UI: Add shortcuts for modifier panels

The shortcuts act on the modifier with its panel under the mouse.
The following shortcuts are enabled by default:
  - Remove modifier: X, Delete
  - Apply modifier: Ctrl A
  - Duplicate modifier: Shift D
More shortcuts can be added in the keymap.

Each panel can now store a custom data RNA pointer, and a new
function is added to get the custom data for the panel under the
cursor. This custom data could be used to refactor the "List Panel
System" to generalize it and integrate it further with RNA.

The same functionality will be added  in further commits where it
applies to constraints, grease pencil modifiers, and effects.

Differential Revision: https://developer.blender.org/D8031

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/makesdna/DNA_screen_types.h b/source/blender/makesdna/DNA_screen_types.h
index eb9f1c1a80a..c34f1faa255 100644
--- a/source/blender/makesdna/DNA_screen_types.h
+++ b/source/blender/makesdna/DNA_screen_types.h
@@ -41,6 +41,7 @@ struct uiLayout;
 struct wmDrawBuffer;
 struct wmTimer;
 struct wmTooltipState;
+struct PointerRNA;
 
 /* TODO Doing this is quite ugly :)
  * Once the top-bar is merged bScreen should be refactored to use ScrAreaMap. */
@@ -135,6 +136,15 @@ typedef struct Panel_Runtime {
 
   /* For instanced panels: Index of the list item the panel corresponds to. */
   int list_index;
+
+  /**
+   * Pointer for storing which data the panel corresponds to.
+   * Useful when there can be multiple instances of the same panel type.
+   *
+   * \note A panel and its subpanels share the same custom data pointer.
+   * This avoids freeing the same pointer twice when panels are removed.
+   */
+  struct PointerRNA *custom_data_ptr;
 } Panel_Runtime;
 
 /** The part from uiBlock that needs saved in file. */