[Qt-interest] 答复: 答复: capture screen
pengliang(彭亮)
pengliang at founder.com
Tue Jun 15 03:20:43 CEST 2010
Hi Alex:
Aha, I agree your point on using "this".
After added " QCoreApplication::processEvents ( QEventLoop::ProcessEventsFlags flags = QEventLoop::AllEvents )" behind hide(), the problem has been fixed.
Thank you very much.
Regards.
Ken
-----邮件原件-----
发件人: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] 代表 Malyushytsky, Alex
发送时间: 2010年6月15日 6:41
收件人: qt-interest at trolltech.com
主题: Re: [Qt-interest] 答复: capture screen
The line mentioned below should be read as:
QTimer::singleShot(0, this, SLOT(capture_screen ()));
Also I want to add the following:
There is nothing wrong with using "this" even though it is not required.
Sometimes it saves you time clearly stating that you are calling the member function and not global one.
There are some commercial / free packages who actually enforce or recommend such style ( for example VTK ).
My own opinion is that using "this" does improve clarity and if you don't tend to combine complicated operations in long lines
have only positive effect on readability and may even improve speed the code is written.
For example VC will provide you a list of available class members and choosing between them may not only save you time on typing,
but also may save you time for additional compilation required if you mistype the member name.
It does not mean that you have to duplicate lines using this and without it though.
Chose the style you prefer and use it where you can.
But during your life as a programmer you will be forced to follow different styles,
sometimes few times per day, depending on the project you will be working on.
Rejecting to do this may prevent you from being hired.
Regards,
Alex
-----Original Message-----
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Malyushytsky, Alex
Sent: Monday, June 14, 2010 3:03 PM
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] 答复: capture screen
I don't think hide does anything beside scheduling an event, which may be not even processed
When you are trying to capture.
I would either try to call
QCoreApplication::processEvents ( QEventLoop::ProcessEventsFlags flags = QEventLoop::AllEvents )
after hide() or made capture_screen() a slot if it is not, moved show() there and used
QTimer::singleShot(0, this, SLOT(_ ()));
to invoke capture. In this case you will have to move show() at the end of capture_screen()
Hope this helps,
Alex
-----Original Message-----
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of pengliang(??)
Sent: Sunday, June 13, 2010 6:51 PM
To: qt-interest at trolltech.com
Subject: [Qt-interest] 答复: capture screen
Hi Luis:
Thank you.
Hi Carsten:
Thanks for your advice.
I have modified them, but the problem still does exist.
-----------------------------------
if(setHideWnd == true) {
hide();
capture_screen();
show();
} else {
Capture_screen();
}
----------------------------------
void MainWindow::capture_screen()
{
QString picture_file= QString("%1/%2").arg(save_dir).arg("picture ");
QPixmap fullscreenmap;
fullscreenmap =QPixmap::grabWindow(QApplication::desktop()->winId());
fullscreenmap.save(picture_file,"JPG",-1);
}
-------------------------------------------
Whether I still made some mistakes?
-----邮件原件-----
发件人: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] 代表 Luis Lezcano Airaldi
发送时间: 2010年6月13日 0:16
收件人: qt-interest at trolltech.com
主题: Re: [Qt-interest] capture screen
El 12/06/10 07:31, Carsten Breuer escribió:
> Hi pengliang,
> hi all,
>
>
>> Please see the snippet bellow. (I want to minimizied the windows
>> and capture the screen, but application capture screen before the window
>> was fully minimized.) why? Can anybody tell me why? Or give me some ideas.
>>
> The code needs a lot of cleanup because if is unnecessary complicated.
> The function windowHideShow is almost useless.
>
> You have created some really funny things here:
>
> this-hide(); LOL
>
> You take the address of the widget and subtract the result of
> hide of it and throw the result away. Funny.
>
> I think you meant this->hide();
> You do the same here: while(this-isHidden())
>
> NEVER EVER use this inside a class without the need of
> doing so! The only reason to use this is to give another
> class a pointer to your instance.
> The use of this is a disease that occur since python programmers
> try to use C++ (in python you have to do it that way with self).
>
> Here some other points:
>
> 1. Why do you want to toggle isHideWnd. No need for that.
> You have two variables doing the same thing
> 2. You try to call functions twice! One time with this, the
> other time correct.
>
> Clean up the code first and REMOVE all the useless "this".
>
>
> Best Regards,
>
That's the problem when they use html in a mailing list. Your client
removed the ">" of this->hide() so you're not seeing it.
Back to the problem, what happens if you uncomment the line
qApp->proccessEvents()? I'm not sure, but that should minimize the
window and then you take the screenshot...
Regards.
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