[QGIS-Developer] Symbology: multiple simple marker symbols are not correctly aligned on top of each other

[Tim Sutton]

Hi

Yes this has bothered me for years too - I always thought it was my fault for not choosing diameter’s that properly ’nest inside each other. e.g. here is my favourite ’Tim Red Dot’ symbol where they aliign nicely:



Inner size 4

Outer size 6

Here is the same symbol:



With Inner 3, outer 6. It looks dodgy in preview (above) but renders ok on the map (below):



Regards

Timi


> On 3 Jul 2020, at 15:42, Andreas Neumann <a.neumann at carto.net> wrote:
> 
> Here is another example:
> 
> square on top of a circle - you can clearly see that the rectangle would have be shifted one pixel to the left and one pixel up to align better:
> 
> <50e68887.png>
> 
> Andreas
> 
> On 2020-07-03 16:35, Andreas Neumann wrote:
> 
>> The situation of the two concentric simple markers is even a bit weirder: if you pan/zoom in the map canvas multiple times, the misalignment changes constantly, the misalignment is off by maybe 1 pixel in random directions. Really strange ...
>> 
>> It almost looks there is a "precision issue" by 1-2 Pixels ...
>> 
>> Andreas
>> 
>> On 2020-07-03 16:27, Andreas Neumann wrote:
>> 
>> Hi,
>> 
>> Here is something that bothered me already for many years in QGIS and I think it might be a long standing issue in QGIS symbology:
>> 
>> When you place two simple markers on top of each other (without any offset), f.e. two circle symbols on top of each other, they are not correctly aligned/centered on top of each other: The alignment is a tiny bit off, but it looks ugly and it annoys me a lot.
>> 
>> 
>> 
>> The misalignment is not only in the preview dialogue but also visible in the map rendering.
>> 
>> In the symbol preview dialog there is a second annoying thing: strokes in the preview are often clipped away, as you can see in the dialog above
>> 
>> Can we do something about it these two annoying issues?
>> 
>> Thanks for helping me solve this issue!
>> 
>> Andreas
>> 
>> 
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—












Tim Sutton

Co-founder: Kartoza
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