCE_AUTOHINT; 793 break; 794 } 795 loadFlags = FT_LOAD_TARGET_NORMAL; 796 if (isLCD(fRec)) { 797 if (fRec.fFlags & SkScalerContext::kLCD_Vertical_Flag) { 798 loadFlags = FT_LOAD_TARGET_LCD_V; 799 } else { 800 loadFlags = FT_LOAD_TARGET_LCD; 801 } 802 } 803 break; 804 default: 805 SkDebugf("---------- UNKNOWN hinting %d\n", fRec.getHinting()); 806 break; 807 } 808 } 809 810 if ((fRec.fFlags & SkScalerContext::kEmbeddedBitmapText_Flag) == 0) { 811 loadFlags |= FT_LOAD_NO_BITMAP; 812 } 813 814 // Always using FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH to get correct 815 // advances, as fontconfig and cairo do. 816 // See http://code.google.com/p/skia/issues/detail?id=222. 817 loadFlags |= FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH; 818 819 fLoadGlyphFlags = loadFlags; 820 fDoLinearMetrics = linearMetrics; 821 } 822 823 // now create the FT_Size 824 825 { 826 FT_Error err; 827 828 err = FT_New_Size(fFace, &fFTSize); 829 if (err != 0) { 830 SkDEBUGF(("SkScalerContext_FreeType::FT_New_Size(%x): FT_Set_Char_Size(0x%x, 0x%x) returned 0x%x\n", 831 fFaceRec->fFontID, fScaleX, fScaleY, err)); 832 fFace = NULL; 833 return; 834 } 835 836 err = FT_Activate_Size(fFTSize); 837 if (err != 0) { 838 SkDEBUGF(("SkScalerContext_FreeType::FT_Activate_Size(%x, 0x%x, 0x%x) returned 0x%x\n", 839 fFaceRec->fFontID, fScaleX, fScaleY, err)); 840 fFTSize = NULL; 841 } 842 843 err = FT_Set_Char_Size( fFace, 844 SkFixedToFDot6(fScaleX), SkFixedToFDot6(fScaleY), 845 72, 72); 846 if (err != 0) { 847 SkDEBUGF(("SkScalerContext_FreeType::FT_Set_Char_Size(%x, 0x%x, 0x%x) returned 0x%x\n", 848 fFaceRec->fFontID, fScaleX, fScaleY, err)); 849 fFace = NULL; 850 return; 851 } 852 853 FT_Set_Transform( fFace, &fMatrix22, NULL); 854 } 855} 856 857SkScalerContext_FreeType::~SkScalerContext_FreeType() { 858 if (fFTSize != NULL) { 859 FT_Done_Size(fFTSize); 860 } 861 862 SkAutoMutexAcquire ac(gFTMutex); 863 864 if (fFace != NULL) { 865 unref_ft_face(fFace); 866 } 867 if (--gFTCount == 0) { 868// SkDEBUGF(("FT_Done_FreeType\n")); 869 FT_Done_FreeType(gFTLibrary); 870 SkDEBUGCODE(gFTLibrary = NULL;) 871 } 872} 873 874/* We call this before each use of the fFace, since we may be sharing 875 this face with other context (at different sizes). 876*/ 877FT_Error SkScalerContext_FreeType::setupSize() { 878 FT_Error err = FT_Activate_Size(fFTSize); 879 880 if (err != 0) { 881 SkDEBUGF(("SkScalerContext_FreeType::FT_Activate_Size(%x, 0x%x, 0x%x) returned 0x%x\n", 882 fFaceRec->fFontID, fScaleX, fScaleY, err)); 883 fFTSize = NULL; 884 } else { 885 // seems we need to reset this every time (not sure why, but without it 886 // I get random italics from some other fFTSize) 887 FT_Set_Transform( fFace, &fMatrix22, NULL); 888 } 889 return err; 890} 891 892void SkScalerContext_FreeType::emboldenOutline(FT_Outline* outline) { 893 FT_Pos strength; 894 strength = FT_MulFix(fFace->units_per_EM, fFace->size->metrics.y_scale) 895 / 24; 896 FT_Outline_Embolden(outline, strength); 897} 898 899unsigned SkScalerContext_FreeType::generateGlyphCount() { 900 return fFace->num_glyphs; 901} 902 903uint16_t SkScalerContext_FreeType::generateCharToGlyph(SkUnichar uni) { 904 return SkToU16(FT_Get_Char_Index( fFace, uni )); 905} 906 907SkUnichar SkScalerContext_FreeType::generateGlyphToChar(uint16_t glyph) { 908 // iterate through each cmap entry, looking for matching glyph indices 909 FT_UInt glyphIndex; 910 SkUnichar charCode = FT_Get_First_Char( fFace, &glyphIndex ); 911 912 while (glyphIndex != 0) { 913 if (glyphIndex == glyph) { 914 return charCode; 915 } 916 charCode = FT_Get_Next_Char( fFace, charCode, &glyphIndex ); 917 } 918 919 return 0; 920} 921 922static FT_Pixel_Mode compute_pixel_mode(SkMask::Format format) { 923 switch (format) { 924 case SkMask::kBW_Format: 925 return FT_PIXEL_MODE_MONO; 926 case SkMask::kA8_Format: 927 default: 928 return FT_PIXEL_MODE_GRAY; 929 } 930} 931 932void SkScalerContext_FreeType::generateAdvance(SkGlyph* glyph) { 933#ifdef FT_ADVANCES_H 934 /* unhinted and light hinted text have linearly scaled advances 935 * which are very cheap to compute with some font formats... 