[Qgis-developer] line renderer and composition mode

[Andrea Peri]

style -> advanced -> symbol-level.

A.


2014-08-27 16:20 GMT+02:00 Andrea Peri <aperi2007 at gmail.com>:
> Your solution is not always good.
>
> You should could use the level symbols to give what symbol won in overlap.
>
> A.
>
>
>
> 2014-08-27 14:53 GMT+02:00 Jürgen E. <jef at norbit.de>:
>> Hi,
>>
>> any objections to have the line symbol layer render in composition mode
>> "source"?
>>
>> I have a layer with multiple levels of administrative boundaries, where higher
>> level boundaries (eg. state) lie over lower level boundaries (county). Lower
>> level boundaries should not be visible if there is a higher level boundary on
>> top of them.  The styles are dash-dotted - so the lines don't fully cover the
>> lines below.
>>
>> I could solve that by putting a white line on the bottom of the symbol, but
>> that would also mean that layers below are covered, that I still would like
>> see.
>>
>> Rendering the line in "source" composition would allow to have a fully
>> transparent line symbol layers on the bottom of the symbol that would overwrite
>> the already rendered lines on that layer with transparency.
>>
>> Is that already possible in a different way (without resorting to multiple
>> vector layers) to achieve the same?   Or does it introduce some problem that I
>> didn't think of?   It could still be optional...
>>
>>
>> Jürgen
>>
>>
>> diff --git a/src/core/symbology-ng/qgslinesymbollayerv2.cpp b/src/core/symbology-ng/qgslinesymbollayerv2.cpp
>> index 5a06f23..e21474a 100644
>> --- a/src/core/symbology-ng/qgslinesymbollayerv2.cpp
>> +++ b/src/core/symbology-ng/qgslinesymbollayerv2.cpp
>> @@ -207,10 +207,12 @@ void QgsSimpleLineSymbolLayerV2::renderPolygonOutline( const QPolygonF& points,
>>      return;
>>    }
>>
>> +  p->save();
>> +  p->setCompositionMode( QPainter::CompositionMode_Source );
>> +
>>    if ( mDrawInsidePolygon )
>>    {
>>      //only drawing the line on the interior of the polygon, so set clip path for painter
>> -    p->save();
>>      QPainterPath clipPath;
>>      clipPath.addPolygon( points );
>>
>> @@ -236,11 +238,8 @@ void QgsSimpleLineSymbolLayerV2::renderPolygonOutline( const QPolygonF& points,
>>        renderPolyline( ring, context );
>>    }
>>
>> -  if ( mDrawInsidePolygon )
>> -  {
>> -    //restore painter to reset clip path
>> -    p->restore();
>> -  }
>> +  //restore painter's composition mode and reset clip path
>> +  p->restore();
>>
>>  }
>>
>> @@ -252,6 +251,9 @@ void QgsSimpleLineSymbolLayerV2::renderPolyline( const QPolygonF& points, QgsSym
>>      return;
>>    }
>>
>> +  p->save();
>> +  p->setCompositionMode( QPainter::CompositionMode_Source );
>> +
>>    double offset = 0.0;
>>    applyDataDefinedSymbology( context, mPen, mSelPen, offset );
>>
>> @@ -280,6 +282,8 @@ void QgsSimpleLineSymbolLayerV2::renderPolyline( const QPolygonF& points, QgsSym
>>      for ( int part = 0; part < mline.count(); ++part )
>>        p->drawPolyline( mline[ part ] );
>>    }
>> +
>> +  p->restore();
>>  }
>>
>>  QgsStringMap QgsSimpleLineSymbolLayerV2::properties() const
>>
>>
>>
>> --
>> Jürgen E. Fischer         norBIT GmbH               Tel. +49-4931-918175-31
>> Dipl.-Inf. (FH)           Rheinstraße 13            Fax. +49-4931-918175-50
>> Software Engineer         D-26506 Norden               http://www.norbit.de
>>
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>
>
>
> --
> -----------------
> Andrea Peri
> . . . . . . . . .
> qwerty àèìòù
> -----------------



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Andrea Peri
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