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/*
* Copyright 2017 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkPoint3.h"
#include "SkRefCnt.h"
#ifndef SkAtlasTextRenderer_DEFINED
#define SkAtlasTextRenderer_DEFINED
/**
* This is the base class for a renderer implemented by the SkAtlasText client. The
* SkAtlasTextContext issues texture creations, deletions, uploads, and vertex draws to the
* renderer. The renderer must perform those actions in the order called to correctly render
* the text drawn to SkAtlasTextTargets.
*/
class SK_API SkAtlasTextRenderer : public SkRefCnt {
public:
enum class AtlasFormat {
/** Unsigned normalized 8 bit single channel format. */
kA8
};
struct SDFVertex {
/** Position in device space (not normalized). The third component is w (not z). */
SkPoint3 fPosition;
/** Color, same value for all four corners of a glyph quad. */
uint32_t fColor;
/** Texture coordinate (in texel units, not normalized). */
int16_t fTextureCoordX;
int16_t fTextureCoordY;
};
virtual ~SkAtlasTextRenderer() = default;
/**
* Create a texture of the provided format with dimensions 'width' x 'height'
* and return a unique handle.
*/
virtual void* createTexture(AtlasFormat, int width, int height) = 0;
/**
* Delete the texture with the passed handle.
*/
virtual void deleteTexture(void* textureHandle) = 0;
/**
* Place the pixel data specified by 'data' in the texture with handle
* 'textureHandle' in the rectangle ['x', 'x' + 'width') x ['y', 'y' + 'height').
* 'rowBytes' specifies the byte offset between successive rows in 'data' and will always be
* a multiple of the number of bytes per pixel.
* The pixel format of data is the same as that of 'textureHandle'.
*/
virtual void setTextureData(void* textureHandle, const void* data, int x, int y, int width,
int height, size_t rowBytes) = 0;
/**
* Draws glyphs using SDFs. The SDF data resides in 'textureHandle'. The array
* 'vertices' provides interleaved device-space positions, colors, and
* texture coordinates. There are are 4 * 'quadCnt' entries in 'vertices'.
*/
virtual void drawSDFGlyphs(void* targetHandle, void* textureHandle, const SDFVertex vertices[],
int quadCnt) = 0;
/** Called when a SkAtlasTextureTarget is destroyed. */
virtual void targetDeleted(void* targetHandle) = 0;
};
#endif
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