Add color emoji fallback for distance field text.

src/gpu/GrDistanceFieldTextContext.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrDistanceFieldTextContext.h"
 #include "GrAtlas.h"
 #include "GrBitmapTextContext.h"
@@ skipping 276 matching lines @@
 
     SkDrawCacheProc glyphCacheProc = fSkPaint.getDrawCacheProc();
 
     SkAutoGlyphCacheNoGamma    autoCache(fSkPaint, &fDeviceProperties, NULL);
     SkGlyphCache*              cache = autoCache.getCache();
     GrFontScaler*              fontScaler = GetGrFontScaler(cache);
 
     setup_gamma_texture(fContext, cache, fDeviceProperties, &fGammaTexture);
 
     const char*        stop = text + byteLength;
+    SkTArray<char>     fallbackTxt;
+    SkTArray<SkScalar> fallbackPos;
 
     if (SkPaint::kLeft_Align == fSkPaint.getTextAlign()) {
         while (text < stop) {
+            const char* lastText = text;
             // the last 2 parameters are ignored
             const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 
             if (glyph.fWidth) {
                 SkScalar x = offset.x() + pos[0];
                 SkScalar y = offset.y() + (2 == scalarsPerPosition ? pos[1] : 0);
 
-                this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
-                                                glyph.getSubXFixed(),
-                                                glyph.getSubYFixed()),
-                                  SkScalarToFixed(x),
-                                  SkScalarToFixed(y),
-                                  fontScaler);
+                if (!this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
+                                                     glyph.getSubXFixed(),
+                                                     glyph.getSubYFixed()),
+                                       SkScalarToFixed(x),
+                                       SkScalarToFixed(y),
+                                       fontScaler)) {
+                    // couldn't append, send to fallback
+                    fallbackTxt.push_back_n(text-lastText, lastText);
+                    fallbackPos.push_back(pos[0]);
+                    if (2 == scalarsPerPosition) {
+                        fallbackPos.push_back(pos[1]);
+                    }
+                }
             }
             pos += scalarsPerPosition;
         }
     } else {
         SkScalar alignMul = SkPaint::kCenter_Align == fSkPaint.getTextAlign() ? SK_ScalarHalf
                                                                               : SK_Scalar1;
         while (text < stop) {
+            const char* lastText = text;
             // the last 2 parameters are ignored
             const SkGlyph& glyph = glyphCacheProc(cache, &text, 0, 0);
 
             if (glyph.fWidth) {
                 SkScalar x = offset.x() + pos[0];
                 SkScalar y = offset.y() + (2 == scalarsPerPosition ? pos[1] : 0);
 
                 SkScalar advanceX = SkFixedToScalar(glyph.fAdvanceX)*alignMul*fTextRatio;
                 SkScalar advanceY = SkFixedToScalar(glyph.fAdvanceY)*alignMul*fTextRatio;
 
-                this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
-                                                glyph.getSubXFixed(),
-                                                glyph.getSubYFixed()),
-                                  SkScalarToFixed(x - advanceX),
-                                  SkScalarToFixed(y - advanceY),
-                                  fontScaler);
+                if (!this->appendGlyph(GrGlyph::Pack(glyph.getGlyphID(),
+                                                     glyph.getSubXFixed(),
+                                                     glyph.getSubYFixed()),
+                                       SkScalarToFixed(x - advanceX),
+                                       SkScalarToFixed(y - advanceY),
+                                       fontScaler)) {
+                    // couldn't append, send to fallback
+                    fallbackTxt.push_back_n(text-lastText, lastText);
+                    fallbackPos.push_back(pos[0]);
+                    if (2 == scalarsPerPosition) {
+                        fallbackPos.push_back(pos[1]);
+                    }
+                }
             }
             pos += scalarsPerPosition;
         }
     }
 
     this->finish();
+    
+    if (fallbackTxt.count() > 0) {
+        fFallbackTextContext->drawPosText(paint, skPaint, fallbackTxt.begin(), fallbackTxt.count(),
+                                          fallbackPos.begin(), scalarsPerPosition, offset);
+    }
 }
 
 static inline GrColor skcolor_to_grcolor_nopremultiply(SkColor c) {
     unsigned r = SkColorGetR(c);
     unsigned g = SkColorGetG(c);
     unsigned b = SkColorGetB(c);
     return GrColorPackRGBA(r, g, b, 0xff);
 }
 
 void GrDistanceFieldTextContext::setupCoverageEffect(const SkColor& filteredColor) {
@@ skipping 39 matching lines @@
                                                                                 params, flags));
 #endif
         }
         fEffectTextureUniqueID = textureUniqueID;
         fEffectColor = filteredColor;
         fEffectFlags = flags;
     }
     
