public override void DrawRect(NSRect aRect)
{
// calculate the number of tick intervals since the hourglass was shown
NSDate dateNow = NSDate.DateWithTimeIntervalSinceNow(0);
double timeElapsed = dateNow.TimeIntervalSinceReferenceDate - iTimeShown;
int numIntervals = (int)(timeElapsed / 0.06);
// save graphics state for restoring later
NSGraphicsContext context = NSGraphicsContext.CurrentContext;
context.SaveGraphicsState();
// apply transforms to rotate the foreground image
NSImage bkgd = Properties.Resources.IconHourglass;
NSImage frgd = Properties.Resources.IconHourglass2;
NSAffineTransform xform1 = new NSAffineTransform();
xform1.TranslateXByYBy(Bounds.Width * 0.5f, Bounds.Height * 0.5f);
xform1.Concat();
NSAffineTransform xform2 = new NSAffineTransform();
xform2.RotateByDegrees(-45.0f * (numIntervals % 8));
xform2.Concat();
bool scale = Bounds.Width < frgd.Size.width || Bounds.Height < frgd.Size.height;
NSAffineTransform xform3 = null;
if (scale)
{
float scaleX = Bounds.Width / frgd.Size.width;
float scaleY = Bounds.Height / frgd.Size.height;
float ratio = scaleX > scaleY ? scaleX : scaleY;
xform3 = new NSAffineTransform();
xform3.ScaleBy(ratio);
xform3.Concat();
}
NSAffineTransform xform4 = new NSAffineTransform();
xform4.TranslateXByYBy(-frgd.Size.width * 0.5f, -frgd.Size.height * 0.5f);
xform4.Concat();
// draw background and foreground
bkgd.DrawAtPointFromRectOperationFraction(Bounds.origin, NSRect.NSZeroRect, NSCompositingOperation.NSCompositeSourceOver, 1.0f);
frgd.DrawAtPointFromRectOperationFraction(Bounds.origin, NSRect.NSZeroRect, NSCompositingOperation.NSCompositeSourceOver, 1.0f);
// clean up
xform1.Release();
xform2.Release();
if (scale)
{
xform3.Release();
}
xform4.Release();
context.RestoreGraphicsState();
// schedule another timer event
this.PerformSelectorWithObjectAfterDelay(ObjectiveCRuntime.Selector("timerUpdate"), null, 0.06);
}
