X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=src%2Flibnr%2Fnr-rect.h;h=46aff13f4fa938212f39df8654abeaacd1cdcaf5;hb=1c2557cd7259a8166f07b7982a44e040a44d4db1;hp=dd7caa897ea100c4a59704df33943926033ada89;hpb=8d10164b2636a9ee8b6ab5c5182143c0e50de3d4;p=inkscape.git

diff --git a/src/libnr/nr-rect.h b/src/libnr/nr-rect.h
index dd7caa897..46aff13f4 100644
--- a/src/libnr/nr-rect.h
+++ b/src/libnr/nr-rect.h
@@ -31,9 +31,10 @@ namespace NR {
 /** 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].  A rectangle may be empty, in the
+ * sense of having zero area, but it will always contain at least one
+ * point.  Infinities are also permitted.
+ */
 class Rect {
 public:
     Rect() : _min(-_inf(), -_inf()), _max(_inf(), _inf()) {}
@@ -52,9 +53,9 @@ public:
     /** returns the midpoint of this rect. */
     Point midpoint() const;
 
-    /** does this rectangle have zero area? */
-    bool isEmpty() const {
-        return isEmpty<X>() || isEmpty<Y>();
+    /** True iff either width or height is less than \a epsilon. */
+    bool isEmpty(double epsilon=1e-6) const {
+        return isEmpty<X>(epsilon) || isEmpty<Y>(epsilon);
     }
 
     bool intersects(Rect const &r) const {
@@ -125,35 +126,7 @@ public:
         _max[NR::Y] += by;
     }
 
-    /** Returns the set of points shared by both rectangles. */
-    static Maybe<Rect> intersection(Maybe<Rect> const &a, Maybe<Rect> const &b);
-
-    /** Returns the smallest rectangle that encloses both rectangles. */
-    static Maybe<Rect> union_bounds(Maybe<Rect> const &a, Maybe<Rect> const &b)
-    {
-        if (!a) {
-            return b;
-        } else if (!b) {
-            return a;
-        } else {
-            return union_bounds(*a, *b);
-        }
-    }
-    static Rect union_bounds(Maybe<Rect> const &a, Rect const &b) {
-        if (a) {
-            return union_bounds(*a, b);
-        } else {
-            return b;
-        }
-    }
-    static Rect union_bounds(Rect const &a, Maybe<Rect> const &b) {
-        if (b) {
-            return union_bounds(a, *b);
-        } else {
-            return a;
-        }
-    }
-    static Rect union_bounds(Rect const &a, Rect const &b);
+    void growBy (gdouble by);
 
     /** Scales the rect by s, with origin at 0, 0 */
     inline Rect operator*(double const s) const {
@@ -172,6 +145,8 @@ public:
     friend inline std::ostream &operator<<(std::ostream &out_file, NR::Rect const &in_rect);
 
 private:
+    Rect(Nothing) : _min(1, 1), _max(-1, -1) {}
+
     static double _inf() {
         return std::numeric_limits<double>::infinity();
     }
@@ -181,9 +156,9 @@ private:
         return _max[axis] - _min[axis];
     }
 
-    template <Dim2 axis>
-    bool isEmpty() const {
-        return !( _min[axis] < _max[axis] );
+    template <NR::Dim2 axis>
+    bool isEmpty(double epsilon) const {
+        return extent<axis>() < epsilon;
     }
 
     template <Dim2 axis>
@@ -203,10 +178,57 @@ private:
 
     Point _min, _max;
 
-    /* evil, but temporary */
-    friend class Maybe<Rect>;
+    friend class MaybeStorage<Rect>;
+    friend Maybe<Rect> intersection(Maybe<Rect> const &, Maybe<Rect> const &);
+    friend Rect union_bounds(Rect const &, Rect const &);
 };
 
+template <>
+class MaybeStorage<Rect> {
+public:
+    MaybeStorage() : _rect(Nothing()) {}
+    MaybeStorage(Rect const &rect) : _rect(rect) {}
+
+    bool is_nothing() const {
+        return _rect._min[X] > _rect._max[X];
+    }
+    Rect const &value() const { return _rect; }
+    Rect &value() { return _rect; }
+
+private:
+    Rect _rect;
+};
+
+/** Returns the set of points shared by both rectangles. */
+Maybe<Rect> intersection(Maybe<Rect> const & a, Maybe<Rect> const & b);
+
+/** Returns the smallest rectangle that encloses both rectangles. */
+Rect union_bounds(Rect const &a, Rect const &b);
+inline Rect union_bounds(Maybe<Rect> const & a, Rect const &b) {
+    if (a) {
+        return union_bounds(*a, b);
+    } else {
+        return b;
+    }
+}
+inline Rect union_bounds(Rect const &a, Maybe<Rect> const & b) {
+    if (b) {
+        return union_bounds(a, *b);
+    } else {
+        return a;
+    }
+}
+inline Maybe<Rect> union_bounds(Maybe<Rect> const & a, Maybe<Rect> const & b)
+{
+    if (!a) {
+        return b;
+    } else if (!b) {
+        return a;
+    } else {
+        return union_bounds(*a, *b);
+    }
+}
+
 /** A function to print out the rectange if sent to an output
     stream. */
 inline std::ostream
@@ -243,6 +265,7 @@ struct NRRect {
 #define nr_rect_d_set_empty(r) (*(r) = NR_RECT_EMPTY)
 #define nr_rect_l_set_empty(r) (*(r) = NR_RECT_L_EMPTY)
 
+/** "Empty" here includes the case of zero width or zero height. */
 #define nr_rect_d_test_empty(r) ((r) && NR_RECT_DFLS_TEST_EMPTY(r))
 #define nr_rect_l_test_empty(r) ((r) && NR_RECT_DFLS_TEST_EMPTY(r))