Tweak Tool: supports select & tweak on LMB (with RMB-select key-map)

Support for differentiating the tweak tool from the 3D cursor when
select is set to RMB.

This is currently an experimental preference:
Tweak Tool: Left Mouse Select & Drag

When enabled the tweak tool can now tweak the existing selection
without de-selecting first, a single click can be used to replace
the selection.
This matches selection in the graph & node editors.

This preferences is only available with "Developer Extras" enabled.

Ref T96544.

release/scripts/presets/keyconfig/Blender.py

@@ -85,6 +85,18 @@ class Prefs(bpy.types.KeyConfigPreferences):
         ),
         update=update_fn,
     )
+
+    # Experimental: only show with developer extras, see: T96544.
+    use_tweak_tool_lmb_interaction: BoolProperty(
+        name="Tweak Tool: Left Mouse Select & Move",
+        description=(
+            "The tweak tool is activated immediately instead of placing the cursor. "
+            "This is an experimental preference and may be removed"
+        ),
+        default=False,
+        update=update_fn,
+    )
+
     use_alt_click_leader: BoolProperty(
         name="Alt Click Tool Prompt",
         description=(
@@ -236,6 +248,7 @@ class Prefs(bpy.types.KeyConfigPreferences):
 
         prefs = context.preferences
 
+        show_developer_ui = prefs.view.show_developer_ui
         is_select_left = (self.select_mouse == 'LEFT')
         use_mouse_emulate_3_button = (
             prefs.inputs.use_mouse_emulate_3_button and
@@ -270,6 +283,10 @@ class Prefs(bpy.types.KeyConfigPreferences):
         row = sub.row()
         row.prop(self, "use_select_all_toggle")
 
+        if show_developer_ui and (not is_select_left):
+            row = sub.row()
+            row.prop(self, "use_tweak_tool_lmb_interaction")
+
         # 3DView settings.
         col = layout.column()
         col.label(text="3D View")
@@ -301,6 +318,7 @@ def load():
     kc = context.window_manager.keyconfigs.new(IDNAME)
     kc_prefs = kc.preferences
 
+    show_developer_ui = prefs.view.show_developer_ui
     is_select_left = (kc_prefs.select_mouse == 'LEFT')
     use_mouse_emulate_3_button = (
         prefs.inputs.use_mouse_emulate_3_button and
@@ -322,6 +340,10 @@ def load():
             use_gizmo_drag=(is_select_left and kc_prefs.gizmo_action == 'DRAG'),
             use_fallback_tool=True,
             use_fallback_tool_rmb=(False if is_select_left else kc_prefs.rmb_action == 'FALLBACK_TOOL'),
+            use_tweak_tool_lmb_interaction=(
+                False if is_select_left else
+                (show_developer_ui and kc_prefs.use_tweak_tool_lmb_interaction)
+            ),
             use_alt_tool_or_cursor=(
                 (not use_mouse_emulate_3_button) and
                 (kc_prefs.use_alt_tool if is_select_left else kc_prefs.use_alt_cursor)

release/scripts/presets/keyconfig/keymap_data/blender_default.py

@@ -31,6 +31,7 @@ class Params:
         "context_menu_event",
         "cursor_set_event",
         "cursor_tweak_event",
+        "use_tweak_tool_lmb_interaction",
         "use_mouse_emulate_3_button",
 
         # User preferences:
@@ -102,6 +103,7 @@ class Params:
             use_gizmo_drag=True,
             use_fallback_tool=False,
             use_fallback_tool_rmb=False,
+            use_tweak_tool_lmb_interaction=False,
             use_v3d_tab_menu=False,
             use_v3d_shade_ex_pie=False,
             use_v3d_mmb_pan=False,
@@ -129,6 +131,7 @@ class Params:
                 self.tool_maybe_tweak_value = 'PRESS'
             else:
                 self.tool_maybe_tweak_value = 'CLICK_DRAG'
+            self.use_tweak_tool_lmb_interaction = use_tweak_tool_lmb_interaction
 
             self.context_menu_event = {"type": 'W', "value": 'PRESS'}
 
@@ -150,6 +153,7 @@ class Params:
             self.action_mouse = 'RIGHTMOUSE'
             self.tool_mouse = 'LEFTMOUSE'
             self.tool_maybe_tweak_value = 'CLICK_DRAG'
+            self.use_tweak_tool_lmb_interaction = False
 
             if self.legacy:
                 self.context_menu_event = {"type": 'W', "value": 'PRESS'}
@@ -457,6 +461,19 @@ def _template_items_tool_select(params, operator, cursor_operator, fallback, *,
              {"properties": [(extend, True)]}),
         ]
     else:
+        # Experimental support for LMB interaction for the tweak tool.
+        if params.use_tweak_tool_lmb_interaction and not fallback:
+            return [
+                (operator, {"type": 'LEFTMOUSE', "value": 'PRESS'},
+                 {"properties": [("deselect_all", True), ("select_passthrough", True)]}),
+                (operator, {"type": 'LEFTMOUSE', "value": 'CLICK'},
+                 {"properties": [("deselect_all", True)]}),
+                (operator, {"type": 'LEFTMOUSE', "value": 'PRESS', "shift": True},
+                 {"properties": [("deselect_all", False), ("toggle", True)]}),
+                ("transform.translate", {"type": 'LEFTMOUSE', "value": 'CLICK_DRAG'},
+                 {"properties": [("release_confirm", True)]}),
+            ]
+
         # For right mouse, set the cursor.
         return [
             (cursor_operator, {"type": 'LEFTMOUSE', "value": 'PRESS'}, None),