UI: Drag and Drop Modifiers, Layout Updates

This patch implements the list panel system D7490 for modifiers.
It also moves modifier drawing to a callback in ModifierTypeInfo
in line with the extensible architecture refactoring goal T75724.

This adds a PanelRegister callback and utilities for registering
panels and subpanels. It also adds the callbacks for expansion saving
and drag and drop reordering described in D7490.

These utilities, callbacks, and other common UI elements shared
between modifiers live in MOD_ui_common.c.

Because modifier buttons are now in panels, we can make use of
subpanels for organization. The UI layouts also use the single
column layout style consistently used elsewhere in Blender.
Additionally, the mode-setting buttons are aligned and ordered
consistently with the outliner.

However, the large number of UI changes in this patch may mean
that additional polishing is required in master.

Thanks to William Reynish (@billreynish) who did a fair amount of the
layout work and to Julian Eisel (@Severin) for consistent help.

Differential Revision: https://developer.blender.org/D7498

1 files changed, 3 insertions, 0 deletions

diff --git a/source/blender/modifiers/intern/MOD_weightvg_util.h b/source/blender/modifiers/intern/MOD_weightvg_util.h
index 50597d43112..725574dc0a5 100644
--- a/source/blender/modifiers/intern/MOD_weightvg_util.h
+++ b/source/blender/modifiers/intern/MOD_weightvg_util.h
@@ -30,9 +30,11 @@ struct MDeformWeight;
 struct Mesh;
 struct ModifierEvalContext;
 struct Object;
+struct PointerRNA;
 struct RNG;
 struct Scene;
 struct Tex;
+struct uiLayout;
 
 /*
  * XXX I'd like to make modified weights visible in WeightPaint mode,
@@ -89,4 +91,5 @@ void weightvg_update_vg(struct MDeformVert *dvert,
                         const float rem_thresh,
                         const bool do_normalize);
 
+void weightvg_ui_common(const bContext *C, PointerRNA *ob_ptr, PointerRNA *ptr, uiLayout *layout);
 #endif /* __MOD_WEIGHTVG_UTIL_H__ */