// Copyright 2022 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. // ----------------------------------------------------------------------------- // // Sharp RGB to YUV conversion. #ifndef WEBP_SHARPYUV_SHARPYUV_H_ #define WEBP_SHARPYUV_SHARPYUV_H_ #ifdef __cplusplus extern "C" { #endif #ifndef SHARPYUV_EXTERN #ifdef WEBP_EXTERN #define SHARPYUV_EXTERN … #else // This explicitly marks library functions and allows for changing the // signature for e.g., Windows DLL builds. #if defined(_WIN32) && defined(WEBP_DLL) #define SHARPYUV_EXTERN … #elif defined(__GNUC__) && __GNUC__ >= 4 #define SHARPYUV_EXTERN … #else #define SHARPYUV_EXTERN … #endif /* defined(_WIN32) && defined(WEBP_DLL) */ #endif /* WEBP_EXTERN */ #endif /* SHARPYUV_EXTERN */ #ifndef SHARPYUV_INLINE #ifdef WEBP_INLINE #define SHARPYUV_INLINE … #else #ifndef _MSC_VER #if defined(__cplusplus) || !defined(__STRICT_ANSI__) || \ (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) #define SHARPYUV_INLINE … #else #define SHARPYUV_INLINE #endif #else #define SHARPYUV_INLINE … #endif /* _MSC_VER */ #endif /* WEBP_INLINE */ #endif /* SHARPYUV_INLINE */ // SharpYUV API version following the convention from semver.org #define SHARPYUV_VERSION_MAJOR … #define SHARPYUV_VERSION_MINOR … #define SHARPYUV_VERSION_PATCH … // Version as a uint32_t. The major number is the high 8 bits. // The minor number is the middle 8 bits. The patch number is the low 16 bits. #define SHARPYUV_MAKE_VERSION(MAJOR, MINOR, PATCH) … #define SHARPYUV_VERSION … // Returns the library's version number, packed in hexadecimal. See // SHARPYUV_VERSION. SHARPYUV_EXTERN int SharpYuvGetVersion(void); // RGB to YUV conversion matrix, in 16 bit fixed point. // y = rgb_to_y[0] * r + rgb_to_y[1] * g + rgb_to_y[2] * b + rgb_to_y[3] // u = rgb_to_u[0] * r + rgb_to_u[1] * g + rgb_to_u[2] * b + rgb_to_u[3] // v = rgb_to_v[0] * r + rgb_to_v[1] * g + rgb_to_v[2] * b + rgb_to_v[3] // Then y, u and v values are divided by 1<<16 and rounded. SharpYuvConversionMatrix; SharpYuvOptions; // Enums for transfer functions, as defined in H.273, // https://www.itu.int/rec/T-REC-H.273-202107-I/en SharpYuvTransferFunctionType; // Converts RGB to YUV420 using a downsampling algorithm that minimizes // artefacts caused by chroma subsampling. // This is slower than standard downsampling (averaging of 4 UV values). // Assumes that the image will be upsampled using a bilinear filter. If nearest // neighbor is used instead, the upsampled image might look worse than with // standard downsampling. // r_ptr, g_ptr, b_ptr: pointers to the source r, g and b channels. Should point // to uint8_t buffers if rgb_bit_depth is 8, or uint16_t buffers otherwise. // rgb_step: distance in bytes between two horizontally adjacent pixels on the // r, g and b channels. If rgb_bit_depth is > 8, it should be a // multiple of 2. // rgb_stride: distance in bytes between two vertically adjacent pixels on the // r, g, and b channels. If rgb_bit_depth is > 8, it should be a // multiple of 2. // rgb_bit_depth: number of bits for each r/g/b value. One of: 8, 10, 12, 16. // Note: 16 bit input is truncated to 14 bits before conversion to yuv. // yuv_bit_depth: number of bits for each y/u/v value. One of: 8, 10, 12. // y_ptr, u_ptr, v_ptr: pointers to the destination y, u and v channels. Should // point to uint8_t buffers if yuv_bit_depth is 8, or uint16_t buffers // otherwise. // y_stride, u_stride, v_stride: distance in bytes between two vertically // adjacent pixels on the y, u and v channels. If yuv_bit_depth > 8, they // should be multiples of 2. // width, height: width and height of the image in pixels // This function calls SharpYuvConvertWithOptions with a default transfer // function of kSharpYuvTransferFunctionSrgb. SHARPYUV_EXTERN int SharpYuvConvert(const void* r_ptr, const void* g_ptr, const void* b_ptr, int rgb_step, int rgb_stride, int rgb_bit_depth, void* y_ptr, int y_stride, void* u_ptr, int u_stride, void* v_ptr, int v_stride, int yuv_bit_depth, int width, int height, const SharpYuvConversionMatrix* yuv_matrix); struct SharpYuvOptions { … }; // Internal, version-checked, entry point SHARPYUV_EXTERN int SharpYuvOptionsInitInternal(const SharpYuvConversionMatrix*, SharpYuvOptions*, int); // Should always be called, to initialize a fresh SharpYuvOptions // structure before modification. SharpYuvOptionsInit() must have succeeded // before using the 'options' object. static SHARPYUV_INLINE int SharpYuvOptionsInit( const SharpYuvConversionMatrix* yuv_matrix, SharpYuvOptions* options) { … } SHARPYUV_EXTERN int SharpYuvConvertWithOptions( const void* r_ptr, const void* g_ptr, const void* b_ptr, int rgb_step, int rgb_stride, int rgb_bit_depth, void* y_ptr, int y_stride, void* u_ptr, int u_stride, void* v_ptr, int v_stride, int yuv_bit_depth, int width, int height, const SharpYuvOptions* options); // TODO(b/194336375): Add YUV444 to YUV420 conversion. Maybe also add 422 // support (it's rarely used in practice, especially for images). #ifdef __cplusplus } // extern "C" #endif #endif // WEBP_SHARPYUV_SHARPYUV_H_
Codebase Browser
godot