SkTypeface.cpp revision 35fe7372b1b897a77578a220c334e1fb36d144e9 
1/*
2 * Copyright 2011 The Android Open Source Project
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 "SkAdvancedTypefaceMetrics.h"
9#include "SkFontDescriptor.h"
10#include "SkFontHost.h"
11#include "SkStream.h"
12#include "SkTypeface.h"
13
14SK_DEFINE_INST_COUNT(SkTypeface)
15
16//#define TRACE_LIFECYCLE
17
18#ifdef TRACE_LIFECYCLE
19    static int32_t gTypefaceCounter;
20#endif
21
22SkTypeface::SkTypeface(Style style, SkFontID fontID, bool isFixedPitch)
23    : fUniqueID(fontID), fStyle(style), fIsFixedPitch(isFixedPitch) {
24#ifdef TRACE_LIFECYCLE
25    SkDebugf("SkTypeface: create  %p fontID %d total %d\n",
26             this, fontID, ++gTypefaceCounter);
27#endif
28}
29
30SkTypeface::~SkTypeface() {
31#ifdef TRACE_LIFECYCLE
32    SkDebugf("SkTypeface: destroy %p fontID %d total %d\n",
33             this, fUniqueID, --gTypefaceCounter);
34#endif
35}
36
37///////////////////////////////////////////////////////////////////////////////
38
39class SkEmptyTypeface : public SkTypeface {
40public:
41    SkEmptyTypeface() : SkTypeface(SkTypeface::kNormal, 0, true) { }
42protected:
43    virtual SkStream* onOpenStream(int* ttcIndex) const SK_OVERRIDE { return NULL; }
44    virtual SkScalerContext* onCreateScalerContext(const SkDescriptor*) const SK_OVERRIDE {
45        return NULL;
46    }
47    virtual void onFilterRec(SkScalerContextRec*) const SK_OVERRIDE { }
48    virtual SkAdvancedTypefaceMetrics* onGetAdvancedTypefaceMetrics(
49                                SkAdvancedTypefaceMetrics::PerGlyphInfo,
50                                const uint32_t*, uint32_t) const SK_OVERRIDE { return NULL; }
51    virtual void onGetFontDescriptor(SkFontDescriptor*, bool*) const SK_OVERRIDE { }
52    virtual int onCharsToGlyphs(const void* chars, Encoding encoding,
53                                uint16_t glyphs[], int glyphCount) const SK_OVERRIDE {
54        if (glyphs && glyphCount > 0) {
55            sk_bzero(glyphs, glyphCount * sizeof(glyphs[0]));
56        }
57        return 0;
58    }
59    virtual int onCountGlyphs() const SK_OVERRIDE { return 0; };
60    virtual int onGetUPEM() const SK_OVERRIDE { return 0; };
61    class EmptyLocalizedStrings : public SkTypeface::LocalizedStrings {
62    public:
63        virtual bool next(SkTypeface::LocalizedString*) SK_OVERRIDE { return false; }
64    };
65    virtual SkTypeface::LocalizedStrings* onCreateFamilyNameIterator() const SK_OVERRIDE {
66        return SkNEW(EmptyLocalizedStrings);
67    };
68    virtual int onGetTableTags(SkFontTableTag tags[]) const SK_OVERRIDE { return 0; }
69    virtual size_t onGetTableData(SkFontTableTag, size_t, size_t, void*) const SK_OVERRIDE {
70        return 0;
71    }
72    virtual SkTypeface* onRefMatchingStyle(Style) const SK_OVERRIDE { return NULL; }
73};
74
75SkTypeface* SkTypeface::GetDefaultTypeface(Style style) {
76    // we keep a reference to this guy for all time, since if we return its
77    // fontID, the font cache may later on ask to resolve that back into a
78    // typeface object.
79    static const uint32_t FONT_STYLE_COUNT = 4;
80    static SkTypeface* gDefaultTypefaces[FONT_STYLE_COUNT];
81    SkASSERT((unsigned)style < FONT_STYLE_COUNT);
82
83    // mask off any other bits to avoid a crash in SK_RELEASE
84    style = (Style)(style & 0x03);
85
86    if (NULL == gDefaultTypefaces[style]) {
87        gDefaultTypefaces[style] = SkFontHost::CreateTypeface(NULL, NULL, style);
88    }
89    if (NULL == gDefaultTypefaces[style]) {
90        gDefaultTypefaces[style] = SkNEW(SkEmptyTypeface);
91    }
92
93    return gDefaultTypefaces[style];
94}
95
96SkTypeface* SkTypeface::RefDefault(Style style) {
97    return SkRef(GetDefaultTypeface(style));
98}
99
100uint32_t SkTypeface::UniqueID(const SkTypeface* face) {
101    if (NULL == face) {
102        face = GetDefaultTypeface();
103    }
104    return face->uniqueID();
105}
106
107bool SkTypeface::Equal(const SkTypeface* facea, const SkTypeface* faceb) {
108    return SkTypeface::UniqueID(facea) == SkTypeface::UniqueID(faceb);
109}
110
111///////////////////////////////////////////////////////////////////////////////
112
113SkTypeface* SkTypeface::CreateFromName(const char name[], Style style) {
114    if (NULL == name) {
115        return RefDefault(style);
116    }
117    return SkFontHost::CreateTypeface(NULL, name, style);
118}
119
120SkTypeface* SkTypeface::CreateFromTypeface(const SkTypeface* family, Style s) {
121    if (family && family->style() == s) {
122        family->ref();
123        return const_cast<SkTypeface*>(family);
124    }
125    return SkFontHost::CreateTypeface(family, NULL, s);
126}
127
128SkTypeface* SkTypeface::CreateFromStream(SkStream* stream) {
129    return SkFontHost::CreateTypefaceFromStream(stream);
130}
131
132SkTypeface* SkTypeface::CreateFromFile(const char path[]) {
133    return SkFontHost::CreateTypefaceFromFile(path);
134}
135
136///////////////////////////////////////////////////////////////////////////////
137
138void SkTypeface::serialize(SkWStream* wstream) const {
139    bool isLocal = false;
140    SkFontDescriptor desc(this->style());
141    this->onGetFontDescriptor(&desc, &isLocal);
142
143    desc.serialize(wstream);
144    if (isLocal) {
145        int ttcIndex;   // TODO: write this to the stream?
