[QGIS-Developer] QgsMapCanvas refresh for geometries only possible?

[Mark Johnson]

I have the impression that when in the main QGis Canvas only a geometry
(with QgsMapTool / QgsVectorLayer) is being changed, only the geometry is
being refreshed and not the underlining Rasters (which have not changed).

I would like to know how this is done since I am working with an adapted
Georeferencer with QgsMapTool / QgsVectorLayer for the points, where when
the Pixel-Point is moved in the Georeferencer-MapCanvas both the geometry
and the Raster are being refreshed, which when multiple points need to be
moved is quite time consuming.

I have looked through the QgisApp, QgsMapTool, QgsMapLayer/QgsVectorLayer
classes but I fail to see what is being done differently.

If an hint could be given where this done, I would be grateful.

Mark Johnson
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/qgis-developer/attachments/20180530/48571722/attachment.html>