add rotated text demo

svn path=/trunk/gtk-sharp/; revision=43417

sample/GtkDemo/DemoRotatedText.cs

@@ -0,0 +1,94 @@
+using System;
+using Gtk;
+using Pango;
+
+namespace GtkDemo
+{
+	[Demo ("Rotated Text", "DemoRotatedText.cs")]
+	public class DemoRotatedText : Window
+	{
+		const int RADIUS = 150;
+		const int N_WORDS = 10;
+
+		public DemoRotatedText () : base ("Rotated text")
+		{
+			DrawingArea drawingArea = new DrawingArea ();
+			Gdk.Color white = new Gdk.Color (0xff, 0xff, 0xff);
+
+			// This overrides the background color from the theme
+			drawingArea.ModifyBg (StateType.Normal, white);
+			drawingArea.ExposeEvent += new ExposeEventHandler (RotatedTextExposeEvent);
+
+			this.Add (drawingArea);
+			this.DeleteEvent += new DeleteEventHandler (OnWinDelete);
+			this.SetDefaultSize (2 * RADIUS, 2 * RADIUS);
+			this.ShowAll ();
+		}
+
+		void RotatedTextExposeEvent (object sender, ExposeEventArgs a)
+		{
+			DrawingArea drawingArea = sender as DrawingArea;
+
+			int width = drawingArea.Allocation.Width;
+			int height = drawingArea.Allocation.Height;
+
+			double deviceRadius;
+
+			// Get the default renderer for the screen, and set it up for drawing 
+			Gdk.PangoRenderer renderer = new Gdk.PangoRenderer (drawingArea.Screen);
+			renderer.Drawable = drawingArea.GdkWindow;
+			renderer.Gc = drawingArea.Style.BlackGC;
+
+			// Set up a transformation matrix so that the user space coordinates for
+			// the centered square where we draw are [-RADIUS, RADIUS], [-RADIUS, RADIUS]
+			// We first center, then change the scale
+			deviceRadius = Math.Min (width, height) / 2;
+			Matrix matrix = new Matrix ();
+			matrix.Translate (deviceRadius + (width - 2 * deviceRadius) / 2, deviceRadius + (height - 2 * deviceRadius) / 2);
+			matrix.Scale (deviceRadius / RADIUS, deviceRadius / RADIUS);
+
+			// Create a PangoLayout, set the font and text
+			Context context = drawingArea.CreatePangoContext ();
+			Pango.Layout layout = new Pango.Layout (context);
+			layout.SetText ("Text");
+			FontDescription desc = FontDescription.FromString ("Sans Bold 27");
+			layout.FontDescription = desc;
+
+			// Draw the layout N_WORDS times in a circle
+			for (int i = 0; i < N_WORDS; i++)
+			{
+				Gdk.Color color = new Gdk.Color ();
+				Matrix rotatedMatrix = matrix;
+				int w, h;
+				double angle = (360 * i) / N_WORDS;
+
+				// Gradient from red at angle == 60 to blue at angle == 300
+				color.Red = (ushort) (65535 * (1 + Math.Cos ((angle - 60) * Math.PI / 180)) / 2);
+				color.Green = 0;
+				color.Blue = (ushort) (65535 - color.Red);
+
+				renderer.SetOverrideColor (RenderPart.Foreground, color);
+
+				rotatedMatrix.Rotate (angle);
+				context.Matrix = rotatedMatrix;
+
+				// Inform Pango to re-layout the text with the new transformation matrix
+				layout.ContextChanged ();
+				layout.GetSize (out w, out h);
+				renderer.DrawLayout (layout, - w / 2, (int) (- RADIUS * Pango.Scale.PangoScale));
+			}
+
+			// Clean up default renderer, since it is shared
+			renderer.SetOverrideColor (RenderPart.Foreground, Gdk.Color.Zero);
+			renderer.Drawable = null;
+			renderer.Gc = null;
+		}
+
+		void OnWinDelete (object sender, DeleteEventArgs a)
+		{
+			this.Hide ();
+			this.Dispose ();
+		}
+	}
+}
+

sample/GtkDemo/Makefile.am

@@ -25,6 +25,7 @@ sources = \
 	DemoMenus.cs			\
 	DemoPanes.cs			\
 	DemoPixbuf.cs			\
+	DemoRotatedText.cs		\
 	DemoSizeGroup.cs		\
 	DemoStockBrowser.cs		\
 	DemoTextView.cs			\

sample/GtkDemo/TODO

@@ -6,9 +6,12 @@ General
 DemoMain
  - syntax highlighting
 
-"Change Display" is missing
+RotatedText
+ - doesn't quite work yet
+
+IconView
+ - missing
+
+Chang Display
+ - missing
 
-Future
-------
-IconView - gtk 2.6
-RotatedText - pango 1.6