936 */ 937 if (fDoLinearMetrics) { 938 SkAutoMutexAcquire ac(gFTMutex); 939 940 if (this->setupSize()) { 941 glyph->zeroMetrics(); 942 return; 943 } 944 945 FT_Error error; 946 FT_Fixed advance; 947 948 error = FT_Get_Advance( fFace, glyph->getGlyphID(fBaseGlyphCount), 949 fLoadGlyphFlags | FT_ADVANCE_FLAG_FAST_ONLY, 950 &advance ); 951 if (0 == error) { 952 glyph->fRsbDelta = 0; 953 glyph->fLsbDelta = 0; 954 glyph->fAdvanceX = advance; // advance *2/3; //DEBUG 955 glyph->fAdvanceY = 0; 956 return; 957 } 958 } 959#endif /* FT_ADVANCES_H */ 960 /* otherwise, we need to load/hint the glyph, which is slower */ 961 this->generateMetrics(glyph); 962 return; 963} 964 965void SkScalerContext_FreeType::getBBoxForCurrentGlyph(SkGlyph* glyph, 966 FT_BBox* bbox, 967 bool snapToPixelBoundary) { 968 969 FT_Outline_Get_CBox(&fFace->glyph->outline, bbox); 970 971 if (fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) { 972 int dx = FixedToDot6(glyph->getSubXFixed()); 973 int dy = FixedToDot6(glyph->getSubYFixed()); 974 // negate dy since freetype-y-goes-up and skia-y-goes-down 975 bbox->xMin += dx; 976 bbox->yMin -= dy; 977 bbox->xMax += dx; 978 bbox->yMax -= dy; 979 } 980 981 // outset the box to integral boundaries 982 if (snapToPixelBoundary) { 983 bbox->xMin &= ~63; 984 bbox->yMin &= ~63; 985 bbox->xMax = (bbox->xMax + 63) & ~63; 986 bbox->yMax = (bbox->yMax + 63) & ~63; 987 } 988} 989 990void SkScalerContext_FreeType::updateGlyphIfLCD(SkGlyph* glyph) { 991 if (isLCD(fRec)) { 992 glyph->fWidth += gLCDExtra; 993 glyph->fLeft -= gLCDExtra >> 1; 994 } 995} 996 997void SkScalerContext_FreeType::generateMetrics(SkGlyph* glyph) { 998 SkAutoMutexAcquire ac(gFTMutex); 999 1000 glyph->fRsbDelta = 0; 1001 glyph->fLsbDelta = 0; 1002 1003 FT_Error err; 1004 1005 if (this->setupSize()) { 1006 goto ERROR; 1007 } 1008 1009 err = FT_Load_Glyph( fFace, glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags ); 1010 if (err != 0) { 1011 SkDEBUGF(("SkScalerContext_FreeType::generateMetrics(%x): FT_Load_Glyph(glyph:%d flags:%d) returned 0x%x\n", 1012 fFaceRec->fFontID, glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags, err)); 1013 ERROR: 1014 glyph->zeroMetrics(); 1015 return; 1016 } 1017 1018 SkFixed vLeft, vTop; 1019 1020 switch ( fFace->glyph->format ) { 1021 case FT_GLYPH_FORMAT_OUTLINE: { 1022 FT_BBox bbox; 1023 1024 if (0 == fFace->glyph->outline.n_contours) { 1025 glyph->fWidth = 0; 1026 glyph->fHeight = 0; 1027 glyph->fTop = 0; 1028 glyph->fLeft = 0; 1029 break; 1030 } 1031 1032 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1033 emboldenOutline(&fFace->glyph->outline); 1034 } 1035 1036 getBBoxForCurrentGlyph(glyph, &bbox, true); 1037 1038 glyph->fWidth = SkToU16((bbox.xMax - bbox.xMin) >> 6); 1039 glyph->fHeight = SkToU16((bbox.yMax - bbox.yMin) >> 6); 1040 glyph->fTop = -SkToS16(bbox.yMax >> 6); 1041 glyph->fLeft = SkToS16(bbox.xMin >> 6); 1042 1043 if ((fRec.fFlags & SkScalerContext::kVertical_Flag)) { 1044 vLeft = Dot6ToFixed(bbox.xMin); 1045 vTop = Dot6ToFixed(bbox.yMax); 1046 } 1047 1048 updateGlyphIfLCD(glyph); 