<?php
namespace Intervention\Image\Gd\Commands;
use Intervention\Image\Commands\AbstractCommand;
class MaskCommand extends AbstractCommand
{
/**
* Applies an alpha mask to an image
*
* @param \Intervention\Image\Image $image
* @return boolean
*/
public function execute($image)
{
$mask_source = $this->argument(0)->value();
$mask_w_alpha = $this->argument(1)->type('bool')->value(false);
$image_size = $image->getSize();
// create empty canvas
$canvas = $image->getDriver()->newImage($image_size->width, $image_size->height, [0,0,0,0]);
// build mask image from source
$mask = $image->getDriver()->init($mask_source);
$mask_size = $mask->getSize();
// resize mask to size of current image (if necessary)
if ($mask_size != $image_size) {
$mask->resize($image_size->width, $image_size->height);
}
imagealphablending($canvas->getCore(), false);
if ( ! $mask_w_alpha) {
// mask from greyscale image
imagefilter($mask->getCore(), IMG_FILTER_GRAYSCALE);
}
// redraw old image pixel by pixel considering alpha map
for ($x=0; $x < $image_size->width; $x++) {
for ($y=0; $y < $image_size->height; $y++) {
$color = $image->pickColor($x, $y, 'array');
$alpha = $mask->pickColor($x, $y, 'array');
if ($mask_w_alpha) {
$alpha = $alpha[3]; // use alpha channel as mask
} else {
if ($alpha[3] == 0) { // transparent as black
$alpha = 0;
} else {
// $alpha = floatval(round((($alpha[0] + $alpha[1] + $alpha[3]) / 3) / 255, 2));
// image is greyscale, so channel doesn't matter (use red channel)
$alpha = floatval(round($alpha[0] / 255, 2));
}
}
// preserve alpha of original image...
if ($color[3] < $alpha) {
$alpha = $color[3];
}
// replace alpha value
$color[3] = $alpha;
// redraw pixel
$canvas->pixel($color, $x, $y);
}
}
// replace current image with masked instance
$image->setCore($canvas->getCore());
return true;
}
}