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- // Copyright 2010 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.
- // -----------------------------------------------------------------------------
- //
- // Main decoding functions for WebP images.
- //
- // Author: Skal (pascal.massimino@gmail.com)
- #ifndef WEBP_WEBP_DECODE_H_
- #define WEBP_WEBP_DECODE_H_
- #include "./types.h"
- #ifdef __cplusplus
- 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 and return 0 in
- // case of formatting error.
- // 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().
- // Returns NULL in case of error.
- 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
- WEBP_EXTERN(uint8_t*) WebPDecodeYUV(const uint8_t* data, size_t data_size,
- 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);
- WEBP_EXTERN(uint8_t*) WebPDecodeARGBInto(
- const uint8_t* data, size_t data_size,
- uint8_t* output_buffer, size_t output_buffer_size, int output_stride);
- WEBP_EXTERN(uint8_t*) WebPDecodeBGRAInto(
- 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.
- };
- struct WebPYUVABuffer { // view as YUVA
- 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
- struct WebPDecBuffer {
- WEBP_CSP_MODE colorspace; // Colorspace.
- int width, height; // Dimensions.
- int is_external_memory; // If true, 'internal_memory' pointer is not used.
- union {
- WebPRGBABuffer RGBA;
- WebPYUVABuffer YUVA;
- } u; // Nameless union of buffer parameters.
- uint32_t pad[4]; // padding for later use
- uint8_t* private_memory; // Internally allocated memory (only when
- // is_external_memory is false). Should not be used
- // externally, but accessed via the buffer union.
- };
- // Internal, version-checked, entry point
- WEBP_EXTERN(int) WebPInitDecBufferInternal(WebPDecBuffer*, int);
- // Initialize the structure as empty. Must be called before any other use.
- // Returns false in case of version mismatch
- static WEBP_INLINE int WebPInitDecBuffer(WebPDecBuffer* buffer) {
- 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.
- WEBP_EXTERN(void) WebPFreeDecBuffer(WebPDecBuffer* buffer);
- //------------------------------------------------------------------------------
- // Enumeration of the status codes
- typedef enum VP8StatusCode {
- 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(&buffer);
- // buffer.colorspace = mode;
- // ...
- // WebPIDecoder* idec = WebPINewDecoder(&buffer);
- // while (has_more_data) {
- // // ... (get additional data)
- // status = WebPIAppend(idec, new_data, new_data_size);
- // if (status != VP8_STATUS_SUSPENDED ||
- // break;
- // }
- //
- // // The above call decodes the current available buffer.
- // // Part of the image can now be refreshed by calling to
- // // 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
- // set to 1. 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.
- // Returns NULL if the allocation failed.
- WEBP_EXTERN(WebPIDecoder*) WebPINewDecoder(WebPDecBuffer* output_buffer);
- // This function allocates and initializes an incremental-decoder object, which
- // will output the RGB/A samples specified by 'csp' into a preallocated
- // 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_EXTERN(WebPIDecoder*) WebPINewRGB(
- 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.
- WEBP_EXTERN(WebPIDecoder*) WebPINewYUV(
- 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(
- WebPIDecoder* idec, const uint8_t* data, size_t data_size);
- // 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.
- WEBP_EXTERN(uint8_t*) WebPIDecGetRGB(
- const WebPIDecoder* idec, int* last_y,
- 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(
- const WebPIDecoder* idec, int* left, int* top, int* width, int* height);
- //------------------------------------------------------------------------------
- // 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.no_fancy_upsampling = 1;
- 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(
- const uint8_t*, size_t, WebPBitstreamFeatures*, int);
- // 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.
- static WEBP_INLINE VP8StatusCode WebPGetFeatures(
- const uint8_t* data, size_t data_size,
- WebPBitstreamFeatures* features) {
- return WebPGetFeaturesInternal(data, data_size, features,
- WEBP_DECODER_ABI_VERSION);
- }
- // Decoding options
- struct WebPDecoderOptions {
- 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.
- struct WebPDecoderConfig {
- WebPBitstreamFeatures input; // Immutable bitstream features (optional)
- WebPDecBuffer output; // Output buffer (can point to external mem)
- WebPDecoderOptions options; // Decoding options
- };
- // Internal, version-checked, entry point
- WEBP_EXTERN(int) WebPInitDecoderConfigInternal(WebPDecoderConfig*, int);
- // 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.
- static WEBP_INLINE int WebPInitDecoderConfig(WebPDecoderConfig* config) {
- 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.
- // 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).
- 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).
- WEBP_EXTERN(VP8StatusCode) WebPDecode(const uint8_t* data, size_t data_size,
- WebPDecoderConfig* config);
- #ifdef __cplusplus
- } // extern "C"
- #endif
- #endif /* WEBP_WEBP_DECODE_H_ */
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