improved precision in placing grids and guides. (Bug 1373311)

Fixed bugs:
  - https://launchpad.net/bugs/1373311

(bzr r13868)

2 files changed, 22 insertions, 5 deletions

diff --git a/src/sp-guide.cpp b/src/sp-guide.cpp
index 3eecb2783..890c1f597 100644
--- a/src/sp-guide.cpp
+++ b/src/sp-guide.cpp
@@ -198,8 +198,15 @@ SPGuide *SPGuide::createSPGuide(SPDocument *doc, Geom::Point const &pt1, Geom::P
 
     SPRoot *root = doc->getRoot();
     if( root->viewBox_set ) {
-        newx = newx * root->viewBox.width()  / root->width.computed;
-        newy = newy * root->viewBox.height() / root->height.computed;
+        // check to see if scaling is uniform
+        if(Geom::are_near((root->viewBox.width() * root->height.computed) / (root->width.computed * root->viewBox.height()), 1.0, Geom::EPSILON)) {
+            double px2vbunit = (root->viewBox.width()/root->width.computed + root->viewBox.height()/root->height.computed)/2.0;
+            newx = newx * px2vbunit;
+            newy = newy * px2vbunit;
+        } else {
+            newx = newx * root->viewBox.width()  / root->width.computed;
+            newy = newy * root->viewBox.height() / root->height.computed;
+        }
     }
 
     sp_repr_set_point(repr, "position", Geom::Point( newx, newy ));
@@ -341,8 +348,15 @@ void SPGuide::moveto(Geom::Point const point_on_line, bool const commit)
 
         SPRoot *root = document->getRoot();
         if( root->viewBox_set ) {
-            newx = newx * root->viewBox.width()  / root->width.computed;
-            newy = newy * root->viewBox.height() / root->height.computed;
+            // check to see if scaling is uniform
+            if(Geom::are_near((root->viewBox.width() * root->height.computed) / (root->width.computed * root->viewBox.height()), 1.0, Geom::EPSILON)) {
+                double px2vbunit = (root->viewBox.width()/root->width.computed + root->viewBox.height()/root->height.computed)/2.0;
+                newx = newx * px2vbunit;
+                newy = newy * px2vbunit;
+            } else {
+                newx = newx * root->viewBox.width()  / root->width.computed;
+                newy = newy * root->viewBox.height() / root->height.computed;
+            }
         }
 
         //XML Tree being used here directly while it shouldn't be.
diff --git a/src/ui/widget/registered-widget.cpp b/src/ui/widget/registered-widget.cpp
index bbf542987..298377af3 100644
--- a/src/ui/widget/registered-widget.cpp
+++ b/src/ui/widget/registered-widget.cpp
@@ -245,7 +245,10 @@ RegisteredScalarUnit::on_value_changed()
         if (doc) {
             SPRoot *root = doc->getRoot();
             if (root->viewBox_set) {
-                if (_user_units == RSU_x) { 
+                // check to see if scaling is uniform
+                if(Geom::are_near((root->viewBox.width() * root->height.computed) / (root->width.computed * root->viewBox.height()), 1.0, Geom::EPSILON)) {
+                    scale = (root->viewBox.width() / root->width.computed + root->viewBox.height() / root->height.computed)/2.0;
+                } else if (_user_units == RSU_x) { 
                     scale = root->viewBox.width() / root->width.computed;
                 } else {
                     scale = root->viewBox.height() / root->height.computed;