qt-interest@trolltech.com
[Top] [All Lists]

Re: fastest way to display images in QT

Subject: Re: fastest way to display images in QT
From: Qingning Huo
Date: Mon, 14 Feb 2005 16:34:32 +0000
Stephan,

Thanks for your kind reply.  However, I still have some questions.

On Mon, 14 Feb 2005 22:02:21 +0100 (CET), Stephan Stapel
<stephan.stapel@xxxxxx> wrote:
> > I am wondering what is the fastest way to display an Image in a QT widget.
> > It is just strajght forward painting.  Rotation or resizing is not
> > necessary.  It seems easy to do, but I failed to get a satisfactory
> > result.
> 
> imho, the fastest way will be using a GL painter along with a texture/
> image cache in Qt4. Unfortunately, currently there is only a QPixmapCache
> implementation, Qt4 lacks a QImageCache implementation.

I can't quite understand this paragraph.  Shall I upgrade to QT4, and then take 
advantage of the GL painter?  As I am stuck with QT3 right now, shall I use
QPixmapCache instead.

> This would be definitely the fastest way (at least on Windows) since you
> can buffer large amounts of images without having to pay attention for the
> ability of HBITMAP structures. I assume similar limitations for X11.
> 

Having read a little document of QPixmapCache, I don't think it is applicable
for my case.  The program I am working on is a video application.  So, I am
showing images of 320x240 at about 25 fps.  Using QPixmap, my program
uses quite a lot CPU cycles.  But, it's kind of hard to cache images.

Hope this clarifies my situation. Looking forward to your further comment.

Thanks,
Qingning

--
List archive and information: http://lists.trolltech.com/qt-interest/

<Prev in Thread] Current Thread [Next in Thread>