1049 1050 break; 1051 } 1052 1053 case FT_GLYPH_FORMAT_BITMAP: 1054 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1055 FT_GlyphSlot_Own_Bitmap(fFace->glyph); 1056 FT_Bitmap_Embolden(gFTLibrary, &fFace->glyph->bitmap, kBitmapEmboldenStrength, 0); 1057 } 1058 glyph->fWidth = SkToU16(fFace->glyph->bitmap.width); 1059 glyph->fHeight = SkToU16(fFace->glyph->bitmap.rows); 1060 glyph->fTop = -SkToS16(fFace->glyph->bitmap_top); 1061 glyph->fLeft = SkToS16(fFace->glyph->bitmap_left); 1062 break; 1063 1064 default: 1065 SkDEBUGFAIL("unknown glyph format"); 1066 goto ERROR; 1067 } 1068 1069 if ((fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) == 0) { 1070 glyph->fAdvanceX = SkFDot6ToFixed(fFace->glyph->advance.x); 1071 glyph->fAdvanceY = -SkFDot6ToFixed(fFace->glyph->advance.y); 1072 if (fRec.fFlags & kDevKernText_Flag) { 1073 glyph->fRsbDelta = SkToS8(fFace->glyph->rsb_delta); 1074 glyph->fLsbDelta = SkToS8(fFace->glyph->lsb_delta); 1075 } 1076 } else { 1077 glyph->fAdvanceX = SkFixedMul(fMatrix22.xx, fFace->glyph->linearHoriAdvance); 1078 glyph->fAdvanceY = -SkFixedMul(fMatrix22.yx, fFace->glyph->linearHoriAdvance); 1079 } 1080 1081 if ((fRec.fFlags & SkScalerContext::kVertical_Flag) 1082 && fFace->glyph->format == FT_GLYPH_FORMAT_OUTLINE) { 1083 1084 //TODO: do we need to specially handle SubpixelPositioning and Kerning? 1085 1086 FT_Matrix identityMatrix; 1087 identityMatrix.xx = identityMatrix.yy = SK_Fixed1; 1088 identityMatrix.xy = identityMatrix.yx = 0; 1089 1090 // if the matrix is not the identity matrix then we need to re-load the 1091 // glyph with the identity matrix to get the necessary bounding box 1092 if (memcmp(&fMatrix22, &identityMatrix, sizeof(FT_Matrix)) != 0) { 1093 1094 FT_Set_Transform(fFace, &identityMatrix, NULL); 1095 1096 err = FT_Load_Glyph( fFace, glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags ); 1097 if (err != 0) { 1098 SkDEBUGF(("SkScalerContext_FreeType::generateMetrics(%x): FT_Load_Glyph(glyph:%d flags:%d) returned 0x%x\n", 1099 fFaceRec->fFontID, glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags, err)); 1100 goto ERROR; 1101 } 1102 1103 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1104 emboldenOutline(&fFace->glyph->outline); 1105 } 1106 } 1107 1108 // bounding box of the unskewed and unscaled glyph 1109 FT_BBox bbox; 1110 getBBoxForCurrentGlyph(glyph, &bbox); 1111 1112 // compute the vertical gap above and below the glyph if the glyph were 1113 // centered within the linearVertAdvance 1114 SkFixed vGap = (fFace->glyph->linearVertAdvance - Dot6ToFixed(bbox.yMax - bbox.yMin)) / 2; 1115 1116 // the origin point of the glyph when rendered vertically 1117 FT_Vector vOrigin; 1118 vOrigin.x = fFace->glyph->linearHoriAdvance / 2; 1119 vOrigin.y = vGap + Dot6ToFixed(bbox.yMax); 1120 1121 // transform the vertical origin based on the matrix of the actual glyph 1122 FT_Vector_Transform(&vOrigin, &fMatrix22); 1123 1124 // compute a new offset vector for the glyph by subtracting the vertical 1125 // origin from the original horizontal offset vector 1126 glyph->fLeft = SkFixedRoundToInt(vLeft - vOrigin.x); 1127 glyph->fTop = -SkFixedRoundToInt(vTop - vOrigin.y); 1128 1129 updateGlyphIfLCD(glyph); 1130 1131 // use the vertical advance values computed by freetype 1132 glyph->fAdvanceX = -SkFixedMul(fMatrix22.xy, fFace->glyph->linearVertAdvance); 1133 glyph->fAdvanceY = SkFixedMul(fMatrix22.yy, fFace->glyph->linearVertAdvance); 1134 } 1135 1136 1137#ifdef ENABLE_GLYPH_SPEW 1138 SkDEBUGF(("FT_Set_Char_Size(this:%p sx:%x sy:%x ", this, fScaleX, fScaleY)); 1139 SkDEBUGF(("Metrics(glyph:%d