[Qt-interest] paint one image over other continously

[Ulf-Alexander v. Ceumern-Lindenstjerna]

Hi,

I assume that you only transfer the partial images from the client to
the server and that you get the original coordinates
(originalCoordinates) of the image from the client.
And I assume that you assemble the images (pixmapFromClient) to a new
image on the server (serverPixmap). 

QPoint originalCoordinates; // get from client
QPixmap pixmap(pixmapFromClient);

QPainter(&serverPixmap); // you could also paint directly on your widget
by overriding paintEvent!
painter.drawPixmap(originalCoordinates, pixmapFromClient);

This way you only overwrite a certain part of the serverImage.

Look at it this way: only update the regions of the images that have
changed and leave the rest intact.

About the flickering: Qt has double buffering enabled, so you should not
see any flicker if you paint your widget with a QPainter.

Regards, Ulf

> -----Original Message-----
> From: Rahulkumar Tibdewal
[mailto:rahulkumar_tibdewal at persistent.co.in]
> Sent: Friday, September 25, 2009 11:11 AM
> To: Ulf-Alexander v. Ceumern-Lindenstjerna
> Cc: qt-interest at trolltech.com
> Subject: RE: [Qt-interest] paint one image over other continously
> 
> 
> Thanks.
> 
> I also don't intend to overwrite the original image.
> I am getting pieces of images from client machine and  I want to
> display them on server machine.
> On server machine I need to put all pieces in place so that It appear
> as a continuous non flickering image of client desktop.
> 
> I tried your method but it's not working for me. Can you please help
me
> with some written sample code.
> 
> Thanks
> Rahul
> 
> 
> 
> -----Original Message-----
> From: Ulf-Alexander v. Ceumern-Lindenstjerna
> [mailto:ceumern at vrmagic.com]
> Sent: Friday, September 25, 2009 2:11 PM
> To: Rahulkumar Tibdewal
> Cc: qt-interest at trolltech.com
> Subject: RE: [Qt-interest] paint one image over other continously
> 
> 
> Well then don't overwrite the image data ?!
> 
> Here is what I would do:
> 
> Open a QPainter on the target image and use
> QPainter::drawPixmap(...sourceImage...)
> (http://doc.trolltech.com/4.5/qpainter.html#drawPixmap)
> 
> If you could provide more information about how exactly you are
drawing
> the image, more people would be able to help.
> 
> HTH, Ulf
> 
> > -----Original Message-----
> > From: qt-interest-bounces at trolltech.com [mailto:qt-interest-
> > bounces at trolltech.com] On Behalf Of Rahulkumar Tibdewal
> > Sent: Friday, September 25, 2009 10:29 AM
> > To: John McClurkin; qt-interest at trolltech.com
> > Subject: Re: [Qt-interest] paint one image over other continously
> >
> > It's not a question of calling update(). Update will simply invoke
> > paint event again. I want my previous image should not get
> overwritten.
> >
> > Thanks
> > Rahul
> >
> >
> >
> >
> > -----Original Message-----
> > From: qt-interest-bounces at trolltech.com [mailto:qt-interest-
> > bounces at trolltech.com] On Behalf Of John McClurkin
> > Sent: Thursday, September 24, 2009 8:45 PM
> > To: qt-interest at trolltech.com
> > Subject: Re: [Qt-interest] paint one image over other continously
> >
> > Rahulkumar Tibdewal wrote:
> > > Hello All,
> > >
> > >
> > >
> > > I am developing the application where server can monitor the
client
> > > desktop. I am sending the images continuously from client to
server
> > so
> > > that server can see client desktop.
> > >
> > > Images are sent whenever there is any change on client desktop.
> i.e.
> > > only changing rectangle images are sent for performance reasons.
> > >
> > >
> > >
> > > My Question is how can I paint continuously appearing images from
> > client.
> > >
> > > I want to paint one image over other to its proper location
> > continuously
> > > so that it appear and continuous visualization of desktop, I am
not
> > sure
> > > how's that possible.
> > >
> > By calling update() on the server widget that displays the client
> > desktop whenever a new image is received? Really, this question is
> too
> > vague to allow people to help you.
> > _______________________________________________
> > Qt-interest mailing list
> > Qt-interest at trolltech.com
> > http://lists.trolltech.com/mailman/listinfo/qt-interest
> >
> > DISCLAIMER
> > ==========
> > This e-mail may contain privileged and confidential information
which
> > is the property of Persistent Systems Ltd. It is intended only for
> the
> > use of the individual or entity to which it is addressed. If you are
> > not the intended recipient, you are not authorized to read, retain,
> > copy, print, distribute or use this message. If you have received
> this
> > communication in error, please notify the sender and delete all
> copies
> > of this message. Persistent Systems Ltd. does not accept any
> liability
> > for virus infected mails.
> >
> > _______________________________________________
> > Qt-interest mailing list
> > Qt-interest at trolltech.com
> > http://lists.trolltech.com/mailman/listinfo/qt-interest
> 
> DISCLAIMER
> ==========
> This e-mail may contain privileged and confidential information which
> is the property of Persistent Systems Ltd. It is intended only for the
> use of the individual or entity to which it is addressed. If you are
> not the intended recipient, you are not authorized to read, retain,
> copy, print, distribute or use this message. If you have received this
> communication in error, please notify the sender and delete all copies
> of this message. Persistent Systems Ltd. does not accept any liability
> for virus infected mails.