Exif.php: add helper query functions

inc/Data/Exif.php

@@ -21,4 +21,40 @@ class Exif {
 	public static function exifOrientationOnSide(int $exif_orientation): bool {
 		return $exif_orientation >= 5 && $exif_orientation <= 8;
 	}
+
+	/**
+	 * Gives the rotation in degrees of the given exif orientation.
+	 *
+	 * @param int $exif_orientation One of the EXIF_ORIENTATION_* constants.
+	 * @return int Rotation in degrees.
+	 */
+	public static function exifOrientationDegrees(int $exif_orientation): int {
+		switch ($exif_orientation) {
+			case self::EXIF_ORIENTATION_UNDEFINED:
+			case self::EXIF_ORIENTATION_0_UPRIGHT:
+			case self::EXIF_ORIENTATION_0_FLIPPED:
+				return 0;
+			case self::EXIF_ORIENTATION_180_UPRIGHT:
+			case self::EXIF_ORIENTATION_180_FLIPPED:
+				return 180;
+			case self::EXIF_ORIENTATION_90_UPRIGHT:
+			case self::EXIF_ORIENTATION_90_FLIPPED:
+				return 90;
+			case self::EXIF_ORIENTATION_270_UPRIGHT:
+			case self::EXIF_ORIENTATION_270_FLIPPED:
+				return 270;
+			default:
+				throw new \RuntimeException("Invalid exif orientation '$exif_orientation'");
+		}
+	}
+
+	/**
+	 * If the given exif orientation flips the image.
+	 *
+	 * @param int $exif_orientation One of the EXIF_ORIENTATION_* constants.
+	 * @return bool If the image is flipped.
+	 */
+	public static function exifOrientationIsFlipped(int $exif_orientation): bool {
+		return $exif_orientation % 2 == 0;
+	}
 }

inc/Data/ImageMetadata.php

@@ -2,8 +2,10 @@
 namespace Vichan\Data;
 
 
-class ImageMetadataResult {
+class ImageMetadata {
+	// NOT affected by the exit orientation.
 	public int $width;
+	// NOT affected by the exif orientation.
 	public int $height;
 	public string $mime;
 	public ?int $exif_orientation;

inc/Service/Media/CmdMagickImageMetadataReader.php

@@ -1,7 +1,7 @@
 <?php
 namespace Vichan\Service\Media;
 
-use Vichan\Data\{Exif, ImageMetadataResult};
+use Vichan\Data\{Exif, ImageMetadata};
 use Vichan\Functions\Mime;
 
 
@@ -47,7 +47,7 @@ class CmdMagickImageMetadataReader implements ImageMetadataReader {
 		$this->prefix = $prefix;
 	}
 
-	public function getMetadata(string $file_path): ImageMetadataResult {
+	public function getMetadata(string $file_path): ImageMetadata {
 		$arg = \escapeshellarg("$file_path[0]");
 		$ret_exec = shell_exec_error("{$this->prefix} identify -format \"%w %h %m\" $arg");
 
@@ -65,6 +65,6 @@ class CmdMagickImageMetadataReader implements ImageMetadataReader {
 
 		$mime = Mime\ext_to_mime($ext) ?? 'application/octet-stream';
 		$exif_orientation = self::parseOrientation($orientation_str);
-		return new ImageMetadataResult($width, $height, $mime, $exif_orientation);
+		return new ImageMetadata($width, $height, $mime, $exif_orientation);
 	}
 }

inc/Service/Media/DefaultImageMetadataReader.php

@@ -2,7 +2,7 @@
 namespace Vichan\Service\Media;
 
 use Vichan\Data\Driver\Metadata\ExifReaderFactory;
-use Vichan\Data\{Exif, ImageMetadataResult};
+use Vichan\Data\ImageMetadata;
 
 
 /**
@@ -21,7 +21,7 @@ class DefaultImageMetadataReader implements ImageMetadataReader {
 		$this->exif_reader_factory = $exif_reader_factory;
 	}
 
-	public function getMetadata(string $file_path): ImageMetadataResult {
+	public function getMetadata(string $file_path): ImageMetadata {
 		$ret = \getimagesize($file_path, $info);
 		if ($ret === false) {
 			throw new \RuntimeException("Could not read image sizes of '$file_path'");
@@ -38,13 +38,8 @@ class DefaultImageMetadataReader implements ImageMetadataReader {
 		$exif_reader = $this->exif_reader_factory->getReader($mime);
 		if ($exif_reader !== null) {
 			$orientation = $exif_reader->getOrientation($file_path);
-			if ($orientation !== null && Exif::exifOrientationOnSide($orientation)) {
-				$tmp = $width;
-				$width = $height;
-				$height = $tmp;
-			}
 		}
 
-		return new ImageMetadataResult($width, $height, $mime, $orientation);
+		return new ImageMetadata($width, $height, $mime, $orientation);
 	}
 }

inc/Service/Media/GdMediaHandler.php

@@ -1,7 +1,7 @@
 <?php
 namespace Vichan\Service\Media;
 
-use Vichan\Data\ThumbGenerationResult;
+use Vichan\Data\{Exif, ThumbGenerationResult};
 use Vichan\Functions\{Fs, Mime};
 
 
@@ -13,6 +13,7 @@ class GdMediaHandler implements MediaHandler {
 
 
 	private bool $strip_redraw;
+	private ImageMetadataReader $image_metadate_reader;
 
 
 	private static function imageCreateFrom(string $file, string $mime): mixed {
@@ -33,7 +34,7 @@ class GdMediaHandler implements MediaHandler {
 		return false;
 	}
 
-	public static function imageSaveTo(mixed $gd, string $file, string $mime) {
+	private static function imageSaveTo(mixed $gd, string $file, string $mime) {
 		// Somebody should tune the quality and speed values...
 		// Won't be me.
 		switch ($mime) {
@@ -53,8 +54,7 @@ class GdMediaHandler implements MediaHandler {
 		return false;
 	}
 
-	private static function createCanvas(string $mime, int $width, int $height) {
-		$gd = \imagecreatetruecolor($width, $height);
+	private static function enableTransparency(mixed $gd, string $mime) {
 		switch ($mime) {
 			case 'image/png':
 				\imagecolortransparent($gd, \imagecolorallocatealpha($gd, 0, 0, 0, 0));
@@ -66,6 +66,11 @@ class GdMediaHandler implements MediaHandler {
 				\imagesavealpha($gd, true);
 				break;
 		}
+	}
+
+	private static function createCanvas(string $mime, int $width, int $height) {
+		$gd = \imagecreatetruecolor($width, $height);
+		self::enableTransparency($gd, $mime);
 		return $gd;
 	}
 
@@ -130,8 +135,9 @@ class GdMediaHandler implements MediaHandler {
 	 * @param bool $strip_redraw If the EXIF metadata should be stripped by redrawing it.
 	 *                           May cause the loss of color profiles. Orientation is still handled.
 	 */
-	public function __construct(bool $strip_redraw) {
+	public function __construct(bool $strip_redraw, ImageMetadataReader $image_metadate_reader) {
 		$this->strip_redraw = $strip_redraw;
+		$this->image_metadate_reader = $image_metadate_reader;
 	}
 
 	public function supportsMime(string $mime): bool {
@@ -145,10 +151,38 @@ class GdMediaHandler implements MediaHandler {
 	}
 
 	public function openHandle(string $file_path, string $file_mime, int $file_kind): mixed {
+		$metadata = $this->image_metadate_reader->getMetadata($file_path);
+		if ($file_mime !== $file_mime) {
+			throw new \RuntimeException("Mime mismatch on '$file_path'");
+		}
+
 		$gd = self::imageCreateFrom($file_path, $file_mime);
 		if ($gd === false) {
 			throw new \RuntimeException("Could not open '$file_path'");
 		}
+
+		// Fix the orientation once and for all.
+		if ($metadata->exif_orientation !== null) {
+			$degrees = Exif::exifOrientationDegrees($metadata->exif_orientation);
+			$flipped = Exif::exifOrientationIsFlipped($metadata->exif_orientation);
+
+			if ($degrees !== 0) {
+				self::enableTransparency($gd, $file_mime);
+				$gd_other = \imagerotate($gd, $degrees, \imagecolorallocatealpha($gd, 0, 0, 0, 127));
+				\imagedestroy($gd);
+				if ($gd_other === false) {
+					throw new \RuntimeException("Error while correcting rotation of '$file_path'");
+				}
+				$gd = $gd_other;
+			}
+
+			if ($flipped) {
+				if (!\imageflip($gd, \IMG_FLIP_HORIZONTAL)) {
+					throw new \RuntimeException("Error while correcting flipping of '$file_path'");
+				}
+			}
+		}
+
 		return [ $gd, $file_path, $file_mime, $file_kind ];
 	}
 

inc/Service/Media/ImageMetadataReader.php

@@ -1,12 +1,12 @@
 <?php
 namespace Vichan\Service\Media;
 
-use Vichan\Data\ImageMetadataResult;
+use Vichan\Data\ImageMetadata;
 
 
 interface ImageMetadataReader {
 	/**
 	 * @param string $file_path Image file path.
 	 */
-	public function getMetadata(string $file_path): ImageMetadataResult;
+	public function getMetadata(string $file_path): ImageMetadata;
 }