146        SkAutoTUnref<SkStream> rstream(this->openStream(&ttcIndex));
147        if (rstream.get()) {
148            size_t length = rstream->getLength();
149            wstream->writePackedUInt(length);
150            wstream->writeStream(rstream, length);
151        } else {
152            wstream->writePackedUInt(0);
153        }
154    } else {
155        wstream->writePackedUInt(0);
156    }
157}
158
159SkTypeface* SkTypeface::Deserialize(SkStream* stream) {
160    SkFontDescriptor desc(stream);
161    size_t length = stream->readPackedUInt();
162    if (length > 0) {
163        void* addr = sk_malloc_flags(length, 0);
164        if (addr) {
165            SkAutoTUnref<SkMemoryStream> localStream(SkNEW(SkMemoryStream));
166            localStream->setMemoryOwned(addr, length);
167
168            if (stream->read(addr, length) == length) {
169                return SkTypeface::CreateFromStream(localStream.get());
170            } else {
171                // Failed to read the full font data, so fall through and try to create from name.
172                // If this is because of EOF, all subsequent reads from the stream will be EOF.
173                // If this is because of a stream error, the stream is in an error state,
174                // do not attempt to skip any remaining bytes.
175            }
176        } else {
177            // failed to allocate, so just skip and create-from-name
178            stream->skip(length);
179        }
180    }
181
182    return SkTypeface::CreateFromName(desc.getFamilyName(), desc.getStyle());
183}
184
185///////////////////////////////////////////////////////////////////////////////
186
187int SkTypeface::countTables() const {
188    return this->onGetTableTags(NULL);
189}
190
191int SkTypeface::getTableTags(SkFontTableTag tags[]) const {
192    return this->onGetTableTags(tags);
193}
194
195size_t SkTypeface::getTableSize(SkFontTableTag tag) const {
196    return this->onGetTableData(tag, 0, ~0U, NULL);
197}
198
199size_t SkTypeface::getTableData(SkFontTableTag tag, size_t offset, size_t length,
200                                void* data) const {
201    return this->onGetTableData(tag, offset, length, data);
202}
203
204SkStream* SkTypeface::openStream(int* ttcIndex) const {
205    int ttcIndexStorage;
206    if (NULL == ttcIndex) {
207        // So our subclasses don't need to check for null param
208        ttcIndex = &ttcIndexStorage;
209    }
210    return this->onOpenStream(ttcIndex);
211}
212
213int SkTypeface::charsToGlyphs(const void* chars, Encoding encoding,
214                              uint16_t glyphs[], int glyphCount) const {
215    if (glyphCount <= 0) {
216        return 0;
217    }
218    if (NULL == chars || (unsigned)encoding > kUTF32_Encoding) {
219        if (glyphs) {
220            sk_bzero(glyphs, glyphCount * sizeof(glyphs[0]));
221        }
222        return 0;
223    }
224    return this->onCharsToGlyphs(chars, encoding, glyphs, glyphCount);
225}
226
227int SkTypeface::countGlyphs() const {
228    return this->onCountGlyphs();
229}
230
231int SkTypeface::getUnitsPerEm() const {
232    // should we try to cache this in the base-class?
233    return this->onGetUPEM();
234}
235
236bool SkTypeface::getKerningPairAdjustments(const uint16_t glyphs[], int count,
237                                           int32_t adjustments[]) const {
238    SkASSERT(count >= 0);
239    // check for the only legal way to pass a NULL.. everything is 0
240    // in which case they just want to know if this face can possibly support
241    // kerning (true) or never (false).
242    if (NULL == glyphs || NULL == adjustments) {
243        SkASSERT(NULL == glyphs);
244        SkASSERT(0 == count);
245        SkASSERT(NULL == adjustments);
246    }
247    return this->onGetKerningPairAdjustments(glyphs, count, adjustments);
248}
249
250SkTypeface::LocalizedStrings* SkTypeface::createFamilyNameIterator() const {
251    return this->onCreateFamilyNameIterator();
252}
253
254void SkTypeface::getFamilyName(SkString* name) const {
255    bool isLocal = false;
256    SkFontDescriptor desc(this->style());
257    this->onGetFontDescriptor(&desc, &isLocal);
258    name->set(desc.getFamilyName());
259}
260
261SkAdvancedTypefaceMetrics* SkTypeface::getAdvancedTypefaceMetrics(
262                                SkAdvancedTypefaceMetrics::PerGlyphInfo info,
263                                const uint32_t* glyphIDs,
264                                uint32_t glyphIDsCount) const {
265    return this->onGetAdvancedTypefaceMetrics(info, glyphIDs, glyphIDsCount);
266}
267
268SkTypeface* SkTypeface::refMatchingStyle(Style style) const {
269    return this->onRefMatchingStyle(style);
270}
271
272///////////////////////////////////////////////////////////////////////////////
273
274bool SkTypeface::onGetKerningPairAdjustments(const uint16_t glyphs[], int count,
275                                             int32_t adjustments[]) const {
276    return false;
277}
278
279