Remove alpha channel for jpeg and jfif formats

src/main/java/au/com/tpic/avatar/services/AvatarService.java

@@ -9,12 +9,12 @@ import org.springframework.stereotype.Service;
 import org.springframework.util.DigestUtils;
 
 import javax.imageio.ImageIO;
+import java.awt.*;
 import java.awt.geom.AffineTransform;
 import java.awt.image.AffineTransformOp;
 import java.awt.image.BufferedImage;
 import java.awt.image.WritableRaster;
 import java.io.ByteArrayOutputStream;
-import java.io.File;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -26,13 +26,14 @@ import java.util.stream.Stream;
 public class AvatarService {
 
     private final HashMap<String, Path> fileList;
+    private final BufferedImage defaultImage;
     private static final String DEFAULT_FORMAT = "jpg";
-    private static final Path DEFAULT_IMAGE_PATH = new File(AvatarService.class.getResource("/default.jpg").getFile()).toPath();
 
     public AvatarService(AvatarServiceProperites properites) throws IOException {
-        Stream<Path> avatars = Files.walk(properites.getDirectory());
         this.fileList = new HashMap<>();
+        Stream<Path> avatars = Files.walk(properites.getDirectory());
         avatars.filter(this::correctFormat).forEach(path -> this.fileList.put(getFileHash(path), path));
+        this.defaultImage = ImageIO.read(getClass().getResourceAsStream("/default.jpg"));
     }
 
     public ResponseEntity<byte[]> getAvatar(String request, String size) throws IOException {
@@ -42,8 +43,8 @@ public class AvatarService {
             BufferedImage image = (fileList.containsKey(hash)) ? readImageToSize(fileList.get(hash), Integer.parseInt(size)) : generateIdenticons(hash, Integer.parseInt(size));
             return ResponseEntity.ok().contentType(format).body(writeToFormat(image, format.getSubtype()));
         } catch (Exception ignored) {
-            BufferedImage defaultImage = readImageToSize(DEFAULT_IMAGE_PATH, Integer.parseInt(size));
-            return ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(writeToFormat(defaultImage, DEFAULT_FORMAT));
+            BufferedImage resizedDefaultImage = resizeImage(defaultImage, Integer.parseInt(size));
+            return ResponseEntity.ok().contentType(MediaType.IMAGE_JPEG).body(writeToFormat(resizedDefaultImage, DEFAULT_FORMAT));
         }
     }
 
@@ -81,6 +82,10 @@ public class AvatarService {
 
     private BufferedImage readImageToSize(Path imagePath, int size) throws IOException {
         BufferedImage inputImage = ImageIO.read(imagePath.toFile());
+        return resizeImage(inputImage, size);
+    }
+
+    private BufferedImage resizeImage(BufferedImage inputImage, int size) {
         int newHeight = inputImage.getHeight() / inputImage.getWidth() * size;
         ResampleOp resizeOp = new ResampleOp(size, newHeight);
         resizeOp.setFilter(ResampleFilters.getLanczos3Filter());
@@ -89,6 +94,12 @@ public class AvatarService {
 
     private byte[] writeToFormat(BufferedImage image, String format) throws IOException {
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        if (List.of("jpg", "jpeg", "jfif").contains(format)) {
+            // Remove alpha channel
+            BufferedImage result = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_INT_RGB);
+            result.createGraphics().drawImage(image, 0, 0, Color.BLACK, null);
+            image = result;
+        }
         ImageIO.write(image, format, baos);
         return baos.toByteArray();
     }