OnPaint when using Offscreen bitmap

  • Thread starter Thread starter mBird
  • Start date Start date
M

mBird

I am using an offscreen bitmap and I have scrolling.
For now I DrawImage the entire offscreen bitmap -- but that is slow.
Could anyone please tell me how to only DrawImage the portion I need so it
will go faster.
Thank you!

For now I do:
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
e.Graphics.TranslateTransform(
AutoScrollPosition.X, AutoScrollPosition.Y);
e.Graphics.DrawImage(offScreenBmp, 0, 0);
System.Drawing.Size s = new System.Drawing.Size();
s.Width = 0;
s.Height = 2100;
AutoScrollMinSize = s;
}
 
PaintEventArgs has a ClipRectangle property that contains the rectangle
that needs redrawing. You could use that.

Bryan Haber[MSFT]
NET Client QA
 
Back
Top