| // Copyright 2012 Google Inc. All Rights Reserved. |
| // |
| // Use of this source code is governed by a BSD-style license |
| // that can be found in the COPYING file in the root of the source |
| // tree. An additional intellectual property rights grant can be found |
| // in the file PATENTS. All contributing project authors may |
| // be found in the AUTHORS file in the root of the source tree. |
| // ----------------------------------------------------------------------------- |
| // |
| // Image transforms and color space conversion methods for lossless decoder. |
| // |
| // Authors: Vikas Arora (vikaas.arora@gmail.com) |
| // Jyrki Alakuijala (jyrki@google.com) |
| |
| #ifndef WEBP_DSP_LOSSLESS_H_ |
| #define WEBP_DSP_LOSSLESS_H_ |
| |
| #include "../webp/types.h" |
| #include "../webp/decode.h" |
| |
| #if defined(__cplusplus) || defined(c_plusplus) |
| extern "C" { |
| #endif |
| |
| //------------------------------------------------------------------------------ |
| // Image transforms. |
| |
| struct VP8LTransform; // Defined in dec/vp8li.h. |
| |
| // Performs inverse transform of data given transform information, start and end |
| // rows. Transform will be applied to rows [row_start, row_end[. |
| // The *in and *out pointers refer to source and destination data respectively |
| // corresponding to the intermediate row (row_start). |
| void VP8LInverseTransform(const struct VP8LTransform* const transform, |
| int row_start, int row_end, |
| const uint32_t* const in, uint32_t* const out); |
| |
| // Similar to the static method ColorIndexInverseTransform() that is part of |
| // lossless.c, but used only for alpha decoding. It takes uint8_t (rather than |
| // uint32_t) arguments for 'src' and 'dst'. |
| void VP8LColorIndexInverseTransformAlpha( |
| const struct VP8LTransform* const transform, int y_start, int y_end, |
| const uint8_t* src, uint8_t* dst); |
| |
| // Subtracts green from blue and red channels. |
| void VP8LSubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixs); |
| |
| void VP8LResidualImage(int width, int height, int bits, |
| uint32_t* const argb, uint32_t* const argb_scratch, |
| uint32_t* const image); |
| |
| void VP8LColorSpaceTransform(int width, int height, int bits, int step, |
| uint32_t* const argb, uint32_t* image); |
| |
| //------------------------------------------------------------------------------ |
| // Color space conversion. |
| |
| // Converts from BGRA to other color spaces. |
| void VP8LConvertFromBGRA(const uint32_t* const in_data, int num_pixels, |
| WEBP_CSP_MODE out_colorspace, uint8_t* const rgba); |
| |
| //------------------------------------------------------------------------------ |
| // Misc methods. |
| |
| // Computes sampled size of 'size' when sampling using 'sampling bits'. |
| static WEBP_INLINE uint32_t VP8LSubSampleSize(uint32_t size, |
| uint32_t sampling_bits) { |
| return (size + (1 << sampling_bits) - 1) >> sampling_bits; |
| } |
| |
| // Faster logarithm for integers. Small values use a look-up table. |
| #define LOG_LOOKUP_IDX_MAX 256 |
| extern const float kLog2Table[LOG_LOOKUP_IDX_MAX]; |
| extern const float kSLog2Table[LOG_LOOKUP_IDX_MAX]; |
| extern float VP8LFastLog2Slow(int v); |
| extern float VP8LFastSLog2Slow(int v); |
| static WEBP_INLINE float VP8LFastLog2(int v) { |
| return (v < LOG_LOOKUP_IDX_MAX) ? kLog2Table[v] : VP8LFastLog2Slow(v); |
| } |
| // Fast calculation of v * log2(v) for integer input. |
| static WEBP_INLINE float VP8LFastSLog2(int v) { |
| return (v < LOG_LOOKUP_IDX_MAX) ? kSLog2Table[v] : VP8LFastSLog2Slow(v); |
| } |
| |
| |
| // In-place difference of each component with mod 256. |
| static WEBP_INLINE uint32_t VP8LSubPixels(uint32_t a, uint32_t b) { |
| const uint32_t alpha_and_green = |
| 0x00ff00ffu + (a & 0xff00ff00u) - (b & 0xff00ff00u); |
| const uint32_t red_and_blue = |
| 0xff00ff00u + (a & 0x00ff00ffu) - (b & 0x00ff00ffu); |
| return (alpha_and_green & 0xff00ff00u) | (red_and_blue & 0x00ff00ffu); |
| } |
| |
| void VP8LBundleColorMap(const uint8_t* const row, int width, |
| int xbits, uint32_t* const dst); |
| |
| //------------------------------------------------------------------------------ |
| |
| #if defined(__cplusplus) || defined(c_plusplus) |
| } // extern "C" |
| #endif |
| |
| #endif // WEBP_DSP_LOSSLESS_H_ |