From 2718db628bfa334298985c0ce6ca737deeb82bff Mon Sep 17 00:00:00 2001
From: guqing <i@guqing.email>
Date: Sat, 12 Oct 2024 16:31:26 +0800
Subject: [PATCH] fix: vertical images are rotated to horizontal when
 generating thumbnails

---
 api/build.gradle                              |  1 +
 .../core/attachment/ThumbnailGenerator.java   | 33 +++++++++++++++++++
 platform/application/build.gradle             |  2 ++
 3 files changed, 36 insertions(+)

diff --git a/api/build.gradle b/api/build.gradle
index 8185f2a024..046529c443 100644
--- a/api/build.gradle
+++ b/api/build.gradle
@@ -68,6 +68,7 @@ dependencies {
     api "org.thymeleaf.extras:thymeleaf-extras-springsecurity6"
     api 'org.apache.tika:tika-core'
     api "org.imgscalr:imgscalr-lib"
+    api 'com.drewnoakes:metadata-extractor'
 
     api "io.github.resilience4j:resilience4j-spring-boot3"
     api "io.github.resilience4j:resilience4j-reactor"
diff --git a/application/src/main/java/run/halo/app/core/attachment/ThumbnailGenerator.java b/application/src/main/java/run/halo/app/core/attachment/ThumbnailGenerator.java
index ad822f05cb..30b2d7455e 100644
--- a/application/src/main/java/run/halo/app/core/attachment/ThumbnailGenerator.java
+++ b/application/src/main/java/run/halo/app/core/attachment/ThumbnailGenerator.java
@@ -2,6 +2,10 @@
 
 import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
 
+import com.drew.imaging.ImageMetadataReader;
+import com.drew.metadata.Directory;
+import com.drew.metadata.Metadata;
+import com.drew.metadata.exif.ExifIFD0Directory;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -92,9 +96,38 @@ private void generateThumbnail(Path tempImagePath) throws IOException {
         }
         var thumbnail = Scalr.resize(img, Scalr.Method.AUTOMATIC, Scalr.Mode.FIT_TO_WIDTH,
             size.getWidth());
+        // Rotate image if needed
+        var orientation = readExifOrientation(file);
+        if (orientation != null) {
+            thumbnail = Scalr.rotate(thumbnail, orientation);
+        }
         ImageIO.write(thumbnail, formatName, thumbnailFile);
     }
 
+    private static Scalr.Rotation readExifOrientation(File inputFile) {
+        try {
+            Metadata metadata = ImageMetadataReader.readMetadata(inputFile);
+            Directory directory = metadata.getFirstDirectoryOfType(ExifIFD0Directory.class);
+            if (directory != null && directory.containsTag(ExifIFD0Directory.TAG_ORIENTATION)) {
+                return getScalrRotationFromExifOrientation(
+                    directory.getInt(ExifIFD0Directory.TAG_ORIENTATION));
+            }
+        } catch (Exception e) {
+            log.debug("Failed to read EXIF orientation from file: {}", inputFile, e);
+        }
+        return null;
+    }
+
+    private static Scalr.Rotation getScalrRotationFromExifOrientation(int orientation) {
+        // https://www.media.mit.edu/pia/Research/deepview/exif.html#:~:text=0x0112-,Orientation,-unsigned%20short
+        return switch (orientation) {
+            case 3 -> Scalr.Rotation.CW_180;
+            case 6 -> Scalr.Rotation.CW_90;
+            case 8 -> Scalr.Rotation.CW_270;
+            default -> null;
+        };
+    }
+
     private static boolean isUnsupportedFormat(@NonNull String formatName) {
         return UNSUPPORTED_FORMATS.contains(formatName.toLowerCase());
     }
diff --git a/platform/application/build.gradle b/platform/application/build.gradle
index 90311f35e7..396df394c7 100644
--- a/platform/application/build.gradle
+++ b/platform/application/build.gradle
@@ -24,6 +24,7 @@ ext {
     twoFactorAuth = "1.3"
     tika = "2.9.2"
     imgscalr = '4.2'
+    exifExtractor = '2.19.0'
 }
 
 javaPlatform {
@@ -58,6 +59,7 @@ dependencies {
         api "com.j256.two-factor-auth:two-factor-auth:$twoFactorAuth"
         api "org.apache.tika:tika-core:$tika"
         api "org.imgscalr:imgscalr-lib:$imgscalr"
+        api "com.drewnoakes:metadata-extractor:$exifExtractor"
     }
 
 }