How can I paint on a transparent window in MFC?

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I can use the "WS_EX_TRANSPARENT" style to make a window transparent. That does work.

But when I try to paint on the transparent window, a problem occurs. While it's necessary to erase the background of the window to do a good job of painting, the erasure of the window's background turn out to be a problem since it will make the transparent window opaque again and the display will flicker.

I've tried to override the OnEraseBkgnd() function by just returning TRUE and use a null_brush to erase the background of the window myself (a dialog window in my case), but it didn't work. Therefore, I want to know how can I do a good job of painting while keeping the window on which the graphic is painted transparent all the time? I'm hoping that someone can help me! Thanks a lot!

Posted 25-Nov-09 19:50pm

code_enjoy

Updated 22-Aug-21 5:20am

Gordon Brandly

v2

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Radhakrishnan G. · Answer 1 · 2009-11-28T23:32:00

Solution 1

Is it possible to use WS_EX_LAYERED style in this case? and set transparency using SetLayeredWindowAttributes(),[^].

Thanks
Radhakrishnan G.

Posted 28-Nov-09 23:32pm

Radhakrishnan G.

Updated 28-Nov-09 23:36pm

v3

armagedescu · Answer 2 · 2021-08-22T05:20:00

Solution 2

You should use SetWindowRgn, it makes literally any part of your window transparent, read more about it here: SetWindowRgn function (winuser.h) - Win32 apps | Microsoft Docs[^]. Also document your self about creating regions.

Posted 22-Aug-21 5:20am

armagedescu

Comments

Richard MacCutchan 22-Aug-21 12:34pm

This is yet another answer posted to a question that was raised more than eleven years ago. While your efforts are to be admired, it really is better to focus on current questions, where people are actually still waiting for solutions.

OriginalGriff 23-Aug-21 5:04am

The problem is that you've already been picked up as "probable troll" because you are answering old questions.
Most of the time when people do that, it's to "hide" the answers away and rack up reputation points - and we count that as a form of site abuse and kick people from the site. And another member has started that process, for that reason.

I can stop it, but ... Richard and the other member do have a point - and your reply is aggressive in tone which doesn't help your case.
So, talk to me: why are you answering old questions exclusively? If you have a good reason, I'll do my best to stop you getting kicked off. If it's abuse, I'll help them along. But don't wait to long: we take a dim view of "rep point farming" and the kicking process can be remarkably quick!

CHill60 23-Aug-21 7:56am

Possible hacked? Quiet for years then suddenly all this.

OriginalGriff 23-Aug-21 8:22am

Either way, it'll close soon.

CHill60 23-Aug-21 10:00am

"See stackoverflow, there the response to old unanswered question is welcomed" Er ... no it's not. They lock off questions to prevent such a thing

CHill60 23-Aug-21 10:54am

I am familiar with the StackOverflow processes. You do not need a special badge to revive a closed question. If a question receives 3 "Close" votes it will be closed to further answers unless re-opened. That re-opening is reviewed by the community.
However, this is not Stack Overflow. This forum is a "Quick Answers" forum and not really a knowledge base, but all of that is irrelevant - OriginalGriff has tried to guide you on opinions and behaviours of members on this site, none of which appeared "personal". If you choose to ignore him, then that is your right.

armagedescu 23-Aug-21 12:38pm

Anyway I will delete all my replies shortly because I am not intending to share the non technical comments, that's not a psychology forum. These comments were intended to build a discussion, but this is not the right place for such discussions.

OriginalGriff 23-Aug-21 8:59am

Some peopel take rep seriously: they use ity on their resume to make themselves "look better", I think.

Post solutions to old questions looks like that kind of behavior: please refrain in future!

OriginalGriff 23-Aug-21 9:37am

I'm trying to be friendly and warn you of how this site works to help you.
If you choose to ascribe other motives to my comments and continue on your current course of action, then that's your problem, not mine...
Goodbye.

How can I paint on a transparent window in MFC?

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