flags:0x%x) w:%d\n", glyph->getGlyphID(fBaseGlyphCount), fLoadGlyphFlags, glyph->fWidth)); 1140#endif 1141} 1142 1143/////////////////////////////////////////////////////////////////////////////// 1144 1145static int apply_contrast(int srca, int contrast) { 1146 return srca + (((255 - srca) * contrast * srca) / (255*255)); 1147} 1148 1149static void build_power_table(uint8_t table[], float ee) { 1150 for (int i = 0; i < 256; i++) { 1151 float x = i / 255.f; 1152 x = powf(x, ee); 1153 int xx = SkScalarRoundToInt(SkFloatToScalar(x * 255)); 1154 table[i] = SkToU8(xx); 1155 } 1156} 1157 1158static void build_gamma_table(uint8_t table[256], int src, int dst) { 1159 static bool gInit; 1160 static uint8_t powTable[256], invPowTable[256]; 1161 if (!gInit) { 1162 const float g = SK_GAMMA_EXPONENT; 1163 build_power_table(powTable, g); 1164 build_power_table(invPowTable, 1/g); 1165 gInit = true; 1166 } 1167 1168 const int linSrc = powTable[src]; 1169 const int linDst = powTable[dst]; 1170 // have our contrast value taper off to 0 as the src luminance becomes white 1171 const int contrast = SK_GAMMA_CONTRAST * (255 - linSrc) / 255; 1172 1173 for (int i = 0; i < 256; ++i) { 1174 int srca = apply_contrast(i, contrast); 1175 SkASSERT((unsigned)srca <= 255); 1176 int dsta = 255 - srca; 1177 1178 //Calculate the output we want. 1179 int linOut = (linSrc * srca + dsta * linDst) / 255; 1180 SkASSERT((unsigned)linOut <= 255); 1181 int out = invPowTable[linOut]; 1182 1183 //Undo what the blit blend will do. 1184 int result = ((255 * out) - (255 * dst)) / (src - dst); 1185 SkASSERT((unsigned)result <= 255); 1186 1187 table[i] = result; 1188 } 1189} 1190 1191static const uint8_t* getGammaTable(U8CPU luminance) { 1192 static uint8_t gGammaTables[4][256]; 1193 static bool gInited; 1194 if (!gInited) { 1195 build_gamma_table(gGammaTables[0], 0x00, 0xFF); 1196 build_gamma_table(gGammaTables[1], 0x66, 0x99); 1197 build_gamma_table(gGammaTables[2], 0x99, 0x66); 1198 build_gamma_table(gGammaTables[3], 0xFF, 0x00); 1199 1200 gInited = true; 1201 } 1202 SkASSERT(0 == (luminance >> 8)); 1203 return gGammaTables[luminance >> 6]; 1204} 1205 1206#ifndef SK_USE_COLOR_LUMINANCE 1207static const uint8_t* getIdentityTable() { 1208 static bool gOnce; 1209 static uint8_t gIdentityTable[256]; 1210 if (!gOnce) { 1211 for (int i = 0; i < 256; ++i) { 1212 gIdentityTable[i] = i; 1213 } 1214 gOnce = true; 1215 } 1216 return gIdentityTable; 1217} 1218#endif 1219 1220static uint16_t packTriple(unsigned r, unsigned g, unsigned b) { 1221 return SkPackRGB16(r >> 3, g >> 2, b >> 3); 1222} 1223 1224static uint16_t grayToRGB16(U8CPU gray) { 1225 SkASSERT(gray <= 255); 1226 return SkPackRGB16(gray >> 3, gray >> 2, gray >> 3); 1227} 1228 1229static int bittst(const uint8_t data[], int bitOffset) { 1230 SkASSERT(bitOffset >= 0); 1231 int lowBit = data[bitOffset >> 3] >> (~bitOffset & 7); 1232 return lowBit & 1; 1233} 1234 1235static void copyFT2LCD16(const SkGlyph& glyph, const FT_Bitmap& bitmap, 1236 int lcdIsBGR, const uint8_t* tableR, 1237 const uint8_t* tableG, const uint8_t* tableB) { 1238 SkASSERT(glyph.fHeight == bitmap.rows); 1239 uint16_t* dst = reinterpret_cast<uint16_t*>(glyph.fImage); 1240 const size_t dstRB = glyph.rowBytes(); 1241 const int width = glyph.fWidth; 1242 const uint8_t* src = bitmap.buffer; 1243 1244 switch (bitmap.pixel_mode) { 1245 case FT_PIXEL_MODE_MONO: { 1246 for (int y = 0; y < glyph.fHeight; ++y) { 1247 for (int x = 0; x < width; ++x) { 1248 dst[x] = -bittst(src, x); 1249 } 1250 dst = (uint16_t*)((char*)dst + dstRB); 1251 src += bitmap.pitch; 1252 } 1253 } break; 