From 69f5c4dd44b76696be7d8d27f4059d420bd98bcc Mon Sep 17 00:00:00 2001
From: cilix42 <cilix42@users.sourceforge.net>
Date: Wed, 26 Dec 2007 11:19:54 +0000
Subject: [PATCH] Don't show boxes as everted (i.e., always show the same
 sides) during initial drag, regardless of the mouse pointer position.

---
 src/box3d-context.cpp |  4 +++-
 src/box3d.cpp         | 35 +++++++++++++++++++++++++++++++++++
 src/box3d.h           |  4 ++++
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/src/box3d-context.cpp b/src/box3d-context.cpp
index f66647ef7..edc45e8d1 100644
--- a/src/box3d-context.cpp
+++ b/src/box3d-context.cpp
@@ -669,11 +669,13 @@ static void sp_box3d_drag(Box3DContext &bc, guint /*state*/)
     box->orig_corner0 = bc.drag_origin_proj;
     box->orig_corner7 = bc.drag_ptC_proj;
 
+    box3d_check_for_swapped_coords(box);
+
     /* we need to call this from here (instead of from box3d_position_set(), for example)
        because z-order setting must not interfere with display updates during undo/redo */
     box3d_set_z_orders (box);
 
-    box3d_position_set(SP_BOX3D(bc.item));
+    box3d_position_set(box);
 
     // status text
     //GString *Ax = SP_PX_TO_METRIC_STRING(origin[NR::X], desktop->namedview->getDefaultMetric());
diff --git a/src/box3d.cpp b/src/box3d.cpp
index 4044b5647..0f9f8defe 100644
--- a/src/box3d.cpp
+++ b/src/box3d.cpp
@@ -1362,6 +1362,41 @@ box3d_relabel_corners(SPBox3D *box) {
     box3d_swap_coords(box, Proj::Z, true);
 }
 
+static void
+box3d_check_for_swapped_coords(SPBox3D *box, Proj::Axis axis, bool smaller) {
+    box->orig_corner0.normalize();
+    box->orig_corner7.normalize();
+
+    if ((box->orig_corner0[axis] < box->orig_corner7[axis]) != smaller) {
+        box->swapped = (Box3D::Axis) (box->swapped | Proj::toAffine(axis));
+    } else {
+        box->swapped = (Box3D::Axis) (box->swapped & ~Proj::toAffine(axis));
+    }
+}
+
+static void
+box3d_exchange_coords(SPBox3D *box) {
+    box->orig_corner0.normalize();
+    box->orig_corner7.normalize();
+
+    for (int i = 0; i < 3; ++i) {
+        if (box->swapped & Box3D::axes[i]) {
+            double tmp = box->orig_corner0[i];
+            box->orig_corner0[i] = box->orig_corner7[i];
+            box->orig_corner7[i] = tmp;
+        }
+    }
+}
+
+void
+box3d_check_for_swapped_coords(SPBox3D *box) {
+    box3d_check_for_swapped_coords(box, Proj::X, false);
+    box3d_check_for_swapped_coords(box, Proj::Y, false);
+    box3d_check_for_swapped_coords(box, Proj::Z, true);
+
+    box3d_exchange_coords(box);
+}
+
 void
 box3d_add_to_selection(SPBox3D *box) {
     Persp3D *persp = box3d_get_perspective(box);
diff --git a/src/box3d.h b/src/box3d.h
index d34ac1ae0..d6243d5e0 100644
--- a/src/box3d.h
+++ b/src/box3d.h
@@ -43,6 +43,8 @@ struct SPBox3D : public SPGroup {
     Proj::Pt3 save_corner0;
     Proj::Pt3 save_corner7;
 
+    Box3D::Axis swapped; // to indicate which coordinates are swapped during dragging
+
     gint my_counter; // for debugging only
 };
 
@@ -70,6 +72,8 @@ int box3d_VP_lies_in_PL_sector (SPBox3D const *box, Proj::Axis vpdir, int id1, i
 /* ensures that the coordinates of corner0 and corner7 are in the correct order (to prevent everted boxes) */
 void box3d_relabel_corners(SPBox3D *box);
 
+void box3d_check_for_swapped_coords(SPBox3D *box);
+
 void box3d_add_to_selection(SPBox3D *box);
 void box3d_remove_from_selection(SPBox3D *box);
 void box3d_mark_transformed(SPBox3D *box);
-- 
2.30.2