Gauge can be clockwise

pygal/config.py

@@ -20,10 +20,9 @@
 
 from copy import deepcopy
 
+from pygal import formatters
 from pygal.interpolate import INTERPOLATIONS
 from pygal.style import DefaultStyle, Style
-from pygal import formatters
-
 
 CONFIG_ITEMS = []
 callable = type(lambda: 1)
@@ -258,6 +257,12 @@ class Config(CommonConfig):
         str)
 
     # Look #
+    clockwise = Key(
+        False, bool, "Look",
+        "Clockwise",
+        "Set to True to make the gauge clockwise."
+        )
+
     title = Key(
         None, str, "Look",
         "Graph title.", "Leave it to None to disable title.")

pygal/graph/gauge.py

@@ -23,7 +23,7 @@
 
 from pygal._compat import is_str
 from pygal.graph.graph import Graph
-from pygal.util import alter, compute_scale, cut, decorate
+from pygal.util import alter, compose, compute_scale, cut, decorate
 from pygal.view import PolarThetaLogView, PolarThetaView
 
 
@@ -45,6 +45,11 @@ def _set_view(self):
             self.height - self.margin_box.y,
             self._box)
 
+    def clockwiser(self, point):
+        x_0, _ = self.view((0, 90))
+        new_x = 2*x_0 - point[0]
+        return (new_x, point[1])
+
     def needle(self, serie):
         """Draw a needle for each value"""
         serie_node = self.svg.serie(serie)
@@ -53,7 +58,11 @@ def needle(self, serie):
                 continue
 
             def point(x, y):
-                return '%f %f' % self.view((x, y))
+                if self.clockwise:
+                    transform = compose(self.clockwiser, self.view)
+                else:
+                    transform = self.view
+                return '%f %f' % transform((x, y))
 
             val = self._format(serie, i)
             metadata = serie.metadata.get(i)
@@ -75,18 +84,24 @@ def point(x, y):
             if self.logarithmic:
                 w = min(w, self._min - self._min * 10 ** -10)
 
+            sweep_flag = '0' if self.clockwise else '1'
+
             alter(
                 self.svg.node(
-                    gauges, 'path', d='M %s L %s A %s 1 0 1 %s Z' % (
+                    gauges, 'path', d='M %s L %s A %s 1 0 %s %s Z' % (
                         point(.85, theta),
                         point(self.needle_width, theta - w),
                         '%f %f' % (self.needle_width, self.needle_width),
+                        sweep_flag,
                         point(self.needle_width, theta + w),
                     ),
                     class_='line reactive tooltip-trigger'),
                 metadata)
 
             x, y = self.view((.75, theta))
+            if self.clockwise:
+                x, y = self.clockwiser((x, y))
+
             self._tooltip_data(
                 gauges, val, x, y,
                 xlabel=self._get_x_label(i))
@@ -96,6 +111,14 @@ def _y_axis(self, draw_axes=True):
         """Override y axis to plot a polar axis"""
         axis = self.svg.node(self.nodes['plot'], class_="axis x gauge")
 
+        if self.clockwise:
+            for i in range(int(len(self._y_labels)/2)):
+                (label_1, theta_1) = self._y_labels[i]
+                (label_2, theta_2) = self._y_labels[len(self._y_labels)-i-1]
+                temp_theta = theta_2
+                self._y_labels[len(self._y_labels)-i-1] = (label_2, theta_1)
+                self._y_labels[i] = (label_1, temp_theta)
+
         for i, (label, theta) in enumerate(self._y_labels):
             guides = self.svg.node(axis, class_='guides')
 
@@ -112,6 +135,7 @@ def _y_axis(self, draw_axes=True):
                     else ''))
 
             x, y = self.view((.9, theta))
+
             self.svg.node(
                 guides, 'text',
                 x=x,
@@ -149,6 +173,7 @@ def _compute_y_labels(self):
             self.min_, self.max_, self.logarithmic,
             self.order_min, self.min_scale, self.max_scale
         )
+
         if self.y_labels:
             self._y_labels = []
             for i, y_label in enumerate(self.y_labels):

pygal/graph/graph.py

@@ -22,14 +22,13 @@
 
 from math import ceil, cos, sin, sqrt
 
+from pygal import stats
 from pygal._compat import is_list_like, is_str, to_str
 from pygal.graph.public import PublicApi
 from pygal.interpolate import INTERPOLATIONS
-from pygal import stats
-from pygal.util import (
-    cached_property, compute_scale, cut, decorate,
-    get_text_box, get_texts_box, majorize, rad, reverse_text_len,
-    split_title, truncate, filter_kwargs)
+from pygal.util import (cached_property, compute_scale, cut, decorate,
+                        filter_kwargs, get_text_box, get_texts_box, majorize,
+                        rad, reverse_text_len, split_title, truncate)
 from pygal.view import LogView, ReverseView, View, XYLogView
 
 

pygal/util.py

@@ -23,10 +23,9 @@
 
 import re
 from decimal import Decimal
+from math import ceil, cos, floor, log10, pi, sin
 
-from math import ceil, floor, log10, pi, cos, sin
-
-from pygal._compat import to_unicode, u, _ellipsis
+from pygal._compat import _ellipsis, to_unicode, u
 
 
 def float_format(number):