Nearly working

pygal/bar.py

@@ -0,0 +1,81 @@
+from pygal import Serie, Margin, Label
+from pygal.svg import Svg
+from pygal.base import BaseGraph
+
+
+class Bar(BaseGraph):
+    """Bar graph"""
+
+    def __init__(self, width, height, precision=5,
+               format='g', style=None):
+        self.width = width
+        self.height = height
+        self.svg = Svg(width, height, style=style)
+        self.label_font_size = 12
+        self.format = format
+        self.precision = precision
+        self.series = []
+        self.x_labels = self.y_labels = self.title = None
+
+    def add(self, title, values):
+        self.series.append(
+            Serie(title, values))
+
+    def _label(self, label):
+        return Label(('{:.%d%s}' % (
+            self.precision, self.format)).format(label), label)
+
+    def _y_labels(self, ymin, ymax):
+        step = (ymax - ymin) / 20.
+        if not step:
+            return [self._label(ymin)]
+        label = ymin
+        labels = []
+        while label <= ymax:
+            labels.append(self._label(label))
+            label += step
+        return labels
+
+    def validate(self):
+        assert len(self.series)
+        if self.x_labels:
+            assert len(self.series[0].values) == len(self.x_labels)
+        for serie in self.series:
+            assert len(self.series[0].values) == len(serie.values)
+
+    def draw(self):
+        self.validate()
+        x_step = len(self.series[0].values) + 1
+        x_pos = [x / float(x_step) for x in range(x_step)
+        ] if x_step > 1 else [0, 1]  # Center if only one value
+        x_ranges = zip(x_pos, x_pos[1:])
+
+        vals = [val for serie in self.series for val in serie.values]
+        margin = Margin(*(4 * [10]))
+        ymin, ymax = min(vals), max(vals)
+        if self.x_labels:
+            x_labels = [Label(label, sum(x_ranges[i]) / 2)
+                         for i, label in enumerate(self.x_labels)]
+        y_labels = self.y_labels or self._y_labels(ymin, ymax)
+        series_labels = [serie.title for serie in self.series]
+        margin.left += 10 + max(
+            map(len, [l.label for l in y_labels])) * 0.6 * self.label_font_size
+        if self.x_labels:
+            margin.bottom += 10 + self.label_font_size
+        margin.right += 20 + max(
+            map(len, series_labels)) * 0.6 * self.label_font_size
+        margin.top += 10 + self.label_font_size
+
+        # Actual drawing
+        self.svg.set_view(margin, ymin, ymax)
+        self.svg.graph(margin)
+        if self.x_labels:
+            self.svg.x_axis(x_labels)
+        self.svg.y_axis(y_labels)
+        self.svg.legend(margin, series_labels)
+        self.svg.title(margin, self.title)
+        for serie_index, serie in enumerate(self.series):
+            serie_node = self.svg.serie(serie_index)
+            self.svg.bar(serie_node, [
+                ((x_ranges[i][0], v), (x_ranges[i][1], v))
+                for i, v in enumerate(serie.values)])

pygal/svg.py

@@ -147,6 +147,20 @@ class Svg(object):
         self.node(serie, 'path',
                   d='M%s L%s' % (origin, svg_values), class_='line')
 
+    def bar(self, serie, values, origin=None):
+        view_values = map(lambda x: (self.view(x[0]), self.view(x[1])), values)
+
+        for i, ((x, y), (X, Y)) in enumerate(view_values):
+            width = X - x
+            padding = .1 * width
+            width = width - 2 * padding
+            self.node(serie, 'rect',
+                      width=width,
+                      height=self.view.y(0) - y,
+                      x=x + padding,
+                      y=y,
+                      class_='rect')
+
     def render(self):
         return etree.tostring(
             self.root, pretty_print=True,

pygal/test/test_bar.py

@@ -0,0 +1,11 @@
+from pygal.bar import Bar
+from math import cos, sin
+
+
+def test_simple_bar():
+    bar = Bar(800, 600, precision=2, format='f')
+    rng = [12, 3, 30, 4, 0]
+    bar.add('test1', rng)
+    bar.x_labels = map(str, rng)
+    bar.title = "Bar test"
+    bar._in_browser()

pygal/test/test_line.py

@@ -17,4 +17,4 @@ def test_one_dot():
     line = Line(800, 600)
     line.add('one dot', [12])
     line.x_labels = ['one']
-    line._in_browser()
+    line.render()