X-Git-Url: https://git.decadent.org.uk/gitweb/?a=blobdiff_plain;f=geometry.hpp;fp=geometry.hpp;h=a26332784c8a9008574c57cfdfdcf80f9d830870;hb=f5d9069647f70b7aab8e656f59cf42176c419461;hp=0000000000000000000000000000000000000000;hpb=1c05822d40aae48b8a9a971ba909641379d0709e;p=videolink.git

diff --git a/geometry.hpp b/geometry.hpp
new file mode 100644
index 0000000..a263327
--- /dev/null
+++ b/geometry.hpp
@@ -0,0 +1,51 @@
+// Copyright 2005-6 Ben Hutchings <ben@decadent.org.uk>.
+// See the file "COPYING" for licence details.
+
+#ifndef INC_GEOMETRY_HPP
+#define INC_GEOMETRY_HPP
+
+struct rectangle
+{
+    int left, top;     // inclusive
+    int right, bottom; // exclusive
+
+    rectangle operator|=(const rectangle & other)
+	{
+	    if (other.empty())
+	    {
+		// use current extents unchanged
+	    }
+	    else if (empty())
+	    {
+		// use other extents
+		*this = other;
+	    }
+	    else
+	    {
+		// find rectangle enclosing both extents
+		left = std::min(left, other.left);
+		top = std::min(top, other.top);
+		right = std::max(right, other.right);
+		bottom = std::max(bottom, other.bottom);
+	    }
+
+	    return *this;
+	}
+
+    rectangle operator&=(const rectangle & other)
+	{
+	    // find rectangle enclosed in both extents
+	    left = std::max(left, other.left);
+	    top = std::max(top, other.top);
+	    right = std::max(left, std::min(right, other.right));
+	    bottom = std::max(top, std::min(bottom, other.bottom));
+	    return *this;
+	}
+
+    bool empty() const
+	{
+	    return left == right || bottom == top;
+	}
+};
+
+#endif // !INC_GEOMETRY_HPP