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 "SkGScalerContext.h"
9#include "SkGlyph.h"
10#include "SkPath.h"
11#include "SkCanvas.h"
12
13class SkGScalerContext : public SkScalerContext {
14public:
15    SkGScalerContext(SkGTypeface*, const SkDescriptor*);
16    virtual ~SkGScalerContext();
17
18protected:
19    virtual unsigned generateGlyphCount() SK_OVERRIDE;
20    virtual uint16_t generateCharToGlyph(SkUnichar) SK_OVERRIDE;
21    virtual void generateAdvance(SkGlyph*) SK_OVERRIDE;
22    virtual void generateMetrics(SkGlyph*) SK_OVERRIDE;
23    virtual void generateImage(const SkGlyph&) SK_OVERRIDE;
24    virtual void generatePath(const SkGlyph&, SkPath*) SK_OVERRIDE;
25    virtual void generateFontMetrics(SkPaint::FontMetrics* mX,
26                                     SkPaint::FontMetrics* mY) SK_OVERRIDE;
27
28private:
29    SkGTypeface*     fFace;
30    SkScalerContext* fProxy;
31    SkMatrix         fMatrix;
32};
33
34#define STD_SIZE    1
35
36#include "SkDescriptor.h"
37
38SkGScalerContext::SkGScalerContext(SkGTypeface* face, const SkDescriptor* desc)
39        : SkScalerContext(face, desc)
40        , fFace(face)
41{
42
43    size_t  descSize = SkDescriptor::ComputeOverhead(1) + sizeof(SkScalerContext::Rec);
44    SkAutoDescriptor ad(descSize);
45    SkDescriptor*    newDesc = ad.getDesc();
46
47    newDesc->init();
48    void* entry = newDesc->addEntry(kRec_SkDescriptorTag,
49                                    sizeof(SkScalerContext::Rec), &fRec);
50    {
51        SkScalerContext::Rec* rec = (SkScalerContext::Rec*)entry;
52        rec->fTextSize = STD_SIZE;
53        rec->fPreScaleX = SK_Scalar1;
54        rec->fPreSkewX = 0;
55        rec->fPost2x2[0][0] = rec->fPost2x2[1][1] = SK_Scalar1;
56        rec->fPost2x2[1][0] = rec->fPost2x2[0][1] = 0;
57    }
58    SkASSERT(descSize == newDesc->getLength());
59    newDesc->computeChecksum();
60
61    fProxy = face->proxy()->createScalerContext(newDesc);
62
63    fRec.getSingleMatrix(&fMatrix);
64    fMatrix.preScale(SK_Scalar1 / STD_SIZE, SK_Scalar1 / STD_SIZE);
65}
66
67SkGScalerContext::~SkGScalerContext() {
68    SkDELETE(fProxy);
69}
70
71unsigned SkGScalerContext::generateGlyphCount() {
72    return fProxy->getGlyphCount();
73}
74
75uint16_t SkGScalerContext::generateCharToGlyph(SkUnichar uni) {
76    return fProxy->charToGlyphID(uni);
77}
78
79void SkGScalerContext::generateAdvance(SkGlyph* glyph) {
80    fProxy->getAdvance(glyph);
81
82    SkVector advance;
83    fMatrix.mapXY(SkFixedToScalar(glyph->fAdvanceX),
84                  SkFixedToScalar(glyph->fAdvanceY), &advance);
85    glyph->fAdvanceX = SkScalarToFixed(advance.fX);
86    glyph->fAdvanceY = SkScalarToFixed(advance.fY);
87}
88
89void SkGScalerContext::generateMetrics(SkGlyph* glyph) {
90    fProxy->getMetrics(glyph);
91
92    SkVector advance;
93    fMatrix.mapXY(SkFixedToScalar(glyph->fAdvanceX),
94                  SkFixedToScalar(glyph->fAdvanceY), &advance);
95    glyph->fAdvanceX = SkScalarToFixed(advance.fX);
96    glyph->fAdvanceY = SkScalarToFixed(advance.fY);
97
98    SkPath path;
99    fProxy->getPath(*glyph, &path);
100    path.transform(fMatrix);
101
102    SkRect storage;
103    const SkPaint& paint = fFace->paint();
104    const SkRect& newBounds = paint.doComputeFastBounds(path.getBounds(),
105                                                        &storage,
106                                                        SkPaint::kFill_Style);
107    SkIRect ibounds;
108    newBounds.roundOut(&ibounds);
109    glyph->fLeft = ibounds.fLeft;
110    glyph->fTop = ibounds.fTop;
111    glyph->fWidth = ibounds.width();
112    glyph->fHeight = ibounds.height();
113    glyph->fMaskFormat = SkMask::kARGB32_Format;
114}
115
116void SkGScalerContext::generateImage(const SkGlyph& glyph) {
117    if (SkMask::kARGB32_Format == glyph.fMaskFormat) {
118        SkPath path;
119        fProxy->getPath(glyph, &path);
120
121        SkBitmap bm;
122        bm.installPixels(SkImageInfo::MakeN32Premul(glyph.fWidth, glyph.fHeight),
123                         glyph.fImage, glyph.rowBytes());
124        bm.eraseColor(0);
125
126        SkCanvas canvas(bm);
127        canvas.translate(-SkIntToScalar(glyph.fLeft),
128                         -SkIntToScalar(glyph.fTop));
129        canvas.concat(fMatrix);
130        canvas.drawPath(path, fFace->paint());
131    } else {
132        fProxy->getImage(glyph);
133    }
134}
135
