Add workaround for AOSP bug with decoding single channel hardware gai…

…nmaps using BitmapFactory.

Android U devices that use skiagl for hwui renderering (currently the vast majority) have a bug
where uplading single channel bitmaps to hardware bitmaps fails. This bug essentially breaks
single channel gainmap rendering using hardware bitmaps, which is a common use case on devices
that have Ultra HDR as the default capture format.

The workaround is as follows:
1. Detect the presence of the bug by attempting to copy a 1x1 single channel bitmap to hardware.
2. Memoize the result
3. For BitmapFactory.decode* calls, if the input bitmap has a gainmap, copy it to a three-channel
gainmap. This step seems wasteful, but in practice, the Android OS already does some copying when
creating hardware bitmaps. Also, more importantly, there is an AOSP fix for this bug, and as
devices are updated with this fix, this flow will no longer be exercised.

library/src/main/java/com/bumptech/glide/GlideBuilder.java

@@ -499,6 +499,17 @@ public GlideBuilder setPreserveGainmapAndColorSpaceForTransformations(boolean is
     return this;
   }
 
+  /**
+   * Fixes decoding of hardware gainmaps from Ultra HDR images on Android U.
+   *
+   * <p>Without this flag on, gainmaps may be dropped when decoding Ultra HDR on Android U devices
+   * using skiagl for hwui..
+   */
+  public GlideBuilder setEnableHardwareGainmapFixOnU(boolean isEnabled) {
+    glideExperimentsBuilder.update(new EnableHardwareGainmapFixOnU(), isEnabled);
+    return this;
+  }
+
   /**
    * @deprecated This method does nothing. It will be hard coded and removed in a future release
    *     without further warning.
@@ -618,6 +629,9 @@ static final class ManualOverrideHardwareBitmapMaxFdCount implements Experiment
    */
   static final class PreserveGainmapAndColorSpaceForTransformations implements Experiment {}
 
+  /** Fixes decoding of hardware gainmaps from Ultra HDR images on Android U. */
+  static final class EnableHardwareGainmapFixOnU implements Experiment {}
+
   static final class EnableImageDecoderForBitmaps implements Experiment {}
 
   /** See {@link #setLogRequestOrigins(boolean)}. */

library/src/main/java/com/bumptech/glide/RegistryFactory.java

@@ -12,6 +12,7 @@
 import android.os.ParcelFileDescriptor;
 import androidx.annotation.Nullable;
 import androidx.tracing.Trace;
+import com.bumptech.glide.GlideBuilder.EnableHardwareGainmapFixOnU;
 import com.bumptech.glide.GlideBuilder.EnableImageDecoderForBitmaps;
 import com.bumptech.glide.GlideBuilder.PreserveGainmapAndColorSpaceForTransformations;
 import com.bumptech.glide.gifdecoder.GifDecoder;
@@ -160,7 +161,8 @@ private static void initializeDefaults(
             resources.getDisplayMetrics(),
             bitmapPool,
             arrayPool,
-            experiments.isEnabled(PreserveGainmapAndColorSpaceForTransformations.class));
+            experiments.isEnabled(PreserveGainmapAndColorSpaceForTransformations.class),
+            experiments.isEnabled(EnableHardwareGainmapFixOnU.class));
 
     ResourceDecoder<ByteBuffer, Bitmap> byteBufferBitmapDecoder;
     ResourceDecoder<InputStream, Bitmap> streamBitmapDecoder;

library/src/main/java/com/bumptech/glide/load/resource/bitmap/Downsampler.java

@@ -65,6 +65,7 @@ public final class Downsampler {
    */
   public static final Option<PreferredColorSpace> PREFERRED_COLOR_SPACE =
       Option.memory("com.bumptech.glide.load.resource.bitmap.Downsampler.PreferredColorSpace");
+
   /**
    * Indicates the {@link com.bumptech.glide.load.resource.bitmap.DownsampleStrategy} option that
    * will be used to calculate the sample size to use to downsample an image given the original and
@@ -74,6 +75,7 @@ public final class Downsampler {
    */
   @Deprecated
   public static final Option<DownsampleStrategy> DOWNSAMPLE_STRATEGY = DownsampleStrategy.OPTION;
+
   /**
    * Ensure that the size of the bitmap is fixed to the requested width and height of the resource
    * from the caller. The final resource dimensions may differ from the requested width and height,
@@ -140,6 +142,7 @@ public void onDecodeComplete(BitmapPool bitmapPool, Bitmap downsampled) {
   private final List<ImageHeaderParser> parsers;
   private final HardwareConfigState hardwareConfigState = HardwareConfigState.getInstance();
   private final boolean preserveGainmapAndColorSpaceForTransformations;
+  private final boolean enableHardwareGainmapFixOnU;
 
   public Downsampler(
       List<ImageHeaderParser> parsers,
@@ -151,7 +154,8 @@ public Downsampler(
         displayMetrics,
         bitmapPool,
         byteArrayPool,
-        /* preserveGainmapAndColorSpaceForTransformations= */ false);
+        /* preserveGainmapAndColorSpaceForTransformations= */ false,
+        /* enableHardwareGainmapFixOnU= */ false);
   }
 
