1 #Topic Text_Blob_Builder 2 #Alias Text_Blob_Builder_Reference ## 3 4 #Class SkTextBlobBuilder 5 6 #Code 7 #Populate 8 ## 9 10 Helper class for constructing SkTextBlob. 11 12 # ------------------------------------------------------------------------------ 13 14 #Struct RunBuffer 15 #Line # storage for Glyphs and Glyph positions ## 16 17 #Code 18 struct RunBuffer { 19 SkGlyphID* glyphs; 20 SkScalar* pos; 21 char* utf8text; 22 uint32_t* clusters; 23 }; 24 ## 25 26 RunBuffer supplies storage for Glyphs and positions within a run. 27 28 A run is a sequence of Glyphs sharing Font_Metrics and positioning. 29 Each run may position its Glyphs in one of three ways: 30 by specifying where the first Glyph is drawn, and allowing Font_Metrics to 31 determine the advance to subsequent Glyphs; by specifying a baseline, and 32 the position on that baseline for each Glyph in run; or by providing Point 33 array, one per Glyph. 34 35 #Member SkGlyphID* glyphs 36 #Line # storage for Glyphs in run ## 37 glyphs points to memory for one or more Glyphs. glyphs memory must be 38 written to by the caller. 39 ## 40 41 #Member SkScalar* pos 42 #Line # storage for positions in run ## 43 pos points to memory for Glyph positions. Depending on how RunBuffer 44 is allocated, pos may point to zero bytes per Glyph, one Scalar per Glyph, 45 or one Point per Glyph. 46 ## 47 48 #Member char* utf8text 49 #Line # reserved for future use ## 50 Reserved for future use. utf8text should not be read or written. 51 ## 52 53 #Member uint32_t* clusters 54 #Line # reserved for future use ## 55 Reserved for future use. clusters should not be read or written. 56 ## 57 58 #SeeAlso allocRun allocRunPos allocRunPosH 59 60 #Struct RunBuffer ## 61 62 # ------------------------------------------------------------------------------ 63 64 #Method SkTextBlobBuilder() 65 #In Constructors 66 #Line # constructs with default values ## 67 #Populate 68 69 #Example 70 SkTextBlobBuilder builder; 71 sk_sp<SkTextBlob> blob = builder.make(); 72 SkDebugf("blob " "%s" " nullptr", blob == nullptr ? "equals" : "does not equal"); 73 #StdOut 74 blob equals nullptr 75 ## 76 ## 77 78 #SeeAlso make SkTextBlob::MakeFromText 79 80 #Method ## 81 82 # ------------------------------------------------------------------------------ 83 84 #Method ~SkTextBlobBuilder() 85 #In Constructors 86 #Line # deletes storage ## 87 #Populate 88 89 #NoExample 90 ## 91 92 #SeeAlso SkTextBlobBuilder() 93 94 #Method ## 95 96 # ------------------------------------------------------------------------------ 97 98 #Method sk_sp<SkTextBlob> make() 99 #In Constructors 100 #Line # constructs Text_Blob from bulider ## 101 #Populate 102 103 #Example 104 SkTextBlobBuilder builder; 105 sk_sp<SkTextBlob> blob = builder.make(); 106 SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); 107 SkPaint paint; 108 paint.setTextEncoding(kGlyphID_SkTextEncoding); 109 SkFont font; 110 paint.textToGlyphs("x", 1, builder.allocRun(font, 1, 20, 20).glyphs); 111 blob = builder.make(); 112 SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); 113 blob = builder.make(); 114 SkDebugf("blob " "%s" " nullptr\n", blob == nullptr ? "equals" : "does not equal"); 115 #StdOut 116 blob equals nullptr 117 blob does not equal nullptr 118 blob equals nullptr 119 ## 120 ## 121 122 #SeeAlso SkTextBlob::MakeFromText 123 124 #Method ## 125 126 # ------------------------------------------------------------------------------ 127 128 #Method const RunBuffer& allocRun(const SkFont& font, int count, SkScalar x, SkScalar y, 129 const SkRect* bounds = nullptr) 130 #In Allocator 131 #Line # returns writable glyph buffer at Point ## 132 133 #Populate 134 135 #Example 136 #Height 60 137 SkTextBlobBuilder builder; 138 SkFont font; 139 SkPaint paint; 140 const SkTextBlobBuilder::RunBuffer& run = builder.allocRun(font, 5, 20, 20); 141 paint.textToGlyphs("hello", 5, run.glyphs); 142 canvas->drawRect({20, 20, 30, 30}, paint); 143 canvas->drawTextBlob(builder.make(), 20, 20, paint); 144 ## 145 146 #SeeAlso allocRunPosH allocRunPos 147 148 #Method ## 149 150 # ------------------------------------------------------------------------------ 151 152 #Method const RunBuffer& allocRunPosH(const SkFont& font, int count, SkScalar y, 153 const SkRect* bounds = nullptr) 154 #In Allocator 155 #Line # returns writable glyph and x-axis position buffers ## 156 157 #Populate 158 159 #Example 160 #Height 60 161 SkTextBlobBuilder builder; 162 SkPaint paint; 163 SkFont font; 164 const SkTextBlobBuilder::RunBuffer& run = builder.allocRunPosH(font, 5, 20); 165 paint.textToGlyphs("hello", 5, run.glyphs); 166 SkScalar positions[] = {0, 10, 20, 40, 80}; 167 memcpy(run.pos, positions, sizeof(positions)); 168 canvas->drawTextBlob(builder.make(), 20, 20, paint); 169 ## 170 171 #SeeAlso allocRunPos allocRun 172 173 #Method ## 174 175 # ------------------------------------------------------------------------------ 176 177 #Method const RunBuffer& allocRunPos(const SkFont& font, int count, 178 const SkRect* bounds = nullptr) 179 #In Allocator 180 #Line # returns writable glyph and Point buffers ## 181 182 #Populate 183 184 #Example 185 #Height 90 186 SkTextBlobBuilder builder; 187 SkPaint paint; 188 SkFont font; 189 const SkTextBlobBuilder::RunBuffer& run = builder.allocRunPos(font, 5); 190 paint.textToGlyphs("hello", 5, run.glyphs); 191 SkPoint positions[] = {{0, 0}, {10, 10}, {20, 20}, {40, 40}, {80, 80}}; 192 memcpy(run.pos, positions, sizeof(positions)); 193 canvas->drawTextBlob(builder.make(), 20, 20, paint); 194 ## 195 196 #SeeAlso allocRunPosH allocRun 197 198 #Method ## 199 200 #Class SkTextBlobBuilder ## 201 202 #Topic Text_Blob_Builder ## 203