136void SkGScalerContext::generatePath(const SkGlyph& glyph, SkPath* path) {
137    fProxy->getPath(glyph, path);
138    path->transform(fMatrix);
139}
140
141void SkGScalerContext::generateFontMetrics(SkPaint::FontMetrics*,
142                                           SkPaint::FontMetrics* metrics) {
143    fProxy->getFontMetrics(metrics);
144    if (metrics) {
145        SkScalar scale = fMatrix.getScaleY();
146        metrics->fTop = SkScalarMul(metrics->fTop, scale);
147        metrics->fAscent = SkScalarMul(metrics->fAscent, scale);
148        metrics->fDescent = SkScalarMul(metrics->fDescent, scale);
149        metrics->fBottom = SkScalarMul(metrics->fBottom, scale);
150        metrics->fLeading = SkScalarMul(metrics->fLeading, scale);
151        metrics->fAvgCharWidth = SkScalarMul(metrics->fAvgCharWidth, scale);
152        metrics->fXMin = SkScalarMul(metrics->fXMin, scale);
153        metrics->fXMax = SkScalarMul(metrics->fXMax, scale);
154        metrics->fXHeight = SkScalarMul(metrics->fXHeight, scale);
155    }
156}
157
158///////////////////////////////////////////////////////////////////////////////
159
160#include "SkTypefaceCache.h"
161
162SkGTypeface::SkGTypeface(SkTypeface* proxy, const SkPaint& paint)
163    : SkTypeface(proxy->style(), SkTypefaceCache::NewFontID(), false)
164    , fProxy(SkRef(proxy))
165    , fPaint(paint) {}
166
167SkGTypeface::~SkGTypeface() {
168    fProxy->unref();
169}
170
171SkScalerContext* SkGTypeface::onCreateScalerContext(
172                                            const SkDescriptor* desc) const {
173    return SkNEW_ARGS(SkGScalerContext, (const_cast<SkGTypeface*>(this), desc));
174}
175
176void SkGTypeface::onFilterRec(SkScalerContextRec* rec) const {
177    fProxy->filterRec(rec);
178    rec->setHinting(SkPaint::kNo_Hinting);
179    rec->fMaskFormat = SkMask::kARGB32_Format;
180}
181
182SkAdvancedTypefaceMetrics* SkGTypeface::onGetAdvancedTypefaceMetrics(
183                                SkAdvancedTypefaceMetrics::PerGlyphInfo info,
184                                const uint32_t* glyphIDs,
185                                uint32_t glyphIDsCount) const {
186    return fProxy->getAdvancedTypefaceMetrics(info, glyphIDs, glyphIDsCount);
187}
188
189SkStream* SkGTypeface::onOpenStream(int* ttcIndex) const {
190    return fProxy->openStream(ttcIndex);
191}
192
193void SkGTypeface::onGetFontDescriptor(SkFontDescriptor* desc,
194                                      bool* isLocal) const {
195    fProxy->getFontDescriptor(desc, isLocal);
196}
197
198int SkGTypeface::onCharsToGlyphs(const void* chars, Encoding encoding,
199                                 uint16_t glyphs[], int glyphCount) const {
200    return fProxy->charsToGlyphs(chars, encoding, glyphs, glyphCount);
201}
202
203int SkGTypeface::onCountGlyphs() const {
204    return fProxy->countGlyphs();
205}
206
207int SkGTypeface::onGetUPEM() const {
208    return fProxy->getUnitsPerEm();
209}
210
211SkTypeface::LocalizedStrings* SkGTypeface::onCreateFamilyNameIterator() const {
212    return fProxy->createFamilyNameIterator();
213}
214
215int SkGTypeface::onGetTableTags(SkFontTableTag tags[]) const {
216    return fProxy->getTableTags(tags);
217}
218
219size_t SkGTypeface::onGetTableData(SkFontTableTag tag, size_t offset,
220                                    size_t length, void* data) const {
221    return fProxy->getTableData(tag, offset, length, data);
222}
223
224///////////////////////////////////////////////////////////////////////////////
225
226#if 0
227// under construction -- defining a font purely in terms of skia primitives
228// ala an SVG-font.
229class SkGFont : public SkRefCnt {
230public:
231    virtual ~SkGFont();
232
233    int unicharToGlyph(SkUnichar) const;
234
235    int countGlyphs() const { return fCount; }
236
237    float getAdvance(int index) const {
238        SkASSERT((unsigned)index < (unsigned)fCount);
239        return fGlyphs[index].fAdvance;
240    }
241
242    const SkPath& getPath(int index) const {
243        SkASSERT((unsigned)index < (unsigned)fCount);
244        return fGlyphs[index].fPath;
245    }
246
247private:
248    struct Glyph {
249        SkUnichar   fUni;
250        float       fAdvance;
251        SkPath      fPath;
252    };
253    int fCount;
254    Glyph* fGlyphs;
255
256    friend class SkGFontBuilder;
257    SkGFont(int count, Glyph* array);
258};
259
260class SkGFontBuilder {
261public:
262
263};
264#endif
265