486 lines
23 KiB
C
486 lines
23 KiB
C
// Copyright 2011 Google Inc. All Rights Reserved.
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//
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// Use of this source code is governed by a BSD-style license
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// that can be found in the COPYING file in the root of the source
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// tree. An additional intellectual property rights grant can be found
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// in the file PATENTS. All contributing project authors may
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// be found in the AUTHORS file in the root of the source tree.
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// -----------------------------------------------------------------------------
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//
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// WebP encoder: main interface
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//
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// Author: Skal (pascal.massimino@gmail.com)
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#ifndef WEBP_WEBP_ENCODE_H_
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#define WEBP_WEBP_ENCODE_H_
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#include "./types.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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#define WEBP_ENCODER_ABI_VERSION 0x0201 // MAJOR(8b) + MINOR(8b)
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// Note: forward declaring enumerations is not allowed in (strict) C and C++,
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// the types are left here for reference.
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// typedef enum WebPImageHint WebPImageHint;
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// typedef enum WebPEncCSP WebPEncCSP;
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// typedef enum WebPPreset WebPPreset;
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// typedef enum WebPEncodingError WebPEncodingError;
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typedef struct WebPConfig WebPConfig;
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typedef struct WebPPicture WebPPicture; // main structure for I/O
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typedef struct WebPAuxStats WebPAuxStats;
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typedef struct WebPMemoryWriter WebPMemoryWriter;
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// Return the encoder's version number, packed in hexadecimal using 8bits for
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// each of major/minor/revision. E.g: v2.5.7 is 0x020507.
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WEBP_EXTERN(int) WebPGetEncoderVersion(void);
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//------------------------------------------------------------------------------
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// One-stop-shop call! No questions asked:
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// Returns the size of the compressed data (pointed to by *output), or 0 if
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// an error occurred. The compressed data must be released by the caller
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// using the call 'free(*output)'.
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// These functions compress using the lossy format, and the quality_factor
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// can go from 0 (smaller output, lower quality) to 100 (best quality,
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// larger output).
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WEBP_EXTERN(size_t) WebPEncodeRGB(const uint8_t* rgb,
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int width, int height, int stride,
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float quality_factor, uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeBGR(const uint8_t* bgr,
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int width, int height, int stride,
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float quality_factor, uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeRGBA(const uint8_t* rgba,
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int width, int height, int stride,
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float quality_factor, uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeBGRA(const uint8_t* bgra,
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int width, int height, int stride,
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float quality_factor, uint8_t** output);
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// These functions are the equivalent of the above, but compressing in a
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// lossless manner. Files are usually larger than lossy format, but will
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// not suffer any compression loss.
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WEBP_EXTERN(size_t) WebPEncodeLosslessRGB(const uint8_t* rgb,
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int width, int height, int stride,
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uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeLosslessBGR(const uint8_t* bgr,
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int width, int height, int stride,
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uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeLosslessRGBA(const uint8_t* rgba,
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int width, int height, int stride,
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uint8_t** output);
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WEBP_EXTERN(size_t) WebPEncodeLosslessBGRA(const uint8_t* bgra,
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int width, int height, int stride,
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uint8_t** output);
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//------------------------------------------------------------------------------
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// Coding parameters
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// Image characteristics hint for the underlying encoder.
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typedef enum WebPImageHint {
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WEBP_HINT_DEFAULT = 0, // default preset.
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WEBP_HINT_PICTURE, // digital picture, like portrait, inner shot
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WEBP_HINT_PHOTO, // outdoor photograph, with natural lighting
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WEBP_HINT_GRAPH, // Discrete tone image (graph, map-tile etc).
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WEBP_HINT_LAST
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} WebPImageHint;
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// Compression parameters.
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struct WebPConfig {
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int lossless; // Lossless encoding (0=lossy(default), 1=lossless).
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float quality; // between 0 (smallest file) and 100 (biggest)
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int method; // quality/speed trade-off (0=fast, 6=slower-better)
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WebPImageHint image_hint; // Hint for image type (lossless only for now).
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// Parameters related to lossy compression only:
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int target_size; // if non-zero, set the desired target size in bytes.
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// Takes precedence over the 'compression' parameter.
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float target_PSNR; // if non-zero, specifies the minimal distortion to
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// try to achieve. Takes precedence over target_size.
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int segments; // maximum number of segments to use, in [1..4]
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int sns_strength; // Spatial Noise Shaping. 0=off, 100=maximum.
