Review Request 127354: improve drawing precision for circles

[David Narváez]

> On March 19, 2016, 5:04 p.m., David Narváez wrote:
> > Thanks for the patch! I would be in favor of dropping the QRect/QPoint usage in these files completely. Could you modify your patch to see how that would look like?
> 
> Maurizio Paolini wrote:
>     After some trying around I realize that dropping QRect in (e.g.) the KigPainter class cannot be done easily.  In particular one should
>     understand the "overlay" concept... If I remember, at least in the early stages of kig development, overlays where used in order to
>     allow for efficent redrawing of the graphic primitives.  I am not even sure that this is still used now!  This was taken from the kgeo
>     project when first starting kig.  If I place an "assert (false)" in "circleOverlayRecurse", then kig crashes... however I don't see the
>     need of using overlays for drawing circles if we use a Qt primitive for doing that.

Interesting, I will check that. I did a quick pass through the code last weekend and was under the impression that there are needs for QRect in several places but KigPainter could do without QRect, but I must have missed this.


- David


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On March 19, 2016, 9:05 a.m., Maurizio Paolini wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://git.reviewboard.kde.org/r/127354/
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> 
> (Updated March 19, 2016, 9:05 a.m.)
> 
> 
> Review request for KDE Edu, David Narváez and Rex Dieter.
> 
> 
> Bugs: 359805
>     http://bugs.kde.org/show_bug.cgi?id=359805
> 
> 
> Repository: kig
> 
> 
> Description
> -------
> 
> QRect object in qt uses integers.  This causes annoying loss of drawing precision when drawing circles (https://bugs.kde.org/show_bug.cgi?id=359805).  Using the QRectF object seems more appropriate.
> 
> 
> Diffs
> -----
> 
>   misc/kigpainter.h e36c153 
>   misc/kigpainter.cpp e547bf2 
>   misc/screeninfo.h b7f94c4 
>   misc/screeninfo.cc 8fdf115 
> 
> Diff: https://git.reviewboard.kde.org/r/127354/diff/
> 
> 
> Testing
> -------
> 
> This is a minimal patch to allow using QRectF when drawing circles.  Perhaps using QRect
> (and QPoint) could be dropped completely in favour of QRectF and QPointF.
> 
> 
> File Attachments
> ----------------
> 
> tangent circles - old behaviour
>   https://git.reviewboard.kde.org/media/uploaded/files/2016/03/19/48f5447f-0904-43ee-8c56-8fc07c03febb__circles_old.png
> tangent circles: new behaviour
>   https://git.reviewboard.kde.org/media/uploaded/files/2016/03/19/5684b1c5-c32c-447b-bed6-53be380f1b87__circles_new.png
> zoom of old behaviour
>   https://git.reviewboard.kde.org/media/uploaded/files/2016/03/19/08937b54-e313-4acf-b482-4bd899d24b30__circles_old_zoom.png
> zoom of new behaviour
>   https://git.reviewboard.kde.org/media/uploaded/files/2016/03/19/e7c0b8fb-af81-43da-b70e-bed3462d73a6__circles_new_zoom.png
> 
> 
> Thanks,
> 
> Maurizio Paolini
> 
>

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