1254 case FT_PIXEL_MODE_GRAY: { 1255 for (int y = 0; y < glyph.fHeight; ++y) { 1256 for (int x = 0; x < width; ++x) { 1257 dst[x] = grayToRGB16(src[x]); 1258 } 1259 dst = (uint16_t*)((char*)dst + dstRB); 1260 src += bitmap.pitch; 1261 } 1262 } break; 1263 default: { 1264 SkASSERT(glyph.fWidth * 3 == bitmap.width); 1265 for (int y = 0; y < glyph.fHeight; y++) { 1266 const uint8_t* triple = src; 1267 if (lcdIsBGR) { 1268 for (int x = 0; x < width; x++) { 1269 dst[x] = packTriple(tableR[triple[2]], 1270 tableG[triple[1]], 1271 tableB[triple[0]]); 1272 triple += 3; 1273 } 1274 } else { 1275 for (int x = 0; x < width; x++) { 1276 dst[x] = packTriple(tableR[triple[0]], 1277 tableG[triple[1]], 1278 tableB[triple[2]]); 1279 triple += 3; 1280 } 1281 } 1282 src += bitmap.pitch; 1283 dst = (uint16_t*)((char*)dst + dstRB); 1284 } 1285 } break; 1286 } 1287} 1288 1289void SkScalerContext_FreeType::generateImage(const SkGlyph& glyph) { 1290 SkAutoMutexAcquire ac(gFTMutex); 1291 1292 FT_Error err; 1293 1294 if (this->setupSize()) { 1295 goto ERROR; 1296 } 1297 1298 err = FT_Load_Glyph( fFace, glyph.getGlyphID(fBaseGlyphCount), fLoadGlyphFlags); 1299 if (err != 0) { 1300 SkDEBUGF(("SkScalerContext_FreeType::generateImage: FT_Load_Glyph(glyph:%d width:%d height:%d rb:%d flags:%d) returned 0x%x\n", 1301 glyph.getGlyphID(fBaseGlyphCount), glyph.fWidth, glyph.fHeight, glyph.rowBytes(), fLoadGlyphFlags, err)); 1302 ERROR: 1303 memset(glyph.fImage, 0, glyph.rowBytes() * glyph.fHeight); 1304 return; 1305 } 1306 1307#ifdef SK_USE_COLOR_LUMINANCE 1308 SkColor lumColor = fRec.getLuminanceColor(); 1309 const uint8_t* tableR = getGammaTable(SkColorGetR(lumColor)); 1310 const uint8_t* tableG = getGammaTable(SkColorGetG(lumColor)); 1311 const uint8_t* tableB = getGammaTable(SkColorGetB(lumColor)); 1312#else 1313 unsigned lum = fRec.getLuminanceByte(); 1314 const uint8_t* tableR; 1315 const uint8_t* tableG; 1316 const uint8_t* tableB; 1317 1318 bool isWhite = lum >= WHITE_LUMINANCE_LIMIT; 1319 bool isBlack = lum <= BLACK_LUMINANCE_LIMIT; 1320 if ((gGammaTables[0] || gGammaTables[1]) && (isBlack || isWhite)) { 1321 tableR = tableG = tableB = gGammaTables[isBlack ? 0 : 1]; 1322 } else { 1323 tableR = tableG = tableB = getIdentityTable(); 1324 } 1325#endif 1326 1327 switch ( fFace->glyph->format ) { 1328 case FT_GLYPH_FORMAT_OUTLINE: { 1329 FT_Outline* outline = &fFace->glyph->outline; 1330 FT_BBox bbox; 1331 FT_Bitmap target; 1332 1333 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1334 emboldenOutline(outline); 1335 } 1336 1337 int dx = 0, dy = 0; 1338 if (fRec.fFlags & SkScalerContext::kSubpixelPositioning_Flag) { 1339 dx = glyph.getSubXFixed() >> 10; 1340 dy = glyph.getSubYFixed() >> 10; 1341 // negate dy since freetype-y-goes-up and skia-y-goes-down 1342 dy = -dy; 1343 } 1344 FT_Outline_Get_CBox(outline, &bbox); 1345 /* 1346 what we really want to do for subpixel is 1347 offset(dx, dy) 1348 compute_bounds 1349 offset(bbox & !63) 1350 but that is two calls to offset, so we do the following, which 1351 achieves the same thing with only one offset call. 1352 */ 1353 FT_Outline_Translate(outline, dx - ((bbox.xMin + dx) & ~63), 1354 dy - ((bbox.yMin + dy) & ~63)); 1355 1356 if (SkMask::kLCD16_Format == glyph.fMaskFormat) { 1357 FT_Render_Glyph(fFace->glyph, FT_RENDER_MODE_LCD); 1358 copyFT2LCD16(glyph, fFace->glyph->bitmap, 1359 fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag, 1360 tableR, tableG, tableB); 1361 } else { 1362 target.width = glyph.fWidth; 1363 target.rows = glyph.fHeight; 1364 target.pitch = glyph.rowBytes(); 1365 target.buffer = reinterpret_cast<uint8_t*>(glyph.fImage); 1366 target.pixel_mode = compute_pixel_mode( 1367 (SkMask::Format)fRec.fMaskFormat); 1368 target.num_grays = 256; 1369 1370 memset(glyph.fImage, 0, glyph.rowBytes() * glyph.fHeight); 1371 FT_Outline_Get_Bitmap(gFTLibrary, outline, &target); 1372 } 1373 } break; 1374 1375 case FT_GLYPH_FORMAT_BITMAP: { 1376 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1377 FT_GlyphSlot_Own_Bitmap(fFace->glyph); 1378 FT_Bitmap_Embolden(gFTLibrary, &fFace->glyph->bitmap, kBitmapEmboldenStrength, 0); 1379 } 1380 SkASSERT_CONTINUE(glyph.fWidth == fFace->glyph->bitmap.width); 1381 SkASSERT_CONTINUE(glyph.fHeight == fFace->glyph->bitmap.rows); 1382 SkASSERT_CONTINUE(glyph.fTop == -fFace->glyph->bitmap_top); 1383 SkASSERT_CONTINUE(glyph.fLeft == fFace->glyph->bitmap_left); 1384 1385 const uint8_t* src = (const uint8_t*)fFace->glyph->bitmap.buffer; 1386 uint8_t* dst = (uint8_t*)glyph.fImage; 1387 1388 if (fFace->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_GRAY || 1389 (fFace->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_MONO && 1390 glyph.fMaskFormat == SkMask::kBW_Format)) { 1391 unsigned srcRowBytes = fFace->glyph->bitmap.pitch; 1392 unsigned dstRowBytes = glyph.rowBytes(); 1393 unsigned minRowBytes = SkMin32(srcRowBytes, dstRowBytes); 1394 unsigned extraRowBytes = dstRowBytes - minRowBytes; 1395 1396 for (int y = fFace->glyph->bitmap.rows - 1; y >= 0; --y) { 1397 memcpy(dst, src, minRowBytes); 1398 memset(dst + minRowBytes, 0, extraRowBytes); 1399 src += srcRowBytes; 1400 dst += dstRowBytes; 1401 } 1402 } else if (fFace->glyph->bitmap.pixel_mode == FT_PIXEL_MODE_MONO && 1403 glyph.fMaskFormat == SkMask::kA8_Format) { 1404 for (int y = 0; y < fFace->glyph->bitmap.rows; ++y) { 1405 uint8_t byte = 0; 1406 int bits = 0; 1407 const uint8_t* src_row = src; 1408 uint8_t* dst_row = dst; 1409 1410 for (int x = 0; x < fFace->glyph->bitmap.width; ++x) { 1411 if (!bits) { 1412 byte = *src_row++; 1413 bits = 8; 1414 } 1415 1416 *dst_row++ = byte & 0x80 ? 0xff : 0; 1417 bits--; 1418 byte <<= 1; 1419 } 1420 1421 src += fFace->glyph->bitmap.pitch; 1422 dst += glyph.rowBytes(); 1423 } 1424 } else if (SkMask::kLCD16_Format == glyph.fMaskFormat) { 1425 copyFT2LCD16(glyph, fFace->glyph->bitmap, 1426 fRec.fFlags & SkScalerContext::kLCD_BGROrder_Flag, 1427 tableR, tableG, tableB); 1428 } else { 1429 SkDEBUGFAIL("unknown glyph bitmap transform needed"); 1430 } 1431 } break; 1432 1433 default: 1434 SkDEBUGFAIL("unknown glyph format"); 1435 goto ERROR; 1436 } 1437 1438// We used to always do this pre-USE_COLOR_LUMINANCE, but with colorlum, 1439// it is optional 1440#if defined(SK_GAMMA_APPLY_TO_A8) || !defined(SK_USE_COLOR_LUMINANCE) 1441 if (SkMask::kA8_Format == glyph.fMaskFormat) { 1442 SkASSERT(tableR == tableG && tableR == tableB); 1443 const uint8_t* table = tableR; 1444 uint8_t* SK_RESTRICT dst = (uint8_t*)glyph.fImage; 1445 unsigned rowBytes = glyph.rowBytes(); 1446 1447 for (int y = glyph.fHeight - 1; y >= 0; --y) { 1448 for (int x = glyph.fWidth - 1; x >= 0; --x) { 1449 dst[x] = table[dst[x]]; 1450 } 1451 dst += rowBytes; 1452 } 1453 } 1454#endif 1455} 1456 1457/////////////////////////////////////////////////////////////////////////////// 1458 1459#define ft2sk(x) SkFixedToScalar((x) << 10) 1460 1461#if FREETYPE_MAJOR >= 2 && FREETYPE_MINOR >= 2 1462 #define CONST_PARAM const 1463#else // older freetype doesn't use const here 1464 #define CONST_PARAM 1465#endif 1466 1467static int move_proc(CONST_PARAM FT_Vector* pt, void* ctx) { 1468 SkPath* path = (SkPath*)ctx; 1469 path->close(); // to close the previous contour (if any) 1470 path->moveTo(ft2sk(pt->x), -ft2sk(pt->y)); 1471 return 0; 1472} 1473 1474static int line_proc(CONST_PARAM FT_Vector* pt, void* ctx) { 1475 SkPath* path = (SkPath*)ctx; 1476 path->lineTo(ft2sk(pt->x), -ft2sk(pt->y)); 1477 return 0; 1478} 1479 1480static int quad_proc(CONST_PARAM FT_Vector* pt0, CONST_PARAM FT_Vector* pt1, 1481 void* ctx) { 1482 SkPath* path = (SkPath*)ctx; 1483 path->quadTo(ft2sk(pt0->x), -ft2sk(pt0->y), ft2sk(pt1->x), -ft2sk(pt1->y)); 1484 return 0; 1485} 1486 1487static int cubic_proc(CONST_PARAM FT_Vector* pt0, CONST_PARAM FT_Vector* pt1, 1488 CONST_PARAM FT_Vector* pt2, void* ctx) { 1489 SkPath* path = (SkPath*)ctx; 1490 path->cubicTo(ft2sk(pt0->x), -ft2sk(pt0->y), ft2sk(pt1->x), 1491 -ft2sk(pt1->y), ft2sk(pt2->x), -ft2sk(pt2->y)); 1492 return 0; 1493} 1494 1495void SkScalerContext_FreeType::generatePath(const SkGlyph& glyph, 1496 SkPath* path) { 1497 SkAutoMutexAcquire ac(gFTMutex); 1498 1499 SkASSERT(&glyph && path); 1500 1501 if (this->setupSize()) { 1502 path->reset(); 1503 return; 1504 } 1505 1506 uint32_t flags = fLoadGlyphFlags; 1507 flags |= FT_LOAD_NO_BITMAP; // ignore embedded bitmaps so we're sure to get the outline 1508 flags &= ~FT_LOAD_RENDER; // don't scan convert (we just want the outline) 1509 1510 FT_Error err = FT_Load_Glyph( fFace, glyph.getGlyphID(fBaseGlyphCount), flags); 1511 1512 if (err != 0) { 1513 SkDEBUGF(("SkScalerContext_FreeType::generatePath: FT_Load_Glyph(glyph:%d flags:%d) returned 0x%x\n", 1514 glyph.getGlyphID(fBaseGlyphCount), flags, err)); 1515 path->reset(); 1516 return; 1517 } 1518 1519 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1520 emboldenOutline(&fFace->glyph->outline); 1521 } 1522 1523 FT_Outline_Funcs funcs; 1524 1525 funcs.move_to = move_proc; 1526 funcs.line_to = line_proc; 1527 funcs.conic_to = quad_proc; 1528 funcs.cubic_to = cubic_proc; 1529 funcs.shift = 0; 1530 funcs.delta = 0; 1531 1532 err = FT_Outline_Decompose(&fFace->glyph->outline, &funcs, path); 1533 1534 if (err != 0) { 1535 SkDEBUGF(("SkScalerContext_FreeType::generatePath: FT_Load_Glyph(glyph:%d flags:%d) returned 0x%x\n", 1536 glyph.getGlyphID(fBaseGlyphCount), flags, err)); 1537 path->reset(); 1538 return; 1539 } 1540 1541 path->close(); 1542} 1543 1544void SkScalerContext_FreeType::generateFontMetrics(SkPaint::FontMetrics* mx, 1545 SkPaint::FontMetrics* my) { 1546 if (NULL == mx && NULL == my) { 1547 return; 1548 } 1549 1550 SkAutoMutexAcquire ac(gFTMutex); 1551 1552 if (this->setupSize()) { 1553 ERROR: 1554 if (mx) { 1555 sk_bzero(mx, sizeof(SkPaint::FontMetrics)); 1556 } 1557 if (my) { 1558 sk_bzero(my, sizeof(SkPaint::FontMetrics)); 1559 } 1560 return; 1561 } 1562 1563 FT_Face face = fFace; 1564 int upem = face->units_per_EM; 1565 if (upem <= 0) { 1566 goto ERROR; 1567 } 1568 1569 SkPoint pts[6]; 1570 SkFixed ys[6]; 1571 SkFixed scaleY = fScaleY; 1572 SkFixed mxy = fMatrix22.xy; 1573 SkFixed myy = fMatrix22.yy; 1574 SkScalar xmin = SkIntToScalar(face->bbox.xMin) / upem; 1575 SkScalar xmax = SkIntToScalar(face->bbox.xMax) / upem; 1576 1577 int leading = face->height - (face->ascender + -face->descender); 1578 if (leading < 0) { 1579 leading = 0; 1580 } 1581 1582 // Try to get the OS/2 table from the font. This contains the specific 1583 // average font width metrics which Windows uses. 1584 TT_OS2* os2 = (TT_OS2*) FT_Get_Sfnt_Table(face, ft_sfnt_os2); 1585 1586 ys[0] = -face->bbox.yMax; 1587 ys[1] = -face->ascender; 1588 ys[2] = -face->descender; 1589 ys[3] = -face->bbox.yMin; 1590 ys[4] = leading; 1591 ys[5] = os2 ? os2->xAvgCharWidth : 0; 1592 1593 SkScalar x_height; 1594 if (os2 && os2->sxHeight) { 1595 x_height = SkFixedToScalar(SkMulDiv(fScaleX, os2->sxHeight, upem)); 1596 } else { 1597 const FT_UInt x_glyph = FT_Get_Char_Index(fFace, 'x'); 1598 if (x_glyph) { 1599 FT_BBox bbox; 1600 FT_Load_Glyph(fFace, x_glyph, fLoadGlyphFlags); 1601 if ((fRec.fFlags & kEmbolden_Flag) && !