[Gtk-sharp-list] BitBlt to render images.

[Miguel de Icaza]

Hello,

> >        * What kind of samples are missing?
> 
> I'm looking for the features to implement a right-to-left, smooth-scrolling
> graph displaying real-time data.  I have an (old) Win32 application which uses
> low-level stuff like BitBlt's etc to achieve this.  I'm not sure at what 
> level I
> could implement the same thing in Gtk#, or whether other Gnome (GnomeCanvas?)
> stuff is needed, though I need it to work on both linux and Win32.

I have attached a program that does the right-to-left rendering using
BitBlt.  It depends on an image called "/tmp/a.png" to be available as
this is the image rendered.

This program uses Gdk.Pixbufs (which are client-side images), because it
was fast for me to use, but you might want to use server-side for a
sample like this as you would avoid sending the images from your app to
X on every iteration.

Also, this program has no error checking ;-)

Miguel.

using System;
using Gtk;
using GLib;

class Demo {
	static DrawingArea d;
	static int x;
	static Gdk.Pixbuf pixbuf;
	
	static void Main ()
	{
		Application.Init ();
		Window w = new Window ("H");
		d = new DrawingArea ();
		d.SetSizeRequest (200, 200);
		d.ExposeEvent += new ExposeEventHandler (ExposeHandler);
		
		w.Add (d);
		w.ShowAll ();

		pixbuf = new Gdk.Pixbuf ("/tmp/a.png");

		GLib.Timeout.Add (100, new TimeoutHandler (queue_repaint));
		Application.Run ();
	}

	static bool queue_repaint ()
	{
		x += 5;
		d.QueueDrawArea (0, 0, d.Allocation.Width, d.Allocation.Height);

		if (x == pixbuf.Width)
			return false;
		
		return true;
	}

	static void ExposeHandler (object a , Gtk.ExposeEventArgs args)
	{
                Gdk.Window win = args.Event.Window;

                win.DrawPixbuf (d.Style.WhiteGC, pixbuf, 0, 0, d.Allocation.Width-x, 0, x, d.Allocation.Height, Gdk.RgbDither.None, 0, 0);
	}
}