Creates a new RenderMode for FlutterView (#19143)

Author: bparrishMines

ci/licenses_golden/licenses_flutter

@@ -689,6 +689,7 @@ FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/Flutt
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterEngineProvider.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterFragment.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterFragmentActivity.java
+FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterImageView.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterSplashView.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterSurfaceView.java
 FILE: ../../../flutter/shell/platform/android/io/flutter/embedding/android/FlutterTextureView.java

shell/platform/android/BUILD.gn

@@ -135,6 +135,7 @@ android_java_sources = [
   "io/flutter/embedding/android/FlutterEngineProvider.java",
   "io/flutter/embedding/android/FlutterFragment.java",
   "io/flutter/embedding/android/FlutterFragmentActivity.java",
+  "io/flutter/embedding/android/FlutterImageView.java",
   "io/flutter/embedding/android/FlutterSplashView.java",
   "io/flutter/embedding/android/FlutterSurfaceView.java",
   "io/flutter/embedding/android/FlutterTextureView.java",

shell/platform/android/io/flutter/embedding/android/FlutterImageView.java

@@ -0,0 +1,106 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.embedding.android;
+
+import android.annotation.SuppressLint;
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.ColorSpace;
+import android.hardware.HardwareBuffer;
+import android.media.Image;
+import android.media.Image.Plane;
+import android.media.ImageReader;
+import android.view.View;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+/**
+ * Paints a Flutter UI provided by an {@link android.media.ImageReader} onto a {@link
+ * android.graphics.Canvas}.
+ *
+ * <p>A {@code FlutterImageView} is intended for situations where a developer needs to render a
+ * Flutter UI, but also needs to render an interactive {@link
+ * io.flutter.plugin.platform.PlatformView}.
+ *
+ * <p>This {@code View} takes an {@link android.media.ImageReader} that provides the Flutter UI in
+ * an {@link android.media.Image} and renders it to the {@link android.graphics.Canvas} in {@code
+ * onDraw}.
+ */
+@SuppressLint("ViewConstructor")
+@TargetApi(19)
+public class FlutterImageView extends View {
+  private final ImageReader imageReader;
+  @Nullable private Image nextImage;
+  @Nullable private Image currentImage;
+
+  /**
+   * Constructs a {@code FlutterImageView} with an {@link android.media.ImageReader} that provides
+   * the Flutter UI.
+   */
+  public FlutterImageView(@NonNull Context context, @NonNull ImageReader imageReader) {
+    super(context, null);
+    this.imageReader = imageReader;
+  }
+
+  /** Acquires the next image to be drawn to the {@link android.graphics.Canvas}. */
+  @TargetApi(19)
+  public void acquireLatestImage() {
+    nextImage = imageReader.acquireLatestImage();
+    invalidate();
+  }
+
+  @Override
+  protected void onDraw(Canvas canvas) {
+    super.onDraw(canvas);
+    if (nextImage == null) {
+      return;
+    }
+
+    if (currentImage != null) {
+      currentImage.close();
+    }
+    currentImage = nextImage;
+    nextImage = null;
+
+    if (android.os.Build.VERSION.SDK_INT >= 29) {
+      drawImageBuffer(canvas);
+      return;
+    }
+
+    drawImagePlane(canvas);
+  }
+
+  @TargetApi(29)
+  private void drawImageBuffer(@NonNull Canvas canvas) {
+    final HardwareBuffer buffer = currentImage.getHardwareBuffer();
+
+    final Bitmap bitmap = Bitmap.wrapHardwareBuffer(buffer, ColorSpace.get(ColorSpace.Named.SRGB));
+    canvas.drawBitmap(bitmap, 0, 0, null);
+  }
+
+  private void drawImagePlane(@NonNull Canvas canvas) {
+    if (currentImage == null) {
+      return;
+    }
+
+    final Plane[] imagePlanes = currentImage.getPlanes();
+    if (imagePlanes.length != 1) {
+      return;
+    }
+
+    final Plane imagePlane = imagePlanes[0];
+    final int desiredWidth = imagePlane.getRowStride() / imagePlane.getPixelStride();
+    final int desiredHeight = currentImage.getHeight();
+
+    final Bitmap bitmap =
+        android.graphics.Bitmap.createBitmap(
+            desiredWidth, desiredHeight, android.graphics.Bitmap.Config.ARGB_8888);
+
+    bitmap.copyPixelsFromBuffer(imagePlane.getBuffer());
+    canvas.drawBitmap(bitmap, 0, 0, null);
+  }
+}

shell/platform/android/io/flutter/embedding/android/FlutterView.java

@@ -79,6 +79,7 @@ public class FlutterView extends FrameLayout implements MouseCursorPlugin.MouseC
   // Internal view hierarchy references.
   @Nullable private FlutterSurfaceView flutterSurfaceView;
   @Nullable private FlutterTextureView flutterTextureView;
+  @Nullable private FlutterImageView flutterImageView;
   @Nullable private RenderSurface renderSurface;
   private final Set<FlutterUiDisplayListener> flutterUiDisplayListeners = new HashSet<>();
   private boolean isFlutterUiDisplayed;
@@ -155,7 +156,8 @@ public FlutterView(@NonNull Context context) {
 
