RE: [XaraXtreme-dev] Strange rendering problem

[Martin Wuerthner <lists@xxxxxxxxxxxxxxx>]

In message <5056CBC646CB4047BB26120F4377DB71CB6C2A@xxxxxxxxxxxxxxxxxxx 
>
          "Neil Howe" <NeilH@xxxxxxxx> wrote:

> Yes, I just tried this in the latest release build and I see the problem
> just as you describe. Perhaps this is a problem in Gavin's CDraw changes
> that were checked in Monday.
> 
> Are you using CDraw 4.1 or 4.2 Martin (XaraLX -v)?

I am using 4.2, and if I link with an old copy of 4.1, the problem 
does indeed go away, so it is very likely to be a CDraw problem.

Martin

>> -----Original Message-----
>> From: owner-dev@xxxxxxxxxxxxxxxx [mailto:owner-dev@xxxxxxxxxxxxxxxx]
> On
>> Behalf Of Martin Wuerthner
>> Sent: 29 March 2006 11:23
>> To: dev@xxxxxxxxxxxxxx
>> Subject: [XaraXtreme-dev] Strange rendering problem
>> 
>> Is it just me or do others see this rendering problem, too? This is on
>> x86, SuSE 10.0, wxWidgets 2.6.3-rc2, source revision 731 without any
>> changes, debug build.
>> 
>> At certain zoom percentages a spurious black background appears that
>> is of the size of the bounding box of all objects on the page. The
>> background can be wiped away by moving an object over it but reappears
>> when the area is scrolled into view again.
>> 
>> This is how I can provoke the problem reliably:
>> 
>> 1. Start XaraLX
>> 2. Create a new file - it will be displayed at 100% zoom
>> 3. Draw an ellipse in the middle of the page and set its size to 500
>>    by 300 pixels.
>> 4. Give it a red fill (not necessary to trigger the problem but it
>>    shows more clearly what is going on later)
>> 5. Select the magnifier tool and change to 202% zoom.
>> 
>> Here, this causes a black background the size of the ellipse's
>> bounding box to appear underneath the ellipse. If additional objects
>> are drawn the background extends to encompass their bounding boxes. If
>> the zoom percentage is changed to 200%, the problem goes away, but it
>> occurs at many other zoom levels, too, though usually "even" levels
>> like 500% work fine.
>> 
>> For instance:
>> 310%     works fine
>> 311%       goes wrong
>> 312%-314%  go wrong
>> 315%     works fine
>> 316%-318%  go wrong
>> 319%     works fine
>> 320%       goes wrong
>> 
>> The Double buffering and Background rendering entries in the Debug
>> menu do not have any effect, by the way.
>> 
>> I have an old revision around (609), which works fine in this respect,
>> so the error has been introduced somewhere inbetween.
>> 
>> Martin