Windows Forms Programming in Visual Basic .NET

Optimized Drawing

If you're drawing using page units, transformations, and regions, it's likely that you're heavy into drawing. If that's the case, you'll be interested in ways to optimize your drawings for responsiveness and smooth operation. First and foremost, you'll want to avoid drawing anything that doesn't need drawing. You can do that in one of two ways: redraw only what needs to be redrawn, or don't draw unnecessarily in the first place.

First, invalidate only the portion of your drawing surface that needs to be refreshed. In other words, when drawing the internal state of your form or control, don't invalidate the whole thing if only a small part of the state has changed:

 Dim lotsOfNumbers() As Single Function GetRegionWhereNumberIsShow(number ...