Re: Gtk2::TreeView performance

["Philipp E. Letschert" <phil uni-koblenz de>]

On Mon, Dec 04, 2006 at 06:41:21PM +0100, Quentin wrote:
> On Mon, 2006-12-04 at 16:12 +0100, Philipp E. Letschert wrote:
> > Hi,
> > 
> > I've run into some performance troubles with Gtk2::TreeView.
> > 
> > What I do is: Read a file with a couple of ten-thousand of lines (or more),
> > about 50 fields per line and build a hash from it. This is the data I put into a
> > Gtk2::Liststore for the TreeView. Each row can be displayed colored, depending
> > on a certain column value. The user can select which of the 50 columns he would
> > like to see, after changes of this selection the whole TreeView is rebuild.
> > 
> > To make things more complicated each column should be sortable and reorderable,
> > and the user should be able to perform actions on selected rows. All these
> > things work, but it is amazingly slow, once the number of rows exceeds 10000.
> > 
> > 
> > I've done lots of experimenting and some research and found these hints:
> > 
> > - set fixed with and fixed height
> >   did this, but no real performance gain
> > - disable sorting while building the treeview
> >   did this via $colum->set_sortable(FALSE), but no real performance gain
> > - write a custom cellrenderer
> >   don't really know how to do this with performance in mind, just found the
> >   cellrenderer_* examples in the docs
> > - only load the rows into the treeview that actually fit into the window
> >   no clue how to do this
> > 
> > It would be great if someone with a real clue could shed some light, if such a
> > high-performance TreeView is possible with perl-gtk, and how an approach could
> > look like.
> > I'm afraid a possible answer could be: "No! use C++ instead".
> > 
> > Since a solution to this problem is interesting to me I would also like to help
> > in developing some demo code for the examples section.  
> > 
> 
> I experimented quite a bit with treeview performance (with some help by
> muppet) for my program (gmusicbrowser). You don't need to use C/C++ to
> have good performance, the speed of the song list in my program doesn't
> depends only on the number of displayed rows.
> I did it some time ago, so I may have forgotten/confused some things.
> There is 2 distinct source of slowness:
> 
> The simpler problem is caused by the auto-sizing : (it seems you got
> that bit)
>  - if the column is set to auto-width, gtk2 has to compute the width of
> every row, which of course will be slow for a big treeview, so you have
> to set every column to fixed-width
>  - Gtk2 also have to compute the height of every row (to correctly set
> the scrollbar), that can be prevented by setting
> $treeview->set('fixed-height-mode' => TRUE)
> 
> 
> The harder-to-fix problem is the filling of the ListStore.
> 
> The only way to completely avoid that is to make your own ListStore, in
> my case all the data were already in a perl array of array. So I made a
> ListStore that just use the already existing perl array for storage. No
> filling.
> The only drawback is I have to tell gtk2 when the perl array has changed
> by calling ListStore's row_inserted/row_deleted/row_changed methods or
> unsetting/resetting the treeview model for a full update (but loose the
> treeview state).
> I'm sure it could be made cleaner with some Tied perl magic, but I fear
> it could degrade performance.
> 
> A much simpler way, but that doesn't eliminate all the filling, is using
> a one-column ListStore that just contains the index/key for each row.
> Then you create columns with $treeview->insert_column_with_data_func(),
> which use the index/key of the row to retrieve the data from your perl
> arrary/hash, and set the cell properties accordingly.
> Using a custom CellRenderer would work the same way, but it's more
> suited when you want to draw things differently than with the existing
> CellRenderers.
> 
> Both ways (custom ListStore and insert_column_with_data_func) have the
> advantage, that you can easily add/remove columns, without rebuilding
> the list.
> 
> You can check my program for an axample of custom ListStore
> (http://squentin.free.fr/gmusicbrowser/download.html), in the
> gmusicbrowser_list.pm file.
> But be warned there is very few comments in the code, and it could use
> some cleanups. Feel free to ask me for more explanations.
> 
> For sorting the list, I do it myself in perl, gtk2 can only sort the
> list on one criteria, which has to be in the ListStore.
> 
> Quentin

Hey Quentin,

your response was extremely helpful to me. I've downloaded gmusicbrowser and
found the relevant lines, that generate the custom store for the treeview.
I think this is exactly the sample code I was looking for. (I've found 
other things in your code to learn from as well...).

I'm going to try get it working and will contact you if I run into
troubles.

Thx! Philipp