Getting Started X11 window application

draw2d/src/cmd/testX11draw.go

@@ -0,0 +1,63 @@
+package main
+
+import (
+	"fmt"
+	"exp/draw"
+	"exp/draw/x11"
+	"image"
+	"math"
+	//"draw2d"
+	"draw2d.googlecode.com/svn/trunk/draw2d/src/pkg/draw2d"
+)
+
+func main() {
+	window, err := x11.NewWindow()
+	if(err != nil) {
+		fmt.Printf("Cannot open an x11 window\n")
+		return
+	}
+	screen := window.Screen()
+	if rgba, ok := screen.(*image.RGBA); ok {
+		gc := draw2d.NewGraphicContext(rgba)
+		gc.SetStrokeColor(image.Black)
+		gc.SetFillColor(image.White)
+		gc.Clear()
+		for i := 0.0 ; i < 360; i = i + 10 {// Go from 0 to 360 degrees in 10 degree steps
+		  gc.BeginPath()              		// Start a new path
+		  gc.Save()                			// Keep rotations temporary
+		  gc.MoveTo(144, 144)
+		  gc.Rotate(i * (math.Pi / 180.0))	// Rotate by degrees on stack from 'for'
+		  gc.RLineTo(72, 0)
+		  gc.Stroke()
+		  gc.Restore()           			// Get back the unrotated state
+		}
+		fmt.Printf("This is an rgba image\n")
+	
+		window.FlushImage()
+		
+		gc.SetLineWidth(3)
+		nbclick := 0
+		for {
+			
+			switch evt := (<-window.EventChan()).(type) {
+			case draw.KeyEvent:
+				if(evt.Key == 'q') {
+					window.Close()
+				}
+			case draw.MouseEvent:
+				if(evt.Buttons & 1 != 0) {
+					if(nbclick % 2 == 0) {
+						gc.MoveTo(float(evt.Loc.X),float(evt.Loc.Y))
+					} else {
+						gc.LineTo(float(evt.Loc.X),float(evt.Loc.Y))
+						gc.Stroke()
+						window.FlushImage()
+					}
+					nbclick = nbclick + 1
+				}
+			}
+		}
+	} else {
+		fmt.Printf("Not an RGBA image!\n")
+	}
+}