Comments by Bob Namenottaken

Bob Namenottaken 11-Jul-11 8:38am View

Thank you. I understand that - I just don't like the idea of wasting the time with the copy. But I'm ok if "that's the way it is". I was just wondering if experienced programmers had a tcehnique to avoid the copy.

Bob Namenottaken 9-Jul-11 12:40pm View

What I meant was you draw everything onto your in-memory screen-sized array and then call the Invalidate function when done. When WM_PAINT comes along you paint the whole thing in one shot.

I understand you could get more complicated and detect regions that have changed and start invalidating based on regions, etc. I suppose you could even use a timer to invalidate, set a flag to stop drawing, update the screen and then clear the flag... and myriad other ways, too... I really appreciate your insight. My son and I are going to play around with this over weekend.

Bob Namenottaken 9-Jul-11 8:05am View

This now makes me wonder why so many programmers discuss the use of double buffering. It seems to me this technique of 1) create in-memory, 2) invalidate, 3) WM_PAINT is inherently double-buffering. Why so many articles advising double buffering and how to do it?

Bob Namenottaken 8-Jul-11 20:09pm View

The code works, thanks again.

Bob Namenottaken 8-Jul-11 19:24pm View

Thank you so much!

Bob Namenottaken 8-Jul-11 18:19pm View

Ahh, that's a serious issue I never knew. So you maintain an in-memory image of your screen (assuming you're drawing images to the screen), then call a Validate or Update function and then Windows graciously invites you to WM_PAINT your screen? (At which time you use your example code to transfer your in-memory image to the screen?)

Bob Namenottaken 8-Jul-11 18:01pm View

Or am I completely mis-reading the example code and wrongly assuming it is used for WM_PAINT responses?

Bob Namenottaken 8-Jul-11 18:00pm View

Why is it necessary to perform this only in response to WM_PAINT? Do programs need to update a locally-owned in-memory bitmap and then wait for a WM_PAINT to get it on the screen? I realize WM_PAINT is needed in case the program is minimized, re-sized or moved - but can't a program just put a bitmap on the screen anytime anywhere in its code?

Bob Namenottaken 8-Jul-11 17:39pm View

Thank you, I'm going to play around with this tonight. I always thought Windows functions should've been more obvious (with a prefix of win_) for example.

I really appreciate the assistance with this. I was actually going to add that I didn't need code, just a list of the minimal requirements - but this is great!

Comments by Bob Namenottaken (Top 9 by date)