Major and minor x-axis labels

Adds options to
- specify major labels manually
- specify major labels automatically based on an interval
- specify major labels automatically based on a count
- suppress diplay of minor labels
- give major labels a different font size
The 'x_labels_num_limit' option has been removed. This functionality can also be achieved with the new options and now works for other graph types than Line.

pygal/config.py

@@ -140,10 +140,21 @@ class Config(object):
         "Leave it to None to disable x labels display.",
         str)
 
-    x_labels_num_limit = Key(None, int, "Label", 
-            "Limits the number of X labels, defaults to None",
-            "If none, there will be as many x labels as provided in x_labels. When provided - limits the number of X labels"
-            )
+    x_labels_major = Key(
+        None, list, "Label",
+        "X labels that will be marked major.",
+        str)
+
+    x_labels_major_every = Key(
+        None, int, "Label",
+        "Mark every n-th x label as major.")
+
+    x_labels_major_count = Key(
+        None, int, "Label",
+        "Mark n evenly distributed labels as major.")
+
+    show_minor_x_labels = Key(
+        True, bool, "Label", "Set to false to hide x-labels not marked major")
 
     y_labels = Key(
         None, list, "Label",
@@ -198,6 +209,8 @@ class Config(object):
         "No data", str, "Text", "Text to display when no data is given")
 
     label_font_size = Key(10, int, "Text", "Label font size")
+
+    major_label_font_size = Key(10, int, "Text", "Major label font size")
 
     value_font_size = Key(8, int, "Text", "Value font size")
 

pygal/css/base.css

@@ -37,6 +37,11 @@
   font-size: {{ font_sizes.label }};
 }
 
+.axis text.major {
+  font-family: monospace;
+  font-size: {{ font_sizes.major_label }};
+}
+
 .series text {
   font-family: monospace;
   font-size: {{ font_sizes.value }};

pygal/graph/graph.py

@@ -131,8 +131,25 @@ def _x_axis(self, draw_axes=True):
                           d='M%f %f v%f' % (0, 0, self.view.height),
                           class_='line')
         lastlabel = self._x_labels[-1][0]
+        if self.x_labels_major:
+            x_labels_major = self.x_labels_major
+        elif self.x_labels_major_every:
+            x_labels_major = [self._x_labels[i][0] for i in xrange(
+                0, len(self._x_labels), self.x_labels_major_every)]
+        elif self.x_labels_major_count:
+            label_count = len(self._x_labels)
+            major_count = self.x_labels_major_count
+            if (major_count >= label_count):
+                x_labels_major = [label[0] for label in self._x_labels]
+            else:
+                x_labels_major = [self._x_labels[
+                    int(i * (label_count - 1) / (major_count - 1))][0]  
+                    for i in xrange(major_count)]
+        else:
+            x_labels_major = []
         for label, position in self._x_labels:
-            major = is_major(position)
+            major = label in x_labels_major
+            if not (self.show_minor_x_labels or major): continue
             guides = self.svg.node(axis, class_='guides')
             x = self.view.x(position)
             y = self.view.height + 5
@@ -162,7 +179,8 @@ def _x_axis(self, draw_axes=True):
             secondary_ax = self.svg.node(
                 self.nodes['plot'], class_="axis x x2")
             for label, position in self._x_2nd_labels:
-                major = is_major(position)
+                major = label in x_labels_major
+                if not (self.show_minor_x_labels or major): continue
                 # it is needed, to have the same structure as primary axis
                 guides = self.svg.node(secondary_ax, class_='guides')
                 x = self.view.x(position)

pygal/graph/line.py

@@ -87,10 +87,7 @@ def line(self, serie_node, serie, rescale=False):
                 self.svg.node(dots, 'circle', cx=x, cy=y, r=self.dots_size,
                               class_='dot reactive tooltip-trigger')
                 self._tooltip_data(
-                    dots, "%s: %s" % (
-                        self.x_labels[i], val)
-                    if self.x_labels and self.x_labels_num_limit
-                    else val, x, y)
+                    dots, val, x, y)
                 self._static_value(
                     serie_node, val,
                     x + self.value_font_size,
@@ -114,13 +111,7 @@ def _compute(self):
         self._points(x_pos)
 
         if self.x_labels:
-            x_labels = zip(self.x_labels, x_pos)
-            if (self.x_labels_num_limit and
-                    len(x_labels) > self.x_labels_num_limit):
-                step = (len(x_labels) - 1) / (self.x_labels_num_limit - 1)
-                x_labels = [x_labels[int(i * step)]
-                            for i in range(self.x_labels_num_limit)]
-            self._x_labels = x_labels
+            self._x_labels = zip(self.x_labels, x_pos)
         else:
             self._x_labels = None
 

pygal/graph/radar.py

@@ -72,19 +72,39 @@ def _x_axis(self, draw_axes=True):
         format_ = lambda x: '%f %f' % x
         center = self.view((0, 0))
         r = self._rmax
+        if self.x_labels_major:
+            x_labels_major = self.x_labels_major
+        elif self.x_labels_major_every:
+            x_labels_major = [self._x_labels[i][0] for i in xrange(
+                0, len(self._x_labels), self.x_labels_major_every)]
+        elif self.x_labels_major_count:
+            label_count = len(self._x_labels)
+            major_count = self.x_labels_major_count
+            if (major_count >= label_count):
+                x_labels_major = [label[0] for label in self._x_labels]
+            else:
+                x_labels_major = [self._x_labels[
+                    int(i * label_count / major_count)][0]  
+                    for i in xrange(major_count)]
+        else:
+            x_labels_major = []
+
         for label, theta in self._x_labels:
+            major = label in x_labels_major
+            if not (self.show_minor_x_labels or major): continue
             guides = self.svg.node(axis, class_='guides')
             end = self.view((r, theta))
             self.svg.node(
                 guides, 'path',
                 d='M%s L%s' % (format_(center), format_(end)),
-                class_='line')
+                class_='%sline'%('major ' if major else ''))
             r_txt = (1 - self._box.__class__.margin) * self._box.ymax
             pos_text = self.view((r_txt, theta))
             text = self.svg.node(
                 guides, 'text',
                 x=pos_text[0],
-                y=pos_text[1])
+                y=pos_text[1],
+                class_='major' if major else '')
             text.text = label
             angle = - theta + pi / 2
             if cos(angle) < 0: