1 /* 2 * Copyright 2017 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 "SkPoint3.h" 9 #include "SkRefCnt.h" 10 11 #ifndef SkAtlasTextRenderer_DEFINED 12 #define SkAtlasTextRenderer_DEFINED 13 14 /** 15 * This is the base class for a renderer implemented by the SkAtlasText client. The 16 * SkAtlasTextContext issues texture creations, deletions, uploads, and vertex draws to the 17 * renderer. The renderer must perform those actions in the order called to correctly render 18 * the text drawn to SkAtlasTextTargets. 19 */ 20 class SK_API SkAtlasTextRenderer : public SkRefCnt { 21 public: 22 enum class AtlasFormat { 23 /** Unsigned normalized 8 bit single channel format. */ 24 kA8 25 }; 26 27 struct SDFVertex { 28 /** Position in device space (not normalized). The third component is w (not z). */ 29 SkPoint3 fPosition; 30 /** Color, same value for all four corners of a glyph quad. */ 31 uint32_t fColor; 32 /** Texture coordinate (in texel units, not normalized). */ 33 SkIPoint16 fTextureCoord; 34 }; 35 36 virtual ~SkAtlasTextRenderer() = default; 37 38 /** 39 * Create a texture of the provided format with dimensions 'width' x 'height' 40 * and return a unique handle. 41 */ 42 virtual void* createTexture(AtlasFormat, int width, int height) = 0; 43 44 /** 45 * Delete the texture with the passed handle. 46 */ 47 virtual void deleteTexture(void* textureHandle) = 0; 48 49 /** 50 * Place the pixel data specified by 'data' in the texture with handle 51 * 'textureHandle' in the rectangle ['x', 'x' + 'width') x ['y', 'y' + 'height'). 52 * 'rowBytes' specifies the byte offset between successive rows in 'data' and will always be 53 * a multiple of the number of bytes per pixel. 54 * The pixel format of data is the same as that of 'textureHandle'. 55 */ 56 virtual void setTextureData(void* textureHandle, const void* data, int x, int y, int width, 57 int height, size_t rowBytes) = 0; 58 59 /** 60 * Draws glyphs using SDFs. The SDF data resides in 'textureHandle'. The array 61 * 'vertices' provides interleaved device-space positions, colors, and 62 * texture coordinates. There are are 4 * 'quadCnt' entries in 'vertices'. 63 */ 64 virtual void drawSDFGlyphs(void* targetHandle, void* textureHandle, const SDFVertex vertices[], 65 int quadCnt) = 0; 66 67 /** Called when a SkAtlasTextureTarget is destroyed. */ 68 virtual void targetDeleted(void* targetHandle) = 0; 69 }; 70 71 #endif 72
