Convert an image resource to grayscale.

Note that transparent GIFs loose transparency when desaturated.

Parameters

$image: An image object. The $image->resource value will be modified by this call.

Return value

TRUE or FALSE, based on success.

See also

image_desaturate()

Related topics

File

modules/system/image.gd.inc, line 235

Code

function image_gd_desaturate(stdClass $image) {
    // PHP installations using non-bundled GD do not have imagefilter.
    if (!function_exists('imagefilter')) {
        watchdog('image', 'The image %file could not be desaturated because the imagefilter() function is not available in this PHP installation.', array(
            '%file' => $image->source,
        ));
        return FALSE;
    }
    return imagefilter($image->resource, IMG_FILTER_GRAYSCALE);
}

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