72 lines
2.5 KiB
C
72 lines
2.5 KiB
C
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/*
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* Copyright 2017 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#include "SkPoint.h"
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#include "SkRefCnt.h"
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#ifndef SkAtlasTextRenderer_DEFINED
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#define SkAtlasTextRenderer_DEFINED
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/**
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* This is the base class for a renderer implemented by the SkAtlasText client. The
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* SkAtlasTextContext issues texture creations, deletions, uploads, and vertex draws to the
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* renderer. The renderer must perform those actions in the order called to correctly render
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* the text drawn to SkAtlasTextTargets.
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*/
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class SK_API SkAtlasTextRenderer : public SkRefCnt {
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public:
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enum class AtlasFormat {
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/** Unsigned normalized 8 bit single channel format. */
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kA8
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};
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struct SDFVertex {
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/** Position in device space (not normalized). */
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SkPoint fPosition;
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/** Color, same value for all four corners of a glyph quad. */
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uint32_t fColor;
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/** Texture coordinate (in texel units, not normalized). */
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SkIPoint16 fTextureCoord;
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};
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virtual ~SkAtlasTextRenderer() = default;
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/**
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* Create a texture of the provided format with dimensions 'width' x 'height'
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* and return a unique handle.
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*/
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virtual void* createTexture(AtlasFormat, int width, int height) = 0;
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/**
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* Delete the texture with the passed handle.
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*/
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virtual void deleteTexture(void* textureHandle) = 0;
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/**
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* Place the pixel data specified by 'data' in the texture with handle
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* 'textureHandle' in the rectangle ['x', 'x' + 'width') x ['y', 'y' + 'height').
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* 'rowBytes' specifies the byte offset between successive rows in 'data' and will always be
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* a multiple of the number of bytes per pixel.
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* The pixel format of data is the same as that of 'textureHandle'.
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*/
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virtual void setTextureData(void* textureHandle, const void* data, int x, int y, int width,
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int height, size_t rowBytes) = 0;
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/**
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* Draws glyphs using SDFs. The SDF data resides in 'textureHandle'. The array
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* 'vertices' provides interleaved device-space positions, colors, and
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* texture coordinates. There are are 4 * 'quadCnt' entries in 'vertices'.
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*/
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virtual void drawSDFGlyphs(void* targetHandle, void* textureHandle, const SDFVertex vertices[],
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int quadCnt) = 0;
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/** Called when a SkAtlasTextureTarget is destroyed. */
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virtual void targetDeleted(void* targetHandle) = 0;
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};
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#endif
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