On Wed, 29 Jan 2020 19:38:44 GMT, Mike Wey wrote:

On 29-01-2020 15:14, Ron Tarrant wrote:

So the coordinates of a drawing area start at x=0 y=0.

In this case it is also easier to call queueDraw to invalidate the complete drawingArea/Widget.

Oh, wow. Thanks, Mike. All this time, I've been doing it wrong. And that's for the tip about queueDraw(). Takes all the worry out of it.

You've helped me solve a problem in another example I've been working on, too. I was about to abandon it, but now that this has come to light...

So again, thank you, sir. You've saved the day.