// 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.

// -----------------------------------------------------------------------------

//

//

// Author: Skal (pascal.massimino@gmail.com)

#ifndef WEBP_WEBP_DECODE_H_

#define WEBP_WEBP_DECODE_H_

#include "./types.h"

extern "C" {

#endif

#define WEBP_DECODER_ABI_VERSION 0x0208 // MAJOR(8b) + MINOR(8b)

// Note: forward declaring enumerations is not allowed in (strict) C and C++,

// the types are left here for reference.

// typedef enum VP8StatusCode VP8StatusCode;

// typedef enum WEBP_CSP_MODE WEBP_CSP_MODE;

typedef struct WebPRGBABuffer WebPRGBABuffer;

typedef struct WebPYUVABuffer WebPYUVABuffer;

typedef struct WebPDecBuffer WebPDecBuffer;

typedef struct WebPIDecoder WebPIDecoder;

typedef struct WebPBitstreamFeatures WebPBitstreamFeatures;

typedef struct WebPDecoderOptions WebPDecoderOptions;

typedef struct WebPDecoderConfig WebPDecoderConfig;

// Return the decoder's version number, packed in hexadecimal using 8bits for

// each of major/minor/revision. E.g: v2.5.7 is 0x020507.

WEBP_EXTERN(int) WebPGetDecoderVersion(void);

// Retrieve basic header information: width, height.

// This function will also validate the header, returning true on success,

// false otherwise. '*width' and '*height' are only valid on successful return.

// Pointers 'width' and 'height' can be passed NULL if deemed irrelevant.

WEBP_EXTERN(int) WebPGetInfo(const uint8_t* data, size_t data_size,

int* width, int* height);

// Decodes WebP images pointed to by 'data' and returns RGBA samples, along

// with the dimensions in *width and *height. The ordering of samples in

// memory is R, G, B, A, R, G, B, A... in scan order (endian-independent).

// The returned pointer should be deleted calling WebPFree().

WEBP_EXTERN(uint8_t*) WebPDecodeRGBA(const uint8_t* data, size_t data_size,

int* width, int* height);

// Same as WebPDecodeRGBA, but returning A, R, G, B, A, R, G, B... ordered data.

WEBP_EXTERN(uint8_t*) WebPDecodeARGB(const uint8_t* data, size_t data_size,

int* width, int* height);

// Same as WebPDecodeRGBA, but returning B, G, R, A, B, G, R, A... ordered data.

WEBP_EXTERN(uint8_t*) WebPDecodeBGRA(const uint8_t* data, size_t data_size,

int* width, int* height);

// Same as WebPDecodeRGBA, but returning R, G, B, R, G, B... ordered data.

// If the bitstream contains transparency, it is ignored.

WEBP_EXTERN(uint8_t*) WebPDecodeRGB(const uint8_t* data, size_t data_size,

int* width, int* height);

// Same as WebPDecodeRGB, but returning B, G, R, B, G, R... ordered data.

WEBP_EXTERN(uint8_t*) WebPDecodeBGR(const uint8_t* data, size_t data_size,

int* width, int* height);

// Decode WebP images pointed to by 'data' to Y'UV format(*). The pointer

// returned is the Y samples buffer. Upon return, *u and *v will point to

// the U and V chroma data. These U and V buffers need NOT be passed to

// WebPFree(), unlike the returned Y luma one. The dimension of the U and V

// planes are both (*width + 1) / 2 and (*height + 1)/ 2.

// Upon return, the Y buffer has a stride returned as '*stride', while U and V

// have a common stride returned as '*uv_stride'.

// Return NULL in case of error.

// (*) Also named Y'CbCr. See: http://en.wikipedia.org/wiki/YCbCr

int* width, int* height,

uint8_t** u, uint8_t** v,

int* stride, int* uv_stride);

// Releases memory returned by the WebPDecode*() functions above.

WEBP_EXTERN(void) WebPFree(void* ptr);

// These five functions are variants of the above ones, that decode the image

// directly into a pre-allocated buffer 'output_buffer'. The maximum storage

// available in this buffer is indicated by 'output_buffer_size'. If this

// storage is not sufficient (or an error occurred), NULL is returned.

// Otherwise, output_buffer is returned, for convenience.

