[haiku-3rdparty-dev] Re: Capturing control commands in Haiku
- From: Zenja Solaja <solaja@xxxxxxxxx>
- To: haiku-3rdparty-dev@xxxxxxxxxxxxx
- Date: Sat, 5 Sep 2009 14:06:53 +1000
Hi Yash.
Isn't each BControl message application specific? Eg. In my apps, I'd
create my own message associated with each BControl (eg. 'open', 'save'),
but this will always be app specific. BTW - I'm quite sure that you know
that BeOS allows scripting of BMessages - have a look at Hey (
http://wiki.bebits.com/page/HeY).
As far as I know, drawing commands are not sent via messages, instead the
app server directly invokes hook functions - your derived BView class's
method Draw(BRect..). This is different from say Win32 which sends a
WM_PAINT message. Without looking at the source implementation, I'd suspect
BeInc did it this way to synchronise redraws and prevent screen tearing,
since the applications BHandler runs in a seperate thread, hence a lot of
time may pass until your app is scheduled to receive messages, and during
this time you will not actually update the screen. A hook function allows
the app server to directly invoke screen updates. I hope this makes sense,
otherwise I can write a lengthier explanation.
Good luck.
Zenja
On Sat, Sep 5, 2009 at 1:32 PM, Yashasvi A.C. <yashasviac@xxxxxxxxx> wrote:
> Hey guys,
>
> As you know, I am working on an application that catches messages in Haiku
> and analyzes them. That problem was solved a while ago using the
> message_print_hook() command. However, I would like to know if it was
> possible to catch something on a higher level.
>
> Say, for example, I click on a button right now. Using the messages, I can
> capture messages like _MMV, _MDN and so on. These represent the mouse
> movements and clicking. However, its too low level taking the entire system
> into perspective. What I am looking for is probably something like a control
> command i.e. something like BTN_CLK or something when the button is clicked.
> This would sort of give a higher level context on what the mouse click at
> that specific location meant.
>
> Hopefully, that description was clear. Similarly, is there any way to
> capture drawing commands? When the different components of the UI are
> re-drawn continuously on the UI with a Paint() or Update() command or
> something, can we capture the messages/commands that go through then?
>
> Thanks for all your help!
>
> Cheers,
> Yash
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