UI: Port view item features to base class, merge view item button types

No user visible changes expected.

Merges the tree row and grid tile button types, which were mostly doing
the same things. The idea is that there is a button type for
highlighting, as well as supporting general view item features (e.g.
renaming, drag/drop, etc.). So instead there is a view item button type
now. Also ports view item features like renaming, custom context menus,
drag controllers and drop controllers to `ui::AbstractViewItem` (the new
base class for all view items).

This should be quite an improvement because:
- Merges code that was duplicated over view items.
- Mentioned features (renaming, drag & drop, ...) are much easier to
  implement in new view types now. Most of it comes "for free".
- Further features will immediately become availalbe to all views (e.g.
  selection).
- Simplifies APIs, there don't have to be functions for individual view
  item types anymore.
- View item classes are split and thus less overwhelming visually.
- View item buttons now share all code (drawing, handling, etc.)
- We're soon running out of available button types, this commit merges
  two into one.

I was hoping I could do this in multiple smaller commits, but things
were quite intertwined so that would've taken quite some effort.

1 files changed, 10 insertions, 47 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index e2df2d77817..855e72788d2 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -104,8 +104,7 @@ typedef enum {
   UI_WTYPE_LISTITEM,
   UI_WTYPE_PROGRESSBAR,
   UI_WTYPE_NODESOCKET,
-  UI_WTYPE_TREEROW,
-  UI_WTYPE_GRID_TILE,
+  UI_WTYPE_VIEW_ITEM,
 } uiWidgetTypeEnum;
 
 /**
@@ -3672,12 +3671,11 @@ static void widget_progressbar(uiBut *but,
   widgetbase_draw(&wtb_bar, wcol);
 }
 
-static void widget_treerow_exec(uiWidgetColors *wcol,
-                                rcti *rect,
-                                const uiWidgetStateInfo *state,
-                                int UNUSED(roundboxalign),
-                                int indentation,
-                                const float zoom)
+static void widget_view_item(uiWidgetColors *wcol,
+                             rcti *rect,
+                             const uiWidgetStateInfo *state,
+                             int UNUSED(roundboxalign),
+                             const float zoom)
 {
   uiWidgetBase wtb;
   widget_init(&wtb);
@@ -3690,31 +3688,6 @@ static void widget_treerow_exec(uiWidgetColors *wcol,
   if ((state->but_flag & UI_ACTIVE) || (state->but_flag & UI_SELECT)) {
     widgetbase_draw(&wtb, wcol);
   }
-
-  BLI_rcti_resize(rect, BLI_rcti_size_x(rect) - UI_UNIT_X * indentation, BLI_rcti_size_y(rect));
-  BLI_rcti_translate(rect, 0.5f * UI_UNIT_X * indentation, 0);
-}
-
-static void widget_treerow(uiBut *but,
-                           uiWidgetColors *wcol,
-                           rcti *rect,
-                           const uiWidgetStateInfo *state,
-                           int roundboxalign,
-                           const float zoom)
-{
-  uiButTreeRow *tree_row = (uiButTreeRow *)but;
-  BLI_assert(but->type == UI_BTYPE_TREEROW);
-  widget_treerow_exec(wcol, rect, state, roundboxalign, tree_row->indentation, zoom);
-}
-
-static void widget_gridtile(uiWidgetColors *wcol,
-                            rcti *rect,
-                            const uiWidgetStateInfo *state,
-                            int roundboxalign,
-                            const float zoom)
-{
-  /* TODO Reuse tree-row drawing. */
-  widget_treerow_exec(wcol, rect, state, roundboxalign, 0, zoom);
 }
 
 static void widget_nodesocket(uiBut *but,
@@ -4608,14 +4581,9 @@ static uiWidgetType *widget_type(uiWidgetTypeEnum type)
       wt.custom = widget_progressbar;
       break;
 
-    case UI_WTYPE_TREEROW:
-      wt.wcol_theme = &btheme->tui.wcol_view_item;
-      wt.custom = widget_treerow;
-      break;
-
-    case UI_WTYPE_GRID_TILE:
+    case UI_WTYPE_VIEW_ITEM:
       wt.wcol_theme = &btheme->tui.wcol_view_item;
-      wt.draw = widget_gridtile;
+      wt.draw = widget_view_item;
       break;
 
     case UI_WTYPE_NODESOCKET:
@@ -4949,13 +4917,8 @@ void ui_draw_but(const bContext *C, struct ARegion *region, uiStyle *style, uiBu
         fstyle = &style->widgetlabel;
         break;
 
-      case UI_BTYPE_TREEROW:
-        wt = widget_type(UI_WTYPE_TREEROW);
-        fstyle = &style->widgetlabel;
-        break;
-
-      case UI_BTYPE_GRID_TILE:
-        wt = widget_type(UI_WTYPE_GRID_TILE);
+      case UI_BTYPE_VIEW_ITEM:
+        wt = widget_type(UI_WTYPE_VIEW_ITEM);
         fstyle = &style->widgetlabel;
         break;