UI: Better split layout support for checkboxes

Makes the following layout changes possible:
{F8473498} {F8473499} {F8473502}

The next commit will contain many layout changes to make good use of
these new possibilities. The result should be more consistent, easier to
read and should give a more organized impression. Additionally, it
should be possible to replace many sub-panels with compacter layouts.

Main changes:
* Checkboxes now respect the property split layouts
* Add support for row and column headers (i.e.
  `uiLayout.column(heading="Foo")`, `uiLayout.row(heading="Bar")`). If the
  first property added to this layout doesn't insert anything into the label
  split column, the heading is inserted there. Otherwise, it's inserted as own
  item.
* Add support for manually inserting decorators for an existing item
  (`uiLayout.prop_decorator()`). That way layout creators can manually insert
  this, which was the only way I saw to support property split layouts with a
  checkbox before the actual property. {F8471883}
* Autogenerated layouts for operator properties look bad if there are only
  checkboxes (which only use half the region width). So before creating the
  layout, we iterate over visible properties and disable split layout if all
  are booleans. I think this is fine, if needed we could also add layout hints
  to operators.
* `uiTemplateOperatorPropertyButs()` now handles macros itself, the caller
  used to be responsible for this. Code that didn't handle these so far never
  used macros I think, so this change should be invisible.
* Remove manual property split layout from autogenerated operator properties
  layout.
* Padding of checkboxes is tweaked to make their label visually more connected
  to the checkboxes.
* Support split layout for menus (should work for `uiLayout.menu()`,
  `.operator_menu_enum()`, `.prop_menu_enum()`, maybe more)

Maniphest Task: https://developer.blender.org/T65965

Differential Revision: https://developer.blender.org/D7427

Reviewed by: Brecht Van Lommel, William Reynish, Pablo Vazques

1 files changed, 14 insertions, 9 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index 03f2fddc168..064fa14a75e 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -2429,7 +2429,7 @@ static void widget_draw_text_icon(const uiFontStyle *fstyle,
   const bool show_menu_icon = ui_but_draw_menu_icon(but);
   float alpha = (float)wcol->text[3] / 255.0f;
   char password_str[UI_MAX_DRAW_STR];
-  bool no_text_padding = false;
+  bool no_text_padding = but->drawflag & UI_BUT_NO_TEXT_PADDING;
 
   ui_but_text_password_hide(password_str, but, false);
 
@@ -4161,10 +4161,10 @@ static void widget_optionbut(uiWidgetColors *wcol,
 
   /* smaller */
   delta = 1 + BLI_rcti_size_y(&recttemp) / 8;
-  recttemp.xmin += delta;
-  recttemp.ymin += delta;
-  recttemp.xmax -= delta;
-  recttemp.ymax -= delta;
+  BLI_rcti_resize(
+      &recttemp, BLI_rcti_size_x(&recttemp) - delta * 2, BLI_rcti_size_y(&recttemp) - delta * 2);
+  /* Keep one edge in place. */
+  BLI_rcti_translate(&recttemp, text_before_widget ? delta : -delta, 0);
 
   rad = wcol->roundness * BLI_rcti_size_y(&recttemp);
   round_box_edges(&wtb, UI_CNR_ALL, &recttemp, rad);
@@ -4176,13 +4176,13 @@ static void widget_optionbut(uiWidgetColors *wcol,
 
   widgetbase_draw(&wtb, wcol);
 
-  /* text space */
-  const float offset = BLI_rcti_size_y(rect) * 0.7 + delta;
+  /* Text space - factor is really just eyeballed. */
+  const float offset = delta * 0.9;
   if (text_before_widget) {
-    rect->xmax -= offset;
+    rect->xmax = recttemp.xmin - offset;
   }
   else {
-    rect->xmin += offset;
+    rect->xmin = recttemp.xmax + offset;
   }
 }
 
@@ -4739,9 +4739,14 @@ void ui_draw_but(const bContext *C, ARegion *region, uiStyle *style, uiBut *but,
       case UI_BTYPE_CHECKBOX_N:
         if (!(but->flag & UI_HAS_ICON)) {
           wt = widget_type(UI_WTYPE_CHECKBOX);
+
           if ((but->drawflag & (UI_BUT_TEXT_LEFT | UI_BUT_TEXT_RIGHT)) == 0) {
             but->drawflag |= UI_BUT_TEXT_LEFT;
           }
+          /* widget_optionbut() carefully sets the text rectangle for fine tuned paddings. If the
+           * text drawing were to add its own padding, DPI and zoom factor would be applied twice
+           * in the final padding, so it's difficult to control it. */
+          but->drawflag |= UI_BUT_NO_TEXT_PADDING;
         }
         else {
           wt = widget_type(UI_WTYPE_TOGGLE);