Image effect callback; Colorize an image resource.

Parameters

object $image: An image object returned by image_load().

array $data: An array of attributes to use when performing the colorize effect with the following items:

• "color": The web-style hex color to use when colorizing the image.

Return value

bool TRUE on success. FALSE on failure to colorize image.

Related topics

2 string references to 'image_example_colorize_effect'

image_example_image_effect_info in image_example/image_example.module

Implements hook_image_effect_info().

image_example_image_styles_alter in image_example/image_example.module

Implements hook_image_styles_alter().

File

image_example/image_example.module, line 303

Code

function image_example_colorize_effect(&$image, $data) {
    // Image manipulation should be done to the $image->resource, which will be
    // automatically saved as a new image once all effects have been applied.
    // If your effect makes changes to the $image->resource that relate to any
    // information stored in the $image->info array (width, height, etc.) you
    // should update that information as well. See modules/system/image.gd.inc
    // for examples of functions that perform image manipulations.
    //
    // Not all GD installations are created equal. It is a good idea to check for
    // the existence of image manipulation functions before using them.
    // PHP installations using non-bundled GD do not have imagefilter(). More
    // information about image manipulation functions is available in the PHP
    // manual. http://www.php.net/manual/en/book.image.php
    if (!function_exists('imagefilter')) {
        watchdog('image', 'The image %image could not be colorized because the imagefilter() function is not available in this PHP installation.', array(
            '%file' => $image->source,
        ));
        return FALSE;
    }
    // Verify that Drupal is using the PHP GD library for image manipulations
    // since this effect depends on functions in the GD library.
    if ($image->toolkit != 'gd') {
        watchdog('image', 'Image colorize failed on %path. Using non GD toolkit.', array(
            '%path' => $image->source,
        ), WATCHDOG_ERROR);
        return FALSE;
    }
    // Convert short #FFF syntax to full #FFFFFF syntax.
    if (strlen($data['color']) == 4) {
        $c = $data['color'];
        $data['color'] = $c[0] . $c[1] . $c[1] . $c[2] . $c[2] . $c[3] . $c[3];
    }
    // Convert #FFFFFF syntax to hexadecimal colors.
    $data['color'] = hexdec(str_replace('#', '0x', $data['color']));
    // Convert the hexadecimal color value to a color index value.
    $rgb = array();
    for ($i = 16; $i >= 0; $i -= 8) {
        $rgb[] = $data['color'] >> $i & 0xff;
    }
    // First desaturate the image, and then apply the new color.
    imagefilter($image->resource, IMG_FILTER_GRAYSCALE);
    imagefilter($image->resource, IMG_FILTER_COLORIZE, $rgb[0], $rgb[1], $rgb[2]);
    return TRUE;
}