Hi,

Long story:
>From the early days of Merkaartor, Qt had a problem when we were drawing
long roads at high zoom levels. Somehow, the drawing was not properly
clipped and an insane large bitmap was created by Qt to draw the road and
then only clipped to be drawn on screen. So we resolved to implement our own
clipping.

Recently I noticed (at least on my test systems) that it was no longer
necessary and removing self-clipping would allow to remove the dependency on
Boost and specifically Boost::Geometry
Not knowing precisely when that was solved on the Qt side, I disabled
self-clipping for Qt >= 4.6.0.

My Test systems (which do no not have the problem) are:
Win 7 / Qt 4.6.3 / ATI
Ubunutu 10.04 / Qt 4.6.2 / Virtualbox
Ubuntu 64 10.10 / Qt 4.7.0 / Virtualbox

Could those affected by the problem add to http://merkaartor.be/issues/3206:
- Their OS version
- Their Qt version
- Their graphic card brand

The goal is to find a proper pattern (if any). If none can be identified,
I'll think about some other way...

Thanks in advance
- Chris -


On Mon, Dec 20, 2010 at 08:10, <[email protected]> wrote:

>  Issue #3206 has been reported by Jean-Claude Repetto.
> ------------------------------
> Bug #3206: Performance issue <http://merkaartor.be/issues/3206>
>
>    - Author: Jean-Claude Repetto
>    - Status: New
>    - Priority: High
>    - Assigned to:
>    - Category:
>    - Target version:
>    - Resolution:
>
> The current (17 december 2010) trunk version is very slow (about 40 times
> slower than a mid-october version). For example, dragging a node takes from
> 8 to 10 seconds, while with an older version it took a fraction of second.
> I used "git bisect" to check the exact version where the problem appeared :
>
> aef25d136e1b7cb2858027356b32a71ea821d97b is the first bad commit
> commit aef25d136e1b7cb2858027356b32a71ea821d97b
> Author: Chris "Koying" Browet <[email protected]>
> Date: Mon Nov 1 03:31:55 2010 +0100
>
> Spatialite cont'd
>     Do not self-clip QpainterPath anymore
>
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