Add snapping setting logic for QPolyMod as well.

src/qged/plugins/polygon/QPolyMod.cpp

@@ -66,6 +66,8 @@ QPolyMod::QPolyMod()
     QObject::connect(ps->sketch_name, &QLineEdit::textEdited, this, &QPolyMod::sketch_name_edit_str);
     QObject::connect(ps->view_name, &QLineEdit::editingFinished, this, &QPolyMod::sketch_name_edit);
     QObject::connect(ps->sketch_name, &QLineEdit::editingFinished, this, &QPolyMod::sketch_name_update);
+    QObject::connect(ps, &QPolySettings::grid_snapping_changed, this, &QPolyMod::toggle_grid_snapping);
+    QObject::connect(ps, &QPolySettings::line_snapping_changed, this, &QPolyMod::toggle_line_snapping);
 
     QGroupBox *modpolyBox = new QGroupBox("Modify Polygon");
     QVBoxLayout *mod_poly_gl = new QVBoxLayout;
@@ -825,6 +827,61 @@ QPolyMod::view_name_update()
     emit view_updated(QG_VIEW_REFRESH);
 }
 
+
+void
+QPolyMod::toggle_line_snapping(bool s)
+{
+    line_snapping = s;
+}
+
+void
+QPolyMod::toggle_grid_snapping(bool s)
+{
+    grid_snapping = s;
+}
+
+void
+QPolyMod::config_line_snapping(struct bview *v, struct bv_scene_obj *co)
+{
+    if (!v)
+	return;
+    v->gv_s->gv_snap_flags = BV_SNAP_VIEW;
+    bu_ptbl_reset(&v->gv_s->gv_snap_objs);
+    if (!line_snapping) {
+	v->gv_s->gv_snap_lines = 0;
+    } else {
+	// Turn snapping on if we have other polygons to snap to
+	struct bu_ptbl *view_objs = bv_view_objs(v, BV_VIEW_OBJS);
+	if (!view_objs)
+	    return;
+	for (size_t i = 0; i < BU_PTBL_LEN(view_objs); i++) {
+	    struct bv_scene_obj *s = (struct bv_scene_obj *)BU_PTBL_GET(view_objs, i);
+	    if (s == co)
+		continue;
+	    if (s->s_type_flags & BV_POLYGONS)
+		bu_ptbl_ins(&v->gv_s->gv_snap_objs, (long *)s);
+	}
+	if (BU_PTBL_LEN(&v->gv_s->gv_snap_objs)) {
+	    v->gv_s->gv_snap_lines = 1;
+	} else {
+	    v->gv_s->gv_snap_lines = 0;
+	}
+    }
+}
+
+void
+QPolyMod::config_grid_snapping(struct bview *v)
+{
+    if (!v)
+	return;
+    v->gv_s->gv_snap_flags = BV_SNAP_VIEW;
+    if (!grid_snapping) {
+	v->gv_s->gv_grid.snap = 0;
+    } else {
+	v->gv_s->gv_grid.snap = 1;
+    }
+}
+
 void
 QPolyMod::propagate_update(int)
 {
@@ -862,6 +919,9 @@ QPolyMod::eventFilter(QObject *, QEvent *e)
     cf->v = (p) ? p->s_v : gedp->ged_gvp;
     cf->ptype = (ip) ? ip->type : BV_POLYGON_GENERAL;
 
+    config_line_snapping(cf->v, cf->wp);
+    config_grid_snapping(cf->v);
+
     // Connect whatever the current filter is to pass on updating signals from
     // the libqtcad logic.
     QObject::connect(cf, &QgPolyFilter::view_updated, this, &QPolyMod::propagate_update);

src/qged/plugins/polygon/QPolyMod.h

@@ -94,6 +94,10 @@ class QPolyMod : public QWidget
 	void view_name_edit_str(const QString &);
 	void view_name_edit();
 	void view_name_update();
+	void toggle_line_snapping(bool);
+	void config_line_snapping(struct bview *, struct bv_scene_obj *);
+	void toggle_grid_snapping(bool);
+	void config_grid_snapping(struct bview *);
 
     protected:
 	bool eventFilter(QObject *, QEvent *);
@@ -103,6 +107,8 @@ class QPolyMod : public QWidget
 	int poly_cnt = 0;
 	struct bv_scene_obj *p = NULL;
 	bool do_bool = false;
+	bool line_snapping = false;
+	bool grid_snapping = false;
 
 	QgPolyFilter *cf = NULL;
 	QPolyUpdateFilter *puf;