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 #ifndef SkTextBlob_DEFINED 9 #define SkTextBlob_DEFINED 10 11 #include "SkPaint.h" 12 #include "SkRefCnt.h" 13 #include "SkTArray.h" 14 #include "SkTDArray.h" 15 16 class SkReadBuffer; 17 class SkWriteBuffer; 18 19 /** \class SkTextBlob 20 21 SkTextBlob combines multiple text runs into an immutable, ref-counted structure. 22 */ 23 class SK_API SkTextBlob : public SkRefCnt { 24 public: 25 /** 26 * Returns the blob bounding box. 27 */ 28 const SkRect& bounds() const { return fBounds; } 29 30 /** 31 * Return a non-zero, unique value representing the text blob. 32 */ 33 uint32_t uniqueID() const; 34 35 /** 36 * Serialize to a buffer. 37 */ 38 void flatten(SkWriteBuffer&) const; 39 40 /** 41 * Recreate an SkTextBlob that was serialized into a buffer. 42 * 43 * @param SkReadBuffer Serialized blob data. 44 * @return A new SkTextBlob representing the serialized data, or NULL if the buffer is 45 * invalid. 46 */ 47 static const SkTextBlob* CreateFromBuffer(SkReadBuffer&); 48 49 private: 50 enum GlyphPositioning { 51 kDefault_Positioning = 0, // Default glyph advances -- zero scalars per glyph. 52 kHorizontal_Positioning = 1, // Horizontal positioning -- one scalar per glyph. 53 kFull_Positioning = 2 // Point positioning -- two scalars per glyph. 54 }; 55 56 class RunRecord; 57 58 class RunIterator { 59 public: 60 RunIterator(const SkTextBlob* blob); 61 62 bool done() const; 63 void next(); 64 65 uint32_t glyphCount() const; 66 const uint16_t* glyphs() const; 67 const SkScalar* pos() const; 68 const SkPoint& offset() const; 69 void applyFontToPaint(SkPaint*) const; 70 GlyphPositioning positioning() const; 71 72 private: 73 const RunRecord* fCurrentRun; 74 int fRemainingRuns; 75 76 SkDEBUGCODE(uint8_t* fStorageTop;) 77 }; 78 79 SkTextBlob(int runCount, const SkRect& bounds); 80 81 virtual ~SkTextBlob(); 82 virtual void internal_dispose() const SK_OVERRIDE; 83 84 static unsigned ScalarsPerGlyph(GlyphPositioning pos); 85 86 friend class SkBaseDevice; 87 friend class SkTextBlobBuilder; 88 friend class TextBlobTester; 89 90 const int fRunCount; 91 const SkRect fBounds; 92 mutable uint32_t fUniqueID; 93 94 SkDEBUGCODE(size_t fStorageSize;) 95 96 // The actual payload resides in externally-managed storage, following the object. 97 // (see the .cpp for more details) 98 99 typedef SkRefCnt INHERITED; 100 }; 101 102 /** \class SkTextBlobBuilder 103 104 Helper class for constructing SkTextBlobs. 105 */ 106 class SK_API SkTextBlobBuilder { 107 public: 108 SkTextBlobBuilder(); 109 110 ~SkTextBlobBuilder(); 111 112 /** 113 * Returns an immutable SkTextBlob for the current runs/glyphs. The builder is reset and 114 * can be reused. 115 */ 116 const SkTextBlob* build(); 117 118 /** 119 * Glyph and position buffers associated with a run. 120 * 121 * A run is a sequence of glyphs sharing the same font metrics and positioning mode. 122 */ 123 struct RunBuffer { 124 uint16_t* glyphs; 125 SkScalar* pos; 126 }; 127 128 /** 129 * Allocates a new default-positioned run and returns its writable glyph buffer 130 * for direct manipulation. 131 * 132 * @param font The font to be used for this run. 133 * @param count Number of glyphs. 134 * @param x,y Position within the blob. 135 * @param bounds Optional run bounding box. If known in advance (!= NULL), it will 136 * be used when computing the blob bounds, to avoid re-measuring. 137 * 138 * @return A writable glyph buffer, valid until the next allocRun() or 139 * build() call. The buffer is guaranteed to hold @count@ glyphs. 140 */ 141 const RunBuffer& allocRun(const SkPaint& font, int count, SkScalar x, SkScalar y, 142 const SkRect* bounds = NULL); 143 144 /** 145 * Allocates a new horizontally-positioned run and returns its writable glyph and position 146 * buffers for direct manipulation. 147 * 148 * @param font The font to be used for this run. 149 * @param count Number of glyphs. 150 * @param y Vertical offset within the blob. 151 * @param bounds Optional run bounding box. If known in advance (!= NULL), it will 152 * be used when computing the blob bounds, to avoid re-measuring. 153 * 154 * @return Writable glyph and position buffers, valid until the next allocRun() 155 * or build() call. The buffers are guaranteed to hold @count@ elements. 156 */ 157 const RunBuffer& allocRunPosH(const SkPaint& font, int count, SkScalar y, 158 const SkRect* bounds = NULL); 159 160 /** 161 * Allocates a new fully-positioned run and returns its writable glyph and position 162 * buffers for direct manipulation. 163 * 164 * @param font The font to be used for this run. 165 * @param count Number of glyphs. 166 * @param bounds Optional run bounding box. If known in advance (!= NULL), it will 167 * be used when computing the blob bounds, to avoid re-measuring. 168 * 169 * @return Writable glyph and position buffers, valid until the next allocRun() 170 * or build() call. The glyph buffer and position buffer are 171 * guaranteed to hold @count@ and 2 * @count@ elements, respectively. 172 */ 173 const RunBuffer& allocRunPos(const SkPaint& font, int count, const SkRect* bounds = NULL); 174 175 private: 176 void reserve(size_t size); 177 void allocInternal(const SkPaint& font, SkTextBlob::GlyphPositioning positioning, 178 int count, SkPoint offset, const SkRect* bounds); 179 bool mergeRun(const SkPaint& font, SkTextBlob::GlyphPositioning positioning, 180 int count, SkPoint offset); 181 void updateDeferredBounds(); 182 183 SkAutoTMalloc<uint8_t> fStorage; 184 size_t fStorageSize; 185 size_t fStorageUsed; 186 187 SkRect fBounds; 188 int fRunCount; 189 bool fDeferredBounds; 190 size_t fLastRun; // index into fStorage 191 192 RunBuffer fCurrentRunBuffer; 193 }; 194 195 #endif // SkTextBlob_DEFINED 196