   /**
    * Deprecated - use {@link #FlutterView(Context, FlutterSurfaceView)} or {@link
-   * #FlutterView(Context, FlutterTextureView)} instead.
+   * #FlutterView(Context, FlutterTextureView)} or {@link #FlutterView(Context, FlutterImageView)}
+   * instead.
    */
   @Deprecated
   public FlutterView(@NonNull Context context, @NonNull RenderMode renderMode) {
@@ -164,9 +166,12 @@ public FlutterView(@NonNull Context context, @NonNull RenderMode renderMode) {
     if (renderMode == RenderMode.surface) {
       flutterSurfaceView = new FlutterSurfaceView(context);
       renderSurface = flutterSurfaceView;
-    } else {
+    } else if (renderMode == RenderMode.texture) {
       flutterTextureView = new FlutterTextureView(context);
       renderSurface = flutterTextureView;
+    } else {
+      throw new IllegalArgumentException(
+          String.format("RenderMode not supported with this constructor: ", renderMode));
     }
 
     init();
@@ -216,6 +221,18 @@ public FlutterView(@NonNull Context context, @NonNull FlutterTextureView flutter
     this(context, null, flutterTextureView);
   }
 
+  /**
+   * Constructs a {@code FlutterView} programmatically, without any XML attributes, uses the given
+   * {@link FlutterImageView} to render the Flutter UI.
+   *
+   * <p>{@code FlutterView} requires an {@code Activity} instead of a generic {@code Context} to be
+   * compatible with {@link PlatformViewsController}.
+   */
+  @TargetApi(19)
+  public FlutterView(@NonNull Context context, @NonNull FlutterImageView flutterImageView) {
+    this(context, null, flutterImageView);
+  }
+
   /**
    * Constructs a {@code FlutterView} in an XML-inflation-compliant manner.
    *
@@ -243,9 +260,12 @@ public FlutterView(
       flutterSurfaceView =
           new FlutterSurfaceView(context, transparencyMode == TransparencyMode.transparent);
       renderSurface = flutterSurfaceView;
-    } else {
+    } else if (renderMode == RenderMode.texture) {
       flutterTextureView = new FlutterTextureView(context);
       renderSurface = flutterTextureView;
+    } else {
+      throw new IllegalArgumentException(
+          String.format("RenderMode not supported with this constructor: ", renderMode));
     }
 
     init();
@@ -275,15 +295,30 @@ private FlutterView(
     init();
   }
 
+  @TargetApi(19)
+  private FlutterView(
+      @NonNull Context context,
+      @Nullable AttributeSet attrs,
+      @NonNull FlutterImageView flutterImageView) {
+    super(context, attrs);
+
+    this.flutterImageView = flutterImageView;
+
+    init();
+  }
+
   private void init() {
     Log.v(TAG, "Initializing FlutterView");
 
     if (flutterSurfaceView != null) {
       Log.v(TAG, "Internally using a FlutterSurfaceView.");
       addView(flutterSurfaceView);
-    } else {
+    } else if (flutterTextureView != null) {
       Log.v(TAG, "Internally using a FlutterTextureView.");
       addView(flutterTextureView);
+    } else {
+      Log.v(TAG, "Internally using a FlutterImageView.");
+      addView(flutterImageView);
     }
 
     // FlutterView needs to be focusable so that the InputMethodManager can interact with it.
@@ -1018,7 +1053,16 @@ public enum RenderMode {
      * android.graphics.SurfaceTexture} are required, developers should strongly prefer the {@link
      * RenderMode#surface} render mode.
      */
-    texture
+    texture,
+    /**
+     * {@code RenderMode}, which paints Paints a Flutter UI provided by an {@link
+     * android.media.ImageReader} onto a {@link android.graphics.Canvas}. This mode is not as
+     * performant as {@link RenderMode#surface}, but a {@code FlutterView} in this mode can handle
+     * full interactivity with a {@link io.flutter.plugin.platform.PlatformView}. Unless {@link
+     * io.flutter.plugin.platform.PlatformView}s are required developers should strongly prefer the
+     * {@link RenderMode#surface} render mode.
+     */
+    image
   }
 
   /**

shell/platform/android/io/flutter/embedding/android/RenderMode.java

@@ -21,5 +21,14 @@ public enum RenderMode {
    * Views}. Unless the special capabilities of a {@link android.graphics.SurfaceTexture} are
    * required, developers should strongly prefer the {@link #surface} render mode.
    */
-  texture
+  texture,
+  /**
+   * {@code RenderMode}, which paints Paints a Flutter UI provided by an {@link
+   * android.media.ImageReader} onto a {@link android.graphics.Canvas}. This mode is not as
+   * performant as {@link RenderMode#surface}, but a {@code FlutterView} in this mode can handle
+   * full interactivity with a {@link io.flutter.plugin.platform.PlatformView}. Unless {@link
+   * io.flutter.plugin.platform.PlatformView}s are required developers should strongly prefer the
+   * {@link RenderMode#surface} render mode.
+   */
+  image
 }

shell/platform/android/test/io/flutter/embedding/android/FlutterViewTest.java

@@ -12,6 +12,7 @@
 import android.content.Context;
 import android.content.res.Configuration;
 import android.content.res.Resources;
+import android.media.ImageReader;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.WindowInsets;
@@ -370,6 +371,17 @@ public void systemInsetHandlesFullscreenNavbarLeft() {
     assertEquals(100, viewportMetricsCaptor.getValue().paddingRight);
   }
 
+  @Test
+  public void flutterImageView_acquiresImageAndInvalidates() {
+    final ImageReader mockReader = mock(ImageReader.class);
+    final FlutterImageView imageView =
+        spy(new FlutterImageView(RuntimeEnvironment.application, mockReader));
+
+    imageView.acquireLatestImage();
+    verify(mockReader, times(1)).acquireLatestImage();
+    verify(imageView, times(1)).invalidate();
+  }
+
   /*
    * A custom shadow that reports fullscreen flag for system UI visibility
    */