Adjust mini bitmap size for color extraction

Make sure that ImageWallpaper's color extractor rescales the bitmap
exactly like WallapperColors#fromBitmap does.

This should avoid slightly changing the colors and failing some
screenshot tests when totally moving the color extraction logic to
ImageWallpaper.

Flag: NA, currently the mini bitmap is unused
Bug: 328791519
Test: atest WallpaperLocalColorExtractorTest
Change-Id: I9f90b452106c0f6a84ee50ab0559ef868b79941b

2 files changed, 15 insertions, 15 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractor.java b/packages/SystemUI/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractor.java
index d37dfb49c5e5..3c9259c233fc 100644
--- a/packages/SystemUI/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractor.java
+++ b/packages/SystemUI/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractor.java
@@ -51,7 +51,7 @@ public class WallpaperLocalColorExtractor {
     private Bitmap mMiniBitmap;
 
     @VisibleForTesting
-    static final int SMALL_SIDE = 128;
+    static final int MINI_BITMAP_MAX_AREA = 112 * 112;
 
     private static final String TAG = WallpaperLocalColorExtractor.class.getSimpleName();
     private static final @NonNull RectF LOCAL_COLOR_BOUNDS =
@@ -326,12 +326,12 @@ public class WallpaperLocalColorExtractor {
 
     private Bitmap createMiniBitmap(@NonNull Bitmap bitmap) {
         Trace.beginSection("WallpaperLocalColorExtractor#createMiniBitmap");
-        // if both sides of the image are larger than SMALL_SIDE, downscale the bitmap.
-        int smallestSide = Math.min(bitmap.getWidth(), bitmap.getHeight());
-        float scale = Math.min(1.0f, (float) SMALL_SIDE / smallestSide);
+        // if the area of the image is greater than MINI_BITMAP_MAX_AREA, downscale the bitmap.
+        int area = bitmap.getWidth() * bitmap.getHeight();
+        double scale = Math.min(1, Math.sqrt((double) MINI_BITMAP_MAX_AREA / area));
         Bitmap result = createMiniBitmap(bitmap,
-                (int) (scale * bitmap.getWidth()),
-                (int) (scale * bitmap.getHeight()));
+                Math.max(1, (int) (scale * bitmap.getWidth())),
+                Math.max(1, (int) (scale * bitmap.getHeight())));
         Trace.endSection();
         return result;
     }
diff --git a/packages/SystemUI/tests/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractorTest.java b/packages/SystemUI/tests/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractorTest.java
index 0eba21ada789..33d09c1be696 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractorTest.java
+++ b/packages/SystemUI/tests/src/com/android/systemui/wallpapers/WallpaperLocalColorExtractorTest.java
@@ -59,8 +59,8 @@ import java.util.concurrent.Executor;
 @RunWith(AndroidTestingRunner.class)
 @TestableLooper.RunWithLooper
 public class WallpaperLocalColorExtractorTest extends SysuiTestCase {
-    private static final int LOW_BMP_WIDTH = 128;
-    private static final int LOW_BMP_HEIGHT = 128;
+    private static final int LOW_BMP_WIDTH = 112;
+    private static final int LOW_BMP_HEIGHT = 112;
     private static final int HIGH_BMP_WIDTH = 3000;
     private static final int HIGH_BMP_HEIGHT = 4000;
     private static final int VERY_LOW_BMP_WIDTH = 1;
@@ -189,7 +189,7 @@ public class WallpaperLocalColorExtractorTest extends SysuiTestCase {
 
     /**
      * Test that for bitmaps of random dimensions, the mini bitmap is always created
-     * with either a width <= SMALL_SIDE or a height <= SMALL_SIDE
+     * with an area <= MINI_BITMAP_MAX_AREA
      */
     @Test
     public void testMiniBitmapCreation() {
@@ -203,14 +203,14 @@ public class WallpaperLocalColorExtractorTest extends SysuiTestCase {
             spyColorExtractor.onBitmapChanged(bitmap);
 
             assertThat(mMiniBitmapUpdatedCount).isEqualTo(1);
-            assertThat(Math.min(mMiniBitmapWidth, mMiniBitmapHeight))
-                    .isAtMost(WallpaperLocalColorExtractor.SMALL_SIDE);
+            assertThat(mMiniBitmapWidth * mMiniBitmapHeight)
+                    .isAtMost(WallpaperLocalColorExtractor.MINI_BITMAP_MAX_AREA);
         }
     }
 
     /**
-     * Test that for bitmaps with both width and height <= SMALL_SIDE,
-     * the mini bitmap is always created with both width and height <= SMALL_SIDE
+     * Test that for bitmaps with both width and height <= LOW_BMP_WIDTH,
+     * the mini bitmap is always created with an area <= MINI_BITMAP_MAX_AREA
      */
     @Test
     public void testSmallMiniBitmapCreation() {
@@ -224,8 +224,8 @@ public class WallpaperLocalColorExtractorTest extends SysuiTestCase {
             spyColorExtractor.onBitmapChanged(bitmap);
 
             assertThat(mMiniBitmapUpdatedCount).isEqualTo(1);
-            assertThat(Math.max(mMiniBitmapWidth, mMiniBitmapHeight))
-                    .isAtMost(WallpaperLocalColorExtractor.SMALL_SIDE);
+            assertThat(mMiniBitmapWidth * mMiniBitmapHeight)
+                    .isAtMost(WallpaperLocalColorExtractor.MINI_BITMAP_MAX_AREA);
         }
     }