l_layer_isVisible: Return visibility flag of layer
Description
Hidden or invisible layers are not rendered. This function
queries whether a layer is visible/rendered or not.
Usage
l_layer_isVisible(widget, layer)
Arguments
widget
widget path or layer object of class 'l_layer'
layer
layer id. If the widget argument is of class 'l_layer'
then the layer argument is not used
Value
TRUE or FALSE depending whether the layer is visible or
not.
Details
Visibile layers are rendered, invisible ones are not. If any
ancestor of a layer is set to be invisible then the layer is not rendered
either. The layer visibility flag can be checked with
l_layer_isVisible and the actual visibility (i.e. are all the
ancesters visibile too) can be checked with
l_layer_layerVisibility.
Note that layer visibility is not a state of the layer itself,
instead is information that is part of the layer collection (i.e. its
parent widget).