src/third_party/skia/src/gpu/GrDistanceFieldTextContext.cpp

   1 /*
   2  * Copyright 2013 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "GrDistanceFieldTextContext.h"
   9 #include "GrAtlas.h"
  10 #include "GrBitmapTextContext.h"
  11 #include "GrDrawTarget.h"
  12 #include "GrDrawTargetCaps.h"
  13 #include "GrFontScaler.h"
  14 #include "GrGpu.h"
  15 #include "GrIndexBuffer.h"
  16 #include "GrStrokeInfo.h"
  17 #include "GrTexturePriv.h"
  18 #include "GrTextStrike.h"
  19 #include "GrTextStrike_impl.h"
  20
  21 #include "SkAutoKern.h"
  22 #include "SkColorFilter.h"
  23 #include "SkDistanceFieldGen.h"
  24 #include "SkDraw.h"
  25 #include "SkGlyphCache.h"
  26 #include "SkGpuDevice.h"
  27 #include "SkPath.h"
  28 #include "SkRTConf.h"
  29 #include "SkStrokeRec.h"
  30 #include "effects/GrDistanceFieldTextureEffect.h"
  31
  32 SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
  33                 "Dump the contents of the font cache before every purge.");
  34
  35 static const int kSmallDFFontSize = 32;
  36 static const int kSmallDFFontLimit = 32;
  37 static const int kMediumDFFontSize = 78;
  38 static const int kMediumDFFontLimit = 78;
  39 static const int kLargeDFFontSize = 192;
  40
  41 namespace {
  42 // position + texture coord
  43 extern const GrVertexAttrib gTextVertexAttribs[] = {
  44     {kVec2f_GrVertexAttribType, 0,                kPosition_GrVertexAttribBinding},
  45     {kVec2f_GrVertexAttribType, sizeof(SkPoint) , kGeometryProcessor_GrVertexAttribBinding}
  46 };
  47
  48 static const size_t kTextVASize = 2 * sizeof(SkPoint);
  49
  50 // position + color + texture coord
  51 extern const GrVertexAttrib gTextVertexWithColorAttribs[] = {
  52     {kVec2f_GrVertexAttribType,  0,                                 kPosition_GrVertexAttribBinding},
  53     {kVec4ub_GrVertexAttribType, sizeof(SkPoint),                   kColor_GrVertexAttribBinding},
  54     {kVec2f_GrVertexAttribType,  sizeof(SkPoint) + sizeof(GrColor), kGeometryProcessor_GrVertexAttribBinding}
  55 };
  56
  57 static const size_t kTextVAColorSize = 2 * sizeof(SkPoint) + sizeof(GrColor);
  58
  59 static const int kVerticesPerGlyph = 4;
  60 static const int kIndicesPerGlyph = 6;
  61 };
  62
  63 GrDistanceFieldTextContext::GrDistanceFieldTextContext(GrContext* context,
  64                                                        const SkDeviceProperties& properties,
  65                                                        bool enable)
  66                                                     : GrTextContext(context, properties) {
  67 #if SK_FORCE_DISTANCEFIELD_FONTS
  68     fEnableDFRendering = true;
  69 #else
  70     fEnableDFRendering = enable;
  71 #endif
  72     fStrike = NULL;
  73     fGammaTexture = NULL;
  74
  75     fEffectTextureUniqueID = SK_InvalidUniqueID;
  76     fEffectColor = GrColor_ILLEGAL;
  77     fEffectFlags = kInvalid_DistanceFieldEffectFlag;
  78
  79     fVertices = NULL;
  80     fCurrVertex = 0;
  81     fAllocVertexCount = 0;
  82     fTotalVertexCount = 0;
  83     fCurrTexture = NULL;
  84
  85     fVertexBounds.setLargestInverted();
  86 }
  87
  88 GrDistanceFieldTextContext* GrDistanceFieldTextContext::Create(GrContext* context,
  89                                                                const SkDeviceProperties& props,
  90                                                                bool enable) {
  91     GrDistanceFieldTextContext* textContext = SkNEW_ARGS(GrDistanceFieldTextContext,
  92                                                          (context, props, enable));
  93     textContext->fFallbackTextContext = GrBitmapTextContext::Create(context, props);
  94
  95     return textContext;
  96 }
  97
  98 GrDistanceFieldTextContext::~GrDistanceFieldTextContext() {
  99     this->finish();
 100     SkSafeSetNull(fGammaTexture);
 101 }
 102
 103 bool GrDistanceFieldTextContext::canDraw(const SkPaint& paint) {
 104     if (!fEnableDFRendering && !paint.isDistanceFieldTextTEMP()) {
 105         return false;
 106     }
 107
 108     // rasterizers and mask filters modify alpha, which doesn't
 109     // translate well to distance
 110     if (paint.getRasterizer() || paint.getMaskFilter() ||
 111         !fContext->getTextTarget()->caps()->shaderDerivativeSupport()) {
 112         return false;
 113     }
 114
 115     // TODO: add some stroking support
 116     if (paint.getStyle() != SkPaint::kFill_Style) {
 117         return false;
 118     }
 119
 120     // TODO: choose an appropriate maximum scale for distance fields and
 121     //       enable perspective
 122     if (SkDraw::ShouldDrawTextAsPaths(paint, fContext->getMatrix())) {
 123         return false;
 124     }
 125
 126     return true;
 127 }
 128
 129 inline void GrDistanceFieldTextContext::init(const GrPaint& paint, const SkPaint& skPaint) {
 130     GrTextContext::init(paint, skPaint);
 131
 132     fStrike = NULL;
 133
 134     const SkMatrix& ctm = fContext->getMatrix();
 135
 136     // getMaxScale doesn't support perspective, so neither do we at the moment
 137     SkASSERT(!ctm.hasPerspective());
 138     SkScalar maxScale = ctm.getMaxScale();
 139     SkScalar textSize = fSkPaint.getTextSize();
 140     SkScalar scaledTextSize = textSize;
 141     // if we have non-unity scale, we need to choose our base text size
 142     // based on the SkPaint's text size multiplied by the max scale factor
 143     // TODO: do we need to do this if we're scaling down (i.e. maxScale < 1)?
 144     if (maxScale > 0 && !SkScalarNearlyEqual(maxScale, SK_Scalar1)) {
 145         scaledTextSize *= maxScale;
 146     }
 147
 148     fVertices = NULL;
 149     fCurrVertex = 0;
 150     fAllocVertexCount = 0;
 151     fTotalVertexCount = 0;
 152
 153     if (scaledTextSize <= kSmallDFFontLimit) {
 154         fTextRatio = textSize / kSmallDFFontSize;
 155         fSkPaint.setTextSize(SkIntToScalar(kSmallDFFontSize));
 156 #if DEBUG_TEXT_SIZE
 157         fSkPaint.setColor(SkColorSetARGB(0xFF, 0x00, 0x00, 0xFF));
 158         fPaint.setColor(GrColorPackRGBA(0x00, 0x00, 0xFF, 0xFF));
 159 #endif
 160     } else if (scaledTextSize <= kMediumDFFontLimit) {
 161         fTextRatio = textSize / kMediumDFFontSize;
 162         fSkPaint.setTextSize(SkIntToScalar(kMediumDFFontSize));
 163 #if DEBUG_TEXT_SIZE
 164         fSkPaint.setColor(SkColorSetARGB(0xFF, 0x00, 0xFF, 0x00));
 165         fPaint.setColor(GrColorPackRGBA(0x00, 0xFF, 0x00, 0xFF));
 166 #endif
 167     } else {
 168         fTextRatio = textSize / kLargeDFFontSize;
 169         fSkPaint.setTextSize(SkIntToScalar(kLargeDFFontSize));
 170 #if DEBUG_TEXT_SIZE
 171         fSkPaint.setColor(SkColorSetARGB(0xFF, 0xFF, 0x00, 0x00));
 172         fPaint.setColor(GrColorPackRGBA(0xFF, 0x00, 0x00, 0xFF));
 173 #endif
 174     }
 175
 176     fUseLCDText = fSkPaint.isLCDRenderText();
 177
 178     fSkPaint.setLCDRenderText(false);
 179     fSkPaint.setAutohinted(false);
 180     fSkPaint.setHinting(SkPaint::kNormal_Hinting);
