[Freeciv-Dev] Re: (PR#7385) overview isn't updated

["Raimar Falke" <i-freeciv-lists@xxxxxxxxxxxxx>]

<URL: http://rt.freeciv.org/Ticket/Display.html?id=7385 >

On Sun, Feb 08, 2004 at 11:19:01AM -0800, Jason Dorje Short wrote:
> > The problem is much worse. The overview isn't updated at all (except
> > for expose and recentering). A clear sign that I rushed the patch too
> > much and so it got too less testing.
> > 
> > The fix is to draw (copy to screen + white rectangle) the complete
> > overview at unqueue_mapview_updates.
> 
> That's definitely not "the" fix; it's horribly inefficient. 

I agree that it is more inefficient then it could be.

> unqueue_mapview_updates may be called many times because if there's 
> nothing to be done it's not supposed to do anything.  But if it always 
> copies the _entire_ overview to the screen then it becomes quite slow.
> 
> For instance this function is called before each animation.  Do we 
> really need to redraw the overview each time?

Alternative suggestions:
 - a flag which is set every time the overview (backing store) is
 updated and cleared when the backing store is copied to the screen
 - perform the graphical operation we do to the backing store also to
 the window. This is what the old code did. However there is a problem
 and I'm not sure if this was a bug in the old code or the old code
 too some measures to prevent it: the overview rectangle will be
 destroyed this way.

I'm for the first alternative. It also resembles what we do with the
main mapview.

        Raimar

-- 
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