img_load_resize()

QNX SDP8.0Image Library ReferenceAPIDeveloperProgramming

Decode and resize a frame from a stream

Synopsis:

#include <img/img.h>

int img_load_resize( img_lib_t                    ilib,
                     io_stream_t                 *input,
                     const img_decode_callouts_t *callouts,
                     img_t                       *img );

Arguments:

ilib
A handle for the image library, returned by img_lib_attach().
input
The input stream.
callouts
A pointer to an img_decode_callouts_t structure that provides system callouts for the decoder. If you specify NULL for this value, a set of default callouts is supplied.
img
The address of an img_t structure the function fills in with information about the decoded frame.

If you set the image width and height (img.w and img.h) before calling this function, then the image is sized to fit the specified dimensions rather than clipped, as it is with img_load_file(). The resizing is performed on-the-fly during the decoding, without incurring the memory penalty of loading the entire original image and then subsequently resizing it.

If you specify only one of the dimensions, then the other is calculated based on the aspect ratio of the original image.

Note:
You need to also set the corresponding dimension flag in the img structure. For example, if you specify the width, you need to set the IMG_W bit in flags.

Library:

libimg

Use the -l img option to qcc to link against this library.

Description:

This function decodes a frame from a stream, and optionally resizes it if the image width and height are specified. This function decodes only the first frame encountered.

At least these callouts are supported:

Returns:

IMG_ERR_OK
Success
IMG_ERR_CORRUPT
Invalid data encountered in the file, preventing the decoding from proceeding. Some of the frame may be intact.
IMG_ERR_DLL
An error occurred processing the DLL that handles the file type. Check to make sure that the DLL is not missing or corrupt.
IMG_ERR_FILE
Error accessing path (errno is set).
IMG_ERR_FORMAT
No appropriate codec could be found. The codec you require could be missing or corrupt, or the file could be corrupt.
IMG_ERR_INTR
Decoding was interrupted by application.
IMG_ERR_MEM
Memory-allocation failure.
IMG_ERR_NODATA
No frame data was present. This error is highly unlikely, as files generally contain at least one frame.
IMG_ERR_NOSUPPORT
Output data not supported; the codec and application could not agree on an output format.
IMG_ERR_TRUNC
Premature end of file encountered. Some of the frame may be intact.

Classification:

Image library

Safety:
Signal handlerNo
ThreadNo
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