From 0a2efb9eacfc32f126b51f93654203f6952df9c7 Mon Sep 17 00:00:00 2001
From: tc-wleite <wladimir.leite@gmail.com>
Date: Wed, 15 Mar 2023 11:15:17 -0300
Subject: [PATCH] Param can be null in readAlpha(). Copy alphaRaster to dst in
 this case.

---
 .../imageio/plugins/webp/WebPImageReader.java              | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/imageio/imageio-webp/src/main/java/com/twelvemonkeys/imageio/plugins/webp/WebPImageReader.java b/imageio/imageio-webp/src/main/java/com/twelvemonkeys/imageio/plugins/webp/WebPImageReader.java
index c0347f6c..c4a638e9 100644
--- a/imageio/imageio-webp/src/main/java/com/twelvemonkeys/imageio/plugins/webp/WebPImageReader.java
+++ b/imageio/imageio-webp/src/main/java/com/twelvemonkeys/imageio/plugins/webp/WebPImageReader.java
@@ -560,7 +560,12 @@ final class WebPImageReader extends ImageReaderBase {
 
         // Copy into destination raster
         WritableRaster dstRaster = destination.getAlphaRaster();
-        VP8LDecoder.copyIntoRasterWithParams(alphaRaster, dstRaster, param);
+        if (param == null) {
+            dstRaster.setRect(alphaRaster);
+        } 
+        else {
+            VP8LDecoder.copyIntoRasterWithParams(alphaRaster, dstRaster, param);
+        }
     }
 
     private int getPredictorAlpha(WritableRaster alphaRaster, int filtering, int y, int x) {