[Android] Speed up the method 'FlutterRenderer.getBitmap'

Author: ColdPaleLight

shell/platform/android/platform_view_android_jni_impl.cc

@@ -49,6 +49,10 @@ static fml::jni::ScopedJavaGlobalRef<jclass>* g_texture_wrapper_class = nullptr;
 
 static fml::jni::ScopedJavaGlobalRef<jclass>* g_java_long_class = nullptr;
 
+static fml::jni::ScopedJavaGlobalRef<jclass>* g_bitmap_class = nullptr;
+
+static fml::jni::ScopedJavaGlobalRef<jclass>* g_bitmap_config_class = nullptr;
+
 // Called By Native
 
 static jmethodID g_flutter_callback_info_constructor = nullptr;
@@ -115,6 +119,12 @@ static jmethodID g_overlay_surface_id_method = nullptr;
 
 static jmethodID g_overlay_surface_surface_method = nullptr;
 
+static jmethodID g_bitmap_create_bitmap_method = nullptr;
+
+static jmethodID g_bitmap_copy_pixels_from_buffer_method = nullptr;
+
+static jmethodID g_bitmap_config_value_of = nullptr;
+
 // Mutators
 static fml::jni::ScopedJavaGlobalRef<jclass>* g_mutators_stack_class = nullptr;
 static jmethodID g_mutators_stack_init_method = nullptr;
@@ -337,70 +347,31 @@ static jobject GetBitmap(JNIEnv* env, jobject jcaller, jlong shell_holder) {
     return nullptr;
   }
 
-  const SkISize& frame_size = screenshot.frame_size;
-  jsize pixels_size = frame_size.width() * frame_size.height();
-  jintArray pixels_array = env->NewIntArray(pixels_size);
-  if (pixels_array == nullptr) {
-    return nullptr;
-  }
-
-  jint* pixels = env->GetIntArrayElements(pixels_array, nullptr);
-  if (pixels == nullptr) {
-    return nullptr;
-  }
-
-  auto* pixels_src = static_cast<const int32_t*>(screenshot.data->data());
-
-  // Our configuration of Skia does not support rendering to the
-  // BitmapConfig.ARGB_8888 format expected by android.graphics.Bitmap.
-  // Convert from kRGBA_8888 to kBGRA_8888 (equivalent to ARGB_8888).
-  for (int i = 0; i < pixels_size; i++) {
-    int32_t src_pixel = pixels_src[i];
-    uint8_t* src_bytes = reinterpret_cast<uint8_t*>(&src_pixel);
-    std::swap(src_bytes[0], src_bytes[2]);
-    pixels[i] = src_pixel;
-  }
-
-  env->ReleaseIntArrayElements(pixels_array, pixels, 0);
-
-  jclass bitmap_class = env->FindClass("android/graphics/Bitmap");
-  if (bitmap_class == nullptr) {
-    return nullptr;
-  }
-
-  jmethodID create_bitmap = env->GetStaticMethodID(
-      bitmap_class, "createBitmap",
-      "([IIILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
-  if (create_bitmap == nullptr) {
-    return nullptr;
-  }
-
-  jclass bitmap_config_class = env->FindClass("android/graphics/Bitmap$Config");
-  if (bitmap_config_class == nullptr) {
-    return nullptr;
-  }
-
-  jmethodID bitmap_config_value_of = env->GetStaticMethodID(
-      bitmap_config_class, "valueOf",
-      "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;");
-  if (bitmap_config_value_of == nullptr) {
-    return nullptr;
-  }
-
   jstring argb = env->NewStringUTF("ARGB_8888");
   if (argb == nullptr) {
     return nullptr;
   }
 
   jobject bitmap_config = env->CallStaticObjectMethod(
-      bitmap_config_class, bitmap_config_value_of, argb);
+      g_bitmap_config_class->obj(), g_bitmap_config_value_of, argb);
   if (bitmap_config == nullptr) {
     return nullptr;
   }
 
