This PR and commit adds the functionality to arrange nodes in VisualScript/VisualShader editor. The layout generated by this
feature is compact, with minimum crossings between connections
& uniform horizontal & vertical gaps between the nodes.
This work has been sponsored by GSoC '21.
Full list of additions/changes:
• Added arrange_nodes() method in GraphEdit module.
• This method computes new positions for all the selected
nodes by forming blocks and compressing them.
The nodes are moved to these new positions.
• Adding this method to GraphEdit makes it available for
use in VisualScript/VisualShaders editors and its other
subclasses.
• Button with an icon has been added to call arrange_nodes() in GraphEdit.
• This button is inherited by VisualScript/VisualShaders editors
to invoke the method.
• Undo/redo is functional with this method.
• By using signals in arrange_nodes(), position changes are registered
in undo/redo stack of the subclass that is using the method.
• Metadata of the method has been updated in ClassDB
• Method description has been added to class reference of GraphEdit
* Added a new macro SNAME() that constructs and caches a local stringname.
* Subsequent usages use the cached version.
* Since these use a global static variable, a second refcounter of static usages need to be kept for cleanup time.
* Replaced all theme usages by this new macro.
* Replace all signal emission usages by this new macro.
* Replace all call_deferred usages by this new macro.
This is part of ongoing work to optimize GUI and the editor.
The Adaptive text editor theme is the default, and has therefore
been renamed Default for consistency with the Default theme preset.
It keeps its automatic dark/light switch status.
The Default text editor theme was actually a legacy Godot 2-style theme,
so it has been renamed to Godot 2 to match the theme preset.
Its background color has been changed to be a constant opaque color,
since the new editor theme made the theme look less good on a translucent
background. The previous background color on light theme also lacked
contrast.
