Merge "Use median instead of mean for sampling border luma" into rvc-dev (3e7dd917) · Commits · e / os / android_frameworks_base

services/core/java/com/android/server/wm/ScreenRotationAnimation.java

+1 −1

Original line number	Diff line number	Diff line
		@@ -205,7 +205,7 @@ class ScreenRotationAnimation {
		SurfaceControl.ScreenshotGraphicBuffer gb =
		mService.mDisplayManagerInternal.screenshot(displayId);
		if (gb != null) {
		mStartLuma = RotationAnimationUtils.getAvgBorderLuma(gb.getGraphicBuffer(),
		mStartLuma = RotationAnimationUtils.getMedianBorderLuma(gb.getGraphicBuffer(),
		gb.getColorSpace());
		try {
		surface.attachAndQueueBufferWithColorSpace(gb.getGraphicBuffer(),

services/core/java/com/android/server/wm/utils/RotationAnimationUtils.java

+17 −11

Original line number	Diff line number	Diff line
		@@ -26,6 +26,8 @@ import android.view.Display;
		import android.view.Surface;
		import android.view.SurfaceControl;

		import java.util.Arrays;


		/** Helper functions for the {@link com.android.server.wm.ScreenRotationAnimation} class*/
		public class RotationAnimationUtils {
		@@ -35,31 +37,35 @@ public class RotationAnimationUtils {
		* luminance at the borders of the bitmap
		* @return the average luminance of all the pixels at the borders of the bitmap
		*/
		public static float getAvgBorderLuma(GraphicBuffer graphicBuffer, ColorSpace colorSpace) {
		public static float getMedianBorderLuma(GraphicBuffer graphicBuffer, ColorSpace colorSpace) {
		Bitmap hwBitmap = Bitmap.wrapHardwareBuffer(graphicBuffer, colorSpace);
		if (hwBitmap == null) {
		return 0;
		}

		Bitmap swaBitmap = hwBitmap.copy(Bitmap.Config.ARGB_8888, false);
		float totalLuma = 0;
		int height = swaBitmap.getHeight();
		int width = swaBitmap.getWidth();
		float[] borderLumas = new float[2 * width + 2 * height];
		int i;
		for (i = 0; i < width; i++) {
		totalLuma += swaBitmap.getColor(i, 0).luminance();
		totalLuma += swaBitmap.getColor(i, height - 1).luminance();
		int index = 0;
		for (i = 0; i < width; i++, index += 2) {
		borderLumas[index] = swaBitmap.getColor(i, 0).luminance();
		borderLumas[index + 1] = swaBitmap.getColor(i, height - 1).luminance();
		}
		for (i = 0; i < height; i++) {
		totalLuma += swaBitmap.getColor(0, i).luminance();
		totalLuma += swaBitmap.getColor(width - 1, i).luminance();
		for (i = 0; i < height; i++, index += 2) {
		borderLumas[index] = swaBitmap.getColor(0, i).luminance();
		borderLumas[index + 1] = swaBitmap.getColor(width - 1, i).luminance();
		}
		return totalLuma / (2 * width + 2 * height);
		// Oh, is this too simple and inefficient for you?
		// How about implementing a O(n) solution? https://en.wikipedia.org/wiki/Median_of_medians
		Arrays.sort(borderLumas);
		return borderLumas[borderLumas.length / 2];
		}

		/**
		* Gets the average border luma by taking a screenshot of the {@param surfaceControl}.
		* @see #getAvgBorderLuma(GraphicBuffer, ColorSpace)
		* @see #getMedianBorderLuma(GraphicBuffer, ColorSpace)
		*/
		public static float getLumaOfSurfaceControl(Display display, SurfaceControl surfaceControl) {
		if (surfaceControl == null) {
		@@ -75,7 +81,7 @@ public class RotationAnimationUtils {
		return 0;
		}

		return RotationAnimationUtils.getAvgBorderLuma(buffer.getGraphicBuffer(),
		return RotationAnimationUtils.getMedianBorderLuma(buffer.getGraphicBuffer(),
		buffer.getColorSpace());
		}

services/tests/wmtests/src/com/android/server/wm/utils/RotationAnimationUtilsTest.java

+19 −7

Original line number	Diff line number	Diff line
		@@ -50,7 +50,7 @@ public class RotationAnimationUtilsTest {
		public void blackLuma() {
		Bitmap swBitmap = createBitmap(0);
		GraphicBuffer gb = swBitmapToGraphicsBuffer(swBitmap);
		float borderLuma = RotationAnimationUtils.getAvgBorderLuma(gb, mColorSpace);
		float borderLuma = RotationAnimationUtils.getMedianBorderLuma(gb, mColorSpace);
		assertEquals(0, borderLuma, 0);
		}

		@@ -58,7 +58,15 @@ public class RotationAnimationUtilsTest {
		public void whiteLuma() {
		Bitmap swBitmap = createBitmap(1);
		GraphicBuffer gb = swBitmapToGraphicsBuffer(swBitmap);
		float borderLuma = RotationAnimationUtils.getAvgBorderLuma(gb, mColorSpace);
		float borderLuma = RotationAnimationUtils.getMedianBorderLuma(gb, mColorSpace);
		assertEquals(1, borderLuma, 0);
		}

		@Test
		public void unevenBitmapDimens() {
		Bitmap swBitmap = createBitmap(1, BITMAP_WIDTH + 1, BITMAP_HEIGHT + 1);
		GraphicBuffer gb = swBitmapToGraphicsBuffer(swBitmap);
		float borderLuma = RotationAnimationUtils.getMedianBorderLuma(gb, mColorSpace);
		assertEquals(1, borderLuma, 0);
		}

		@@ -67,7 +75,7 @@ public class RotationAnimationUtilsTest {
		Bitmap swBitmap = createBitmap(1);
		setBorderLuma(swBitmap, 0);
		GraphicBuffer gb = swBitmapToGraphicsBuffer(swBitmap);
		float borderLuma = RotationAnimationUtils.getAvgBorderLuma(gb, mColorSpace);
		float borderLuma = RotationAnimationUtils.getMedianBorderLuma(gb, mColorSpace);
		assertEquals(0, borderLuma, 0);
		}

		@@ -76,7 +84,7 @@ public class RotationAnimationUtilsTest {
		Bitmap swBitmap = createBitmap(0);
		setBorderLuma(swBitmap, 1);
		GraphicBuffer gb = swBitmapToGraphicsBuffer(swBitmap);
		float borderLuma = RotationAnimationUtils.getAvgBorderLuma(gb, mColorSpace);
		float borderLuma = RotationAnimationUtils.getMedianBorderLuma(gb, mColorSpace);
		assertEquals(1, borderLuma, 0);
		}

		@@ -123,9 +131,13 @@ public class RotationAnimationUtilsTest {
		}

		private Bitmap createBitmap(float luma) {
		Bitmap bitmap = Bitmap.createBitmap(BITMAP_WIDTH, BITMAP_HEIGHT, ARGB_8888);
		for (int i = 0; i < BITMAP_WIDTH; i++) {
		for (int j = 0; j < BITMAP_HEIGHT; j++) {
		return createBitmap(luma, BITMAP_WIDTH, BITMAP_HEIGHT);
		}

		private Bitmap createBitmap(float luma, int width, int height) {
		Bitmap bitmap = Bitmap.createBitmap(width, height, ARGB_8888);
		for (int i = 0; i < width; i++) {
		for (int j = 0; j < height; j++) {
		bitmap.setPixel(i, j, Color.argb(1, luma, luma, luma));
		}
		}