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int filter_strength; // range: [0 = off .. 100 = strongest]
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int filter_sharpness; // range: [0 = off .. 7 = least sharp]
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int filter_type; // filtering type: 0 = simple, 1 = strong (only used
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// if filter_strength > 0 or autofilter > 0)
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int autofilter; // Auto adjust filter's strength [0 = off, 1 = on]
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int alpha_compression; // Algorithm for encoding the alpha plane (0 = none,
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// 1 = compressed with WebP lossless). Default is 1.
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int alpha_filtering; // Predictive filtering method for alpha plane.
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// 0: none, 1: fast, 2: best. Default if 1.
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int alpha_quality; // Between 0 (smallest size) and 100 (lossless).
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// Default is 100.
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int pass; // number of entropy-analysis passes (in [1..10]).
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int show_compressed; // if true, export the compressed picture back.
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// In-loop filtering is not applied.
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int preprocessing; // preprocessing filter (0=none, 1=segment-smooth)
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int partitions; // log2(number of token partitions) in [0..3]. Default
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// is set to 0 for easier progressive decoding.
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int partition_limit; // quality degradation allowed to fit the 512k limit
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// on prediction modes coding (0: no degradation,
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// 100: maximum possible degradation).
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int emulate_jpeg_size; // If true, compression parameters will be remapped
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// to better match the expected output size from
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// JPEG compression. Generally, the output size will
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// be similar but the degradation will be lower.
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int thread_level; // If non-zero, try and use multi-threaded encoding.
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int low_memory; // If set, reduce memory usage (but increase CPU use).
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uint32_t pad[5]; // padding for later use
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};
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// Enumerate some predefined settings for WebPConfig, depending on the type
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// of source picture. These presets are used when calling WebPConfigPreset().
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typedef enum WebPPreset {
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WEBP_PRESET_DEFAULT = 0, // default preset.
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WEBP_PRESET_PICTURE, // digital picture, like portrait, inner shot
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WEBP_PRESET_PHOTO, // outdoor photograph, with natural lighting
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WEBP_PRESET_DRAWING, // hand or line drawing, with high-contrast details
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WEBP_PRESET_ICON, // small-sized colorful images
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WEBP_PRESET_TEXT // text-like
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} WebPPreset;
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// Internal, version-checked, entry point
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WEBP_EXTERN(int) WebPConfigInitInternal(WebPConfig*, WebPPreset, float, int);
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// Should always be called, to initialize a fresh WebPConfig structure before
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// modification. Returns false in case of version mismatch. WebPConfigInit()
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// must have succeeded before using the 'config' object.
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// Note that the default values are lossless=0 and quality=75.
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static WEBP_INLINE int WebPConfigInit(WebPConfig* config) {
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return WebPConfigInitInternal(config, WEBP_PRESET_DEFAULT, 75.f,
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WEBP_ENCODER_ABI_VERSION);
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}
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// This function will initialize the configuration according to a predefined
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// set of parameters (referred to by 'preset') and a given quality factor.
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// This function can be called as a replacement to WebPConfigInit(). Will
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// return false in case of error.
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static WEBP_INLINE int WebPConfigPreset(WebPConfig* config,
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WebPPreset preset, float quality) {
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return WebPConfigInitInternal(config, preset, quality,
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WEBP_ENCODER_ABI_VERSION);
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}
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// Returns true if 'config' is non-NULL and all configuration parameters are
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// within their valid ranges.
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WEBP_EXTERN(int) WebPValidateConfig(const WebPConfig* config);
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//------------------------------------------------------------------------------
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// Input / Output
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// Structure for storing auxiliary statistics (mostly for lossy encoding).
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struct WebPAuxStats {
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int coded_size; // final size
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float PSNR[5]; // peak-signal-to-noise ratio for Y/U/V/All/Alpha
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int block_count[3]; // number of intra4/intra16/skipped macroblocks
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int header_bytes[2]; // approximate number of bytes spent for header
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// and mode-partition #0
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int residual_bytes[3][4]; // approximate number of bytes spent for
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// DC/AC/uv coefficients for each (0..3) segments.
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int segment_size[4]; // number of macroblocks in each segments
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int segment_quant[4]; // quantizer values for each segments
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int segment_level[4]; // filtering strength for each segments [0..63]
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int alpha_data_size; // size of the transparency data
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int layer_data_size; // size of the enhancement layer data
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// lossless encoder statistics
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uint32_t lossless_features; // bit0:predictor bit1:cross-color transform
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// bit2:subtract-green bit3:color indexing
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int histogram_bits; // number of precision bits of histogram
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int transform_bits; // precision bits for transform
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int cache_bits; // number of bits for color cache lookup
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int palette_size; // number of color in palette, if used
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int lossless_size; // final lossless size
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uint32_t pad[4]; // padding for later use
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};
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// Signature for output function. Should return true if writing was successful.
