Bug report #3420
QgsMapCanvas not rendering raster layers in QGIS 1.7
Status: | Closed | ||
---|---|---|---|
Priority: | Low | ||
Assignee: | Martin Dobias | ||
Category: | Map Canvas | ||
Affected QGIS version: | Regression?: | No | |
Operating System: | Debian | Easy fix?: | No |
Pull Request or Patch supplied: | Resolution: | fixed | |
Crashes QGIS or corrupts data: | Copied to github as #: | 13480 |
Description
I've found a problem when using the QgsMapCanvas in new version of QGIS which is not present in the previous version.
When using QgsMapCanvas in Python like this:
layer = [[QgsRasterLayer]](filePath, fileInfo.completeBaseName()) mapRegistry = [[QgsMapLayerRegistry]].instance().addMapLayer(layer, False) layerSet = [] mapCanvasLayer = [[QgsMapCanvasLayer]](layer, True) layerSet.append(mapCanvasLayer) self.canvas.setExtent(layer.extent()) self.canvas.enableAntiAliasing(True) self.canvas.freeze(False) self.canvas.setLayerSet(layerSet) self.canvas.setVisible(True) self.canvas.refresh()
The debug console says the raster was render without issues, the extent was set correctly, but the raster is not showing on the canvas (MirrorMap python plugin has the problem too).
After working through the C++ source code of QgsMapCanvas, I've noticed that most of the resizeEvent's code is now in the paintEvent. For some reason repaint is not called once the canvas resizes, hence the code (previously in the resiveEvent) is never executed. The important part of the code is:
mMap->resize( QSize( width, height ) );
which when called renders the raster correctly. I've adapted the python code of my plug-in as follows:
layer = [[QgsRasterLayer]](filePath, fileInfo.completeBaseName()) mapRegistry = [[QgsMapLayerRegistry]].instance().addMapLayer(layer, False) layerSet = [] mapCanvasLayer = [[QgsMapCanvasLayer]](layer, True) layerSet.append(mapCanvasLayer) self.canvas.setExtent(layer.extent()) self.canvas.enableAntiAliasing(True) self.canvas.freeze(False) self.canvas.setLayerSet(layerSet) width = self.canvas.size().width() #NEW CODE height = self.canvas.size().height() #NEW CODE self.canvas.map().resize( QSize( width, height ) ) #NEW CODE self.canvas.setVisible(True) self.canvas.refresh()
Every time I add a raster layer to the canvas, I have to manually resize the map of the canvas.
I'm not sure if this is a bug, or if it has to be this way. Is there any other or better way doing this?
History
#1 Updated by goocreations - over 13 years ago
- Resolution set to fixed
- Status changed from Open to Closed
Hey here is a solution to this problem (hopefully). Just added the paintEvent to the Python bindings. I've attached a patch.