Add rendered image callback for CefBrowserOsr/CefRenderer (fixes chromiumembedded#432)

Author: Osiris-Team

java/org/cef/SystemBootstrap.java

@@ -13,7 +13,9 @@ public class SystemBootstrap {
     /**
      * Simple interface for how a library by name should be loaded.
      */
-    static public interface Loader { public void loadLibrary(String libname); }
+    static public interface Loader {
+        public void loadLibrary(String libname);
+    }
 
     /**
      * Default implementation is to call System.loadLibrary

java/org/cef/browser/CefBrowserOsr.java

@@ -60,9 +60,11 @@
 import java.util.Arrays;
 import java.util.concurrent.Callable;
 import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
+import java.util.function.Consumer;
 
 import javax.swing.MenuSelectionManager;
 import javax.swing.SwingUtilities;
@@ -84,6 +86,9 @@ class CefBrowserOsr extends CefBrowser_N implements CefRenderHandler {
     private int depth_per_component = 8;
     private boolean isTransparent_;
 
+    private CopyOnWriteArrayList<Consumer<CefPaintEvent>> onPaintListeners =
+            new CopyOnWriteArrayList<>();
+
     CefBrowserOsr(CefClient client, String url, boolean transparent, CefRequestContext context) {
         this(client, url, transparent, context, null, null);
     }
@@ -354,6 +359,22 @@ public void onPopupSize(CefBrowser browser, Rectangle size) {
         renderer_.onPopupSize(size);
     }
 
+    @Override
+    public void addOnPaintListener(Consumer<CefPaintEvent> listener) {
+        onPaintListeners.add(listener);
+    }
+
+    @Override
+    public void setOnPaintListener(Consumer<CefPaintEvent> listener) {
+        onPaintListeners.clear();
+        onPaintListeners.add(listener);
+    }
+
+    @Override
+    public void removeOnPaintListener(Consumer<CefPaintEvent> listener) {
+        onPaintListeners.remove(listener);
+    }
+
     @Override
     public void onPaint(CefBrowser browser, boolean popup, Rectangle[] dirtyRects,
             ByteBuffer buffer, int width, int height) {
@@ -376,6 +397,13 @@ public void run() {
                 canvas_.display();
             }
         });
+        if (!onPaintListeners.isEmpty()) {
+            CefPaintEvent paintEvent =
+                    new CefPaintEvent(browser, popup, dirtyRects, buffer, width, height);
+            for (Consumer<CefPaintEvent> l : onPaintListeners) {
+                l.accept(paintEvent);
+            }
+        }
     }
 
     @Override

java/org/cef/browser/CefPaintEvent.java

@@ -0,0 +1,51 @@
+// Copyright (c) 2024 The Chromium Embedded Framework 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 org.cef.browser;
+
+import java.awt.*;
+import java.nio.ByteBuffer;
+
+public class CefPaintEvent {
+    private final CefBrowser browser;
+    private final boolean popup;
+    private final Rectangle[] dirtyRects;
+    private final ByteBuffer renderedFrame;
+    private final int width;
+    private final int height;
+
+    public CefPaintEvent(CefBrowser browser, boolean popup, Rectangle[] dirtyRects,
+            ByteBuffer renderedFrame, int width, int height) {
+        this.browser = browser;
+        this.popup = popup;
+        this.dirtyRects = dirtyRects;
+        this.renderedFrame = renderedFrame;
+        this.width = width;
+        this.height = height;
+    }
+
+    public CefBrowser getBrowser() {
+        return browser;
+    }
+
+    public boolean getPopup() {
+        return popup;
+    }
+
+    public Rectangle[] getDirtyRects() {
+        return dirtyRects;
+    }
+
+    public ByteBuffer getRenderedFrame() {
+        return renderedFrame;
+    }
+
+    public int getWidth() {
+        return width;
+    }
+
+    public int getHeight() {
+        return height;
+    }
+}

java/org/cef/handler/CefAppHandlerAdapter.java

@@ -32,9 +32,10 @@ public void onBeforeCommandLineProcessing(String process_type, CefCommandLine co
                     continue;
                 }
                 // Arguments with '--', '-' and, on Windows, '/' prefixes are considered switches.
-                int switchCnt = arg.startsWith("--")
-                        ? 2
-                        : arg.startsWith("/") ? 1 : arg.startsWith("-") ? 1 : 0;
+                int switchCnt = arg.startsWith("--") ? 2
+                        : arg.startsWith("/")        ? 1
+                        : arg.startsWith("-")        ? 1
+                                                     : 0;
                 switch (switchCnt) {
                     case 2:
                         // An argument of "--" will terminate switch parsing with all subsequent

java/org/cef/handler/CefRenderHandler.java

@@ -5,11 +5,13 @@
 package org.cef.handler;
 
 import org.cef.browser.CefBrowser;
+import org.cef.browser.CefPaintEvent;
 import org.cef.callback.CefDragData;
 
 import java.awt.Point;
 import java.awt.Rectangle;
 import java.nio.ByteBuffer;
+import java.util.function.Consumer;
 
 /**
  * Implement this interface to handle events when window rendering is disabled.
@@ -65,6 +67,24 @@ public interface CefRenderHandler {
     public void onPaint(CefBrowser browser, boolean popup, Rectangle[] dirtyRects,
             ByteBuffer buffer, int width, int height);
 
+    /**
+     * Add provided listener.
+     * @param listener Code that gets executed after a frame was rendered.
+     */
+    public void addOnPaintListener(Consumer<CefPaintEvent> listener);
+
+    /**
+     * Remove existing listeners and replace with provided listener.
+     * @param listener Code that gets executed after a frame was rendered.
+     */
+    public void setOnPaintListener(Consumer<CefPaintEvent> listener);
+
+    /**
+     * Remove provided listener.
+     * @param listener Code that gets executed after a frame was rendered.
+     */
+    public void removeOnPaintListener(Consumer<CefPaintEvent> listener);
+
     /**
      * Handle cursor changes.
      * @param browser The browser generating the event.