mirror of
https://github.com/webmproject/libwebp.git
synced 2025-04-17 14:26:48 +02:00
48f827574e
The new modes are
MODE_rgbA
MODE_bgrA
MODE_Argb
MODE_rgbA_4444
It's binary incompatible, since the enums changed.
While at it, i removed the now unneeded KeepAlpha methods.
-> Saved ~12k of code!
* made explicit mention that alpha_plane is persistent,
so we have access to the full alpha plane data at all time.
Incremental decoding of alpha was planned for, but not
implemented. So better not dragged this constaint for now
and make the code easier until we revisit that.
Change-Id: Idaba281a6ca819965ca062d1c23329f36d90c7ff
115 lines
4.0 KiB
C
115 lines
4.0 KiB
C
// Copyright 2010 Google Inc. All Rights Reserved.
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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_DSP_YUV_H_
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#define WEBP_DSP_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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extern uint8_t VP8kClip4Bits[YUV_RANGE_MAX - YUV_RANGE_MIN];
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static WEBP_INLINE 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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static WEBP_INLINE void VP8YuvToRgb565(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] & 0xf8) |
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(VP8kClip[y + g_off - YUV_RANGE_MIN] >> 5));
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rgb[1] = (((VP8kClip[y + g_off - YUV_RANGE_MIN] << 3) & 0xe0) |
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(VP8kClip[y + b_off - YUV_RANGE_MIN] >> 3));
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}
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static WEBP_INLINE void VP8YuvToArgbKeepA(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const argb) {
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// Don't update Aplha (argb[0])
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VP8YuvToRgb(y, u, v, argb + 1);
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}
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static WEBP_INLINE void VP8YuvToArgb(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const argb) {
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argb[0] = 0xff;
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VP8YuvToArgbKeepA(y, u, v, argb);
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}
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static WEBP_INLINE void VP8YuvToRgba4444KeepA(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const argb) {
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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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// Don't update Aplha (last 4 bits of argb[1])
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argb[0] = ((VP8kClip4Bits[y + r_off - YUV_RANGE_MIN] << 4) |
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VP8kClip4Bits[y + g_off - YUV_RANGE_MIN]);
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argb[1] = (argb[1] & 0x0f) | (VP8kClip4Bits[y + b_off - YUV_RANGE_MIN] << 4);
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}
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static WEBP_INLINE void VP8YuvToRgba4444(uint8_t y, uint8_t u, uint8_t v,
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uint8_t* const argb) {
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argb[1] = 0x0f;
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VP8YuvToRgba4444KeepA(y, u, v, argb);
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}
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static WEBP_INLINE 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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static WEBP_INLINE void VP8YuvToBgra(uint8_t y, uint8_t u, uint8_t v,
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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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static WEBP_INLINE void VP8YuvToRgba(uint8_t y, uint8_t u, uint8_t v,
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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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static WEBP_INLINE uint32_t VP8Clip4Bits(uint8_t c) {
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const uint32_t v = (c + 8) >> 4;
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return (v > 15) ? 15 : v;
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}
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// Must be called before everything, to initialize the tables.
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void VP8YUVInit(void);
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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_DSP_YUV_H_ */
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