Add new module for distance field generation.

src/gpu/GrTextStrike.cpp

 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAtlas.h"
 #include "GrGpu.h"
 #include "GrRectanizer.h"
 #include "GrTextStrike.h"
 #include "GrTextStrike_impl.h"
 #include "SkString.h"
 
 #if SK_DISTANCEFIELD_FONTS
-#include "edtaa3.h"
+#include "SkDistanceFieldGen.h"
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #define FONT_CACHE_STATS 0
 #if FONT_CACHE_STATS
 static int g_PurgeCount = 0;
 #endif
 
 GrFontCache::GrFontCache(GrGpu* gpu) : fGpu(gpu) {
@@ skipping 165 matching lines @@
 }
 #endif
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #ifdef SK_DEBUG
     static int gCounter;
 #endif
 
 #if SK_DISTANCEFIELD_FONTS
-#define DISTANCE_FIELD_PAD   4
-#define DISTANCE_FIELD_RANGE (4.0)
+// this acts as the max magnitude for the distance field,
+// as well as the pad we need around the glyph
+#define DISTANCE_FIELD_RANGE   4
 #endif
 
 /*
     The text strike is specific to a given font/style/matrix setup, which is
     represented by the GrHostFontScaler object we are given in getGlyph().
 
     We map a 32bit glyphID to a GrGlyph record, which in turn points to a
     atlas and a position within that texture.
  */
 
@@ skipping 32 matching lines @@
                                      GrFontScaler* scaler) {
     SkIRect bounds;
     if (!scaler->getPackedGlyphBounds(packed, &bounds)) {
         return NULL;
     }
 
     GrGlyph* glyph = fPool.alloc();
 #if SK_DISTANCEFIELD_FONTS
     // expand bounds to hold full distance field data
     if (fUseDistanceField) {
-        bounds.fLeft   -= DISTANCE_FIELD_PAD;
-        bounds.fRight  += DISTANCE_FIELD_PAD;
-        bounds.fTop    -= DISTANCE_FIELD_PAD;
-        bounds.fBottom += DISTANCE_FIELD_PAD;
+        bounds.fLeft   -= DISTANCE_FIELD_RANGE;
+        bounds.fRight  += DISTANCE_FIELD_RANGE;
+        bounds.fTop    -= DISTANCE_FIELD_RANGE;
+        bounds.fBottom += DISTANCE_FIELD_RANGE;
     }
 #endif
     glyph->init(packed, bounds);
     fCache.insert(packed, glyph);
     return glyph;
 }
 
 void GrTextStrike::removePlot(const GrPlot* plot) {
     SkTDArray<GrGlyph*>& glyphArray = fCache.getArray();
     for (int i = 0; i < glyphArray.count(); ++i) {
@@ skipping 17 matching lines @@
     SkASSERT(fCache.contains(glyph));
     SkASSERT(NULL == glyph->fPlot);
 
     SkAutoRef ar(scaler);
 
     int bytesPerPixel = GrMaskFormatBytesPerPixel(fMaskFormat);
 
     GrPlot* plot;
 #if SK_DISTANCEFIELD_FONTS
     if (fUseDistanceField) {
-        SkASSERT(1 == bytesPerPixel);
-
         // we've already expanded the glyph dimensions to match the final size
         // but must shrink back down to get the packed glyph data
         int dfWidth = glyph->width();
         int dfHeight = glyph->height();
-        int width = dfWidth - 2*DISTANCE_FIELD_PAD;
-        int height = dfHeight - 2*DISTANCE_FIELD_PAD;
-        size_t stride = width*bytesPerPixel;
+        int width = dfWidth - 2*DISTANCE_FIELD_RANGE;
+        int height = dfHeight - 2*DISTANCE_FIELD_RANGE;
+        int stride = width*bytesPerPixel;
 
         size_t size = width * height * bytesPerPixel;
         SkAutoSMalloc<1024> storage(size);
         if (!scaler->getPackedGlyphImage(glyph->fPackedID, width, height, stride, storage.get())) {
             return false;
         }
 
