mirror of
https://github.com/webmproject/libwebp.git
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67 lines
2.1 KiB
C
67 lines
2.1 KiB
C
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// Copyright 2010 Google Inc.
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//
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// This code is licensed under the same terms as WebM:
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// Software License Agreement: http://www.webmproject.org/license/software/
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// Additional IP Rights Grant: http://www.webmproject.org/license/additional/
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// -----------------------------------------------------------------------------
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//
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// inline YUV->RGB conversion function
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#ifndef WEBP_DECODE_YUV_H_
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#define WEBP_DECODE_YUV_H_
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#include "webp/decode_vp8.h"
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#if defined(__cplusplus) || defined(c_plusplus)
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extern "C" {
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#endif
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enum { YUV_FIX = 16, // fixed-point precision
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YUV_RANGE_MIN = -227, // min value of r/g/b output
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YUV_RANGE_MAX = 256 + 226 // max value of r/g/b output
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};
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extern int16_t VP8kVToR[256], VP8kUToB[256];
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extern int32_t VP8kVToG[256], VP8kUToG[256];
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extern uint8_t VP8kClip[YUV_RANGE_MAX - YUV_RANGE_MIN];
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inline static void VP8YuvToRgb(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const rgb) {
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const int r_off = VP8kVToR[v];
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const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
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const int b_off = VP8kUToB[u];
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rgb[0] = VP8kClip[y + r_off - YUV_RANGE_MIN];
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rgb[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
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rgb[2] = VP8kClip[y + b_off - YUV_RANGE_MIN];
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}
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inline static void VP8YuvToRgba(int y, int u, int v, uint8_t* const rgba) {
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VP8YuvToRgb(y, u, v, rgba);
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rgba[3] = 0xff;
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}
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inline static void VP8YuvToBgr(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const bgr) {
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const int r_off = VP8kVToR[v];
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const int g_off = (VP8kVToG[v] + VP8kUToG[u]) >> YUV_FIX;
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const int b_off = VP8kUToB[u];
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bgr[0] = VP8kClip[y + b_off - YUV_RANGE_MIN];
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bgr[1] = VP8kClip[y + g_off - YUV_RANGE_MIN];
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bgr[2] = VP8kClip[y + r_off - YUV_RANGE_MIN];
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}
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inline static void VP8YuvToBgra(int y, int u, int v, uint8_t* const bgra) {
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VP8YuvToBgr(y, u, v, bgra);
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bgra[3] = 0xff;
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}
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// Must be called before everything, to initialize the tables.
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void VP8YUVInit();
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#if defined(__cplusplus) || defined(c_plusplus)
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} // extern "C"
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#endif
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#endif // WEBP_DECODE_YUV_H_
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