Re: Images and ProgressBars

[Murray Cumming <murrayc murrayc com>]

On Wed, 2006-04-26 at 18:46 -0500, Paul Davis wrote:
> Howdy,
> 
> I've got two questions.  The first is with drawing images.  I've read 
> quite a few of the old mailing list posts on drawing images and the 
> such, I just wanted to see if anyone had any pointers.
> 
> Basically my situation is that I've got a time lapse movie stored as 
> single frames in a non-standard format, and I'm using Gtkmm to provide a 
> movie playback application.  I'll say that I'm not having a problem 
> getting things working.  It works rather well.  I'm getting playback 
> frame rates of 20-30 fps depending on hardware and network speeds ( 
> files are accessed via NFS ).
> 
> I'm going through what I'll call the standard method of using a 
> Gdk::Pixbuf and rendering to a Gtk::DrawingArea.  My question is, is 
> there a better way to do things.  I've got a fairly old Motif 
> application that can whip through the images at upwards of 40 to 50 
> fps.  I know most of you are probably thinking 20-30 is decent, but I'm 
> going to be adding some pre-processing of the images and I want to try 
> and keep things as fast as possible.
> 
> My first guess is that the bottle neck is all of the memory operations I 
> need to do to get the image from my non-standard fromat (8bpp pixel 
> array) to the 24bpp that Pixbuf expects.  So if anyone has any ideas on 
> using a different set of widgets or has an idea on how to draw directly 
> to the screen or something, I'd like to hear.

If you don't get good replies here, I think you might get informative
advice on gtk-list. They are more likely to know about the low-level
performance of different parts of GTK+.

You might also consider making a gstreamer plugin for your non-standard
format. Then you could reuse a lot of gstreamer/totem code.

> My second question is probably simpler to answer.  In the same app, I 
> use a progress bar to display the percentage of the movie played.  I was 
> wondering if its possible to connect an event handler to receive mouse 
> clicks that would translate into a fraction of the progress bar.  I know 
> that a slider would be the 'appropriate' widget for this type of action, 
> but ProgressBars are prettier, and allow for a text label in the background.

It's probably possible, yes. It does sound like a bad idea.

-- 
Murray Cumming
murrayc murrayc com
www.murrayc.com
www.openismus.com