WebP IO

gdImagePtr gdImageCreateFromWebp ( FILE  * inFile )

gdImageCreateFromWebp is called to load truecolor images from WebP format files.  Invoke gdImageCreateFromWebp with an already opened pointer to a file containing the desired image.  gdImageCreateFromWebp returns a gdImagePtr to the new truecolor image, or NULL if unable to load the image (most often because the file is corrupt or does not contain a WebP image).  gdImageCreateFromWebp does not close the file.

You can inspect the sx and sy members of the image to determine its size.  The image must eventually be destroyed using gdImageDestroy.

The returned image is always a truecolor image.

Variants

gdImageCreateFromWebpPtr creates an image from WebP data already in memory.

gdImageCreateFromWebpCtx reads its data via the function pointers in a gdIOCtx structure.

Parameters

Returns

A pointer to the new truecolor image.  This will need to be destroyed with gdImageDestroy once it is no longer needed.

On error, returns NULL.

gdImagePtr gdImageCreateFromWebpPtr ( int  size, void  * data )

See gdImageCreateFromWebp.

Parameters

gdImagePtr gdImageCreateFromWebpCtx ( gdIOCtx  * infile )

See gdImageCreateFromWebp.

void gdImageWebpCtx ( gdImagePtr  im, gdIOCtx  * outfile, int  quality )

Write the image as WebP data via a gdIOCtx.  See gdImageWebpEx for more details.

Parameters

Returns

Nothing.

void gdImageWebpEx ( gdImagePtr  im, FILE  * outFile, int  quality )

gdImageWebpEx outputs the specified image to the specified file in WebP format.  The file must be open for writing.  Under MSDOS and all versions of Windows, it is important to use “wb” as opposed to simply “w” as the mode when opening the file, and under Unix there is no penalty for doing so.  gdImageWebpEx does not close the file; your code must do so.

If quality is -1, a reasonable quality value (which should yield a good general quality / size tradeoff for most situations) is used.  Otherwise quality should be a value in the range 0-100, higher quality values usually implying both higher quality and larger image sizes.

If quality is greater than or equal to gdWebpLossless then the image will be written in the lossless WebP format.

Variants

gdImageWebpCtx stores the image using a gdIOCtx struct.

gdImageWebpPtrEx stores the image to RAM.

Parameters

Returns

Nothing.

void gdImageWebp ( gdImagePtr  im, FILE  * outFile )

Variant of gdImageWebpEx which uses the default quality (-1).

Parameters

Returns

Nothing.

void * gdImageWebpPtr ( gdImagePtr  im, int  * size )

See gdImageWebpEx.

void * gdImageWebpPtrEx ( gdImagePtr  im, int  * size, int  quality )

See gdImageWebpEx.