Image: fixed lost alpha after imagecrop() [Closes #202]

Author: dg

src/Utils/Image.php

@@ -366,6 +366,7 @@ public function crop($left, $top, $width, $height)
 		[$r['x'], $r['y'], $r['width'], $r['height']]
 			= static::calculateCutout($this->getWidth(), $this->getHeight(), $left, $top, $width, $height);
 		$this->image = imagecrop($this->image, $r);
+		imagesavealpha($this->image, true);
 		return $this;
 	}
 

tests/Utils/Image.resize.phpt

@@ -140,6 +140,18 @@ test(function () use ($main) { // rotate
 });
 
 
+test(function () use ($main) { // alpha crop
+	$image = Image::fromFile(__DIR__ . '/fixtures.images/alpha1.png');
+	$image->crop(1, 1, 8, 8);
+	Assert::same(file_get_contents(__DIR__ . '/expected/Image.alpha.crop.gd2'), toGd2($image));
+	if (PHP_VERSION_ID < 70200) {
+		Assert::same(file_get_contents(__DIR__ . '/expected/Image.alpha.crop-71.png'), $image->toString($image::PNG));
+	} else {
+		Assert::same(file_get_contents(__DIR__ . '/expected/Image.alpha.crop.png'), $image->toString($image::PNG));
+	}
+});
+
+
 test(function () use ($main) { // alpha resize
 	$image = Image::fromFile(__DIR__ . '/fixtures.images/alpha1.png');
 	$image->resize(20, 20);