   /**
@@ -165,13 +169,37 @@ public Downsampler(
       BitmapPool bitmapPool,
       ArrayPool byteArrayPool,
       boolean preserveGainmapAndColorSpaceForTransformations) {
+    this(
+        parsers,
+        displayMetrics,
+        bitmapPool,
+        byteArrayPool,
+        preserveGainmapAndColorSpaceForTransformations,
+        /* enableHardwareGainmapFixOnU= */ false);
+  }
+
+  /**
+   * @param preserveGainmapAndColorSpaceForTransformations Preserves gainmap and color space for
+   *     transformation, e.g., the color space of wide gamut images or the gainmap of Ultra HDR
+   *     images.
+   * @param enableHardwareGainmapFixOnU Fixes issues with hardware gainmaps on U.
+   */
+  public Downsampler(
+      List<ImageHeaderParser> parsers,
+      DisplayMetrics displayMetrics,
+      BitmapPool bitmapPool,
+      ArrayPool byteArrayPool,
+      boolean preserveGainmapAndColorSpaceForTransformations,
+      boolean enableHardwareGainmapFixOnU) {
     this.parsers = parsers;
     this.displayMetrics = Preconditions.checkNotNull(displayMetrics);
     this.bitmapPool = Preconditions.checkNotNull(bitmapPool);
     this.byteArrayPool = Preconditions.checkNotNull(byteArrayPool);
     this.preserveGainmapAndColorSpaceForTransformations =
         preserveGainmapAndColorSpaceForTransformations;
+    this.enableHardwareGainmapFixOnU = enableHardwareGainmapFixOnU;
   }
+
   public boolean handles(@SuppressWarnings("unused") InputStream is) {
     // We expect Downsampler to handle any available type Android supports.
     return true;
@@ -206,7 +234,8 @@ public Resource<Bitmap> decode(
       ByteBuffer buffer, int requestedWidth, int requestedHeight, Options options)
       throws IOException {
     return decode(
-        new ImageReader.ByteBufferReader(buffer, parsers, byteArrayPool),
+        new ImageReader.ByteBufferReader(
+            buffer, parsers, byteArrayPool, enableHardwareGainmapFixOnU),
         requestedWidth,
         requestedHeight,
         options,
@@ -241,7 +270,8 @@ public Resource<Bitmap> decode(
       DecodeCallbacks callbacks)
       throws IOException {
     return decode(
-        new ImageReader.InputStreamImageReader(is, parsers, byteArrayPool),
+        new ImageReader.InputStreamImageReader(
+            is, parsers, byteArrayPool, enableHardwareGainmapFixOnU),
         requestedWidth,
         requestedHeight,
         options,
@@ -252,7 +282,7 @@ public Resource<Bitmap> decode(
   void decode(byte[] bytes, int requestedWidth, int requestedHeight, Options options)
       throws IOException {
     decode(
-        new ImageReader.ByteArrayReader(bytes, parsers, byteArrayPool),
+        new ImageReader.ByteArrayReader(bytes, parsers, byteArrayPool, enableHardwareGainmapFixOnU),
         requestedWidth,
         requestedHeight,
         options,
@@ -263,7 +293,7 @@ void decode(byte[] bytes, int requestedWidth, int requestedHeight, Options optio
   void decode(File file, int requestedWidth, int requestedHeight, Options options)
       throws IOException {
     decode(
-        new ImageReader.FileReader(file, parsers, byteArrayPool),
+        new ImageReader.FileReader(file, parsers, byteArrayPool, enableHardwareGainmapFixOnU),
         requestedWidth,
         requestedHeight,
         options,
@@ -276,7 +306,7 @@ public Resource<Bitmap> decode(
       throws IOException {
     return decode(
         new ImageReader.ParcelFileDescriptorImageReader(
-            parcelFileDescriptor, parsers, byteArrayPool),
+            parcelFileDescriptor, parsers, byteArrayPool, enableHardwareGainmapFixOnU),
         outWidth,
         outHeight,
         options,