(fFace->style_flags & FT_STYLE_FLAG_BOLD)) { 1602 emboldenOutline(&fFace->glyph->outline); 1603 } 1604 FT_Outline_Get_CBox(&fFace->glyph->outline, &bbox); 1605 x_height = SkFixedToScalar(SkFDot6ToFixed(bbox.yMax)); 1606 } else { 1607 x_height = 0; 1608 } 1609 } 1610 1611 // convert upem-y values into scalar points 1612 for (int i = 0; i < 6; i++) { 1613 SkFixed y = SkMulDiv(scaleY, ys[i], upem); 1614 SkFixed x = SkFixedMul(mxy, y); 1615 y = SkFixedMul(myy, y); 1616 pts[i].set(SkFixedToScalar(x), SkFixedToScalar(y)); 1617 } 1618 1619 if (mx) { 1620 mx->fTop = pts[0].fX; 1621 mx->fAscent = pts[1].fX; 1622 mx->fDescent = pts[2].fX; 1623 mx->fBottom = pts[3].fX; 1624 mx->fLeading = pts[4].fX; 1625 mx->fAvgCharWidth = pts[5].fX; 1626 mx->fXMin = xmin; 1627 mx->fXMax = xmax; 1628 mx->fXHeight = x_height; 1629 } 1630 if (my) { 1631 my->fTop = pts[0].fY; 1632 my->fAscent = pts[1].fY; 1633 my->fDescent = pts[2].fY; 1634 my->fBottom = pts[3].fY; 1635 my->fLeading = pts[4].fY; 1636 my->fAvgCharWidth = pts[5].fY; 1637 my->fXMin = xmin; 1638 my->fXMax = xmax; 1639 my->fXHeight = x_height; 1640 } 1641} 1642 1643//////////////////////////////////////////////////////////////////////// 1644//////////////////////////////////////////////////////////////////////// 1645 1646SkScalerContext* SkFontHost::CreateScalerContext(const SkDescriptor* desc) { 1647 SkScalerContext_FreeType* c = SkNEW_ARGS(SkScalerContext_FreeType, (desc)); 1648 if (!c->success()) { 1649 SkDELETE(c); 1650 c = NULL; 1651 } 1652 return c; 1653} 1654 1655/////////////////////////////////////////////////////////////////////////////// 1656 1657/* Export this so that other parts of our FonttHost port can make use of our 1658 ability to extract the name+style from a stream, using FreeType's api. 1659*/ 1660bool find_name_and_attributes(SkStream* stream, SkString* name, 1661 SkTypeface::Style* style, bool* isFixedWidth) { 1662 FT_Library library; 1663 if (FT_Init_FreeType(&library)) { 1664 return false; 1665 } 1666 1667 FT_Open_Args args; 1668 memset(&args, 0, sizeof(args)); 1669 1670 const void* memoryBase = stream->getMemoryBase(); 1671 FT_StreamRec streamRec; 1672 1673 if (NULL != memoryBase) { 1674 args.flags = FT_OPEN_MEMORY; 1675 args.memory_base = (const FT_Byte*)memoryBase; 1676 args.memory_size = stream->getLength(); 1677 } else { 1678 memset(&streamRec, 0, sizeof(streamRec)); 1679 streamRec.size = stream->read(NULL, 0); 1680 streamRec.descriptor.pointer = stream; 1681 streamRec.read = sk_stream_read; 1682 streamRec.close = sk_stream_close; 1683 1684 args.flags = FT_OPEN_STREAM; 1685 args.stream = &streamRec; 1686 } 1687 1688 FT_Face face; 1689 if (FT_Open_Face(library, &args, 0, &face)) { 1690 FT_Done_FreeType(library); 1691 return false; 1692 } 1693 1694 int tempStyle = SkTypeface::kNormal; 1695 if (face->style_flags & FT_STYLE_FLAG_BOLD) { 1696 tempStyle |= SkTypeface::kBold; 1697 } 1698 if (face->style_flags & FT_STYLE_FLAG_ITALIC) { 1699 tempStyle |= SkTypeface::kItalic; 1700 } 1701 1702 if (name) { 1703 name->set(face->family_name); 1704 } 1705 if (style) { 1706 *style = (SkTypeface::Style) tempStyle; 1707 } 1708 if (isFixedWidth) { 1709 *isFixedWidth = FT_IS_FIXED_WIDTH(face); 1710 } 1711 1712 FT_Done_Face(face); 1713 FT_Done_FreeType(library); 1714 return true; 1715} 1716