Highlight colors are now applied to specific layers or groups [fixes #2]

[Alex-Kent]

The color stored in the layer/group's highlight_color custom property is now always used for the layer/group's color; previously the color used was determined by displayed layer/group name.

This code has has been well tested and only one non-critical issue was observed (likely a QGIS bug, see #2 and qgis/QGIS#60884 for details).

Key changes:

• The layer_colors array is no longer needed and has been removed.

• At instantiation time, the LayerColorDelegate class constructor is passed a reference to the LayerColorPlugin instance rather than to the layer_colors array as was done previously.

• The color to use for a particular layer or group is retrieved in the paint method from the layer/group's highlight_color custom property, see lines 317-322.

Comments

In the paint method, a call to index.data(Qt.DisplayRole) (line 317 in the original code) returns the label as displayed in the layers tree. This is not always the same as the layer or group name that can be retrieved using the QgsMapLayer's name() method. One instance where this is the case is when Show Feature Count has been enabled for a layer.

Fixes #2

[Alex-Kent]

I coded a fix for the QGIS bug mentioned above (qgis/QGIS#60884); the pull request (qgis/QGIS#60897) is currently pended approval/merge.

With the patched version of QGIS this plugin's behavior for Duplicate Layer is correct.