// The parameter 'output_stride' specifies the distance (in bytes)

// between scanlines. Hence, output_buffer_size is expected to be at least

// output_stride x picture-height.

WEBP_EXTERN(uint8_t*) WebPDecodeRGBAInto(

const uint8_t* data, size_t data_size,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

const uint8_t* data, size_t data_size,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

const uint8_t* data, size_t data_size,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

// RGB and BGR variants. Here too the transparency information, if present,

// will be dropped and ignored.

WEBP_EXTERN(uint8_t*) WebPDecodeRGBInto(

const uint8_t* data, size_t data_size,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

WEBP_EXTERN(uint8_t*) WebPDecodeBGRInto(

const uint8_t* data, size_t data_size,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

// WebPDecodeYUVInto() is a variant of WebPDecodeYUV() that operates directly

// into pre-allocated luma/chroma plane buffers. This function requires the

// strides to be passed: one for the luma plane and one for each of the

// chroma ones. The size of each plane buffer is passed as 'luma_size',

// 'u_size' and 'v_size' respectively.

// Pointer to the luma plane ('*luma') is returned or NULL if an error occurred

// during decoding (or because some buffers were found to be too small).

WEBP_EXTERN(uint8_t*) WebPDecodeYUVInto(

const uint8_t* data, size_t data_size,

uint8_t* luma, size_t luma_size, int luma_stride,

uint8_t* u, size_t u_size, int u_stride,

uint8_t* v, size_t v_size, int v_stride);

//------------------------------------------------------------------------------

// Output colorspaces and buffer

// Colorspaces

// Note: the naming describes the byte-ordering of packed samples in memory.

// For instance, MODE_BGRA relates to samples ordered as B,G,R,A,B,G,R,A,...

// Non-capital names (e.g.:MODE_Argb) relates to pre-multiplied RGB channels.

// RGBA-4444 and RGB-565 colorspaces are represented by following byte-order:

// RGBA-4444: [r3 r2 r1 r0 g3 g2 g1 g0], [b3 b2 b1 b0 a3 a2 a1 a0], ...

// RGB-565: [r4 r3 r2 r1 r0 g5 g4 g3], [g2 g1 g0 b4 b3 b2 b1 b0], ...

// In the case WEBP_SWAP_16BITS_CSP is defined, the bytes are swapped for

// these two modes:

// RGBA-4444: [b3 b2 b1 b0 a3 a2 a1 a0], [r3 r2 r1 r0 g3 g2 g1 g0], ...

// RGB-565: [g2 g1 g0 b4 b3 b2 b1 b0], [r4 r3 r2 r1 r0 g5 g4 g3], ...

typedef enum WEBP_CSP_MODE {

MODE_RGB = 0, MODE_RGBA = 1,

MODE_BGR = 2, MODE_BGRA = 3,

MODE_ARGB = 4, MODE_RGBA_4444 = 5,

MODE_RGB_565 = 6,

// RGB-premultiplied transparent modes (alpha value is preserved)

MODE_rgbA = 7,

MODE_bgrA = 8,

MODE_Argb = 9,

MODE_rgbA_4444 = 10,

// YUV modes must come after RGB ones.

MODE_YUV = 11, MODE_YUVA = 12, // yuv 4:2:0

MODE_LAST = 13

} WEBP_CSP_MODE;

// Some useful macros:

static WEBP_INLINE int WebPIsPremultipliedMode(WEBP_CSP_MODE mode) {

return (mode == MODE_rgbA || mode == MODE_bgrA || mode == MODE_Argb ||

mode == MODE_rgbA_4444);

}

static WEBP_INLINE int WebPIsAlphaMode(WEBP_CSP_MODE mode) {

return (mode == MODE_RGBA || mode == MODE_BGRA || mode == MODE_ARGB ||

mode == MODE_RGBA_4444 || mode == MODE_YUVA ||

WebPIsPremultipliedMode(mode));

}

static WEBP_INLINE int WebPIsRGBMode(WEBP_CSP_MODE mode) {

return (mode < MODE_YUV);

}

//------------------------------------------------------------------------------

// WebPDecBuffer: Generic structure for describing the output sample buffer.

struct WebPRGBABuffer { // view as RGBA

uint8_t* rgba; // pointer to RGBA samples

int stride; // stride in bytes from one scanline to the next.

size_t size; // total size of the *rgba buffer.

