[Marble-devel] Ellipses look like polygons

[Josh]

Hi Dennis,

The example, as is, does not produce this issue. If the ellipse is drawn with isGeoProjected=true, then the issue is apparent.

Attached code only changes the call to drawEllipse, to draw a geoprojected circle at the example's home location:

    painter->drawEllipse(home, (60.0/1243.76), (60.0/1853.17), true);

Image shows the issue. Zooming in and out should show the problem.

If you don't see it in master, I'll try building against that.

Thanks for looking!

Josh

On 07/05/2014 03:49 AM, Dennis Nienhüser wrote:
> Hi Josh,
>
> I wasn't able to reproduce that problem in master. Can you provide a
> minimal example in the style of [0] that results in the rendering
> problem on your system?
>
> Regards,
> Dennis
>
> [0]
> http://quickgit.kde.org/?p=marble.git&a=blob&h=a1aa719&f=examples%2Fcpp%2Fgeopainter%2Fmain.cpp
>
> Am 30.06.2014 15:29, schrieb Josh Knox:
>> Hi Torsten,
>>
>> Here's a couple screen shots that shows it clearly, side-by-side.
>>
>> Notice the dashed range rings and the small center red circle. These are all drawn with GeoPainter::drawEllipse. They show the issue I'm seeing.
>>
>> Then compare with the light blue and light red circles, which are drawn from predefined point sets using GeoPainter::drawPolygon. These maintian their nice circular shape.
>>
>> All my uses of drawEllipse are affected like this, so I guess that's the basic test case.
>>
>> Does this demonstrate the issue clear enough?
>>
>> Thanks for looking at this,
>>
>> Josh
>>
>>
>>
>> On 06/27/2014 06:05 PM, Torsten Rahn wrote:
>>> Interesting, I haven't noticed this yet - although this might very well be the case.
>>> Could you provide a test case or maybe a screenshot which shows this change clearly? :)
>>>
>>> Best Regards,
>>> Torsten
>>>
>>> -----Original-Nachricht-----
>>> Betreff: [Marble-devel] Ellipses look like polygons
>>> Datum: Fri, 27 Jun 2014 21:51:41 +0200
>>> Von: Josh Knox <jknox at lauferwind.com>
>>> An: "marble-devel at kde.org" <marble-devel at kde.org>
>>>
>>> Hi All,
>>>
>>> I've been developing an application using Marble 1.5, that I built from source on Ubuntu 12.04.
>>> I recently started migrating to Ubuntu 14.04 which provides packages for Marble 1.8.
>>>
>>> I use circles to mark various track points and areas, using GeoPainter::drawEllipse.
>>>
>>> With Marble 1.5, this worked quite well visually as the ellipses and circles were drawn as ellipses and circles, and were only reduced to small polygons and lines as the view was zoomed out beyond
>>> a scale of 1:100000.
>>>
>>> With the newer version of Marble, anything drawn with drawEllipse is very polygonal, reducing to  squares and lines until I zoom in much closer. Even then, circles still have very noticeable flat edges, especially near 90 and 270 degrees.  Strangely, the upper and lower parts of the are much more "circular".
>>>
>>> Is there some difference between 1.5 and 1.8, when drawingellipses/circles that produces this visual
>>> difference; some optimization/approximation perhaps?
>>>
>>> I'd like to have my circles look like circles again. Any ideas/suggestions for improving this?
>>>
>>> Note that I have some irregular but largely circular shapes that I draw as polygons from a set of p redefined points. These retain their roundness at all zoom levels. Maybe I could just draw all my
>>> various circles as predefined polygons and keep those cached for use as needed. Would really prefer
>>> that drawEllipse worked as it used to though.
>>>
>>> Thanks for any suggestions.
>>>
>>> Josh
>>> _______________________________________________
>>> Marble-devel mailing list
>>> Marble-devel at kde.org
>>> https://mail.kde.org/mailman/listinfo/marble-devel
>>>
>>>
>>>
>>>
>>>
>>
>>
>> _______________________________________________
>> Marble-devel mailing list
>> Marble-devel at kde.org
>> https://mail.kde.org/mailman/listinfo/marble-devel
>
> _______________________________________________
> Marble-devel mailing list
> Marble-devel at kde.org
> https://mail.kde.org/mailman/listinfo/marble-devel
>
>

-------------- next part --------------
A non-text attachment was scrubbed...
Name: marbleEllipseTest.cpp
Type: text/x-c++src
Size: 1060 bytes
Desc: not available
URL: <http://mail.kde.org/pipermail/marble-devel/attachments/20140709/674884f0/attachment-0001.cpp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: marble-test.png
Type: image/png
Size: 1041722 bytes
Desc: not available
URL: <http://mail.kde.org/pipermail/marble-devel/attachments/20140709/674884f0/attachment-0001.png>