-  return env->CallStaticObjectMethod(bitmap_class, create_bitmap, pixels_array,
-                                     frame_size.width(), frame_size.height(),
-                                     bitmap_config);
+  auto bitmap = env->CallStaticObjectMethod(
+      g_bitmap_class->obj(), g_bitmap_create_bitmap_method,
+      screenshot.frame_size.width(), screenshot.frame_size.height(),
+      bitmap_config);
+
+  fml::jni::ScopedJavaLocalRef<jobject> buffer(
+      env,
+      env->NewDirectByteBuffer(const_cast<uint8_t*>(screenshot.data->bytes()),
+                               screenshot.data->size()));
+
+  env->CallVoidMethod(bitmap, g_bitmap_copy_pixels_from_buffer_method,
+                      buffer.obj());
+
+  return bitmap;
 }
 
 static void DispatchPlatformMessage(JNIEnv* env,
@@ -945,6 +916,43 @@ bool RegisterApi(JNIEnv* env) {
     return false;
   }
 
+  g_bitmap_class = new fml::jni::ScopedJavaGlobalRef<jclass>(
+      env, env->FindClass("android/graphics/Bitmap"));
+  if (g_bitmap_class->is_null()) {
+    FML_LOG(ERROR) << "Could not locate Bitmap Class";
+    return false;
+  }
+
+  g_bitmap_create_bitmap_method = env->GetStaticMethodID(
+      g_bitmap_class->obj(), "createBitmap",
+      "(IILandroid/graphics/Bitmap$Config;)Landroid/graphics/Bitmap;");
+  if (g_bitmap_create_bitmap_method == nullptr) {
+    FML_LOG(ERROR) << "Could not locate Bitmap.createBitmap method";
+    return false;
+  }
+
+  g_bitmap_copy_pixels_from_buffer_method = env->GetMethodID(
+      g_bitmap_class->obj(), "copyPixelsFromBuffer", "(Ljava/nio/Buffer;)V");
+  if (g_bitmap_copy_pixels_from_buffer_method == nullptr) {
+    FML_LOG(ERROR) << "Could not locate Bitmap.copyPixelsFromBuffer method";
+    return false;
+  }
+
+  g_bitmap_config_class = new fml::jni::ScopedJavaGlobalRef<jclass>(
+      env, env->FindClass("android/graphics/Bitmap$Config"));
+  if (g_bitmap_config_class->is_null()) {
+    FML_LOG(ERROR) << "Could not locate Bitmap.Config Class";
+    return false;
+  }
+
+  g_bitmap_config_value_of = env->GetStaticMethodID(
+      g_bitmap_config_class->obj(), "valueOf",
+      "(Ljava/lang/String;)Landroid/graphics/Bitmap$Config;");
+  if (g_bitmap_config_value_of == nullptr) {
+    FML_LOG(ERROR) << "Could not locate Bitmap.Config.valueOf method";
+    return false;
+  }
+
   return true;
 }
 

testing/scenario_app/android/BUILD.gn

@@ -10,6 +10,7 @@ _android_sources = [
   "app/src/androidTest/java/dev/flutter/scenarios/EngineLaunchE2ETest.java",
   "app/src/androidTest/java/dev/flutter/scenarios/ExampleInstrumentedTest.java",
   "app/src/androidTest/java/dev/flutter/scenariosui/ExternalTextureTests.java",
+  "app/src/androidTest/java/dev/flutter/scenariosui/GetBitmapTests.java",
   "app/src/androidTest/java/dev/flutter/scenariosui/MemoryLeakTests.java",
   "app/src/androidTest/java/dev/flutter/scenariosui/PlatformTextureUiTests.java",
   "app/src/androidTest/java/dev/flutter/scenariosui/PlatformViewUiTests.java",
@@ -21,6 +22,7 @@ _android_sources = [
   "app/src/androidTest/java/dev/flutter/scenariosui/ScreenshotUtil.java",
   "app/src/androidTest/java/dev/flutter/scenariosui/SpawnEngineTests.java",
   "app/src/main/AndroidManifest.xml",
+  "app/src/main/java/dev/flutter/scenarios/GetBitmapActivity.java",
   "app/src/main/java/dev/flutter/scenarios/PlatformViewsActivity.java",
   "app/src/main/java/dev/flutter/scenarios/SpawnedEngineActivity.java",
   "app/src/main/java/dev/flutter/scenarios/StrictModeFlutterActivity.java",

testing/scenario_app/android/app/src/androidTest/java/dev/flutter/scenariosui/GetBitmapTests.java

