public static void Main(string[] args)
{
Application.Init();
Window win = new Window(WindowType.Toplevel);
VBox vBox = new VBox();
HScale transparencyScale = new HScale(0, 255, 1)
{
Value = 255
};
Image image = new Image();
image.SetSizeRequest(200, 200);
vBox.PackStart(transparencyScale);
vBox.PackStart(image);
win.Add(vBox);
transparencyScale.ValueChanged += delegate {
int transparency = (int)transparencyScale.Value;
byte[] tBytes = BitConverter.GetBytes(transparency);
Gdk.GC red = new Gdk.GC(win.GdkWindow)
{
RgbFgColor = new Gdk.Color(255, 0, 0)
};
Gdk.GC black = new Gdk.GC(win.GdkWindow)
{
RgbFgColor = new Gdk.Color(0, 0, 0)
};
Gdk.GC translucent = new Gdk.GC(win.GdkWindow)
{
RgbFgColor = new Gdk.Color(tBytes[0], tBytes[0], tBytes[0])
};
Gdk.GC visible = new Gdk.GC(win.GdkWindow)
{
RgbFgColor = new Gdk.Color(255, 255, 255)
};
Gdk.Pixmap pixmap = new Gdk.Pixmap(win.GdkWindow, 200, 200);
pixmap.DrawRectangle(black, true, 0, 0, 200, 200);
pixmap.DrawArc(red, true, 20, 20, 160, 160, 0, 23040);
Gdk.Pixmap mask = new Gdk.Pixmap(win.GdkWindow, 200, 200);
mask.DrawRectangle(visible, true, 0, 0, 200, 200);
mask.DrawArc(translucent, true, 0, 0, 100, 100, 0, 23040);
mask.DrawArc(translucent, true, 100, 100, 100, 100, 0, 23040);
image.SetFromPixmap(pixmap, mask);
image.ShowAll();
};
win.ShowAll();
Application.Run();
}
