Macro to check ABI compatibility (same major revision number)
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.
Same as WebPDecodeRGBA, but returning A, R, G, B, A, R, G, B… ordered data.
Same as WebPDecodeRGB, but returning B, G, R, B, G, R… ordered data.
Same as WebPDecodeRGBA, but returning B, G, R, A, B, G, R, A… ordered data.
Same as WebPDecodeRGBA, but returning R, G, B, R, G, B… ordered data.
If the bitstream contains transparency, it is ignored.
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.
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’.
‘width’ and ‘height’ may be NULL, the other pointers must not be.
Returns NULL in case of error.
() Also named Y’CbCr. See: https://en.wikipedia.org/wiki/YCbCr
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).
Releases memory returned by the WebPDecode*() functions (from decode.h).
Free any memory associated with the buffer. Must always be called last.
Note: doesn’t free the ‘buffer’ structure itself.
Return the decoder’s version number, packed in hexadecimal using 8bits for
each of major/minor/revision. E.g: v2.5.7 is 0x020507.
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.
Note: The following chunk sequences (before the raw VP8/VP8L data) are
considered valid by this function:
RIFF + VP8(L)
RIFF + VP8X + (optional chunks) + VP8(L)
ALPH + VP8 <– Not a valid WebP format: only allowed for internal purpose.
VP8(L) <– Not a valid WebP format: only allowed for internal purpose.
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.
Note: The following chunk sequences (before the raw VP8/VP8L data) are
considered valid by this function:
RIFF + VP8(L)
RIFF + VP8X + (optional chunks) + VP8(L)
ALPH + VP8 <– Not a valid WebP format: only allowed for internal purpose.
VP8(L) <– Not a valid WebP format: only allowed for internal purpose.
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.
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. The values in these pointers are only valid on successful (non-NULL)
return.
Deprecated alpha-less version of WebPIDecGetYUVA(): it will ignore the
alpha information (if present). Kept for backward compatibility.
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.
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).
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.
Deletes the WebPIDecoder object and associated memory. Must always be called
if WebPINewDecoder, WebPINewRGB or WebPINewYUV succeeded.
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.
Returns NULL if the allocation failed.
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.
Deprecated version of the above, without the alpha plane.
Kept for backward compatibility.
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.
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.
Initialize the structure as empty. Must be called before any other use.
Returns false in case of version mismatch
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.
Allocates size bytes of memory. Returns NULL upon error. Memory
must be deallocated by calling WebPFree(). This function is made available
by the core libwebp library.