GtkSharp/sample/GtkDemo/DemoPixbuf.cs

// DemoPixbuf.cs: Pixbuf demonstration
//
// Gtk# port of pixbuf demo in gtk-demo app.
//
// Author: Yves Kurz <yves@magnific.ch>
//
// <c> 2003 Yves Kurz

/* Pixbufs
 *
 * A Pixbuf represents an image, normally in RGB or RGBA format.
 * Pixbufs are normally used to load files from disk and perform
 * image scaling.
 *
 * This demo is not all that educational, but looks cool. It was written
 * by Extreme Pixbuf Hacker Federico Mena Quintero. It also shows
 * off how to use DrawingArea to do a simple animation.
 *
 * Look at the Image demo for additional pixbuf usage examples.
 *
 */

using Gdk;
using Gtk;

using System;

namespace GtkDemo 
{
	[Demo ("Pixbuf", "DemoPixbuf.cs")]
	public class DemoPixbuf : Gtk.Window
	{
		const int FrameDelay = 50;
		const int CycleLen = 60;
		const string BackgroundName = "background.jpg";
		
		string [] ImageNames = {
			"apple-red.png",
			"gnome-applets.png",
			"gnome-calendar.png",
			"gnome-foot.png",
			"gnome-gmush.png",
			"gnome-gimp.png",
			"gnome-gsame.png",
			"gnu-keys.png"
		};
		
		// current frame
		Pixbuf frame;
		int frameNum;
	
		// background image
		Pixbuf background;
		int backWidth, backHeight;

		// images
		Pixbuf[] images;

		// drawing area
		DrawingArea drawingArea;

		// Loads the images for the demo 
		void LoadPixbuf ()
		{
			background = Gdk.Pixbuf.LoadFromResource (BackgroundName);

			backWidth = background.Width;
			backHeight = background.Height;

			images = new Pixbuf[ImageNames.Length];
		
			int i = 0;
			foreach (string im in ImageNames) 
				images[i++] = Gdk.Pixbuf.LoadFromResource (im);
		}

		// Expose callback for the drawing area
		void Expose (object o, ExposeEventArgs args)
		{
		        EventExpose ev = args.Event;
			Widget widget = (Widget) o;
			Gdk.Rectangle area = ev.Area;

			frame.RenderToDrawableAlpha(
					widget.GdkWindow,
					0, 0,
					0, 0,
					backWidth, backHeight,
					Gdk.PixbufAlphaMode.Full, 8,
					RgbDither.Normal,
					100, 100);
		}
	
		// timeout handler to regenerate the frame
		bool timeout ()
		{
			background.CopyArea (0, 0, backWidth, backHeight, frame, 0, 0);

			double f = (double) (frameNum % CycleLen) / CycleLen;

			int xmid = backWidth / 2;
			int ymid = backHeight / 2;

			double radius = Math.Min (xmid, ymid) / 2;

			for (int i = 0; i < images.Length; i++) {
				double ang = 2 * Math.PI * i / images.Length - f * 2 *
					Math.PI;

				int iw = images[i].Width;
				int ih = images[i].Height;

				double r = radius + (radius / 3) * Math.Sin (f * 2 * 
					Math.PI);

				int xpos = (int) Math.Floor (xmid + r * Math.Cos (ang) -
					iw / 2 + 0.5);
				int ypos = (int) Math.Floor (ymid + r * Math.Sin (ang) -
					ih / 2 + 0.5);
			
				double k = (i % 2 == 1) ? Math.Sin (f * 2 * Math.PI) : 
					Math.Cos (f * 2 * Math.PI);
				k = 2 * k * k;
				k = Math.Max (0.25, k);

				Rectangle r1, r2, dest;

				r1 = new Rectangle (xpos, ypos,(int) (iw * k),
					(int) (ih * k));

	/* FIXME: Why is that code not working (in the original gtk-demo it works

				r2 = new Rectangle (0, 0, backWidth, backHeight);

				dest = new Rectangle (0, 0, 0, 0);
				r1.Intersect (r2, dest);

				images[i].Composite (frame, dest.x, dest.y, dest.width,
					dest.height, xpos, ypos, k, k,
					InterpType.Nearest, (int) ((i % 2 == 1)
					? Math.Max (127, Math.Abs (255 * Math.Sin (f *
						2 * Math.PI)))
					: Math.Max (127, Math.Abs (255 * Math.Cos (f *
						2 * Math.PI)))));
	*/
				images[i].Composite (frame, r1.X, r1.Y, r1.Width,
					r1.Height, xpos, ypos, k, k,
					InterpType.Nearest, (int) ((i % 2 == 1)
					? Math.Max (127, Math.Abs (255 * Math.Sin (f *
						2 * Math.PI)))
					: Math.Max (127, Math.Abs (255 * Math.Cos (f *
						2 * Math.PI)))));
			}

			drawingArea.QueueDraw ();
			frameNum++;
		
			return true;
		}

		public DemoPixbuf () : base ("Gdk Pixbuf Demo")
		{
			this.DeleteEvent += new DeleteEventHandler (OnWindowDelete);

			try
			{
				LoadPixbuf ();
			} catch (Exception e)
			{
				using (MessageDialog md = new MessageDialog (this,
						DialogFlags.DestroyWithParent,
						MessageType.Error,
						ButtonsType.Close,
						"Error: \n" + e.Message)) {
					md.Run ();
					md.Hide ();
				}

				throw;
			}

			frame = new Pixbuf (Colorspace.Rgb, true, 8, backWidth, 
					backHeight);

			drawingArea = new DrawingArea ();
			drawingArea.ExposeEvent += new ExposeEventHandler (Expose);

			Add (drawingArea);
			GLib.Timeout.Add (FrameDelay, new GLib.TimeoutHandler(timeout)); 

			this.SetDefaultSize (backWidth, backHeight);
	//		this.Resizable = false;
			ShowAll ();
		}

		void OnWindowDelete (object obj, DeleteEventArgs args)
		{
			this.Hide ();
			this.Destroy ();
			args.RetVal = true;
		}
	}
}