mirror of
https://github.com/opencv/opencv.git
synced 2024-12-27 11:28:14 +08:00
105 lines
4.1 KiB
C
105 lines
4.1 KiB
C
// 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_
|