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// data/data_size is the segment of data to write, and 'picture' is for
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// reference (and so one can make use of picture->custom_ptr).
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typedef int (*WebPWriterFunction)(const uint8_t* data, size_t data_size,
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const WebPPicture* picture);
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// WebPMemoryWrite: a special WebPWriterFunction that writes to memory using
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// the following WebPMemoryWriter object (to be set as a custom_ptr).
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struct WebPMemoryWriter {
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uint8_t* mem; // final buffer (of size 'max_size', larger than 'size').
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size_t size; // final size
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size_t max_size; // total capacity
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uint32_t pad[1]; // padding for later use
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};
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// The following must be called first before any use.
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WEBP_EXTERN(void) WebPMemoryWriterInit(WebPMemoryWriter* writer);
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// The custom writer to be used with WebPMemoryWriter as custom_ptr. Upon
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// completion, writer.mem and writer.size will hold the coded data.
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// writer.mem must be freed using the call 'free(writer.mem)'.
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WEBP_EXTERN(int) WebPMemoryWrite(const uint8_t* data, size_t data_size,
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const WebPPicture* picture);
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// Progress hook, called from time to time to report progress. It can return
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// false to request an abort of the encoding process, or true otherwise if
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// everything is OK.
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typedef int (*WebPProgressHook)(int percent, const WebPPicture* picture);
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// Color spaces.
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typedef enum WebPEncCSP {
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// chroma sampling
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WEBP_YUV420 = 0, // 4:2:0
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WEBP_YUV422 = 1, // 4:2:2
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WEBP_YUV444 = 2, // 4:4:4
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WEBP_YUV400 = 3, // grayscale
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WEBP_CSP_UV_MASK = 3, // bit-mask to get the UV sampling factors
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// alpha channel variants
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WEBP_YUV420A = 4,
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WEBP_YUV422A = 5,
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WEBP_YUV444A = 6,
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WEBP_YUV400A = 7, // grayscale + alpha
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WEBP_CSP_ALPHA_BIT = 4 // bit that is set if alpha is present
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} WebPEncCSP;
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// Encoding error conditions.
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typedef enum WebPEncodingError {
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VP8_ENC_OK = 0,
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VP8_ENC_ERROR_OUT_OF_MEMORY, // memory error allocating objects
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VP8_ENC_ERROR_BITSTREAM_OUT_OF_MEMORY, // memory error while flushing bits
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VP8_ENC_ERROR_NULL_PARAMETER, // a pointer parameter is NULL
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VP8_ENC_ERROR_INVALID_CONFIGURATION, // configuration is invalid
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VP8_ENC_ERROR_BAD_DIMENSION, // picture has invalid width/height
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VP8_ENC_ERROR_PARTITION0_OVERFLOW, // partition is bigger than 512k
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VP8_ENC_ERROR_PARTITION_OVERFLOW, // partition is bigger than 16M
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VP8_ENC_ERROR_BAD_WRITE, // error while flushing bytes
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VP8_ENC_ERROR_FILE_TOO_BIG, // file is bigger than 4G
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VP8_ENC_ERROR_USER_ABORT, // abort request by user
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VP8_ENC_ERROR_LAST // list terminator. always last.
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} WebPEncodingError;
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// maximum width/height allowed (inclusive), in pixels
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#define WEBP_MAX_DIMENSION 16383
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// Main exchange structure (input samples, output bytes, statistics)
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struct WebPPicture {
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// INPUT
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//////////////
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// Main flag for encoder selecting between ARGB or YUV input.
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// It is recommended to use ARGB input (*argb, argb_stride) for lossless
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// compression, and YUV input (*y, *u, *v, etc.) for lossy compression
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// since these are the respective native colorspace for these formats.
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int use_argb;
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// YUV input (mostly used for input to lossy compression)
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WebPEncCSP colorspace; // colorspace: should be YUV420 for now (=Y'CbCr).
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int width, height; // dimensions (less or equal to WEBP_MAX_DIMENSION)
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uint8_t *y, *u, *v; // pointers to luma/chroma planes.
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int y_stride, uv_stride; // luma/chroma strides.
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uint8_t* a; // pointer to the alpha plane
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int a_stride; // stride of the alpha plane
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uint32_t pad1[2]; // padding for later use
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// ARGB input (mostly used for input to lossless compression)
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uint32_t* argb; // Pointer to argb (32 bit) plane.
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int argb_stride; // This is stride in pixels units, not bytes.
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uint32_t pad2[3]; // padding for later use
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// OUTPUT
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///////////////
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// Byte-emission hook, to store compressed bytes as they are ready.