 }
 
-void GrDistanceFieldTextContext::appendGlyph(GrGlyph::PackedID packed,
+// Returns true if this method handled the glyph, false if needs to be passed to fallback
+//
+bool GrDistanceFieldTextContext::appendGlyph(GrGlyph::PackedID packed,
                                              SkFixed vx, SkFixed vy,
                                              GrFontScaler* scaler) {
     if (NULL == fDrawTarget) {
-        return;
+        return true;
     }
 
     if (NULL == fStrike) {
         fStrike = fContext->getFontCache()->getStrike(scaler, true);
     }
 
     GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
     if (NULL == glyph || glyph->fBounds.isEmpty()) {
-        return;
+        return true;
     }
 
-    // TODO: support color glyphs
+    // fallback to color glyph support
     if (kA8_GrMaskFormat != glyph->fMaskFormat) {
-        return;
+        return false;
     }
 
     SkScalar sx = SkFixedToScalar(vx);
     SkScalar sy = SkFixedToScalar(vy);
 /*
     // not valid, need to find a different solution for this
     vx += SkIntToFixed(glyph->fBounds.fLeft);
     vy += SkIntToFixed(glyph->fBounds.fTop);
 
     // keep them as ints until we've done the clip-test
@@ skipping 37 matching lines @@
                 fStrike->addGlyphToAtlas(glyph, scaler)) {
                 goto HAS_ATLAS;
             }
         }
 
         if (NULL == glyph->fPath) {
             SkPath* path = SkNEW(SkPath);
             if (!scaler->getGlyphPath(glyph->glyphID(), path)) {
                 // flag the glyph as being dead?
                 delete path;
-                return;
+                return true;
             }
             glyph->fPath = path;
         }
 
         // flush any accumulated draws before drawing this glyph as a path.
         this->flush();
 
         GrContext::AutoMatrix am;
         SkMatrix ctm;
         ctm.setScale(fTextRatio, fTextRatio);
         ctm.postTranslate(sx, sy);
         GrPaint tmpPaint(fPaint);
         am.setPreConcat(fContext, ctm, &tmpPaint);
         GrStrokeInfo strokeInfo(SkStrokeRec::kFill_InitStyle);
         fContext->drawPath(tmpPaint, *glyph->fPath, strokeInfo);
-        return;
+        return true;
     }
 
 HAS_ATLAS:
     SkASSERT(glyph->fPlot);
     GrDrawTarget::DrawToken drawToken = fDrawTarget->getCurrentDrawToken();
     glyph->fPlot->setDrawToken(drawToken);
 
     GrTexture* texture = glyph->fPlot->texture();
     SkASSERT(texture);
 
@@ skipping 95 matching lines @@
         }
         // color comes after position.
         GrColor* colors = reinterpret_cast<GrColor*>(positions + 1);
         for (int i = 0; i < 4; ++i) {
             *colors = fPaint.getColor();
             colors = reinterpret_cast<GrColor*>(reinterpret_cast<intptr_t>(colors) + vertSize);
         }
     }
 
     fCurrVertex += 4;
+    
+    return true;
 }
 
 void GrDistanceFieldTextContext::flush() {
     if (NULL == fDrawTarget) {
         return;
     }
 
     GrDrawState* drawState = fDrawTarget->drawState();
     GrDrawState::AutoRestoreEffects are(drawState);
 
@@ skipping 54 matching lines @@
         fVertexBounds.setLargestInverted();
     }
 }
 
 inline void GrDistanceFieldTextContext::finish() {
     this->flush();
 
     GrTextContext::finish();
 }