[icedtea-web] RFC: Patch to double-buffer applets

[Deepak Bhole]

* Deepak Bhole <dbhole at redhat.com> [2010-11-02 17:31]:
> Hi,
> 
> IcedTea plugin currently does not double-buffer the applet panel. As a
> result, some applets may flicker depending on the machine.
> 
> Attached patch buffers the frame offscreen and then draws it, thereby
> addressing the issue.
> 
> ChangeLog:
> 2010-11-02  Deepak Bhole <dbhole at redhat.com>
> 
>    * plugin/icedteanp/java/sun/applet/PluginAppletViewer.java (update):
>    Override method and implement double-buffering.
> 
> Cheers,
> Deepak


Doh! There shouldn't be a println in there. New patch attached. I also
fixed the variable names for the image and its graphics.

Cheers,
Deepak

> diff -r 6c2527d42900 ChangeLog
> --- a/ChangeLog	Mon Nov 01 11:44:15 2010 -0400
> +++ b/ChangeLog	Tue Nov 02 17:29:03 2010 -0700
> @@ -1,3 +1,8 @@
> +2010-11-02  Deepak Bhole <dbhole at redhat.com>
> +
> +	* plugin/icedteanp/java/sun/applet/PluginAppletViewer.java (update):
> +	Override method and implement double-buffering.
> +
>  2010-11-01  Omair Majid  <omajid at redhat.com>
>  
>  	* Makefile.am (clean-IcedTeaPlugin): Only delete launcher directory if it
> diff -r 6c2527d42900 NEWS
> --- a/NEWS	Mon Nov 01 11:44:15 2010 -0400
> +++ b/NEWS	Tue Nov 02 17:29:03 2010 -0700
> @@ -12,3 +12,4 @@
>  
>  * Initial release of IcedTea-Web
>  * PR542: Plugin fails with NPE on http://www.openprocessing.org/visuals/iframe.php?visualID=2615
> +* Applets are now double-buffered to eliminate flicker in ones that do heavy drawing
> diff -r 6c2527d42900 plugin/icedteanp/java/sun/applet/PluginAppletViewer.java
> --- a/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java	Mon Nov 01 11:44:15 2010 -0400
> +++ b/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java	Tue Nov 02 17:29:03 2010 -0700
> @@ -359,6 +366,9 @@
>  
>       private static Long requestIdentityCounter = 0L;
>       
> +     private Image bufferedPanelImage;
> +     private Graphics bufferedImageGraphics;
> +     
>       /**
>        * Null constructor to allow instantiation via newInstance()
>        */
> @@ -2163,4 +2178,24 @@
>          }
>      }
>       }
> +
> +     /**
> +      * {@inheritDoc}
> +      */
> +     public void update(Graphics g) {
> +
> +    	 System.err.println("Buffering and drawing");
> +    	 
> +    	 // If the image or the graphics don't exist, create new ones
> +    	 if (bufferedPanelImage == null || bufferedImageGraphics == null) {
> +    		 bufferedPanelImage = createImage(getWidth(), getHeight());
> +    		 bufferedImageGraphics = bufferedPanelImage.getGraphics ();
> +    	 }
> +
> +    	 // Paint off-screen
> +    	 paint(bufferedImageGraphics);
> +
> +    	 // Draw the painted image
> +    	 g.drawImage(bufferedPanelImage, 0, 0, this);
> +     }
>   }

-------------- next part --------------
diff -r 6c2527d42900 ChangeLog
--- a/ChangeLog	Mon Nov 01 11:44:15 2010 -0400
+++ b/ChangeLog	Tue Nov 02 17:37:09 2010 -0700
@@ -1,3 +1,8 @@
+2010-11-02  Deepak Bhole <dbhole at redhat.com>
+
+	* plugin/icedteanp/java/sun/applet/PluginAppletViewer.java (update):
+	Override method and implement double-buffering.
+
 2010-11-01  Omair Majid  <omajid at redhat.com>
 
 	* Makefile.am (clean-IcedTeaPlugin): Only delete launcher directory if it
diff -r 6c2527d42900 NEWS
--- a/NEWS	Mon Nov 01 11:44:15 2010 -0400
+++ b/NEWS	Tue Nov 02 17:37:09 2010 -0700
@@ -12,3 +12,4 @@
 
 * Initial release of IcedTea-Web
 * PR542: Plugin fails with NPE on http://www.openprocessing.org/visuals/iframe.php?visualID=2615
+* Applets are now double-buffered to eliminate flicker in ones that do heavy drawing
diff -r 6c2527d42900 plugin/icedteanp/java/sun/applet/PluginAppletViewer.java
--- a/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java	Mon Nov 01 11:44:15 2010 -0400
+++ b/plugin/icedteanp/java/sun/applet/PluginAppletViewer.java	Tue Nov 02 17:37:09 2010 -0700
@@ -359,6 +366,9 @@
 
      private static Long requestIdentityCounter = 0L;
      
+     private Image bufferedFrameImage;
+     private Graphics bufferedFrameImageGraphics;
+     
      /**
       * Null constructor to allow instantiation via newInstance()
       */
@@ -2163,4 +2178,22 @@
         }
     }
      }
+
+     /**
+      * {@inheritDoc}
+      */
+     public void update(Graphics g) {
+
+    	 // If the image or the graphics don't exist, create new ones
+    	 if (bufferedFrameImage == null || bufferedFrameImageGraphics == null) {
+    		 bufferedFrameImage = createImage(getWidth(), getHeight());
+    		 bufferedFrameImageGraphics = bufferedFrameImage.getGraphics ();
+    	 }
+
+    	 // Paint off-screen
+    	 paint(bufferedFrameImageGraphics);
+
+    	 // Draw the painted image
+    	 g.drawImage(bufferedFrameImage, 0, 0, this);
+     }
  }