         // alloc storage for distance field glyph
         size_t dfSize = dfWidth * dfHeight * bytesPerPixel;
         SkAutoSMalloc<1024> dfStorage(dfSize);
+        
+        if (1 == bytesPerPixel) {
+            (void) SkGenerateDistanceFieldFromImage((unsigned char*)dfStorage.get(),
+                                                    (unsigned char*)storage.get(),
+                                                    width, height, DISTANCE_FIELD_RANGE);
+        } else {
+            // TODO: Fix color emoji
+            // for now, copy glyph into distance field storage
+            // this is not correct, but it won't crash
+            sk_bzero(dfStorage.get(), dfSize);
+            unsigned char* ptr = (unsigned char*) storage.get();
+            unsigned char* dfPtr = (unsigned char*) dfStorage.get();
+            size_t dfStride = dfWidth*bytesPerPixel;
+            dfPtr += DISTANCE_FIELD_RANGE*dfStride;
+            dfPtr += DISTANCE_FIELD_RANGE*bytesPerPixel;
 
-        // copy glyph into distance field storage
-        sk_bzero(dfStorage.get(), dfSize);
+            for (int i = 0; i < height; ++i) {
+                memcpy(dfPtr, ptr, stride);
 
-        unsigned char* ptr = (unsigned char*) storage.get();
-        unsigned char* dfPtr = (unsigned char*) dfStorage.get();
-        size_t dfStride = dfWidth*bytesPerPixel;
-        dfPtr += DISTANCE_FIELD_PAD*dfStride;
-        dfPtr += DISTANCE_FIELD_PAD*bytesPerPixel;
-
-        for (int i = 0; i < height; ++i) {
-            memcpy(dfPtr, ptr, stride);
-
-            dfPtr += dfStride;
-            ptr += stride;
-        }
-
-        // generate distance field data
-        SkAutoSMalloc<1024> distXStorage(dfWidth*dfHeight*sizeof(short));
-        SkAutoSMalloc<1024> distYStorage(dfWidth*dfHeight*sizeof(short));
-        SkAutoSMalloc<1024> outerDistStorage(dfWidth*dfHeight*sizeof(double));
-        SkAutoSMalloc<1024> innerDistStorage(dfWidth*dfHeight*sizeof(double));
-        SkAutoSMalloc<1024> gxStorage(dfWidth*dfHeight*sizeof(double));
-        SkAutoSMalloc<1024> gyStorage(dfWidth*dfHeight*sizeof(double));
-
-        short* distX = (short*) distXStorage.get();
-        short* distY = (short*) distYStorage.get();
-        double* outerDist = (double*) outerDistStorage.get();
-        double* innerDist = (double*) innerDistStorage.get();
-        double* gx = (double*) gxStorage.get();
-        double* gy = (double*) gyStorage.get();
-
-        dfPtr = (unsigned char*) dfStorage.get();
-        EDTAA::computegradient(dfPtr, dfWidth, dfHeight, gx, gy);
-        EDTAA::edtaa3(dfPtr, gx, gy, dfWidth, dfHeight, distX, distY, outerDist);
-
-        for (int i = 0; i < dfWidth*dfHeight; ++i) {
-            *dfPtr = 255 - *dfPtr;
-            dfPtr++;
-        }
-        dfPtr = (unsigned char*) dfStorage.get();
-        sk_bzero(gx, sizeof(double)*dfWidth*dfHeight);
-        sk_bzero(gy, sizeof(double)*dfWidth*dfHeight);
-        EDTAA::computegradient(dfPtr, dfWidth, dfHeight, gx, gy);
-        EDTAA::edtaa3(dfPtr, gx, gy, dfWidth, dfHeight, distX, distY, innerDist);
-
-        for (int i = 0; i < dfWidth*dfHeight; ++i) {
-            unsigned char val;
-            double outerval = outerDist[i];
-            if (outerval < 0.0) {
-                outerval = 0.0;
+                dfPtr += dfStride;
+                ptr += stride;
             }
-            double innerval = innerDist[i];
-            if (innerval < 0.0) {
-                innerval = 0.0;
-            }
-            double dist = outerval - innerval;
-            if (dist <= -DISTANCE_FIELD_RANGE) {
-                val = 255;
-            } else if (dist > DISTANCE_FIELD_RANGE) {
-                val = 0;
-            } else {
-                val = (unsigned char)((DISTANCE_FIELD_RANGE-dist)*128.0/DISTANCE_FIELD_RANGE);
-            }
-            *dfPtr++ = val;
         }
 
         // copy to atlas
         plot = fAtlasMgr->addToAtlas(&fAtlas, dfWidth, dfHeight, dfStorage.get(),
                                      &glyph->fAtlasLocation);
 
     } else {
 #endif
         size_t size = glyph->fBounds.area() * bytesPerPixel;
         SkAutoSMalloc<1024> storage(size);
@@ skipping 11 matching lines @@
     }
 #endif
 
     if (NULL == plot) {
         return false;
     }
 
     glyph->fPlot = plot;
     return true;
 }