AW: [Qgis-developer] Addition to QgsRenderContext

Hugentobler Marco marco.hugentobler at
Tue Aug 4 13:29:04 EDT 2009

Hi Magnus

How would you add the transparency to the render context?
The rendercontext is meant to contain information about the rendering procedure as a whole (so not information that is layer or even symbol specific). Is it perhaps possible to extend the cache such that it stores the transparency value for which it is valid (and the resolution, that would be great for printing)? 


-----Ursprüngliche Nachricht-----
Von: qgis-developer-bounces at im Auftrag von Magnus Homann
Gesendet: Di 04.08.2009 17:29
An: qgis-developer at
Betreff: [Qgis-developer] Addition to QgsRenderContext
Is it OK to add transparency setting into the render context? This would make it much easier to
cache point symbols with transparency.

Current contents:

     /**Painter for rendering operations*/
     QPainter* mPainter;

     /**For transformation between coordinate systems. Can be 0 if on-the-fly reprojection is not used*/
     QgsCoordinateTransform* mCoordTransform;

     /**True if vertex markers for editing should be drawn*/
     bool mDrawEditingInformation;

     QgsRectangle mExtent;

     /**If true then no rendered vector elements should be cached as image*/
     bool mForceVectorOutput;

     QgsMapToPixel mMapToPixel;

     /**True if the rendering has been canceled*/
     bool mRenderingStopped;

     /**Factor to scale line widths and point marker sizes*/
     double mScaleFactor;

     /**Factor to scale rasters*/
     double mRasterScaleFactor;

     /**Map scale*/
     double mRendererScale;
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