1 files changed, 48 insertions, 0 deletions
diff --git a/bin/pychart/log_coord.py b/bin/pychart/log_coord.py
new file mode 100644
index 00000000000..e40308c9cf8
--- /dev/null
+++ b/bin/pychart/log_coord.py
@@ -0,0 +1,48 @@
+#
+# Copyright (C) 2000-2005 by Yasushi Saito (yasushi.saito@gmail.com)
+# 
+# Jockey is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2, or (at your option) any
+# later version.
+#
+# Jockey is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+import coord
+import math
+
+class T(coord.T):
+    def get_canvas_pos(self, size, val, min, max):
+        if val <= 0:
+            return 0
+        xminl = math.log(min)
+        xmaxl = math.log(max)
+        vl = math.log(val)
+        return size * (vl-xminl) / float(xmaxl-xminl)
+    def get_tics(self, min, max, interval):
+        "Generate the list of places for drawing tick marks."
+        v = []
+        if min <= 0:
+            raise Exception, "Min value (%s) < 0 in a log coordinate." % min
+        x = min
+        while x <= max:
+            v.append(x)
+            x = x * interval
+        return v
+    def get_min_max(self, dmin, dmax, interval):
+        interval = interval or 10
+	dmin = max(0, dmin) # we can't have a negative value with a log scale.
+        v = 1.0
+        while v > dmin:
+            v = v / interval
+        dmin = v
+        v = 1.0
+        while v < dmax:
+            v = v * interval
+        dmax = v
+
+        return dmin, dmax, interval
+