 181     fSkPaint.setSubpixelText(true);
 182 }
 183
 184 static void setup_gamma_texture(GrContext* context, const SkGlyphCache* cache,
 185                                 const SkDeviceProperties& deviceProperties,
 186                                 GrTexture** gammaTexture) {
 187     if (NULL == *gammaTexture) {
 188         int width, height;
 189         size_t size;
 190
 191 #ifdef SK_GAMMA_CONTRAST
 192         SkScalar contrast = SK_GAMMA_CONTRAST;
 193 #else
 194         SkScalar contrast = 0.5f;
 195 #endif
 196         SkScalar paintGamma = deviceProperties.gamma();
 197         SkScalar deviceGamma = deviceProperties.gamma();
 198
 199         size = SkScalerContext::GetGammaLUTSize(contrast, paintGamma, deviceGamma,
 200                                                 &width, &height);
 201
 202         SkAutoTArray<uint8_t> data((int)size);
 203         SkScalerContext::GetGammaLUTData(contrast, paintGamma, deviceGamma, data.get());
 204
 205         // TODO: Update this to use the cache rather than directly creating a texture.
 206         GrSurfaceDesc desc;
 207         desc.fFlags = kNone_GrSurfaceFlags;
 208         desc.fWidth = width;
 209         desc.fHeight = height;
 210         desc.fConfig = kAlpha_8_GrPixelConfig;
 211
 212         *gammaTexture = context->getGpu()->createTexture(desc, NULL, 0);
 213         if (NULL == *gammaTexture) {
 214             return;
 215         }
 216
 217         (*gammaTexture)->writePixels(0, 0, width, height,
 218                                      (*gammaTexture)->config(), data.get(), 0,
 219                                      GrContext::kDontFlush_PixelOpsFlag);
 220     }
 221 }
 222
 223 void GrDistanceFieldTextContext::onDrawText(const GrPaint& paint, const SkPaint& skPaint,
 224                                           const char text[], size_t byteLength,
 225                                           SkScalar x, SkScalar y) {
 226     SkASSERT(byteLength == 0 || text != NULL);
 227
 228     // nothing to draw
 229     if (text == NULL || byteLength == 0) {
 230         return;
 231     }
 232
 233     SkDrawCacheProc          glyphCacheProc = skPaint.getDrawCacheProc();
 234     SkAutoGlyphCache         autoCache(skPaint, &fDeviceProperties, NULL);
 235     SkGlyphCache*            cache = autoCache.getCache();
 236
 237     SkTArray<SkScalar> positions;
 238
 239     const char* textPtr = text;
 240     SkFixed stopX = 0;
 241     SkFixed stopY = 0;
 242     SkFixed origin;
 243     switch (skPaint.getTextAlign()) {
 244         case SkPaint::kRight_Align: origin = SK_Fixed1; break;
 245         case SkPaint::kCenter_Align: origin = SK_FixedHalf; break;
 246         case SkPaint::kLeft_Align: origin = 0; break;
 247         default: SkFAIL("Invalid paint origin"); return;
 248     }
 249
 250     SkAutoKern autokern;
 251     const char* stop = text + byteLength;
 252     while (textPtr < stop) {
 253         // don't need x, y here, since all subpixel variants will have the
 254         // same advance
 255         const SkGlyph& glyph = glyphCacheProc(cache, &textPtr, 0, 0);
 256
 257         SkFixed width = glyph.fAdvanceX + autokern.adjust(glyph);
 258         positions.push_back(SkFixedToScalar(stopX + SkFixedMul_portable(origin, width)));
 259
 260         SkFixed height = glyph.fAdvanceY;
 261         positions.push_back(SkFixedToScalar(stopY + SkFixedMul_portable(origin, height)));
 262
 263         stopX += width;
 264         stopY += height;
 265     }
