From 4b690b4e43da3a1dfe08148559c6a5ecef62c297 Mon Sep 17 00:00:00 2001
From: Phil <Phil>
Date: Mon, 31 Mar 2014 21:47:37 +0100
Subject: [PATCH] Tooltip Precision Note Added note to describe how to use
 value_formatter field and simple example. This is a follow up to issue 79:
 https://github.com/Kozea/pygal/issues/79

---
 pages/basic_customizations.rst | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/pages/basic_customizations.rst b/pages/basic_customizations.rst
index 3d08114..c7128f6 100644
--- a/pages/basic_customizations.rst
+++ b/pages/basic_customizations.rst
@@ -480,6 +480,21 @@ Font size
   chart = pygal.Line(tooltip_font_size=24)
   chart.add('line', [.0002, .0005, .00035])
 
+Precision
+~~~~~~~~~
+
+``value_formatter``
+
+You can specifiy how the values are displayed on the tooltip using a lambda function.
+The code below shows the values to 2 decimal places.
+
+.. pygal-code::
+
+  chart = pygal.Line(range=(0, 5))
+  chart.add('line', [.070106781, 1.414213562, 3.141592654])
+  chart.value_formatter = lambda x: "%.2f" % x
+
+The datey graph shows the tooltip as "x=? y=?", where the x format is the same as the x_label_format, and the y format is specified via the value_formatter.
 
 Two y axes
 ----------