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WebPWriterFunction writer; // can be NULL
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void* custom_ptr; // can be used by the writer.
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// map for extra information (only for lossy compression mode)
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int extra_info_type; // 1: intra type, 2: segment, 3: quant
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// 4: intra-16 prediction mode,
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// 5: chroma prediction mode,
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// 6: bit cost, 7: distortion
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uint8_t* extra_info; // if not NULL, points to an array of size
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// ((width + 15) / 16) * ((height + 15) / 16) that
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// will be filled with a macroblock map, depending
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// on extra_info_type.
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// STATS AND REPORTS
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///////////////////////////
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// Pointer to side statistics (updated only if not NULL)
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WebPAuxStats* stats;
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// Error code for the latest error encountered during encoding
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WebPEncodingError error_code;
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// If not NULL, report progress during encoding.
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WebPProgressHook progress_hook;
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void* user_data; // this field is free to be set to any value and
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// used during callbacks (like progress-report e.g.).
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uint32_t pad3[3]; // padding for later use
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// Unused for now: original samples (for non-YUV420 modes)
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uint8_t *u0, *v0;
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int uv0_stride;
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uint32_t pad4[7]; // padding for later use
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// PRIVATE FIELDS
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////////////////////
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void* memory_; // row chunk of memory for yuva planes
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void* memory_argb_; // and for argb too.
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void* pad5[2]; // padding for later use
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};
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// Internal, version-checked, entry point
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WEBP_EXTERN(int) WebPPictureInitInternal(WebPPicture*, int);
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// Should always be called, to initialize the structure. Returns false in case
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// of version mismatch. WebPPictureInit() must have succeeded before using the
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// 'picture' object.
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// Note that, by default, use_argb is false and colorspace is WEBP_YUV420.
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static WEBP_INLINE int WebPPictureInit(WebPPicture* picture) {
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return WebPPictureInitInternal(picture, WEBP_ENCODER_ABI_VERSION);
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}
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//------------------------------------------------------------------------------
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// WebPPicture utils
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// Convenience allocation / deallocation based on picture->width/height:
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// Allocate y/u/v buffers as per colorspace/width/height specification.
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// Note! This function will free the previous buffer if needed.
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// Returns false in case of memory error.
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WEBP_EXTERN(int) WebPPictureAlloc(WebPPicture* picture);
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// Release the memory allocated by WebPPictureAlloc() or WebPPictureImport*().
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// Note that this function does _not_ free the memory used by the 'picture'
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// object itself.
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// Besides memory (which is reclaimed) all other fields of 'picture' are
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// preserved.
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WEBP_EXTERN(void) WebPPictureFree(WebPPicture* picture);
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// Copy the pixels of *src into *dst, using WebPPictureAlloc. Upon return, *dst
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// will fully own the copied pixels (this is not a view). The 'dst' picture need
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// not be initialized as its content is overwritten.
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// Returns false in case of memory allocation error.
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WEBP_EXTERN(int) WebPPictureCopy(const WebPPicture* src, WebPPicture* dst);
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// Compute PSNR, SSIM or LSIM distortion metric between two pictures.
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// Result is in dB, stores in result[] in the Y/U/V/Alpha/All order.
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// Returns false in case of error (src and ref don't have same dimension, ...)
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// Warning: this function is rather CPU-intensive.
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WEBP_EXTERN(int) WebPPictureDistortion(
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const WebPPicture* src, const WebPPicture* ref,
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int metric_type, // 0 = PSNR, 1 = SSIM, 2 = LSIM
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float result[5]);
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// self-crops a picture to the rectangle defined by top/left/width/height.
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// Returns false in case of memory allocation error, or if the rectangle is
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// outside of the source picture.
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// The rectangle for the view is defined by the top-left corner pixel
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// coordinates (left, top) as well as its width and height. This rectangle
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// must be fully be comprised inside the 'src' source picture. If the source
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// picture uses the YUV420 colorspace, the top and left coordinates will be
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// snapped to even values.
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WEBP_EXTERN(int) WebPPictureCrop(WebPPicture* picture,
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int left, int top, int width, int height);
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// Extracts a view from 'src' picture into 'dst'. The rectangle for the view
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// is defined by the top-left corner pixel coordinates (left, top) as well
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// as its width and height. This rectangle must be fully be comprised inside
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// the 'src' source picture. If the source picture uses the YUV420 colorspace,
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// the top and left coordinates will be snapped to even values.
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// Picture 'src' must out-live 'dst' picture. Self-extraction of view is allowed
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// ('src' equal to 'dst') as a mean of fast-cropping (but note that doing so,
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// the original dimension will be lost). Picture 'dst' need not be initialized
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// with WebPPictureInit() if it is different from 'src', since its content will
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// be overwritten.