 266     SkASSERT(textPtr == stop);
 267
 268     // now adjust starting point depending on alignment
 269     SkScalar alignX = SkFixedToScalar(stopX);
 270     SkScalar alignY = SkFixedToScalar(stopY);
 271     if (skPaint.getTextAlign() == SkPaint::kCenter_Align) {
 272         alignX = SkScalarHalf(alignX);
 273         alignY = SkScalarHalf(alignY);
 274     } else if (skPaint.getTextAlign() == SkPaint::kLeft_Align) {
 275         alignX = 0;
 276         alignY = 0;
 277     }
 278     x -= alignX;
 279     y -= alignY;
 280     SkPoint offset = SkPoint::Make(x, y);
 281
 282     this->drawPosText(paint, skPaint, text, byteLength, positions.begin(), 2, offset);
 283 }
 284
 285 void GrDistanceFieldTextContext::onDrawPosText(const GrPaint& paint, const SkPaint& skPaint,
 286                                              const char text[], size_t byteLength,
 287                                              const SkScalar pos[], int scalarsPerPosition,
 288                                              const SkPoint& offset) {
 289
 290     SkASSERT(byteLength == 0 || text != NULL);
 291     SkASSERT(1 == scalarsPerPosition || 2 == scalarsPerPosition);
 292
 293     // nothing to draw
 294     if (text == NULL || byteLength == 0 /* no raster clip? || fRC->isEmpty()*/) {
 295         return;
 296     }
 297
 298     this->init(paint, skPaint);
 299
 300     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 301
 302     SkAutoGlyphCacheNoGamma    autoCache(fSkPaint, &fDeviceProperties, NULL);
 303     SkGlyphCache*              cache = autoCache.getCache();
 304     GrFontScaler*              fontScaler = GetGrFontScaler(cache);
 305
 306     setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
 307
 308     int numGlyphs = fSkPaint.textToGlyphs(text, byteLength, NULL);
 309     fTotalVertexCount = kVerticesPerGlyph*numGlyphs;
 310
 311     const char*        stop = text + byteLength;
 312     SkTArray<char>     fallbackTxt;
 313     SkTArray<SkScalar> fallbackPos;
 314
 315     if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
 316         while (text < stop) {
 317             const char* lastText = text;
 318             // the last 2 parameters are ignored
 319             const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 320
 321             if (glyph.fWidth) {
 322                 SkScalar x = offset.x() + pos[0];
 323                 SkScalar y = offset.y() + (2 == scalarsPerPosition ? pos[1] : 0);
 324
 325                 if (!this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
 326                                                      glyph.getSubXFixed(),
 327                                                      glyph.getSubYFixed()),
 328                                        x, y, fontScaler)) {
 329                     // couldn't append, send to fallback
 330                     fallbackTxt.push_back_n(text-lastText, lastText);
 331                     fallbackPos.push_back(pos[0]);
 332                     if (2 == scalarsPerPosition) {
 333                         fallbackPos.push_back(pos[1]);
 334                     }
 335                 }
 336             }
 337             pos += scalarsPerPosition;
 338         }
 339     } else {
 340         SkScalar alignMul = SkPaint::kCenter_Align == fSkPaint.getTextAlign() ? SK_ScalarHalf
 341                                                                               : SK_Scalar1;
 342         while (text < stop) {
 343             const char* lastText = text;