};

uint8_t* y, *u, *v, *a; // pointer to luma, chroma U/V, alpha samples

int y_stride; // luma stride

int u_stride, v_stride; // chroma strides

int a_stride; // alpha stride

size_t y_size; // luma plane size

size_t u_size, v_size; // chroma planes size

size_t a_size; // alpha-plane size

};

// Output buffer

WEBP_CSP_MODE colorspace; // Colorspace.

int width, height; // Dimensions.

int is_external_memory; // If non-zero, 'internal_memory' pointer is not

// used. If value is '2' or more, the external

// memory is considered 'slow' and multiple

// read/write will be avoided.

union {

WebPRGBABuffer RGBA;

WebPYUVABuffer YUVA;

} u; // Nameless union of buffer parameters.

uint32_t pad[4]; // padding for later use

// Internal, version-checked, entry point

// Initialize the structure as empty. Must be called before any other use.

// Returns false in case of version mismatch

return WebPInitDecBufferInternal(buffer, WEBP_DECODER_ABI_VERSION);

}

// Free any memory associated with the buffer. Must always be called last.

// Note: doesn't free the 'buffer' structure itself.

//------------------------------------------------------------------------------

// Enumeration of the status codes

VP8_STATUS_OK = 0,

VP8_STATUS_OUT_OF_MEMORY,

VP8_STATUS_INVALID_PARAM,

VP8_STATUS_BITSTREAM_ERROR,

VP8_STATUS_UNSUPPORTED_FEATURE,

VP8_STATUS_SUSPENDED,

VP8_STATUS_USER_ABORT,

VP8_STATUS_NOT_ENOUGH_DATA

} VP8StatusCode;

//------------------------------------------------------------------------------

// Incremental decoding

//

// This API allows streamlined decoding of partial data.

// Picture can be incrementally decoded as data become available thanks to the

// WebPIDecoder object. This object can be left in a SUSPENDED state if the

// picture is only partially decoded, pending additional input.

// Code example:

//

// WebPInitDecBuffer(&output_buffer);

// output_buffer.colorspace = mode;

// ...

// WebPIDecoder* idec = WebPINewDecoder(&output_buffer);

// while (additional_data_is_available) {

// // ... (get additional data in some new_data[] buffer)

// if (status != VP8_STATUS_OK && status != VP8_STATUS_SUSPENDED) {

// break; // an error occurred.

// }

//

// // The above call decodes the current available buffer.

// // Part of the image can now be refreshed by calling

// // WebPIDecGetRGB()/WebPIDecGetYUVA() etc.

// }

// WebPIDelete(idec);

// Creates a new incremental decoder with the supplied buffer parameter.

// This output_buffer can be passed NULL, in which case a default output buffer

// is used (with MODE_RGB). Otherwise, an internal reference to 'output_buffer'

// is kept, which means that the lifespan of 'output_buffer' must be larger than

// that of the returned WebPIDecoder object.

// The supplied 'output_buffer' content MUST NOT be changed between calls to

// WebPIAppend() or WebPIUpdate() unless 'output_buffer.is_external_memory' is

// not set to 0. In such a case, it is allowed to modify the pointers, size and

// stride of output_buffer.u.RGBA or output_buffer.u.YUVA, provided they remain

// within valid bounds.

// All other fields of WebPDecBuffer MUST remain constant between calls.

// This function allocates and initializes an incremental-decoder object, which

// buffer 'output_buffer'. The size of this buffer is at least

// 'output_buffer_size' and the stride (distance in bytes between two scanlines)

// is specified by 'output_stride'.

// Additionally, output_buffer can be passed NULL in which case the output

// buffer will be allocated automatically when the decoding starts. The

// colorspace 'csp' is taken into account for allocating this buffer. All other

// parameters are ignored.

// Returns NULL if the allocation failed, or if some parameters are invalid.

