Fix rotation center regression caused by my own commit 13512

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

(bzr r13534)

2 files changed, 21 insertions, 9 deletions

diff --git a/src/sp-item.cpp b/src/sp-item.cpp
index 428f9555e..19dc71785 100644
--- a/src/sp-item.cpp
+++ b/src/sp-item.cpp
@@ -234,9 +234,13 @@ void SPItem::setCenter(Geom::Point const &object_centre) {
     document->ensureUpToDate();
 
     // Copied from DocumentProperties::onDocUnitChange()
-    gdouble viewscale_w = this->document->getWidth().value("px") / this->document->getRoot()->viewBox.width();
-    gdouble viewscale_h = this->document->getHeight().value("px")/ this->document->getRoot()->viewBox.height();
-    gdouble viewscale = std::min(viewscale_h, viewscale_w);
+    gdouble viewscale = 1.0;
+    Geom::Rect vb = this->document->getRoot()->viewBox;
+    if ( !vb.hasZeroArea() ) {
+        gdouble viewscale_w = this->document->getWidth().value("px") / vb.width();
+        gdouble viewscale_h = this->document->getHeight().value("px")/ vb.height();
+        viewscale = std::min(viewscale_h, viewscale_w);
+    }
 
     // FIXME this is seriously wrong
     Geom::OptRect bbox = desktopGeometricBounds();
@@ -267,9 +271,13 @@ Geom::Point SPItem::getCenter() const {
     document->ensureUpToDate();
 
     // Copied from DocumentProperties::onDocUnitChange()
-    gdouble viewscale_w = this->document->getWidth().value("px") / this->document->getRoot()->viewBox.width();
-    gdouble viewscale_h = this->document->getHeight().value("px")/ this->document->getRoot()->viewBox.height();
-    gdouble viewscale = std::min(viewscale_h, viewscale_w);
+    gdouble viewscale = 1.0;
+    Geom::Rect vb = this->document->getRoot()->viewBox;
+    if ( !vb.hasZeroArea() ) {
+        gdouble viewscale_w = this->document->getWidth().value("px") / vb.width();
+        gdouble viewscale_h = this->document->getHeight().value("px")/ vb.height();
+        viewscale = std::min(viewscale_h, viewscale_w);
+    }
 
     // FIXME this is seriously wrong
     Geom::OptRect bbox = desktopGeometricBounds();
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,