Update the interpolation reference for a more exhaustive one

pages/interpolations.rst

@@ -9,11 +9,6 @@ Interpolations
 
 .. contents::
 
-To enable interpolation, just specify the interpolation type to:
-
-- quadratic
-- cubic
-
 
 Without interpolation:
 ----------------------
@@ -35,6 +30,7 @@ With cubic interpolation:
   chart = pygal.Line(interpolate='cubic')
   chart.add('line', [1, 5, 17, 12, 5, 10])
 
+
 With quadratic interpolation:
 -----------------------------
 
@@ -46,6 +42,62 @@ With quadratic interpolation:
   chart.add('line', [1, 5, 17, 12, 5, 10])
 
 
+With lagrange interpolation:
+----------------------------
+
+``interpolate``
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='lagrange')
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+
+With trigonometric interpolation:
+---------------------------------
+
+``interpolate``
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='trigonometric')
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+
+With hermite interpolation:
+---------------------------
+
+``interpolate``
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='hermite')
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+
+For hermite you can also pass additionnal parameters to configure tangent behaviour:
+
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='hermite', interpolation_parameters={'type': 'finite_difference'})
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='hermite', interpolation_parameters={'type': 'cardinal', 'c': .75})
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+
+.. pygal-code::
+
+  chart = pygal.Line(interpolate='hermite', interpolation_parameters={'type': 'kochanek_bartels', 'b': -1, 'c': 1, 't': 1})
+  chart.add('line', [1, 5, 17, 12, 5, 10])
+
+For more information see the `wikipedia article <http://en.wikipedia.org/wiki/Cubic_Hermite_spline#Finite_difference>`_
+
+
 Interpolation precision
 -----------------------