Fix T83868: Button animation states no longer visible without emboss

This bug was caused by making it so that non-embossed modifier icon
buttons could become an operator button and retain their red highlight
for disabled modifiers. The icon button needs emboss turned off, but
in earlier versions of Blender, `UI_EMBOSS_NONE` would be overridden
by animation or red alert states.

Instead of abusing "NONE" to mean "none unless there is animation or
red alert", this commit adds a new emboss flag for that situation,
`UI_EMBOSS_NONE_OR_STATUS`, which uses no emboss unless there is an
animation state, or another status. There are only a few situations
where this is necessary, so the change isn't too big.

Differential Revision: https://developer.blender.org/D9902

7 files changed, 30 insertions, 12 deletions

diff --git a/release/scripts/startup/bl_ui/properties_data_mesh.py b/release/scripts/startup/bl_ui/properties_data_mesh.py
index 924a89755f8..a9d7b8d71f3 100644
--- a/release/scripts/startup/bl_ui/properties_data_mesh.py
+++ b/release/scripts/startup/bl_ui/properties_data_mesh.py
@@ -117,12 +117,13 @@ class MESH_UL_shape_keys(UIList):
             split = layout.split(factor=0.66, align=False)
             split.prop(key_block, "name", text="", emboss=False, icon_value=icon)
             row = split.row(align=True)
+            row.emboss = 'UI_EMBOSS_NONE_OR_STATUS'
             if key_block.mute or (obj.mode == 'EDIT' and not (obj.use_shape_key_edit_mode and obj.type == 'MESH')):
                 row.active = False
             if not item.id_data.use_relative:
-                row.prop(key_block, "frame", text="", emboss=False)
+                row.prop(key_block, "frame", text="")
             elif index > 0:
-                row.prop(key_block, "value", text="", emboss=False)
+                row.prop(key_block, "value", text="")
             else:
                 row.label(text="")
             row.prop(key_block, "mute", text="", emboss=False)
diff --git a/source/blender/editors/include/UI_interface.h b/source/blender/editors/include/UI_interface.h
index ced411ef75f..05bedd526ed 100644
--- a/source/blender/editors/include/UI_interface.h
+++ b/source/blender/editors/include/UI_interface.h
@@ -108,6 +108,11 @@ enum {
   UI_EMBOSS_NONE = 1,     /* Nothing, only icon and/or text */
   UI_EMBOSS_PULLDOWN = 2, /* Pulldown menu style */
   UI_EMBOSS_RADIAL = 3,   /* Pie Menu */
+  /**
+   * The same as #UI_EMBOSS_NONE, unless the the button has
+   * a coloring status like an animation state or red alert.
+   */
+  UI_EMBOSS_NONE_OR_STATUS = 4,
 
   UI_EMBOSS_UNDEFINED = 255, /* For layout engine, use emboss from block. */
 };
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index 6e96704271f..404ae0df6a1 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -2915,7 +2915,7 @@ static void draw_constraint_header(uiLayout *layout, Object *ob, bConstraint *co
   }
   else {
     /* enabled */
-    UI_block_emboss_set(block, UI_EMBOSS_NONE);
+    UI_block_emboss_set(block, UI_EMBOSS_NONE_OR_STATUS);
     uiItemR(layout, &ptr, "mute", 0, "", 0);
     UI_block_emboss_set(block, UI_EMBOSS);
 
diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index e92c32bb1bd..7e883851876 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -2520,8 +2520,14 @@ static void widget_active_color(uiWidgetColors *wcol)
 
 static const uchar *widget_color_blend_from_flags(const uiWidgetStateColors *wcol_state,
                                                   int state,
-                                                  int drawflag)
+                                                  int drawflag,
+                                                  const char emboss)
 {
+  /* Explicitly require #UI_EMBOSS_NONE_OR_STATUS for color blending with no emboss. */
+  if (emboss == UI_EMBOSS_NONE) {
+    return NULL;
+  }
+
   if (drawflag & UI_BUT_ANIMATED_CHANGED) {
     return wcol_state->inner_changed_sel;
   }
@@ -2557,7 +2563,7 @@ static void widget_state(uiWidgetType *wt, int state, int drawflag, char emboss)
 
   wt->wcol = *(wt->wcol_theme);
 
-  const uchar *color_blend = widget_color_blend_from_flags(wcol_state, state, drawflag);
+  const uchar *color_blend = widget_color_blend_from_flags(wcol_state, state, drawflag, emboss);
 
   if (state & UI_SELECT) {
     copy_v4_v4_uchar(wt->wcol.inner, wt->wcol.inner_sel);
@@ -2626,7 +2632,7 @@ static void widget_state_numslider(uiWidgetType *wt, int state, int drawflag, ch
   /* call this for option button */
   widget_state(wt, state, drawflag, emboss);
 
