[QGIS-Developer] Rotating selected features programmatically

Wed Aug 7 13:28:49 PDT 2024

I made some progress to get the layer successfully rotated. I tracked my issue to commitChanges.

If I don’t call commitChanges() on the layer the layer is successfully rotated, but as soon as I call commitChanges the layers outer feature goes back to being unrotated but the inner one stays rotated..

If I don’t call it, then I need to manually toggle editing off by right clicking on the layer in the QGIS Layer Panel.  I don’t want the user to have to do that.

If I call commitChanges in the QGIS python console it successfully commits the change and toggles ending off.

From: QGIS-Developer <qgis-developer-bounces at lists.osgeo.org> On Behalf Of Catania, Luke A ERDC-RDE-GRL-VA CIV via QGIS-Developer
Sent: Tuesday, August 6, 2024 11:56 AM
To: Jacky Volpes <jacky.volpes at oslandia.com>; 'qgis-developer' <qgis-developer at lists.osgeo.org>
Subject: Re: [QGIS-Developer] Rotating selected features programmatically

So it seems that when I select all the features, triggering the rotation action deselects them all when I click the left mouse button to rotate and so I am left again with just rotating the center feature.

I thought well maybe select the features after triggering the rotation and that somewhat works in that the features are all still selected when the rotation is triggered, but the rotation then appear not to be centered around the object because when I move the mouse all of the features move across the map and the rotation just changes by hundreds of degrees.  Its like the rotation is happening around some far object rather than the center point.

From: Jacky Volpes <jacky.volpes at oslandia.com<mailto:jacky.volpes at oslandia.com>>
Sent: Tuesday, August 6, 2024 10:06 AM
To: Catania, Luke A ERDC-RDE-GRL-VA CIV <Luke.A.Catania at erdc.dren.mil<mailto:Luke.A.Catania at erdc.dren.mil>>; 'qgis-developer' <qgis-developer at lists.osgeo.org<mailto:qgis-developer at lists.osgeo.org>>
Subject: Re: [QGIS-Developer] Rotating selected features programmatically

Hi Luke,

>  and only rotates the inner most one.

Like I guessed, it's because element_layer_rotated() commits and ends the edition of the layer (and disconnects signal) as soon as the first feature geometry has been changed, so all other change won't follow.

Here is a way to wait for every selected feature to be rotated (feel free to adapt):

def element_layer_rotated(self):
        """When the rotate action is triggered it seems to ignore the ElementPlacementTool events, so in order to end the edit session
        we need to detect a geometryChanged event after the rotation is complete.
        """

        # Do nothing if all the selected features have not been rotated
        if set(self.vector_layer.selectedFeatureIds()) != set(self.vector_layer.editBuffer().changedGeometries().keys()):
                return

        QgsMessageLog.logMessage(f"Element Layer Rotated: {self.vector_layer.name()}", "ElementPlacementTool", Qgis.Info)

        # Disconnect from the signal so we can just commit the changes.
        self.vector_layer.editBuffer().geometryChanged.disconnect(self.element_layer_rotated)

        # Save changes and end edit mode
        self.vector_layer.commitChanges()
        self.vector_layer.endEditCommand()
        self.deactivate()

Regards,

--

Jacky Volpes

Ingénieur développeur SIG - Oslandia
Le 05/08/2024 à 19:44, Catania, Luke A ERDC-RDE-GRL-VA CIV a écrit :
So I found that I could use a selectAll() method on the layer directly rather than use the processing tool, but when I call the trigger on the rotate action it unselects all the features and only rotates the inner most one.

From: QGIS-Developer <qgis-developer-bounces at lists.osgeo.org><mailto:qgis-developer-bounces at lists.osgeo.org> On Behalf Of Catania, Luke A ERDC-RDE-GRL-VA CIV via QGIS-Developer
Sent: Monday, August 5, 2024 1:22 PM
To: Jacky Volpes <jacky.volpes at oslandia.com><mailto:jacky.volpes at oslandia.com>; 'qgis-developer' <qgis-developer at lists.osgeo.org><mailto:qgis-developer at lists.osgeo.org>
Subject: Re: [QGIS-Developer] Rotating selected features programmatically

Well.  Now for some reason my select by expression tool is not selecting any features, so need to figure out why that is happening before implementing this change. I did not make any changes that I can see that would have caused this.