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// Returns false in case of memory allocation error or invalid parameters.
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WEBP_EXTERN(int) WebPPictureView(const WebPPicture* src,
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int left, int top, int width, int height,
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WebPPicture* dst);
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// Returns true if the 'picture' is actually a view and therefore does
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// not own the memory for pixels.
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WEBP_EXTERN(int) WebPPictureIsView(const WebPPicture* picture);
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// Rescale a picture to new dimension width x height.
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// Now gamma correction is applied.
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// Returns false in case of error (invalid parameter or insufficient memory).
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WEBP_EXTERN(int) WebPPictureRescale(WebPPicture* pic, int width, int height);
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// Colorspace conversion function to import RGB samples.
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// Previous buffer will be free'd, if any.
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// *rgb buffer should have a size of at least height * rgb_stride.
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// Returns false in case of memory error.
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WEBP_EXTERN(int) WebPPictureImportRGB(
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WebPPicture* picture, const uint8_t* rgb, int rgb_stride);
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// Same, but for RGBA buffer.
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WEBP_EXTERN(int) WebPPictureImportRGBA(
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WebPPicture* picture, const uint8_t* rgba, int rgba_stride);
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// Same, but for RGBA buffer. Imports the RGB direct from the 32-bit format
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// input buffer ignoring the alpha channel. Avoids needing to copy the data
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// to a temporary 24-bit RGB buffer to import the RGB only.
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WEBP_EXTERN(int) WebPPictureImportRGBX(
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WebPPicture* picture, const uint8_t* rgbx, int rgbx_stride);
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// Variants of the above, but taking BGR(A|X) input.
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WEBP_EXTERN(int) WebPPictureImportBGR(
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WebPPicture* picture, const uint8_t* bgr, int bgr_stride);
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WEBP_EXTERN(int) WebPPictureImportBGRA(
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WebPPicture* picture, const uint8_t* bgra, int bgra_stride);
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WEBP_EXTERN(int) WebPPictureImportBGRX(
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WebPPicture* picture, const uint8_t* bgrx, int bgrx_stride);
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// Converts picture->argb data to the YUVA format specified by 'colorspace'.
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// Upon return, picture->use_argb is set to false. The presence of real
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// non-opaque transparent values is detected, and 'colorspace' will be
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// adjusted accordingly. Note that this method is lossy.
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// Returns false in case of error.
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WEBP_EXTERN(int) WebPPictureARGBToYUVA(WebPPicture* picture,
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WebPEncCSP colorspace);
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// Converts picture->yuv to picture->argb and sets picture->use_argb to true.
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// The input format must be YUV_420 or YUV_420A.
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// Note that the use of this method is discouraged if one has access to the
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// raw ARGB samples, since using YUV420 is comparatively lossy. Also, the
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// conversion from YUV420 to ARGB incurs a small loss too.
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// Returns false in case of error.
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WEBP_EXTERN(int) WebPPictureYUVAToARGB(WebPPicture* picture);
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|
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// Helper function: given a width x height plane of YUV(A) samples
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// (with stride 'stride'), clean-up the YUV samples under fully transparent
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// area, to help compressibility (no guarantee, though).
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WEBP_EXTERN(void) WebPCleanupTransparentArea(WebPPicture* picture);
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|
|
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// Scan the picture 'picture' for the presence of non fully opaque alpha values.
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// Returns true in such case. Otherwise returns false (indicating that the
|
|
// alpha plane can be ignored altogether e.g.).
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WEBP_EXTERN(int) WebPPictureHasTransparency(const WebPPicture* picture);
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|
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//------------------------------------------------------------------------------
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// Main call
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|
|
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// Main encoding call, after config and picture have been initialized.
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// 'picture' must be less than 16384x16384 in dimension (cf WEBP_MAX_DIMENSION),
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// and the 'config' object must be a valid one.
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// Returns false in case of error, true otherwise.
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// In case of error, picture->error_code is updated accordingly.
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// 'picture' can hold the source samples in both YUV(A) or ARGB input, depending
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|
// on the value of 'picture->use_argb'. It is highly recommended to use
|
|
// the former for lossy encoding, and the latter for lossless encoding
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|
// (when config.lossless is true). Automatic conversion from one format to
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|
// another is provided but they both incur some loss.
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|
WEBP_EXTERN(int) WebPEncode(const WebPConfig* config, WebPPicture* picture);
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|
|
|
//------------------------------------------------------------------------------
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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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|
|
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#endif /* WEBP_WEBP_ENCODE_H_ */
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