source/blender/editors/interface/interface_region_popup.cc

@@ -109,6 +109,21 @@ static void ui_popup_block_position(wmWindow *window,
     }
   }
 
+  /* Trim the popup and its contents to the width of the button if the size difference
+   * is small. This avoids cases where the rounded corner clips underneath the button. */
+  const int delta = BLI_rctf_size_x(&block->rect) - BLI_rctf_size_x(&butrct);
+  const float max_radius = (0.5f * U.widget_unit);
+
+  if (delta >= 0 && delta < max_radius) {
+    LISTBASE_FOREACH (uiBut *, bt, &block->buttons) {
+      /* Only trim the right most buttons in multi-column popovers. */
+      if (bt->rect.xmax == block->rect.xmax) {
+        bt->rect.xmax -= delta;
+      }
+    }
+    block->rect.xmax -= delta;
+  }
+
   ui_block_to_window_rctf(butregion, but->block, &block->rect, &block->rect);
 
   /* Compute direction relative to button, based on available space. */
@@ -339,7 +354,26 @@ static void ui_popup_block_position(wmWindow *window,
         block->safety.xmin = block->rect.xmin - s2;
       }
     }
-    block->direction = dir1;
+
+    const bool fully_aligned_with_button = BLI_rctf_size_x(&block->rect) <=
+                                           BLI_rctf_size_x(&butrct) + 1;
+    const bool off_screen_left = (block->rect.xmin < 0);
+    const bool off_screen_right = (block->rect.xmax > win_x);
+
+    if (fully_aligned_with_button) {
+      /* Popup is neither left or right from the button. */
+      dir2 &= ~(UI_DIR_LEFT | UI_DIR_RIGHT);
+    }
+    else if (off_screen_left || off_screen_right) {
+      /* Popup is both left and right from the button. */
+      dir2 |= (UI_DIR_LEFT | UI_DIR_RIGHT);
+    }
+
+    /* Popovers don't need secondary direction. Pulldowns to
+     * the left or right are currently not supported. */
+    const bool no_2nd_dir = (but->type == UI_BTYPE_POPOVER || ui_but_menu_draw_as_popover(but) ||
+                             dir1 & (UI_DIR_RIGHT | UI_DIR_LEFT));
+    block->direction = no_2nd_dir ? dir1 : (dir1 | dir2);
   }
 
   /* Keep a list of these, needed for pull-down menus. */

source/blender/editors/interface/interface_widgets.cc

@@ -2775,11 +2775,20 @@ static void widget_menu_back(
     // rect->ymin -= 4.0;
     // rect->ymax += 4.0;
   }
-  else if (direction == UI_DIR_DOWN) {
-    roundboxalign = (UI_CNR_BOTTOM_RIGHT | UI_CNR_BOTTOM_LEFT);
-  }
-  else if (direction == UI_DIR_UP) {
-    roundboxalign = UI_CNR_TOP_LEFT | UI_CNR_TOP_RIGHT;
+  else if (direction & (UI_DIR_DOWN | UI_DIR_UP)) {
+    if (direction & UI_DIR_DOWN) {
+      roundboxalign = (UI_CNR_BOTTOM_RIGHT | UI_CNR_BOTTOM_LEFT);
+    }
+    else {
+      roundboxalign = (UI_CNR_TOP_LEFT | UI_CNR_TOP_RIGHT);
+    }
+    /* Corner rounding based on secondary direction. */
+    if (direction & UI_DIR_LEFT) {
+      roundboxalign |= (UI_CNR_TOP_RIGHT | UI_CNR_BOTTOM_RIGHT);
+    }
+    if (direction & UI_DIR_RIGHT) {
+      roundboxalign |= (UI_CNR_TOP_LEFT | UI_CNR_BOTTOM_LEFT);
+    }
   }
 
   GPU_blend(GPU_BLEND_ALPHA);
@@ -4742,10 +4751,11 @@ static int widget_roundbox_set(uiBut *but, rcti *rect)
   if (but->active && (but->type != UI_BTYPE_POPOVER) && !ui_but_menu_draw_as_popover(but)) {
     const int direction = ui_but_menu_direction(but);
 
-    if (direction == UI_DIR_UP) {
+    /* Pulldown menus that open above or below a button can have more than one direction. */
+    if (direction & UI_DIR_UP) {
       roundbox &= ~(UI_CNR_TOP_RIGHT | UI_CNR_TOP_LEFT);
     }
-    else if (direction == UI_DIR_DOWN) {
+    else if (direction & UI_DIR_DOWN) {
       roundbox &= ~(UI_CNR_BOTTOM_RIGHT | UI_CNR_BOTTOM_LEFT);
     }
     else if (direction == UI_DIR_LEFT) {