Bar print value positioning with `print_values_position`. Can be `top`, `center` or `bottom` (thanks @chartique) Fix #291

demo/moulinrouge/tests.py

@@ -3,7 +3,7 @@
 from pygal import (
     Bar, Gauge, Pyramid, Funnel, Dot, StackedBar, StackedLine, XY,
     CHARTS_BY_NAME, Config, Line, Histogram, Box,
-    Pie, Treemap, TimeLine, DateLine, Radar,
+    Pie, Treemap, TimeLine, DateLine, Radar, HorizontalBar,
     DateTimeLine)
 
 try:
@@ -353,9 +353,12 @@ def get_test_routes(app):
 
     @app.route('/test/bar/position')
     def test_bar_print_values_position():
-        bar = Bar(print_values=True, print_values_position='top')
-        bar.add('1', [1, 2, 3])
-        bar.add('2', [4, 5, 6])
+        bar = HorizontalBar(print_values=True, print_values_position='top',
+                  style=styles['default'](
+                      value_font_family='googlefont:Raleway',
+                      value_font_size=46))
+        bar.add('1', [-1, 2, 3])
+        bar.add('2', [4, -5, 6])
         bar.x_labels = [2, 4, 6]
         bar.x_labels_major = [4]
         return bar.render_response()

docs/changelog.rst

@@ -5,7 +5,7 @@ Changelog
 2.0.13 UNRELEASED
 ======
 
-* Bar label positioning
+* Bar print value positioning with `print_values_position`. Can be `top`, `center` or `bottom` (thanks @chartique #291)
 
 2.0.12
 ======

pygal/graph/bar.py

@@ -65,11 +65,32 @@ class Bar(Graph):
             x, y, width, height):
         transpose = swap if self.horizontal else ident
         x_center, y_center = transpose((x + width / 2, y + height / 2))
+        x_top, y_top = transpose((x + width, y + height))
+        x_bottom, y_bottom = transpose((x, y))
+        sign = -1 if height < self.zero else 1
         self._tooltip_data(
             parent, val, x_center, y_center, "centered",
             self._get_x_label(i))
+
+        if self.print_values_position == 'top':
+            if self.horizontal:
+                x = x_bottom - sign * self.style.value_font_size / 2
+                y = y_center
+            else:
+                x = x_center
+                y = y_bottom - sign * self.style.value_font_size / 2
+        elif self.print_values_position == 'bottom':
+            if self.horizontal:
+                x = x_top - sign * self.style.value_font_size / 2
+                y = y_center
+            else:
+                x = x_center
+                y = y_top - sign * self.style.value_font_size / 2
+        else:
+            x = x_center
+            y = y_center
         self._static_value(
-            serie_node, val, x_center, y_center, metadata)
+            serie_node, val, x, y, metadata, "centered")
 
     def bar(self, serie, rescale=False):
         """Draw a bar graph for a serie"""
@@ -103,7 +124,6 @@ class Bar(Graph):
             self._box.ymin = min(self._min, self.zero)
         if self._max:
             self._box.ymax = max(self._max, self.zero)
-
         self._x_pos = [
             x / self._len for x in range(self._len + 1)
         ] if self._len > 1 else [0, 1]  # Center if only one value

pygal/graph/graph.py

@@ -491,25 +491,31 @@ class Graph(PublicApi):
             self.svg.node(node, 'desc',
                           class_="x_label").text = to_str(xlabel)
 
-    def _static_value(self, serie_node, value, x, y, metadata):
+    def _static_value(self, serie_node, value, x, y, metadata, classes=None):
         """Write the print value"""
         label = metadata and metadata.get('label')
+        classes = classes and [classes] or []
+
         if self.print_labels and label:
+            label_cls = classes + ['label']
             if self.print_values:
                 y -= self.style.value_font_size / 2
             self.svg.node(
                 serie_node['text_overlay'], 'text',
-                class_='centered label',
+                class_=' '.join(label_cls),
                 x=x,
                 y=y + self.style.value_font_size / 3
             ).text = label
             y += self.style.value_font_size
 
         if self.print_values or self.dynamic_print_values:
+            val_cls = classes + ['value']
+            if self.dynamic_print_values:
+                val_cls.append('showable')
+
             self.svg.node(
                 serie_node['text_overlay'], 'text',
-                class_='centered value%s' % (
-                    ' showable' if self.dynamic_print_values else ''),
+                class_=' '.join(val_cls),
                 x=x,
                 y=y + self.style.value_font_size / 3
             ).text = value if self.print_zeroes or value != '0' else ''
@@ -676,6 +682,16 @@ class Graph(PublicApi):
             self.margin_box.left += height
             self._y_title_height = height + self.spacing
 
+        # Inner margin
+        if self.print_values_position == 'top':
+            gw = self.width - self.margin_box.x
+            gh = self.height - self.margin_box.y
+            alpha = 1.1 * (self.style.value_font_size / gh) * self._box.height
+            if self._max > 0:
+                self._box.ymax += alpha
+            if self._min < 0:
+                self._box.ymin -= alpha
+
     @cached_property
     def _legends(self):
         """Getter for series title"""