WEBP_CSP_MODE csp,

uint8_t* output_buffer, size_t output_buffer_size, int output_stride);

// This function allocates and initializes an incremental-decoder object, which

// will output the raw luma/chroma samples into a preallocated planes if

// supplied. The luma plane is specified by its pointer 'luma', its size

// 'luma_size' and its stride 'luma_stride'. Similarly, the chroma-u plane

// is specified by the 'u', 'u_size' and 'u_stride' parameters, and the chroma-v

// plane by 'v' and 'v_size'. And same for the alpha-plane. The 'a' pointer

// can be pass NULL in case one is not interested in the transparency plane.

// Conversely, 'luma' can be passed NULL if no preallocated planes are supplied.

// In this case, the output buffer will be automatically allocated (using

// MODE_YUVA) when decoding starts. All parameters are then ignored.

// Returns NULL if the allocation failed or if a parameter is invalid.

WEBP_EXTERN(WebPIDecoder*) WebPINewYUVA(

uint8_t* luma, size_t luma_size, int luma_stride,

uint8_t* u, size_t u_size, int u_stride,

uint8_t* v, size_t v_size, int v_stride,

uint8_t* a, size_t a_size, int a_stride);

// Deprecated version of the above, without the alpha plane.

// Kept for backward compatibility.

uint8_t* luma, size_t luma_size, int luma_stride,

uint8_t* u, size_t u_size, int u_stride,

uint8_t* v, size_t v_size, int v_stride);

// Deletes the WebPIDecoder object and associated memory. Must always be called

// if WebPINewDecoder, WebPINewRGB or WebPINewYUV succeeded.

WEBP_EXTERN(void) WebPIDelete(WebPIDecoder* idec);

// Copies and decodes the next available data. Returns VP8_STATUS_OK when

// the image is successfully decoded. Returns VP8_STATUS_SUSPENDED when more

// data is expected. Returns error in other cases.

WEBP_EXTERN(VP8StatusCode) WebPIAppend(

// A variant of the above function to be used when data buffer contains

// partial data from the beginning. In this case data buffer is not copied

// to the internal memory.

// Note that the value of the 'data' pointer can change between calls to

// WebPIUpdate, for instance when the data buffer is resized to fit larger data.

WEBP_EXTERN(VP8StatusCode) WebPIUpdate(

WebPIDecoder* idec, const uint8_t* data, size_t data_size);

// Returns the RGB/A image decoded so far. Returns NULL if output params

// are not initialized yet. The RGB/A output type corresponds to the colorspace

// specified during call to WebPINewDecoder() or WebPINewRGB().

// *last_y is the index of last decoded row in raster scan order. Some pointers

// (*last_y, *width etc.) can be NULL if corresponding information is not

// needed.

int* width, int* height, int* stride);

// Same as above function to get a YUVA image. Returns pointer to the luma

// plane or NULL in case of error. If there is no alpha information

// the alpha pointer '*a' will be returned NULL.

WEBP_EXTERN(uint8_t*) WebPIDecGetYUVA(

const WebPIDecoder* idec, int* last_y,

uint8_t** u, uint8_t** v, uint8_t** a,

int* width, int* height, int* stride, int* uv_stride, int* a_stride);

// Deprecated alpha-less version of WebPIDecGetYUVA(): it will ignore the

// alpha information (if present). Kept for backward compatibility.

static WEBP_INLINE uint8_t* WebPIDecGetYUV(

const WebPIDecoder* idec, int* last_y, uint8_t** u, uint8_t** v,

int* width, int* height, int* stride, int* uv_stride) {

return WebPIDecGetYUVA(idec, last_y, u, v, NULL, width, height,

stride, uv_stride, NULL);

}

// Generic call to retrieve information about the displayable area.

// If non NULL, the left/right/width/height pointers are filled with the visible

// rectangular area so far.

// Returns NULL in case the incremental decoder object is in an invalid state.

// Otherwise returns the pointer to the internal representation. This structure

// is read-only, tied to WebPIDecoder's lifespan and should not be modified.

WEBP_EXTERN(const WebPDecBuffer*) WebPIDecodedArea(

//------------------------------------------------------------------------------

// Advanced decoding parametrization

//

// Code sample for using the advanced decoding API

/*

// A) Init a configuration object

WebPDecoderConfig config;

CHECK(WebPInitDecoderConfig(&config));

// B) optional: retrieve the bitstream's features.

