UI: ignore events in empty region overlap areas

- Resizable areas use 2D view bounds.
- Header uses the button bounds.
- A margin is added to avoid clicking between buttons.
- Region resize edges clamp to the 2D view bounds.

Resovles T61554

1 files changed, 123 insertions, 0 deletions

diff --git a/source/blender/editors/screen/area_query.c b/source/blender/editors/screen/area_query.c
new file mode 100644
index 00000000000..a4bcf622815
--- /dev/null
+++ b/source/blender/editors/screen/area_query.c
@@ -0,0 +1,123 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup edscr
+ *
+ * Query functions for area/region.
+ */
+
+#include "DNA_userdef_types.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_utildefines.h"
+
+#include "RNA_types.h"
+
+#include "WM_api.h"
+
+#include "ED_screen.h"
+
+#include "UI_interface.h"
+#include "UI_view2d.h"
+
+bool ED_region_overlap_isect_x(const ARegion *ar, const int event_x)
+{
+  BLI_assert(ar->overlap);
+  /* No contents, skip it. */
+  if (ar->v2d.mask.xmin == ar->v2d.mask.xmax) {
+    return false;
+  }
+  return BLI_rctf_isect_x(&ar->v2d.tot,
+                          UI_view2d_region_to_view_x(&ar->v2d, event_x - ar->winrct.xmin));
+}
+
+bool ED_region_overlap_isect_y(const ARegion *ar, const int event_y)
+{
+  BLI_assert(ar->overlap);
+  /* No contents, skip it. */
+  if (ar->v2d.mask.ymin == ar->v2d.mask.ymax) {
+    return false;
+  }
+  return BLI_rctf_isect_y(&ar->v2d.tot,
+                          UI_view2d_region_to_view_y(&ar->v2d, event_y - ar->winrct.ymin));
+}
+
+bool ED_region_overlap_isect_xy(const ARegion *ar, const int event_xy[2])
+{
+  return (ED_region_overlap_isect_x(ar, event_xy[0]) &&
+          ED_region_overlap_isect_y(ar, event_xy[1]));
+}
+
+bool ED_region_overlap_isect_x_with_margin(const ARegion *ar, const int event_x, const int margin)
+{
+  BLI_assert(ar->overlap);
+  /* No contents, skip it. */
+  if (ar->v2d.mask.xmin == ar->v2d.mask.xmax) {
+    return false;
+  }
+  int region_x = event_x - ar->winrct.xmin;
+  return ((ar->v2d.tot.xmin <= UI_view2d_region_to_view_x(&ar->v2d, region_x + margin)) &&
+          (ar->v2d.tot.xmax >= UI_view2d_region_to_view_x(&ar->v2d, region_x - margin)));
+}
+
+bool ED_region_overlap_isect_y_with_margin(const ARegion *ar, const int event_y, const int margin)
+{
+  BLI_assert(ar->overlap);
+  /* No contents, skip it. */
+  if (ar->v2d.mask.ymin == ar->v2d.mask.ymax) {
+    return false;
+  }
+  int region_y = event_y - ar->winrct.ymin;
+  return ((ar->v2d.tot.ymin <= UI_view2d_region_to_view_y(&ar->v2d, region_y + margin)) &&
+          (ar->v2d.tot.ymax >= UI_view2d_region_to_view_y(&ar->v2d, region_y - margin)));
+}
+
+bool ED_region_overlap_isect_xy_with_margin(const ARegion *ar,
+                                            const int event_xy[2],
+                                            const int margin)
+{
+  return (ED_region_overlap_isect_x_with_margin(ar, event_xy[0], margin) &&
+          ED_region_overlap_isect_y_with_margin(ar, event_xy[1], margin));
+}
+
+bool ED_region_contains_xy(const ARegion *ar, const int event_xy[2])
+{
+  /* Only use the margin when inside the region. */
+  if (BLI_rcti_isect_pt_v(&ar->winrct, event_xy)) {
+    if (ar->overlap) {
+      const int overlap_margin = UI_REGION_OVERLAP_MARGIN;
+      /* Note the View2D.tot isn't reliable for headers with spacers otherwise
+       * we'd check #ED_region_overlap_isect_xy_with_margin for both bases. */
+      if (ar->v2d.keeptot == V2D_KEEPTOT_STRICT) {
+        /* Header. */
+        rcti rect;
+        BLI_rcti_init_pt_radius(&rect, event_xy, overlap_margin);
+        if (UI_region_but_find_rect_over(ar, &rect) == NULL) {
+          return false;
+        }
+      }
+      else {
+        /* Side-bar & any other kind of overlapping region. */
+        if (!ED_region_overlap_isect_xy_with_margin(ar, event_xy, overlap_margin)) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }
+  return false;
+}