ban empty rectangles entirely and remove isEmpty test

(bzr r2606)

6 files changed, 18 insertions, 19 deletions

diff --git a/src/gradient-chemistry.cpp b/src/gradient-chemistry.cpp
index 82a88faa3..5521f91cb 100644
--- a/src/gradient-chemistry.cpp
+++ b/src/gradient-chemistry.cpp
@@ -260,7 +260,7 @@ sp_gradient_reset_to_userspace (SPGradient *gr, SPItem *item)
     sp_document_ensure_up_to_date(SP_OBJECT_DOCUMENT(item));
     NR::Maybe<NR::Rect> bbox = item->getBounds(NR::identity()); // we need "true" bbox without item_i2d_affine
 
-    g_assert( bbox && !bbox->isEmpty() );
+    g_assert( bbox );
     NR::Coord const width = bbox->dimensions()[NR::X];
     NR::Coord const height = bbox->dimensions()[NR::Y];
 
@@ -318,7 +318,7 @@ sp_gradient_convert_to_userspace(SPGradient *gr, SPItem *item, gchar const *prop
         sp_document_ensure_up_to_date(SP_OBJECT_DOCUMENT(item));
         NR::Matrix bbox2user;
         NR::Maybe<NR::Rect> bbox = item->getBounds(NR::identity()); // we need "true" bbox without item_i2d_affine
-        if ( bbox && !bbox->isEmpty() ) {
+        if ( bbox ) {
             bbox2user = NR::Matrix(bbox->dimensions()[NR::X], 0,
                                    0, bbox->dimensions()[NR::Y],
                                    bbox->min()[NR::X], bbox->min()[NR::Y]);
diff --git a/src/libnr/nr-rect.cpp b/src/libnr/nr-rect.cpp
index 2d4629d42..a9487045a 100644
--- a/src/libnr/nr-rect.cpp
+++ b/src/libnr/nr-rect.cpp
@@ -244,7 +244,12 @@ namespace NR {
 
 Rect::Rect(const Point &p0, const Point &p1)
 : _min(std::min(p0[X], p1[X]), std::min(p0[Y], p1[Y])),
-  _max(std::max(p0[X], p1[X]), std::max(p0[Y], p1[Y])) {}
+  _max(std::max(p0[X], p1[X]), std::max(p0[Y], p1[Y]))
+{
+    if ( _min[X] == _max[X] || _min[Y] == _max[Y] ) {
+        throw EmptyRectangle();
+    }
+}
 
 /** returns the four corners of the rectangle in the correct winding order */
 Point Rect::corner(unsigned i) const {
diff --git a/src/libnr/nr-rect.h b/src/libnr/nr-rect.h
index b632261aa..6ae1e4e99 100644
--- a/src/libnr/nr-rect.h
+++ b/src/libnr/nr-rect.h
@@ -28,12 +28,16 @@
 namespace NR {
     struct Matrix;
 
+class EmptyRectangle : public std::logic_error {
+public:
+    EmptyRectangle() : logic_error("Attempt to create empty rectangle") {}
+};
+
 /** A rectangle is always aligned to the X and Y axis.  This means it
  * can be defined using only 4 coordinates, and determining
  * intersection is very efficient.  The points inside a rectangle are
- * min[dim] <= _pt[dim] <= max[dim].  Emptiness, however, is defined
- * as having zero area, meaning an empty rectangle may still contain
- * points.  Infinities are also permitted. */
+ * min[dim] <= _pt[dim] <= max[dim].  Emptiness, in the sense of having
+ * a zero area, is not permitted.  Infinities are, however. */
 class Rect {
 public:
     Rect() : _min(-_inf(), -_inf()), _max(_inf(), _inf()) {}
@@ -52,11 +56,6 @@ public:
     /** returns the midpoint of this rect. */
     Point midpoint() const;
 
-    /** does this rectangle have zero area? */
-    bool isEmpty() const {
-        return isEmpty<X>() || isEmpty<Y>();
-    }
-
     bool intersects(Rect const &r) const {
         return intersects<X>(r) && intersects<Y>(r);
     }
@@ -154,11 +153,6 @@ private:
     }
 
     template <Dim2 axis>
-    bool isEmpty() const {
-        return !( _min[axis] < _max[axis] );
-    }
-
-    template <Dim2 axis>
     bool intersects(Rect const &r) const {
         return _max[axis] >= r._min[axis] && _min[axis] <= r._max[axis];
     }
diff --git a/src/sp-item-transform.cpp b/src/sp-item-transform.cpp
index 105a91b4c..72a7c39e6 100644
--- a/src/sp-item-transform.cpp
+++ b/src/sp-item-transform.cpp
@@ -103,7 +103,7 @@ get_scale_transform_with_stroke (NR::Rect &bbox_param, gdouble strokewidth, bool
     gdouble h1 = y1 - y0;
     gdouble r0 = strokewidth;
 
-    if (bbox.isEmpty() || bbox.extent(NR::X) < 1e-06 || bbox.extent(NR::Y) < 1e-06) {
+    if (bbox.extent(NR::X) < 1e-06 || bbox.extent(NR::Y) < 1e-06) {
         NR::Matrix move = NR::Matrix(NR::translate(x0 - bbox.min()[NR::X], y0 - bbox.min()[NR::Y]));
         return (move); // cannot scale from empty boxes at all, so only translate
     }
diff --git a/src/sp-offset.cpp b/src/sp-offset.cpp
index e682f394b..ed4db90b7 100644
--- a/src/sp-offset.cpp
+++ b/src/sp-offset.cpp
@@ -585,7 +585,7 @@ sp_offset_set_shape(SPShape *shape)
 
         SPItem *item = shape;
         NR::Maybe<NR::Rect> bbox = sp_item_bbox_desktop (item);
-        if ( bbox && !bbox->isEmpty() ) {
+        if ( bbox ) {
             gdouble size = L2(bbox->dimensions());
             gdouble const exp = NR::expansion(item->transform);
             if (exp != 0)
diff --git a/src/widgets/icon.cpp b/src/widgets/icon.cpp
index 9be74a556..b9ed94c0c 100644
--- a/src/widgets/icon.cpp
+++ b/src/widgets/icon.cpp
@@ -623,7 +623,7 @@ sp_icon_doc_icon( SPDocument *doc, NRArenaItem *root,
             }
 
             /* This is in document coordinates, i.e. pixels */
-            if ( dbox && !dbox->isEmpty() ) {
+            if ( dbox ) {
                 NRGC gc(NULL);
                 /* Update to renderable state */
                 double sf = 1.0;