-  const uchar *color_blend = widget_color_blend_from_flags(wcol_state, state, drawflag);
+  const uchar *color_blend = widget_color_blend_from_flags(wcol_state, state, drawflag, emboss);
   if (color_blend != NULL) {
     /* Set the slider 'item' so that it reflects state settings too.
      * De-saturate so the color of the slider doesn't conflict with the blend color,
@@ -4524,8 +4530,9 @@ void ui_draw_but(const bContext *C, struct ARegion *region, uiStyle *style, uiBu
         break;
     }
   }
-  else if (but->emboss == UI_EMBOSS_NONE) {
-    /* "nothing" */
+  else if (ELEM(but->emboss, UI_EMBOSS_NONE, UI_EMBOSS_NONE_OR_STATUS)) {
+    /* Use the same widget types for both no emboss types. Later on,
+     * #UI_EMBOSS_NONE_OR_STATUS will blend state colors if they apply. */
     switch (but->type) {
       case UI_BTYPE_LABEL:
         wt = widget_type(UI_WTYPE_ICON_LABEL);
diff --git a/source/blender/editors/space_nla/nla_buttons.c b/source/blender/editors/space_nla/nla_buttons.c
index 1d7e5448b92..218fc3b7141 100644
--- a/source/blender/editors/space_nla/nla_buttons.c
+++ b/source/blender/editors/space_nla/nla_buttons.c
@@ -346,7 +346,7 @@ static void nla_panel_stripname(const bContext *C, Panel *panel)
 
   uiItemR(row, &strip_ptr, "name", 0, "", ICON_NLA);
 
-  UI_block_emboss_set(block, UI_EMBOSS_NONE);
+  UI_block_emboss_set(block, UI_EMBOSS_NONE_OR_STATUS);
   uiItemR(row, &strip_ptr, "mute", 0, "", ICON_NONE);
   UI_block_emboss_set(block, UI_EMBOSS);
 }
diff --git a/source/blender/editors/space_outliner/outliner_draw.c b/source/blender/editors/space_outliner/outliner_draw.c
index d2381cf30db..9223da136e1 100644
--- a/source/blender/editors/space_outliner/outliner_draw.c
+++ b/source/blender/editors/space_outliner/outliner_draw.c
@@ -1996,7 +1996,7 @@ static void outliner_draw_mode_column_toggle(uiBlock *block,
         "Change the object in the current mode\n"
         "* Ctrl to add to the current mode");
   }
-
+  UI_block_emboss_set(block, UI_EMBOSS_NONE_OR_STATUS);
   uiBut *but = uiDefIconBut(block,
                             UI_BTYPE_ICON_TOGGLE,
                             0,
@@ -3646,7 +3646,7 @@ void draw_outliner(const bContext *C)
   outliner_tree_dimensions(space_outliner, &tree_width, &tree_height);
 
   /* Default to no emboss for outliner UI. */
-  UI_block_emboss_set(block, UI_EMBOSS_NONE);
+  UI_block_emboss_set(block, UI_EMBOSS_NONE_OR_STATUS);
 
   if (space_outliner->outlinevis == SO_DATA_API) {
     int buttons_start_x = outliner_data_api_buttons_start_x(tree_width);
@@ -3655,7 +3655,7 @@ void draw_outliner(const bContext *C)
 
     UI_block_emboss_set(block, UI_EMBOSS);
     outliner_draw_rnabuts(block, region, space_outliner, buttons_start_x, &space_outliner->tree);
-    UI_block_emboss_set(block, UI_EMBOSS_NONE);
+    UI_block_emboss_set(block, UI_EMBOSS_NONE_OR_STATUS);
   }
   else if (space_outliner->outlinevis == SO_ID_ORPHANS) {
     /* draw user toggle columns */
diff --git a/source/blender/makesrna/intern/rna_ui.c b/source/blender/makesrna/intern/rna_ui.c
index 51cc178ab15..b86f5b789da 100644
--- a/source/blender/makesrna/intern/rna_ui.c
+++ b/source/blender/makesrna/intern/rna_ui.c
@@ -1200,6 +1200,11 @@ static void rna_def_ui_layout(BlenderRNA *brna)
       {UI_EMBOSS_NONE, "NONE", 0, "None", "Draw only text and icons"},
       {UI_EMBOSS_PULLDOWN, "PULLDOWN_MENU", 0, "Pulldown Menu", "Draw pulldown menu style"},
       {UI_EMBOSS_RADIAL, "RADIAL_MENU", 0, "Radial Menu", "Draw radial menu style"},
+      {UI_EMBOSS_NONE_OR_STATUS,
+       "UI_EMBOSS_NONE_OR_STATUS",
+       0,
+       "None or Status",
+       "Draw with no emboss unless the button has a coloring status like an animation state"},
       {0, NULL, 0, NULL, NULL},
   };