Added QgsRect::intersects(QgsRect) predicate

wonder · wonder · commit ef4bad24e6bd · 2008-06-17T00:15:08.000Z
git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@8651 c8812cc2-4d05-0410-92ff-de0c093fc19c
diff --git a/python/core/qgsrect.sip b/python/core/qgsrect.sip
@@ -59,6 +59,8 @@ class QgsRect
     void expand(double, const QgsPoint *c = 0);
     //! return the intersection with the given rectangle
     QgsRect intersect(QgsRect *rect);
+    //! returns true when rectangle intersects with other rectangle
+    bool intersects(const QgsRect& rect) const;
     //! expand the rectangle so that covers both the original rectangle and the given rectangle
     void combineExtentWith(QgsRect *rect);
     //! expand the rectangle so that covers both the original rectangle and the given point
diff --git a/src/core/qgsrect.cpp b/src/core/qgsrect.cpp
@@ -138,6 +138,17 @@ QgsRect QgsRect::intersect(QgsRect * rect) const
   return intersection;
 }
 
+bool QgsRect::intersects(const QgsRect& rect) const
+{
+  double x1 = (xmin > rect.xmin ? xmin : rect.xmin);
+  double x2 = (xmax < rect.xmax ? xmax : rect.xmax);
+  if (x1 > x2) return FALSE;
+  double y1 = (ymin > rect.ymin ? ymin : rect.ymin);
+  double y2 = (ymax < rect.ymax ? ymax : rect.ymax);
+  if (y1 > y2) return FALSE;
+  return TRUE;
+}
+
 
 void QgsRect::combineExtentWith(QgsRect * rect)
 {
diff --git a/src/core/qgsrect.h b/src/core/qgsrect.h
@@ -82,6 +82,8 @@ class CORE_EXPORT QgsRect
     void expand(double, const QgsPoint *c = 0);
     //! return the intersection with the given rectangle
     QgsRect intersect(QgsRect *rect) const;
+    //! returns true when rectangle intersects with other rectangle
+    bool intersects(const QgsRect& rect) const;
     //! expand the rectangle so that covers both the original rectangle and the given rectangle
     void combineExtentWith(QgsRect *rect);
     //! expand the rectangle so that covers both the original rectangle and the given point
