[Lazarus] Lazarus IDE (GTK2) - flicker and slow redraws

[Mattias Gaertner]

On Fri, 25 Apr 2008 14:08:05 +0200
Graeme Geldenhuys <graemeg.lists at gmail.com> wrote:

> Hi,
> 
> I'm not ranting, simply trying to find out if it's a local issue
> (system or software).  Though, none of my other GTK2 applications
> have this problem, only Lazarus.
> 
> I got a svn update of Lazarus today and compiled with GTK2. I
> normally use GTK1.  They IDE looks fine and pretty (anti-aliased
> fonts etc), but usably sucks.
> 
> * Flicking through the menus causes a lot of flicker!
> * Typing in the IDE editor window, cause the current typed text to 
> flicker and it looks like the text cursor jumps back and forward one 
> character as I type.
> * Compiling projects and looking at the Message window. Some serious 
> flicker as the compiler output updates the window.
> 
> Some positives:
> * The dialogs look better.
> * Anti-aliased text makes a major difference.
> * Text seems to fit the dialog better, much less text clipping than 
> under GTK1.
> 
> 
> Is there some debug code enabled for the GTK2 interface, that could 
> explain the slow redrawing speed? It looks like double-buffering is 
> totally disabled in LCL-GTK2.

It does not flicker here (gtk2/ubuntu). So, maybe you just use a
difficult gtk2 theme.

The menus are completely drawn by gtk. If they flicker, then you should
see flickering in other applications too.

But it is true, that the ExtTextOut function, which is used by SynEdit,
under gtk2 is at least 5 times slower than under gtk1. It uses pango
functions, which are great for full unicode support, but snail slow.
Probably the font system must be changed to cairo.


Mattias