1/*
2 * Copyright 2014 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 "GrPathRendering.h"
9#include "SkDescriptor.h"
10#include "SkGlyph.h"
11#include "SkMatrix.h"
12#include "SkTypeface.h"
13#include "GrPathRange.h"
14
15class GlyphGenerator : public GrPathRange::PathGenerator {
16public:
17    GlyphGenerator(const SkTypeface& typeface, const SkDescriptor& desc)
18        : fDesc(desc.copy()),
19          fScalerContext(typeface.createScalerContext(fDesc)) {
20        fFlipMatrix.setScale(1, -1);
21    }
22
23    virtual ~GlyphGenerator() {
24        SkDescriptor::Free(fDesc);
25    }
26
27    virtual int getNumPaths() {
28        return fScalerContext->getGlyphCount();
29    }
30
31    virtual void generatePath(int glyphID, SkPath* out) {
32        SkGlyph skGlyph;
33        skGlyph.init(SkGlyph::MakeID(glyphID));
34        fScalerContext->getMetrics(&skGlyph);
35
36        fScalerContext->getPath(skGlyph, out);
37        out->transform(fFlipMatrix); // Load glyphs with the inverted y-direction.
38    }
39
40    virtual bool isEqualTo(const SkDescriptor& desc) const {
41        return fDesc->equals(desc);
42    }
43
44private:
45    SkDescriptor* const fDesc;
46    const SkAutoTDelete<SkScalerContext> fScalerContext;
47    SkMatrix fFlipMatrix;
48};
49
50GrPathRange* GrPathRendering::createGlyphs(const SkTypeface* typeface,
51                                           const SkDescriptor* desc,
52                                           const SkStrokeRec& stroke) {
53    if (NULL == typeface) {
54        typeface = SkTypeface::GetDefaultTypeface();
55        SkASSERT(NULL != typeface);
56    }
57
58    if (desc) {
59        SkAutoTUnref<GlyphGenerator> generator(SkNEW_ARGS(GlyphGenerator, (*typeface, *desc)));
60        return this->createPathRange(generator, stroke);
61    }
62
63    SkScalerContextRec rec;
64    memset(&rec, 0, sizeof(rec));
65    rec.fFontID = typeface->uniqueID();
66    rec.fTextSize = SkPaint::kCanonicalTextSizeForPaths;
67    rec.fPreScaleX = rec.fPost2x2[0][0] = rec.fPost2x2[1][1] = SK_Scalar1;
68    // Don't bake stroke information into the glyphs, we'll let the GPU do the stroking.
69
70    SkAutoDescriptor ad(sizeof(rec) + SkDescriptor::ComputeOverhead(1));
71    SkDescriptor*    genericDesc = ad.getDesc();
72
73    genericDesc->init();
74    genericDesc->addEntry(kRec_SkDescriptorTag, sizeof(rec), &rec);
75    genericDesc->computeChecksum();
76
77    SkAutoTUnref<GlyphGenerator> generator(SkNEW_ARGS(GlyphGenerator, (*typeface, *genericDesc)));
78    return this->createPathRange(generator, stroke);
79}
80