Fix rotation center regression caused by my own commit 13512

Fixed bugs:
  - https://launchpad.net/bugs/1360953
  - https://launchpad.net/bugs/1360946

(bzr r13534)

1 files changed, 7 insertions, 3 deletions

diff --git a/src/ui/dialog/document-properties.cpp b/src/ui/dialog/document-properties.cpp
index 4e4616724..2757a0ec9 100644
--- a/src/ui/dialog/document-properties.cpp
+++ b/src/ui/dialog/document-properties.cpp
@@ -1736,9 +1736,13 @@ void DocumentProperties::onDocUnitChange()
     prefs->setBool("/options/transform/gradient", true);
     {
         ShapeEditor::blockSetItem(true);
-        gdouble viewscale_w = doc->getWidth().value("px")/doc->getRoot()->viewBox.width();
-        gdouble viewscale_h = doc->getHeight().value("px")/doc->getRoot()->viewBox.height();
-        gdouble viewscale = std::min(viewscale_h, viewscale_w);
+        gdouble viewscale = 1.0;
+        Geom::Rect vb = doc->getRoot()->viewBox;
+        if ( !vb.hasZeroArea() ) {
+            gdouble viewscale_w = doc->getWidth().value("px") / vb.width();
+            gdouble viewscale_h = doc->getHeight().value("px")/ vb.height();
+            viewscale = std::min(viewscale_h, viewscale_w);
+        }
         gdouble scale = Inkscape::Util::Quantity::convert(1, old_doc_unit, doc_unit);
         doc->getRoot()->scaleChildItemsRec(Geom::Scale(scale), Geom::Point(-viewscale*doc->getRoot()->viewBox.min()[Geom::X] +
                                                                             (doc->getWidth().value("px") - viewscale*doc->getRoot()->viewBox.width())/2,