Implementation of new Material handling in the Draft Workbench

[Roy-043]

The new Material handling requires several changes in the Draft Workbench:

Layers/Layer Manager

Layer objects currently have a ShapeColor and a Transparency property. Both are included in the new ShapeAppearance property. The Transparency can therefore be removed. But for some reason that property is available as a separate property for other objects (Part_Box for example). I do not know the reason for that. We should follow whatever is/becomes the standard here. Obviously the OverrideShapeColorChildren property has to be renamed.

The dialog of the Layer Manager has separate columns for ShapeColor ("Face color") and Transparency. ShapeAppearance contains 6 settings. I am not sure if that means we should add 4 columns. There is also the question of conveying to the user that values in 6 columns control a single property. Collapsible columns? A clever button that shows the 6 pieces of ShapeAppearance data and opens a popup dialog to edit this data?

https://wiki.freecad.org/Draft_Layer
https://wiki.freecad.org/Draft_LayerManager

Set/Apply style

The Draft_SetStyle command sets the style for object and annotations. Its task panel is already quite tall. Adding 4 inputs may not be a good idea? Add a collapsible ShapeAppearance section instead? Or split the command into Draft_SetObjectStyle and Draft_SetAnnotationStyle?

https://wiki.freecad.org/Draft_SetStyle
https://wiki.freecad.org/Draft_ApplyStyle

Appearance of compounds (arrays)

The appearance of compounds created by the Draft Workbench is now controlled by the DiffuseColor property. The intention is to have ShapeAppearance handle this. But this is not yet implemented in Material.