 344             // the last 2 parameters are ignored
 345             const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 346
 347             if (glyph.fWidth) {
 348                 SkScalar x = offset.x() + pos[0];
 349                 SkScalar y = offset.y() + (2 == scalarsPerPosition ? pos[1] : 0);
 350
 351                 SkScalar advanceX = SkFixedToScalar(glyph.fAdvanceX)*alignMul*fTextRatio;
 352                 SkScalar advanceY = SkFixedToScalar(glyph.fAdvanceY)*alignMul*fTextRatio;
 353
 354                 if (!this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
 355                                                      glyph.getSubXFixed(),
 356                                                      glyph.getSubYFixed()),
 357                                        x - advanceX, y - advanceY, fontScaler)) {
 358                     // couldn't append, send to fallback
 359                     fallbackTxt.push_back_n(text-lastText, lastText);
 360                     fallbackPos.push_back(pos[0]);
 361                     if (2 == scalarsPerPosition) {
 362                         fallbackPos.push_back(pos[1]);
 363                     }
 364                 }
 365             }
 366             pos += scalarsPerPosition;
 367         }
 368     }
 369
 370     this->finish();
 371
 372     if (fallbackTxt.count() > 0) {
 373         fFallbackTextContext->drawPosText(paint, skPaint, fallbackTxt.begin(), fallbackTxt.count(),
 374                                           fallbackPos.begin(), scalarsPerPosition, offset);
 375     }
 376 }
 377
 378 static inline GrColor skcolor_to_grcolor_nopremultiply(SkColor c) {
 379     unsigned r = SkColorGetR(c);
 380     unsigned g = SkColorGetG(c);
 381     unsigned b = SkColorGetB(c);
 382     return GrColorPackRGBA(r, g, b, 0xff);
 383 }
 384
 385 static void* alloc_vertices(GrDrawTarget* drawTarget, int numVertices, bool useColorVerts) {
 386     if (numVertices <= 0) {
 387         return NULL;
 388     }
 389
 390     // set up attributes
 391     if (useColorVerts) {
 392         drawTarget->drawState()->setVertexAttribs<gTextVertexWithColorAttribs>(
 393                                     SK_ARRAY_COUNT(gTextVertexWithColorAttribs), kTextVAColorSize);
 394     } else {
 395         drawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
 396                                     SK_ARRAY_COUNT(gTextVertexAttribs), kTextVASize);
 397     }
 398     void* vertices = NULL;
 399     bool success = drawTarget->reserveVertexAndIndexSpace(numVertices,
 400                                                           0,
 401                                                           &vertices,
 402                                                           NULL);
 403     GrAlwaysAssert(success);
 404     return vertices;
 405 }
 406
 407 void GrDistanceFieldTextContext::setupCoverageEffect(const SkColor& filteredColor) {
 408     GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kBilerp_FilterMode);
 409     GrTextureParams gammaParams(SkShader::kClamp_TileMode, GrTextureParams::kNone_FilterMode);
 410
 411     uint32_t textureUniqueID = fCurrTexture->getUniqueID();
 412     const SkMatrix& ctm = fContext->getMatrix();
 413
 414     // set up any flags
 415     uint32_t flags = 0;
 416     flags |= ctm.isSimilarity() ? kSimilarity_DistanceFieldEffectFlag : 0;
 417     flags |= fUseLCDText ? kUseLCD_DistanceFieldEffectFlag : 0;
 418     flags |= fUseLCDText && ctm.rectStaysRect() ?
