Theming: Generate favicon sizes to avoid resizing issues done by the browser

fixes #5193

Signed-off-by: Julius Haertl <jus@bitgrid.net>

apps/theming/lib/IconBuilder.php

@@ -56,13 +56,34 @@ class IconBuilder {
 	 */
 	public function getFavicon($app) {
 		try {
-			$icon = $this->renderAppIcon($app, 32);
+			$favicon = new Imagick();
+			$favicon->setFormat("ico");
+			$icon = $this->renderAppIcon($app, 128);
 			if ($icon === false) {
 				return false;
 			}
 			$icon->setImageFormat("png32");
-			$data = $icon->getImageBlob();
+
+			$clone = clone $icon;
+			$clone->scaleImage(16,0);
+			$favicon->addImage($clone);
+
+			$clone = clone $icon;
+			$clone->scaleImage(32,0);
+			$favicon->addImage($clone);
+
+			$clone = clone $icon;
+			$clone->scaleImage(64,0);
+			$favicon->addImage($clone);
+
+			$clone = clone $icon;
+			$clone->scaleImage(128,0);
+			$favicon->addImage($clone);
+
+			$data = $favicon->getImagesBlob();
+			$favicon->destroy();
 			$icon->destroy();
+			$clone->destroy();
 			return $data;
 		} catch (\ImagickException $e) {
 			return false;

apps/theming/tests/IconBuilderTest.php

@@ -71,6 +71,9 @@ class IconBuilderTest extends TestCase {
 		if (count($checkImagick->queryFormats('SVG')) < 1) {
 			$this->markTestSkipped('No SVG provider present.');
 		}
+		if (count($checkImagick->queryFormats('PNG')) < 1) {
+			$this->markTestSkipped('No PNG provider present.');
+		}
 	}
 
 	public function dataRenderAppIcon() {