CHECK(WebPGetFeatures(data, data_size, &config.input) == VP8_STATUS_OK);

// C) Adjust 'config', if needed

config.output.colorspace = MODE_BGRA;

// etc.

// Note that you can also make config.output point to an externally

// supplied memory buffer, provided it's big enough to store the decoded

// picture. Otherwise, config.output will just be used to allocate memory

// and store the decoded picture.

// D) Decode!

CHECK(WebPDecode(data, data_size, &config) == VP8_STATUS_OK);

// E) Decoded image is now in config.output (and config.output.u.RGBA)

// F) Reclaim memory allocated in config's object. It's safe to call

// this function even if the memory is external and wasn't allocated

// by WebPDecode().

WebPFreeDecBuffer(&config.output);

*/

// Features gathered from the bitstream

struct WebPBitstreamFeatures {

int width; // Width in pixels, as read from the bitstream.

int height; // Height in pixels, as read from the bitstream.

int has_alpha; // True if the bitstream contains an alpha channel.

int has_animation; // True if the bitstream is an animation.

int format; // 0 = undefined (/mixed), 1 = lossy, 2 = lossless

uint32_t pad[5]; // padding for later use

};

// Internal, version-checked, entry point

WEBP_EXTERN(VP8StatusCode) WebPGetFeaturesInternal(

// Retrieve features from the bitstream. The *features structure is filled

// with information gathered from the bitstream.

// Returns VP8_STATUS_OK when the features are successfully retrieved. Returns

// VP8_STATUS_NOT_ENOUGH_DATA when more data is needed to retrieve the

// features from headers. Returns error in other cases.

const uint8_t* data, size_t data_size,

WebPBitstreamFeatures* features) {

return WebPGetFeaturesInternal(data, data_size, features,

WEBP_DECODER_ABI_VERSION);

}

// Decoding options

int bypass_filtering; // if true, skip the in-loop filtering

int no_fancy_upsampling; // if true, use faster pointwise upsampler

int use_cropping; // if true, cropping is applied _first_

int crop_left, crop_top; // top-left position for cropping.

// Will be snapped to even values.

int crop_width, crop_height; // dimension of the cropping area

int use_scaling; // if true, scaling is applied _afterward_

int scaled_width, scaled_height; // final resolution

int use_threads; // if true, use multi-threaded decoding

int dithering_strength; // dithering strength (0=Off, 100=full)

int flip; // flip output vertically

int alpha_dithering_strength; // alpha dithering strength in [0..100]

uint32_t pad[5]; // padding for later use

};

// Main object storing the configuration for advanced decoding.

WebPBitstreamFeatures input; // Immutable bitstream features (optional)

WebPDecBuffer output; // Output buffer (can point to external mem)

WebPDecoderOptions options; // Decoding options

// Internal, version-checked, entry point

// Initialize the configuration as empty. This function must always be

// called first, unless WebPGetFeatures() is to be called.

// Returns false in case of mismatched version.

return WebPInitDecoderConfigInternal(config, WEBP_DECODER_ABI_VERSION);

}

// Instantiate a new incremental decoder object with the requested

// configuration. The bitstream can be passed using 'data' and 'data_size'

// parameter, in which case the features will be parsed and stored into

// config->input. Otherwise, 'data' can be NULL and no parsing will occur.

// Note that 'config' can be NULL too, in which case a default configuration

// is used. If 'config' is not NULL, it must outlive the WebPIDecoder object

// as some references to its fields will be used. No internal copy of 'config'

// is made.

// The return WebPIDecoder object must always be deleted calling WebPIDelete().

// Returns NULL in case of error (and config->status will then reflect

// the error condition, if available).

WEBP_EXTERN(WebPIDecoder*) WebPIDecode(const uint8_t* data, size_t data_size,

WebPDecoderConfig* config);

// Non-incremental version. This version decodes the full data at once, taking

// 'config' into account. Returns decoding status (which should be VP8_STATUS_OK

// if the decoding was successful). Note that 'config' cannot be NULL.

WEBP_EXTERN(VP8StatusCode) WebPDecode(const uint8_t* data, size_t data_size,

WebPDecoderConfig* config);

} // extern "C"

#endif

#endif /* WEBP_WEBP_DECODE_H_ */