Canvas.Fillrect vs Rectangle.Fillcolor

Targets Windows
1

I have an app (for teaching purposes) that shows a rectangle and 3 sliders. The sliders correspond with a RGB colorsetting. If you move the slider, the RGB of the rectangle is changed. Nothing fancy here.

When I use the canvas with the g.paint method and the canvas.invalidate method for the sliders I get lots of flicker. The canvas does not allow me to choose Double Buffer, it switches back to off. Don’t know why. GDI+ is On.

When I use a Rectangle and the Rectangle.Fillcolor method, there is no flicker, no matter how fast I move the sliders. How come?
Xojo 2015 3.1 Desktop Windows

2

What is the value of the Canvas’ EraseBackGround property?
If the canvas erases to background color THEN draws your rectangle, you are probably seeing the background flicker through.

3

[quote=240842:@Jeff Tullin]What is the value of the Canvas’ EraseBackGround property?
If the canvas erases to background color THEN draws your rectangle, you are probably seeing the background flicker through.[/quote]
That was ON. Switching it off did the trick… thanks!