Add support for animated webp detection to Glide's ImageHeaderParser.

PiperOrigin-RevId: 421923663
bumptech · Jan 14, 2022 · 42654b2 · 42654b2
1 parent afc37e8
commit 42654b2
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Showing 6 changed files with 281 additions and 24 deletions.
diff --git a/checkstyle.xml b/checkstyle.xml
@@ -71,11 +71,6 @@
         <module name="StaticVariableName" />
         <module name="TypeName" />
 
-        <!-- Allow common trailing comments used to describe suppressions -->
-        <module name="TrailingComment">
-            <property name="legalComment" value="^Public API.?$|^NOPMD.*$" />
-        </module>
-
         <!-- Checks for imports. -->
         <!-- See http://checkstyle.sourceforge.net/config_imports.html -->
         <module name="AvoidStarImport"/>

diff --git a/library/src/main/java/com/bumptech/glide/load/ImageHeaderParser.java b/library/src/main/java/com/bumptech/glide/load/ImageHeaderParser.java
@@ -30,6 +30,8 @@ enum ImageType {
     WEBP_A(true),
     /** WebP type without alpha. */
     WEBP(false),
+    /** All animated webps. */
+    ANIMATED_WEBP(true),
     /** Avif type (may contain alpha). */
     AVIF(true),
     /** Unrecognized type. */
@@ -44,6 +46,17 @@ enum ImageType {
     public boolean hasAlpha() {
       return hasAlpha;
     }
+
+    public boolean isWebp() {
+      switch (this) {
+        case WEBP:
+        case WEBP_A:
+        case ANIMATED_WEBP:
+          return true;
+        default:
+          return false;
+      }
+    }
   }
 
   @NonNull

diff --git a/library/src/main/java/com/bumptech/glide/load/resource/bitmap/DefaultImageHeaderParser.java b/library/src/main/java/com/bumptech/glide/load/resource/bitmap/DefaultImageHeaderParser.java
@@ -1,5 +1,6 @@
 package com.bumptech.glide.load.resource.bitmap;
 
+import static com.bumptech.glide.load.ImageHeaderParser.ImageType.ANIMATED_WEBP;
 import static com.bumptech.glide.load.ImageHeaderParser.ImageType.AVIF;
 import static com.bumptech.glide.load.ImageHeaderParser.ImageType.GIF;
 import static com.bumptech.glide.load.ImageHeaderParser.ImageType.JPEG;
@@ -53,6 +54,7 @@ public final class DefaultImageHeaderParser implements ImageHeaderParser {
   private static final int VP8_HEADER_TYPE_EXTENDED = 0x00000058;
   // 'L'
   private static final int VP8_HEADER_TYPE_LOSSLESS = 0x0000004C;
+  private static final int WEBP_EXTENDED_ANIMATION_FLAG = 1 << 1;
   private static final int WEBP_EXTENDED_ALPHA_FLAG = 1 << 4;
   private static final int WEBP_LOSSLESS_ALPHA_FLAG = 1 << 3;
   // Avif-related
@@ -146,7 +148,13 @@ private ImageType getType(Reader reader) throws IOException {
         // Skip some more length bytes and check for transparency/alpha flag.
         reader.skip(4);
         short flags = reader.getUInt8();
-        return (flags & WEBP_EXTENDED_ALPHA_FLAG) != 0 ? ImageType.WEBP_A : ImageType.WEBP;
+        if ((flags & WEBP_EXTENDED_ANIMATION_FLAG) != 0) {
+          return ANIMATED_WEBP;
+        } else if ((flags & WEBP_EXTENDED_ALPHA_FLAG) != 0) {
+          return ImageType.WEBP_A;
+        } else {
+          return ImageType.WEBP;
+        }
       }
       if ((fourthFourBytes & VP8_HEADER_TYPE_MASK) == VP8_HEADER_TYPE_LOSSLESS) {
         // See chromium.googlesource.com/webm/libwebp/+/master/doc/webp-lossless-bitstream-spec.txt

diff --git a/library/src/main/java/com/bumptech/glide/load/resource/bitmap/Downsampler.java b/library/src/main/java/com/bumptech/glide/load/resource/bitmap/Downsampler.java
@@ -575,7 +575,7 @@ private static void calculateScaling(
     } else if (imageType == ImageType.PNG || imageType == ImageType.PNG_A) {
       powerOfTwoWidth = (int) Math.floor(orientedSourceWidth / (float) powerOfTwoSampleSize);
       powerOfTwoHeight = (int) Math.floor(orientedSourceHeight / (float) powerOfTwoSampleSize);
-    } else if (imageType == ImageType.WEBP || imageType == ImageType.WEBP_A) {
+    } else if (imageType.isWebp()) {
       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
         powerOfTwoWidth = Math.round(orientedSourceWidth / (float) powerOfTwoSampleSize);
         powerOfTwoHeight = Math.round(orientedSourceHeight / (float) powerOfTwoSampleSize);