 419     kRectToRect_DistanceFieldEffectFlag : 0;
 420     bool useBGR = SkPixelGeometryIsBGR(fDeviceProperties.pixelGeometry());
 421     flags |= fUseLCDText && useBGR ? kBGR_DistanceFieldEffectFlag : 0;
 422
 423     // see if we need to create a new effect
 424     if (textureUniqueID != fEffectTextureUniqueID ||
 425         filteredColor != fEffectColor ||
 426         flags != fEffectFlags) {
 427         if (fUseLCDText) {
 428             GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
 429             fCachedGeometryProcessor.reset(GrDistanceFieldLCDTextureEffect::Create(fCurrTexture,
 430                                                                                    params,
 431                                                                                    fGammaTexture,
 432                                                                                    gammaParams,
 433                                                                                    colorNoPreMul,
 434                                                                                    flags));
 435         } else {
 436 #ifdef SK_GAMMA_APPLY_TO_A8
 437             U8CPU lum = SkColorSpaceLuminance::computeLuminance(fDeviceProperties.gamma(),
 438                                                                 filteredColor);
 439             fCachedGeometryProcessor.reset(GrDistanceFieldTextureEffect::Create(fCurrTexture,
 440                                                                                 params,
 441                                                                                 fGammaTexture,
 442                                                                                 gammaParams,
 443                                                                                 lum/255.f,
 444                                                                                 flags));
 445 #else
 446             fCachedGeometryProcessor.reset(GrDistanceFieldNoGammaTextureEffect::Create(fCurrTexture,
 447                                                                                 params, flags));
 448 #endif
 449         }
 450         fEffectTextureUniqueID = textureUniqueID;
 451         fEffectColor = filteredColor;
 452         fEffectFlags = flags;
 453     }
 454
 455 }
 456
 457 // Returns true if this method handled the glyph, false if needs to be passed to fallback
 458 //
 459 bool GrDistanceFieldTextContext::appendGlyph(GrGlyph::PackedID packed,
 460                                              SkScalar sx, SkScalar sy,
 461                                              GrFontScaler* scaler) {
 462     if (NULL == fDrawTarget) {
 463         return true;
 464     }
 465
 466     if (NULL == fStrike) {
 467         fStrike = fContext->getFontCache()->getStrike(scaler, true);
 468     }
 469
 470     GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
 471     if (NULL == glyph || glyph->fBounds.isEmpty()) {
 472         return true;
 473     }
 474
 475     // fallback to color glyph support
 476     if (kA8_GrMaskFormat != glyph->fMaskFormat) {
 477         return false;
 478     }
 479
 480     SkScalar dx = SkIntToScalar(glyph->fBounds.fLeft + SK_DistanceFieldInset);
 481     SkScalar dy = SkIntToScalar(glyph->fBounds.fTop + SK_DistanceFieldInset);
 482     SkScalar width = SkIntToScalar(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
 483     SkScalar height = SkIntToScalar(glyph->fBounds.height() - 2*SK_DistanceFieldInset);
 484
 485     SkScalar scale = fTextRatio;
 486     dx *= scale;
 487     dy *= scale;
 488     sx += dx;
 489     sy += dy;
 490     width *= scale;
 491     height *= scale;
 492     SkRect glyphRect = SkRect::MakeXYWH(sx, sy, width, height);
 493
 494     // check if we clipped out
 495     SkRect dstRect;
 496     const SkMatrix& ctm = fContext->getMatrix();
 497     (void) ctm.mapRect(&dstRect, glyphRect);
 498     if (fClipRect.quickReject(SkScalarTruncToInt(dstRect.left()),
 499                               SkScalarTruncToInt(dstRect.top()),
 500                               SkScalarTruncToInt(dstRect.right()),
 501                               SkScalarTruncToInt(dstRect.bottom()))) {
 502 //            SkCLZ(3);    // so we can set a break-point in the debugger
 503         return true;
 504     }
 505
 506     if (NULL == glyph->fPlot) {
 507         if (!fStrike->glyphTooLargeForAtlas(glyph)) {
 508             if (fStrike->addGlyphToAtlas(glyph, scaler)) {
 509                 goto HAS_ATLAS;
 510             }
 511
 512             // try to clear out an unused plot before we flush
 513             if (fContext->getFontCache()->freeUnusedPlot(fStrike, glyph) &&
 514                 fStrike->addGlyphToAtlas(glyph, scaler)) {
 515                 goto HAS_ATLAS;
 516             }
 517
 518             if (c_DumpFontCache) {
 519 #ifdef SK_DEVELOPER
 520                 fContext->getFontCache()->dump();
 521 #endif
 522             }
 523
 524             // before we purge the cache, we must flush any accumulated draws
 525             this->flush();
 526             fContext->flush();
 527
 528             // we should have an unused plot now
 529             if (fContext->getFontCache()->freeUnusedPlot(fStrike, glyph) &&
 530                 fStrike->addGlyphToAtlas(glyph, scaler)) {
 531                 goto HAS_ATLAS;
 532             }
 533         }
 534
 535         if (NULL == glyph->fPath) {
 536             SkPath* path = SkNEW(SkPath);
 537             if (!scaler->getGlyphPath(glyph->glyphID(), path)) {
 538                 // flag the glyph as being dead?
