Add support for P3 and SRGB in Glide.

Allows users of the library to manually set an option to support displaying wide gamut images with the DISPLAY_P3 color space on P+.  Defaults Glide to using SRGB on O and for all loads where the option isn't set to DISPLAY_P3.

Does not allow callers to specify other color spaces. Does not allow callers to convert SRGB images to DISPLAY_P3. Does not verify that screens/renderers are capable of displaying P3 images when it's requested.

PiperOrigin-RevId: 260580611

Author: sjudd

library/src/main/java/com/bumptech/glide/load/PreferredColorSpace.java

@@ -0,0 +1,36 @@
+package com.bumptech.glide.load;
+
+/**
+ * Glide's supported handling of color spaces on Android O+, defaults to {@link #SRGB}.
+ *
+ * <p>On Android O, Glide will always request SRGB and will ignore this option if set. A bug on
+ * Android O prevents P3 images from being compressed correctly and can result in color distortion.
+ * We may eventually work around this in Glide if sufficient demand arises, but doing so will
+ * require a memory intensive conversion to SRGB prior to compressing Bitmaps to Glide's disk cache.
+ * This work around would also work only for Glide's compression, not for any compression that a
+ * caller performs on a Bitmap returned by Glide.
+ *
+ * <p>On Android P+, Glide supports SRGB and display P3. However, if display p3 is requested, we
+ * will still decode to SRGB unless {@link android.graphics.BitmapFactory.Options#outColorSpace} is
+ * also {@link android.graphics.ColorSpace.Named#DISPLAY_P3}. Preferring P3 for SRGB images adds
+ * unnecessary CPU work to convert back and forth between the color spaces at decode time.
+ *
+ * <p>Using {@link #DISPLAY_P3} is wasteful if either the screen or the renderer do not support P3.
+ * Currently Glide does not attempt to detect whether or not this support is present. Do not use
+ * {@link #DISPLAY_P3} thinking that you're going to get higher quality by default. Only use {@link
+ * #DISPLAY_P3} if you're confident you understand color spaces, your application is working with a
+ * display that supports wide gamut and you've set the appropriate options to render wide gamut
+ * colors. If you've missed one or more of these steps, {@link #DISPLAY_P3} can lead to poor color
+ * quality and washed out looking images. When in doubt, always use {@link #SRGB}, which is Glide's
+ * default.
+ *
+ * <p>As with {@link DecodeFormat} we cannot directly set color spaces, we can only suggest to the
+ * framework which one we want. Setting one of these values is not a guarantee that any returned
+ * Bitmap will actually use the requested color space.
+ */
+public enum PreferredColorSpace {
+  /** Prefers to decode images using {@link android.graphics.ColorSpace.Named#SRGB}. */
+  SRGB,
+  /** Prefers to decode images using {@link android.graphics.ColorSpace.Named#DISPLAY_P3}. */
+  DISPLAY_P3,
+}

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

@@ -4,6 +4,7 @@
 import android.graphics.Bitmap;
 import android.graphics.Bitmap.Config;
 import android.graphics.BitmapFactory;
+import android.graphics.ColorSpace;
 import android.os.Build;
 import android.util.DisplayMetrics;
 import android.util.Log;
@@ -14,6 +15,7 @@
 import com.bumptech.glide.load.ImageHeaderParserUtils;
 import com.bumptech.glide.load.Option;
 import com.bumptech.glide.load.Options;
+import com.bumptech.glide.load.PreferredColorSpace;
 import com.bumptech.glide.load.engine.Resource;
 import com.bumptech.glide.load.engine.bitmap_recycle.ArrayPool;
 import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool;
@@ -48,6 +50,18 @@ public final class Downsampler {
   public static final Option<DecodeFormat> DECODE_FORMAT =
       Option.memory(
           "com.bumptech.glide.load.resource.bitmap.Downsampler.DecodeFormat", DecodeFormat.DEFAULT);
+
+  /**
+   * Sets the {@link PreferredColorSpace} that will be used along with the version of Android and
+   * color space of the requested image to determine the final color space used to decode the image.
+   *
+   * <p>Refer to {@link PreferredColorSpace} for details on how this option works and its various
+   * limitations.
+   */
+  public static final Option<PreferredColorSpace> PREFERRED_COLOR_SPACE =
+      Option.memory(
+          "com.bumptech.glide.load.resource.bitmap.Downsampler.PreferredColorSpace",
+          PreferredColorSpace.SRGB);
   /**
    * 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
@@ -199,6 +213,7 @@ public Resource<Bitmap> decode(
     bitmapFactoryOptions.inTempStorage = bytesForOptions;
 
     DecodeFormat decodeFormat = options.get(DECODE_FORMAT);
+    PreferredColorSpace preferredColorSpace = options.get(PREFERRED_COLOR_SPACE);
     DownsampleStrategy downsampleStrategy = options.get(DownsampleStrategy.OPTION);
     boolean fixBitmapToRequestedDimensions = options.get(FIX_BITMAP_SIZE_TO_REQUESTED_DIMENSIONS);
     boolean isHardwareConfigAllowed =
@@ -211,6 +226,7 @@ public Resource<Bitmap> decode(
               bitmapFactoryOptions,
               downsampleStrategy,
               decodeFormat,
+              preferredColorSpace,
               isHardwareConfigAllowed,
               requestedWidth,
               requestedHeight,
@@ -228,6 +244,7 @@ private Bitmap decodeFromWrappedStreams(
       BitmapFactory.Options options,
       DownsampleStrategy downsampleStrategy,
       DecodeFormat decodeFormat,
+      PreferredColorSpace preferredColorSpace,
       boolean isHardwareConfigAllowed,
       int requestedWidth,
       int requestedHeight,
@@ -328,6 +345,18 @@ private Bitmap decodeFromWrappedStreams(
         setInBitmap(options, bitmapPool, expectedWidth, expectedHeight);
       }
     }
+
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
+      boolean isP3Eligible =
+          preferredColorSpace == PreferredColorSpace.DISPLAY_P3
+              && options.outColorSpace != null
+              && options.outColorSpace.isWideGamut();
+      options.inPreferredColorSpace =
+          ColorSpace.get(isP3Eligible ? ColorSpace.Named.DISPLAY_P3 : ColorSpace.Named.SRGB);
+    } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+      options.inPreferredColorSpace = ColorSpace.get(ColorSpace.Named.SRGB);
+    }
+
     Bitmap downsampled = decodeStream(is, options, callbacks, bitmapPool);
     callbacks.onDecodeComplete(bitmapPool, downsampled);
 
@@ -860,6 +889,7 @@ private static void resetOptions(BitmapFactory.Options decodeBitmapOptions) {
     decodeBitmapOptions.inDensity = 0;
     decodeBitmapOptions.inTargetDensity = 0;
     if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+      decodeBitmapOptions.outColorSpace = null;
       decodeBitmapOptions.outConfig = null;
     }
     decodeBitmapOptions.outWidth = 0;