From 5a9dce518edb2487b76485723401751ac0be0a74 Mon Sep 17 00:00:00 2001
From: Sebastian Franco <fransebas@google.com>
Date: Wed, 8 Dec 2021 13:14:13 -0600
Subject: [PATCH] Combining the Thumbnail bitmap with the background to fix
 background spilling in the front.

What's happening is that we first draw a background,
on top of it, we then draw the Task and because we
have a curvature the corners have pixels with transparency,
and those pixels get combined with the background pixels.
Most tasks have a transparent background or background
of the same color as the task so we don't see this
but for example, Telegram has a white background and
you can see this in the corners.

Fixed by creating a bitmap, drawing the background on it
and then drawing the thumbnail on top of it then using
that bitmap to draw it on the canvas.

Test: Put Telegram in recent Task (shouldn't be the first one) and you won't see a white border. Also when a task was in multitask the backgroudn should be draw.
Fix: 146521490
Change-Id: Id02a64ef472eb07900b0c7c5522d931d5b08f94e
---
 .../quickstep/views/TaskThumbnailView.java    | 33 +++++++++++--------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/quickstep/src/com/android/quickstep/views/TaskThumbnailView.java b/quickstep/src/com/android/quickstep/views/TaskThumbnailView.java
index 60b0d17b40..11f9ddd5b3 100644
--- a/quickstep/src/com/android/quickstep/views/TaskThumbnailView.java
+++ b/quickstep/src/com/android/quickstep/views/TaskThumbnailView.java
@@ -50,6 +50,7 @@ import androidx.core.graphics.ColorUtils;
 import com.android.launcher3.BaseActivity;
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Utilities;
+import com.android.launcher3.icons.BitmapRenderer;
 import com.android.launcher3.util.MainThreadInitializedObject;
 import com.android.launcher3.util.SystemUiController;
 import com.android.quickstep.TaskOverlayFactory.TaskOverlay;
@@ -161,6 +162,23 @@ public class TaskThumbnailView extends View {
         setThumbnail(task, thumbnailData, true /* refreshNow */);
     }
 
+    /**
+     * By combining the two in a single bitmap then we only have to do a single draw
+     * call in the onDraw function. Also, this fixes a bug where the background was
+     * visible in the corners because of anti-aliasing.
+     */
+    public Bitmap combineThumbnailAndBackground(Bitmap bm) {
+        return BitmapRenderer.createHardwareBitmap(bm.getWidth(), bm.getHeight(), c -> {
+            final boolean drawBackgroundOnly = mTask == null || mTask.isLocked;
+            if (drawBackgroundOnly) {
+                c.drawPaint(mBackgroundPaint);
+            } else {
+                c.drawPaint(mBackgroundPaint);
+                c.drawBitmap(bm, 0, 0, null);
+            }
+        });
+    }
+
     /** Updates the shader, paint, matrix to redraw. */
     public void refresh() {
         refresh(false);
@@ -173,6 +191,7 @@ public class TaskThumbnailView extends View {
     private void refresh(boolean shouldRefreshOverlay) {
         if (mThumbnailData != null && mThumbnailData.thumbnail != null) {
             Bitmap bm = mThumbnailData.thumbnail;
+            bm = combineThumbnailAndBackground(bm);
             bm.prepareToDraw();
             mBitmapShader = new BitmapShader(bm, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
             mPaint.setShader(mBitmapShader);
@@ -194,7 +213,6 @@ public class TaskThumbnailView extends View {
      * <p>
      * If dimAlpha is 0, no dimming is applied; if dimAlpha is 1, the thumbnail will be the
      * extracted background color.
-     *
      */
     public void setDimAlpha(float dimAlpha) {
         mDimAlpha = dimAlpha;
@@ -296,18 +314,6 @@ public class TaskThumbnailView extends View {
                 return;
             }
         }
-
-        // Always draw the background since the snapshots might be translucent or partially empty
-        // (For example, tasks been reparented out of dismissing split root when drag-to-dismiss
-        // split screen).
-        canvas.drawRoundRect(x, y, width, height, cornerRadius, cornerRadius, mBackgroundPaint);
-
-        final boolean drawBackgroundOnly = mTask == null || mTask.isLocked || mBitmapShader == null
-                || mThumbnailData == null;
-        if (drawBackgroundOnly) {
-            return;
-        }
-
         canvas.drawRoundRect(x, y, width, height, cornerRadius, cornerRadius, mPaint);
     }
 
@@ -338,7 +344,6 @@ public class TaskThumbnailView extends View {
 
     private void updateThumbnailPaintFilter() {
         ColorFilter filter = getColorFilter(mDimAlpha);
-        mBackgroundPaint.setColorFilter(filter);
         int alpha = (int) (mDimAlpha * 255);
         mDimmingPaintAfterClearing.setAlpha(alpha);
         if (mBitmapShader != null) {