protected static function GDToolkitReflect::alphaGetMin in ImageCache Reflect 8

Compute the minimum alpha value of the pixels of a given image resource.

Warning, this function is very expensive.

Parameters

resource $src_im: Source image link resource.

Return value

int Minimum alpha value in the image resource.

1 call to GDToolkitReflect::alphaGetMin()

GDToolkitReflect::reflect in lib/Drupal/imagecache_reflect/Plugin/ImageToolkit/GDToolkitReflect.php

Creates an image with a reflection-like effect from a provided image.

File

lib/Drupal/imagecache_reflect/Plugin/ImageToolkit/GDToolkitReflect.php, line 227

Contains \Drupal\imagecache_reflect\Plugin\ImageToolkit\GDToolkitReflect.

Class

GDToolkitReflect

Creates a reflect operation for the GD library.

Namespace

Drupal\imagecache_reflect\Plugin\ImageToolkit

Code

protected static function alphaGetMin($src_im) {
  $w = imagesx($src_im);
  $h = imagesy($src_im);

  // Turn alpha blending off.
  imagealphablending($src_im, FALSE);

  // Find the most opaque pixel in the image (smallest alpha value).
  $minalpha = 127;
  for ($x = 0; $x < $w; $x++) {
    for ($y = 0; $y < $h; $y++) {
      $alpha = imagecolorat($src_im, $x, $y) >> 24 & 0xff;
      if ($alpha < $minalpha) {
        $minalpha = $alpha;
      }
    }
  }
  return $minalpha;
}