Use per-typeface sets of glyphs for nvpr text

src/gpu/GrPathRendering.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrPathRendering.h"
+#include "SkDescriptor.h"
+#include "SkGlyph.h"
+#include "SkMatrix.h"
+#include "SkTypeface.h"
+#include "GrPathRange.h"
+
+class GlyphGenerator : public GrPathRange::PathGenerator {
+public:
+    GlyphGenerator(const SkTypeface& typeface, const SkDescriptor& desc)
+        : fDesc(desc.copy()),
+          fScalerContext(typeface.createScalerContext(fDesc)) {
+        fFlipMatrix.setScale(1, -1);
+    }
+
+    virtual ~GlyphGenerator() {
+        SkDescriptor::Free(fDesc);
+    }
+
+    virtual uint32_t getNumPaths() {
+        return fScalerContext->getGlyphCount();
+    }
+
+    virtual void generatePath(uint32_t glyphID, SkPath* out) {
+        SkGlyph skGlyph;
+        skGlyph.init(SkGlyph::MakeID(glyphID));
+        fScalerContext->getMetrics(&skGlyph);
+
+        fScalerContext->getPath(skGlyph, out);
+        out->transform(fFlipMatrix); // Load glyphs with the inverted y-direction.
+    }
+
+    virtual bool isEqualTo(const SkDescriptor& desc) const {
+        return fDesc->equals(desc);
+    }
+
+private:
+    SkDescriptor* const fDesc;
+    const SkAutoTDelete<SkScalerContext> fScalerContext;
+    SkMatrix fFlipMatrix;
+};
+
+GrPathRange* GrPathRendering::createGlyphs(const SkTypeface* typeface,
+                                           const SkDescriptor* desc,
+                                           const SkStrokeRec& stroke) {
+    if (NULL == typeface) {
+        typeface = SkTypeface::GetDefaultTypeface();
+        SkASSERT(NULL != typeface);
+    }
+
+    if (desc) {
+        return this->createPathRange(SkNEW_ARGS(GlyphGenerator, (*typeface, *desc)), stroke);
+    }
+
+    SkScalerContextRec rec;
+    memset(&rec, 0, sizeof(rec));
+    rec.fFontID = typeface->uniqueID();
+    rec.fTextSize = SkPaint::kCanonicalTextSizeForPaths;
+    rec.fPreScaleX = rec.fPost2x2[0][0] = rec.fPost2x2[1][1] = SK_Scalar1;
+    // Don't bake stroke information into the glyphs, we'll let the GPU do the stroking.
+
+    SkAutoDescriptor ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
+    SkDescriptor*    genericDesc = ad.getDesc();
+
+    genericDesc->init();
+    genericDesc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);
+    genericDesc->computeChecksum();
+
+    return this->createPathRange(SkNEW_ARGS(GlyphGenerator, (*typeface, *genericDesc)), stroke);
+}