@@ -0,0 +1,38 @@
+// 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 dev.flutter.scenariosui;
+
+import static org.junit.Assert.*;
+
+import android.content.Intent;
+import android.graphics.Bitmap;
+import androidx.annotation.NonNull;
+import androidx.test.filters.LargeTest;
+import androidx.test.rule.ActivityTestRule;
+import androidx.test.runner.AndroidJUnit4;
+import dev.flutter.scenarios.GetBitmapActivity;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+@RunWith(AndroidJUnit4.class)
+@LargeTest
+public class GetBitmapTests {
+  @Rule @NonNull
+  public ActivityTestRule<GetBitmapActivity> activityRule =
+      new ActivityTestRule<>(
+          GetBitmapActivity.class, /*initialTouchMode=*/ false, /*launchActivity=*/ false);
+
+  @Test
+  public void getBitmap() throws Exception {
+    Intent intent = new Intent(Intent.ACTION_MAIN);
+    intent.putExtra("scenario_name", "get_bitmap");
+    GetBitmapActivity activity = activityRule.launchActivity(intent);
+    Bitmap bitmap = activity.getBitmap();
+
+    assertEquals(bitmap.getPixel(10, 10), 0xFFFF0000);
+    assertEquals(bitmap.getPixel(10, bitmap.getHeight() - 10), 0xFF0000FF);
+  }
+}

testing/scenario_app/android/app/src/main/AndroidManifest.xml

@@ -60,5 +60,17 @@
                 <category android:name="android.intent.category.LAUNCHER" />
             </intent-filter>
         </activity>
+        <activity
+            android:name=".GetBitmapActivity"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:launchMode="singleTop"
+            android:windowSoftInputMode="adjustResize"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
     </application>
 </manifest>

testing/scenario_app/android/app/src/main/java/dev/flutter/scenarios/GetBitmapActivity.java

@@ -0,0 +1,25 @@
+// 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 dev.flutter.scenarios;
+
+import android.graphics.Bitmap;
+import androidx.annotation.Nullable;
+
+public class GetBitmapActivity extends TestActivity {
+
+  @Nullable private volatile Bitmap bitmap;
+
+  @Nullable
+  public Bitmap getBitmap() {
+    waitUntilFlutterRendered();
+    return bitmap;
+  }
+
+  @Nullable
+  protected void notifyFlutterRendered() {
+    bitmap = getFlutterEngine().getRenderer().getBitmap();
+    super.notifyFlutterRendered();
+  }
+}

testing/scenario_app/lib/src/get_bitmap_scenario.dart

@@ -0,0 +1,35 @@
+// 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.
+
+import 'dart:ui';
+
+import 'scenario.dart';
+
+/// Displays a platform texture with the given width and height.
+class GetBitmapScenario extends Scenario {
+  /// Creates the GetBitmap scenario.
+  ///
+  /// The [dispatcher] parameter must not be null.
+  GetBitmapScenario(PlatformDispatcher dispatcher)
+      : super(dispatcher);
+
+  @override
+  void onBeginFrame(Duration duration) {
+    final PictureRecorder recorder = PictureRecorder();
+    final Canvas canvas = Canvas(recorder);
+    canvas.drawRect(Rect.fromLTWH(0, 0, window.physicalSize.width, 300),
+        Paint()..color = const Color(0xFFFF0000));
+    canvas.drawRect(
+        Rect.fromLTWH(0, window.physicalSize.height - 300,
+            window.physicalSize.width, 300),
+        Paint()..color = const Color(0xFF0000FF));
+    final Picture picture = recorder.endRecording();
+    final SceneBuilder builder = SceneBuilder();
+    builder.addPicture(Offset.zero, picture);
+    final Scene scene = builder.build();
+    window.render(scene);
+    picture.dispose();
+    scene.dispose();
+  }
+}

testing/scenario_app/lib/src/scenarios.dart

@@ -6,6 +6,7 @@ import 'dart:ui';
 
 import 'animated_color_square.dart';
 import 'bogus_font_text.dart';
+import 'get_bitmap_scenario.dart';
 import 'initial_route_reply.dart';
 import 'locale_initialization.dart';
 import 'platform_view.dart';
@@ -52,6 +53,7 @@ Map<String, ScenarioFactory> _scenarios = <String, ScenarioFactory>{
   'spawn_engine_works' : () => BogusFontText(PlatformDispatcher.instance),
   'pointer_events': () => TouchesScenario(PlatformDispatcher.instance),
   'display_texture': () => DisplayTexture(PlatformDispatcher.instance),
+  'get_bitmap': () => GetBitmapScenario(PlatformDispatcher.instance),
 };
 
 Map<String, dynamic> _currentScenarioParams = <String, dynamic>{};