How to send message to Desktop Widget

**marcel** · 17th April 2007, 14:42

grabWidget() works only for QWdgets.
I guess you'll have to do a little search on MSDN for this one

**marcel** · 17th April 2007, 14:46

Actually, try this:
http://www.codeproject.com/tools/Win...er_Utility.asp

**jpn** · 17th April 2007, 14:54

QPixmap::grabWindow() takes a native window system identifier (WId).

**shyam prasad** · 17th April 2007, 15:17

Hi,
Thnx Marcel and Jpn for your valuable suggestions.
But the thing is that i want use this capture screen technology on MAC, Linux, and Windows.
So i thought that QT have some support for it but i haven't found anything useful yet.

"Jpn" although grabWindow() can work for me but the whole thing is that how can i know in my QT app that which is active window and how do i get winId of the active window.

And "Marcel" the link you had given me is a useful one i want to use my app across many platforms including MAC, Linux and Windows.

Thnx again for your kind help.

**jpn** · 17th April 2007, 15:56

Originally Posted by shyam prasad

"Jpn" although grabWindow() can work for me but the whole thing is that how can i know in my QT app that which is active window and how do i get winId of the active window.

I'm afraid you need a platform dependent solution for that.

Something like XGetInputFocus(), GetActiveWindow() and so on..

**aamer4yu** · 18th April 2007, 05:12

Did u happen to see the Screen capture example in the Qt demos ?? U can find it under Desktop->Screen capture in the demo....

it uses something like...

originalPixmap = QPixmap::grabWindow(QApplication::desktop()->winId());

am not sure how portable is this.

hope this helps...

**shyam prasad** · 18th April 2007, 07:07

Hi,
Thanks to all for your valuable suggestions.
I know that how it can be done using Windows APIs.
But i haven't done anything in MAC or Linux.
So i don't know how to implement function which can capture active window.
I am not aware of MAC and Linux specific APIs.
And also i don't have any link or documentation like MSDN for Mac and Linux systems.

If anybody have any idea how can i write this function for Mac and Linux then please help me out.

In Window GetWindowFromPoint() gives me the handle of window which i clicked using mouse. and then everything is easy. But i don't know how i can do this using MAC and Linux specific APIs.

Also in my first post i asked whom i should sent this "Alt + PrtScn" message so that it will just dump the Active Window image to the clipboard. I think if i can do this then it will ease my work.

Or can anyone show me the code snippet to capture active window on Mac and Linux, especially Mac OS.

Waiting for valuable suggestions from all of you. Thanks for your interest. I think there are many people who wants to do the same thing.

Thanks in advance.

Shalabh............

**marcel** · 18th April 2007, 07:32

And also i don't have any link or documentation like MSDN for Mac and Linux systems.

For mac: developer.apple.com
For linux: the X server api documentation www.x.org

regards

**aamer4yu** · 18th April 2007, 08:51

from Qt docs...

WId QWidget::winId () const
Returns the window system identifier of the widget.
Portable in principle, but if you use it you are probably about to do something non-portable. Be careful.

what does it mean by portable in principle ??

is this function portable or non portable ??

**marcel** · 18th April 2007, 08:54

It is portable! But in principle

**aamer4yu** · 18th April 2007, 10:04

OK...
so in principle.. its portable !!

**wysota** · 18th April 2007, 10:15

It means that it is portable by itself, but if you use it, you are doing something which is not portable, so portability of the winId() method is not important as it is surrounded by an unportable code.