Nodes: Add support to mute node wires

This patch adds the ability to mute individual wires in the node editor.
This is invoked like the cut links operator but with a new shortcut.

Mute = Ctrl + Alt
Cut = Ctrl

Dragging over wires will toggle the mute state for that wire.
The muted wires are drawn in red with a bar across the center.
Red is used in the nodes context to indicate invalid links, muted links and internal links.

When a wire is muted it exposes the original node buttons which are normally hidden when a wire is connected.

Downstream and upstream links connected using reroute nodes are also muted.

Outside scope of patch:
- Add support for pynodes e.g. Animation Nodes
- Requires minor change to check for muted links using the `is_muted` link property or the `is_linked` socket property.

Maniphest Tasks: T52659

Differential Revision: https://developer.blender.org/D2807

1 files changed, 1 insertions, 0 deletions

diff --git a/source/blender/windowmanager/wm_cursors.h b/source/blender/windowmanager/wm_cursors.h
index b85616deda5..2842538ebf1 100644
--- a/source/blender/windowmanager/wm_cursors.h
+++ b/source/blender/windowmanager/wm_cursors.h
@@ -72,6 +72,7 @@ typedef enum WMCursorType {
   WM_CURSOR_ZOOM_OUT,
 
   WM_CURSOR_NONE,
+  WM_CURSOR_MUTE,
 
   /* --- ALWAYS LAST ----- */
   WM_CURSOR_NUM,