 539                 delete path;
 540                 return true;
 541             }
 542             glyph->fPath = path;
 543         }
 544
 545         // flush any accumulated draws before drawing this glyph as a path.
 546         this->flush();
 547
 548         GrContext::AutoMatrix am;
 549         SkMatrix ctm;
 550         ctm.setScale(fTextRatio, fTextRatio);
 551         ctm.postTranslate(sx - dx, sy - dy);
 552         GrPaint tmpPaint(fPaint);
 553         am.setPreConcat(fContext, ctm, &tmpPaint);
 554         GrStrokeInfo strokeInfo(SkStrokeRec::kFill_InitStyle);
 555         fContext->drawPath(tmpPaint, *glyph->fPath, strokeInfo);
 556
 557         // remove this glyph from the vertices we need to allocate
 558         fTotalVertexCount -= kVerticesPerGlyph;
 559         return true;
 560     }
 561
 562 HAS_ATLAS:
 563     SkASSERT(glyph->fPlot);
 564     GrDrawTarget::DrawToken drawToken = fDrawTarget->getCurrentDrawToken();
 565     glyph->fPlot->setDrawToken(drawToken);
 566
 567     GrTexture* texture = glyph->fPlot->texture();
 568     SkASSERT(texture);
 569
 570     if (fCurrTexture != texture || fCurrVertex + kVerticesPerGlyph > fTotalVertexCount) {
 571         this->flush();
 572         fCurrTexture = texture;
 573         fCurrTexture->ref();
 574     }
 575
 576     bool useColorVerts = !fUseLCDText;
 577
 578     if (NULL == fVertices) {
 579         int maxQuadVertices = kVerticesPerGlyph * fContext->getQuadIndexBuffer()->maxQuads();
 580         fAllocVertexCount = SkMin32(fTotalVertexCount, maxQuadVertices);
 581         fVertices = alloc_vertices(fDrawTarget, fAllocVertexCount, useColorVerts);
 582     }
 583
 584     SkFixed tx = SkIntToFixed(glyph->fAtlasLocation.fX + SK_DistanceFieldInset);
 585     SkFixed ty = SkIntToFixed(glyph->fAtlasLocation.fY + SK_DistanceFieldInset);
 586     SkFixed tw = SkIntToFixed(glyph->fBounds.width() - 2*SK_DistanceFieldInset);
 587     SkFixed th = SkIntToFixed(glyph->fBounds.height() - 2*SK_DistanceFieldInset);
 588
 589     fVertexBounds.joinNonEmptyArg(glyphRect);
 590
 591     size_t vertSize = fUseLCDText ? (2 * sizeof(SkPoint))
 592                                   : (2 * sizeof(SkPoint) + sizeof(GrColor));
 593
 594     SkASSERT(vertSize == fDrawTarget->getDrawState().getVertexStride());
 595
 596     SkPoint* positions = reinterpret_cast<SkPoint*>(
 597                                reinterpret_cast<intptr_t>(fVertices) + vertSize * fCurrVertex);
 598     positions->setRectFan(glyphRect.fLeft, glyphRect.fTop, glyphRect.fRight, glyphRect.fBottom,
 599                           vertSize);
 600
 601     // The texture coords are last in both the with and without color vertex layouts.
 602     SkPoint* textureCoords = reinterpret_cast<SkPoint*>(
 603                                reinterpret_cast<intptr_t>(positions) + vertSize  - sizeof(SkPoint));
 604     textureCoords->setRectFan(SkFixedToFloat(texture->texturePriv().normalizeFixedX(tx)),
 605                               SkFixedToFloat(texture->texturePriv().normalizeFixedY(ty)),
 606                               SkFixedToFloat(texture->texturePriv().normalizeFixedX(tx + tw)),
 607                               SkFixedToFloat(texture->texturePriv().normalizeFixedY(ty + th)),
 608                               vertSize);
 609     if (useColorVerts) {
 610         if (0xFF == GrColorUnpackA(fPaint.getColor())) {
 611             fDrawTarget->drawState()->setHint(GrDrawState::kVertexColorsAreOpaque_Hint, true);
 612         }
 613         // color comes after position.