From: Jacky Volpes <jacky.volpes at oslandia.com<mailto:jacky.volpes at oslandia.com>>
Sent: Monday, August 5, 2024 5:14 AM
To: Catania, Luke A ERDC-RDE-GRL-VA CIV <Luke.A.Catania at erdc.dren.mil<mailto:Luke.A.Catania at erdc.dren.mil>>; 'qgis-developer' <qgis-developer at lists.osgeo.org<mailto:qgis-developer at lists.osgeo.org>>
Subject: Re: [QGIS-Developer] Rotating selected features programmatically

Hi Luke,

My guess is that when more than one feature is selected, and the rotation is ended, geometryChanged signal is emitted for each rotated feature.

element_layer_rotated() is run when the first geometryChanged signal is emitted, and is disconnected, and the layer is saved, and the other geometryChanged signals don't trigger anything.

NB: self.vector_layer.editBuffer().geometryChanged.disconnect()       is risky, if other slots are connected, prefer      self.vector_layer.editBuffer().geometryChanged.disconnect(self.element_layer_rotated)

Regards,

--

Jacky Volpes

Ingénieur développeur SIG - Oslandia
Le 01/08/2024 à 20:29, Catania, Luke A ERDC-RDE-GRL-VA CIV a écrit :
def rotateFeature(self):
        """Find the rotate feature action in QGIS toolbar and trigger it so the user can rotate the element.
        """

        # We want to detect when the rotation is complete with a geometryChanged signal so we can commit the changes and
        # end the edit session.
        self.vector_layer.editBuffer().geometryChanged.connect(self.element_layer_rotated)

        # Get all actions so we can search for the mActionRotateFeature action.
        actions = iface.mainWindow().findChildren(QAction)
        action = [x for x in actions if x.objectName()=='mActionRotateFeature'][0]

        expression = '"Element_Nb" = '
        expression = expression + "\'" + f'{self.element_number}' + "\'"
        QgsMessageLog.logMessage(f"expression: {expression}", "StandoffLayers", Qgis.Info)

        processing.run("qgis:selectbyexpression",
                       {'INPUT':self.vector_layer,
                        'EXPRESSION': expression,
                        'METHOD':0
                        }
        )
        # Inititates rotate feature action allowing to select a snap to value.
        action.trigger()

        QgsMessageLog.logMessage(f"Rotate Feature Action Triggered", "ElementPlacementTool", Qgis.Info)

def element_layer_rotated(self):
        """When the rotate action is triggered it seems to ignore the ElementPlacementTool events, so in order to end the edit session
        we need to detect a geometryChanged event after the rotation is complete.
        """
        QgsMessageLog.logMessage(f"Element Layer Rotated: {self.vector_layer.name()}", "ElementPlacementTool", Qgis.Info)

        # Disconnect from the signal so we can just commit the changes.
        self.vector_layer.editBuffer().geometryChanged.disconnect()

        # Save changes and end edit mode
        self.vector_layer.commitChanges()
        self.vector_layer.endEditCommand()
        self.deactivate()

From: Jacky Volpes <jacky.volpes at oslandia.com><mailto:jacky.volpes at oslandia.com>
Sent: Thursday, August 1, 2024 8:26 AM
To: Catania, Luke A ERDC-RDE-GRL-VA CIV <Luke.A.Catania at erdc.dren.mil><mailto:Luke.A.Catania at erdc.dren.mil>; 'qgis-developer' <qgis-developer at lists.osgeo.org><mailto:qgis-developer at lists.osgeo.org>
Subject: Re: [QGIS-Developer] Rotating selected features programmatically

Hi Luke,

Please provide a PyQGIS code snippet to reproduce. It will be more convenient to comment and suggest modifications.
Thanks,

--

Jacky Volpes

Ingénieur développeur SIG - Oslandia

Le 26/07/2024 à 22:06, Catania, Luke A ERDC-RDE-GRL-VA CIV via QGIS-Developer a écrit :
I am using the select by expression tool through python to select my features and then I trigger rotation through python I see both selected features rotating, but when I click to end the rotation, it only rotated one of the features and left the other one as is.  If I do this through the QGIS using the selection by expression in the selection toolbar and the rotate in the advanced digitizing tool bar rotating both features works fine.

Any Ideas?

Luke

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