What is the Bool for freeze in QGIS?
Freeze/thaw the map canvas. This is used to prevent the canvas from responding to events while layers are being added/removed etc. frozen ( bool = True) – Boolean specifying if the canvas should be frozen (true) or thawed (false). Default is true.
How is the context scope set in QGIS?
Sets an expression context scope for the map canvas. This scope is injected into the expression context used for rendering the map, and can be used to apply specific variable overrides for expression evaluation for the map canvas render. This method will overwrite the existing expression context scope for the canvas.
How to set layers in qgsmapcanvas-QGIS?
Sets the list of layers that should be shown in the canvas. If the map canvas has been associated with a map theme via a call to setTheme (), then any calls to setLayers () are ignored. It is necessary to first clear the theme association by calling setTheme () with an empty string before setLayers () calls can be made. New in version 3.0.
What to avoid when using abbreviations in QGIS?
For consistency with the existing QGIS API and with the Qt API, abbreviations should be avoided. E.g. setDestinationSize instead of setDestSize , setMaximumValue instead of setMaxVal. Acronyms should also be camel cased for consistency. E.g. setXml instead of setXML.
Can a QGIS instance be used in multiple canvases?
The instance is not owned by the canvas, so it is possible to use one instance in multiple canvases. For main canvas in QGIS, do not associate a different instance from the existing one (it is updated from the project’s snapping configuration). New in version 2.8.
What is the scope of the qgsmapcanvas class?
Returns a reference to the expression context scope for the map canvas. This scope is injected into the expression context used for rendering the map, and can be used to apply specific variable overrides for expression evaluation for the map canvas render. New in version 2.12. Emitted when the extents of the map change [signal]