From: Alexander Ebert <ebert@woltlab.com>
Date: Mon, 11 Jan 2021 17:33:56 +0000 (+0100)
Subject: Image adapters now support saving to GIF/JPG/PNG/WebP (#3869)
X-Git-Tag: 5.4.0_Alpha_1~458
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=96fcf43c58aa8f87af1be30f11f5bb090fa13fcc;p=GitHub%2FWoltLab%2FWCF.git

Image adapters now support saving to GIF/JPG/PNG/WebP (#3869)

* Image adapters now support saving to GIF/JPG/PNG/WebP

* Adjusted the usage of exception

* Missing remark on the version support
---

diff --git a/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php b/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
index 9d61e08f67..e68d97e493 100644
--- a/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
+++ b/wcfsetup/install/files/lib/system/image/adapter/GDImageAdapter.class.php
@@ -347,8 +347,11 @@ class GDImageAdapter implements IImageAdapter {
 		
 		ob_start();
 		
+		// fix PNG alpha channel handling
+		// see http://php.net/manual/en/function.imagecopymerge.php#92787
 		imagealphablending($image, false);
 		imagesavealpha($image, true);
+		
 		if ($this->type == IMAGETYPE_GIF) {
 			imagegif($image);
 		}
@@ -493,6 +496,49 @@ class GDImageAdapter implements IImageAdapter {
 		// does nothing
 	}
 	
+	/**
+	 * @inheritDoc
+	 */
+	public function saveImageAs($image, string $filename, string $type, int $quality = 100): void {
+		if (!$this->isImage($image)) {
+			throw new \InvalidArgumentException("Given image is not a valid image resource.");
+		}
+		
+		ob_start();
+		
+		// fix PNG alpha channel handling
+		// see http://php.net/manual/en/function.imagecopymerge.php#92787
+		imagealphablending($image, false);
+		imagesavealpha($image, true);
+		
+		switch ($type) {
+			case "gif":
+				imagegif($image);
+				break;
+				
+			case "jpg":
+			case "jpeg":
+				imagejpeg($image, null, $quality);
+				break;
+				
+			case "png":
+				imagepng($image, null, $quality);
+				break;
+			
+			case "webp":
+				imagewebp($image, null, $quality);
+				break;
+			
+			default:
+				throw new \InvalidArgumentException("Unreachable");
+		}
+		
+		$stream = ob_get_contents();
+		ob_end_clean();
+		
+		file_put_contents($filename, $stream);
+	}
+	
 	/**
 	 * @inheritDoc
 	 */
diff --git a/wcfsetup/install/files/lib/system/image/adapter/IImageAdapter.class.php b/wcfsetup/install/files/lib/system/image/adapter/IImageAdapter.class.php
index 4bef9df373..6b4b9ae4f5 100644
--- a/wcfsetup/install/files/lib/system/image/adapter/IImageAdapter.class.php
+++ b/wcfsetup/install/files/lib/system/image/adapter/IImageAdapter.class.php
@@ -221,6 +221,13 @@ interface IImageAdapter {
 	 */
 	public function overlayImageRelative($file, $position, $margin, $opacity);
 	
+	/**
+	 * Saves an image using a different file type.
+	 * 
+	 * @since 5.4
+	 */
+	public function saveImageAs($image, string $filename, string $type, int $quality = 100): void;
+	
 	/**
 	 * Determines if an image adapter is supported.
 	 * 
diff --git a/wcfsetup/install/files/lib/system/image/adapter/ImageAdapter.class.php b/wcfsetup/install/files/lib/system/image/adapter/ImageAdapter.class.php
index 5f68955439..ff81973d0b 100644
--- a/wcfsetup/install/files/lib/system/image/adapter/ImageAdapter.class.php
+++ b/wcfsetup/install/files/lib/system/image/adapter/ImageAdapter.class.php
@@ -366,6 +366,30 @@ class ImageAdapter implements IImageAdapter, IMemoryAwareImageAdapter {
 		return FileUtil::checkMemoryLimit($width * $height * $channels * 2.1);
 	}
 	
+	/**
+	 * @inheritDoc
+	 */
+	public function saveImageAs($image, string $filename, string $type, int $quality = 100): void {
+		switch ($type) {
+			case "gif":
+			case "jpg":
+			case "jpeg":
+			case "png":
+			case "webp":
+				break;
+				
+			default:
+				throw new \InvalidArgumentException("Unsupported image format '{$type}'.");
+		}
+		
+		if ($quality < 0 || $quality > 100) {
+			throw new \InvalidArgumentException("The quality must be an integer between 0 and 100.");
+		}
+		
+		$this->adapter->saveImageAs($image, $filename, $type, $quality);
+	}
+	
+	
 	/**
 	 * @inheritDoc
 	 */
diff --git a/wcfsetup/install/files/lib/system/image/adapter/ImagickImageAdapter.class.php b/wcfsetup/install/files/lib/system/image/adapter/ImagickImageAdapter.class.php
index eb1912e9ec..09ee4073fa 100644
--- a/wcfsetup/install/files/lib/system/image/adapter/ImagickImageAdapter.class.php
+++ b/wcfsetup/install/files/lib/system/image/adapter/ImagickImageAdapter.class.php
@@ -461,6 +461,46 @@ class ImagickImageAdapter implements IImageAdapter {
 		return $match['version'];
 	}
 	
+	/**
+	 * @inheritDoc
+	 */
+	public function saveImageAs($image, string $filename, string $type, int $quality = 100): void {
+		if (!($image instanceof \Imagick)) {
+			throw new \InvalidArgumentException("Given image is not a valid Imagick-object.");
+		}
+		
+		// Greatly reduces the time required to create the image and drastically
+		// reduces the filesize to more reasonable levels without a visible
+		// quality loss.
+		//
+		// See https://github.com/Imagick/imagick/issues/360
+		if ($image->getImageFormat() == "GIF") {
+			$image = $image->deconstructImages();
+			$image->quantizeImages(256, \Imagick::COLORSPACE_SRGB, 0, false, false);
+		}
+		
+		switch ($type) {
+			case "jpg":
+			case "jpeg":
+				$fileFormat = "jpg";
+				break;
+			
+			case "png":
+				$fileFormat = "png";
+				break;
+			
+			case "webp":
+				$fileFormat = "webp";
+				break;
+			
+			default:
+				throw new \LogicException("Unreachable");
+		}
+		
+		$image->writeImages("{$fileFormat}:{$filename}", true);
+	}
+	
+	
 	/**
 	 * @param string $version
 	 * @return bool