 614         GrColor* colors = reinterpret_cast<GrColor*>(positions + 1);
 615         for (int i = 0; i < 4; ++i) {
 616             *colors = fPaint.getColor();
 617             colors = reinterpret_cast<GrColor*>(reinterpret_cast<intptr_t>(colors) + vertSize);
 618         }
 619     }
 620
 621     fCurrVertex += 4;
 622
 623     return true;
 624 }
 625
 626 void GrDistanceFieldTextContext::flush() {
 627     if (NULL == fDrawTarget) {
 628         return;
 629     }
 630
 631     GrDrawState* drawState = fDrawTarget->drawState();
 632     GrDrawState::AutoRestoreEffects are(drawState);
 633
 634     drawState->setFromPaint(fPaint, fContext->getMatrix(), fContext->getRenderTarget());
 635
 636     if (fCurrVertex > 0) {
 637         // setup our sampler state for our text texture/atlas
 638         SkASSERT(SkIsAlign4(fCurrVertex));
 639
 640         // get our current color
 641         SkColor filteredColor;
 642         SkColorFilter* colorFilter = fSkPaint.getColorFilter();
 643         if (colorFilter) {
 644             filteredColor = colorFilter->filterColor(fSkPaint.getColor());
 645         } else {
 646             filteredColor = fSkPaint.getColor();
 647         }
 648         this->setupCoverageEffect(filteredColor);
 649
 650         // Effects could be stored with one of the cache objects (atlas?)
 651         drawState->setGeometryProcessor(fCachedGeometryProcessor.get());
 652
 653         // Set draw state
 654         if (fUseLCDText) {
 655             GrColor colorNoPreMul = skcolor_to_grcolor_nopremultiply(filteredColor);
 656             if (kOne_GrBlendCoeff != fPaint.getSrcBlendCoeff() ||
 657                 kISA_GrBlendCoeff != fPaint.getDstBlendCoeff() ||
 658                 fPaint.numColorStages()) {
 659                 SkDebugf("LCD Text will not draw correctly.\n");
 660             }
 661             SkASSERT(!drawState->hasColorVertexAttribute());
 662             // We don't use the GrPaint's color in this case because it's been premultiplied by
 663             // alpha. Instead we feed in a non-premultiplied color, and multiply its alpha by
 664             // the mask texture color. The end result is that we get
 665             //            mask*paintAlpha*paintColor + (1-mask*paintAlpha)*dstColor
 666             int a = SkColorGetA(fSkPaint.getColor());
 667             // paintAlpha
 668             drawState->setColor(SkColorSetARGB(a, a, a, a));
 669             // paintColor
 670             drawState->setBlendConstant(colorNoPreMul);
 671             drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
 672         } else {
 673             // set back to normal in case we took LCD path previously.
 674             drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
 675             // We're using per-vertex color.
 676             SkASSERT(drawState->hasColorVertexAttribute());
 677         }
 678         int nGlyphs = fCurrVertex / kVerticesPerGlyph;
 679         fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
 680         fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
 681                                           nGlyphs,
 682                                           kVerticesPerGlyph, kIndicesPerGlyph, &fVertexBounds);
 683         fDrawTarget->resetVertexSource();
 684         fVertices = NULL;
 685         fTotalVertexCount -= fCurrVertex;
 686         fCurrVertex = 0;
 687         SkSafeSetNull(fCurrTexture);
 688         fVertexBounds.setLargestInverted();
 689     }
 690 }
 691
 692 inline void GrDistanceFieldTextContext::finish() {
 693     this->flush();
 694     fTotalVertexCount = 0;
 695
 696     GrTextContext::finish();
 697 }
 698