Trying to fix scale

demo/moulinrouge/__init__.py

@@ -9,6 +9,7 @@ from pygal.bar import Bar
 from pygal.config import Config
 from pygal.style import styles
 # from pygal.pie import Pie
+import math
 import string
 import random
 
@@ -21,8 +22,8 @@ def random_label():
                      random.randrange(4, 30))])
 
 
-def random_value():
-    return random.randrange(0, 15, 1)
+def random_value(min=0, max=15):
+    return random.randrange(min, max, 1)
 
 
 # def generate_vbar(**opts):
@@ -50,11 +51,15 @@ def create_app():
     @app.route("/all-<type>-<style>.svg")
     def all_svg(type, style):
         data = random.randrange(1, 10)
+        order = random.randrange(1, 10)
+        max = 10 ** order
+        min = 10 ** random.randrange(0, order)
         config = Config()
         config.width = 600
         config.height = 400
         config.style = styles[style]
         config.x_labels = [random_label() for i in range(data)]
+        config.title = "%d - %d" % (min, max)
         if type == 'bar':
             g = Bar(config)
         # elif type == 'hbar':
@@ -68,7 +73,7 @@ def create_app():
             return
 
         for i in range(random.randrange(1, 10)):
-            values = [random_value() for i in range(data)]
+            values = [random_value(min, max) for i in range(data)]
             g.add(random_label(), values)
 
         return Response(g.render(), mimetype='image/svg+xml')

pygal/bar.py

@@ -5,8 +5,8 @@ class Bar(BaseGraph):
     """Bar graph"""
 
     def _draw(self):
-        ymin, ymax = 0, max([
-            val for serie in self.series for val in serie.values])
+        vals = [val for serie in self.series for val in serie.values]
+        ymin, ymax = min(min(vals), 0), max(vals)
         x_step = len(self.series[0].values)
         x_pos = [x / float(x_step) for x in range(x_step + 1)
         ] if x_step > 1 else [0, 1]  # Center if only one value

pygal/base.py

@@ -1,7 +1,8 @@
-from pygal import Serie, Label, Margin
+from pygal import Serie, Margin
 from pygal.util import round_to_scale
 from pygal.svg import Svg
 from pygal.config import Config
+import math
 
 
 class BaseGraph(object):
@@ -19,14 +20,19 @@ class BaseGraph(object):
         return object.__getattribute__(self, attr)
 
     def _y_pos(self, ymin, ymax):
-        step = (ymax - ymin) / float(self.max_scale_step)
-        position = ymin
-        if not step:
-            return [position]
+        order = round(math.log10(ymax)) - 1
+        if (ymax - ymin) / float(10 ** order) < 4:
+            order -= 1
+        step = 10 ** order
         positions = set()
-        while position < (ymax + step):
-            positions.add(round_to_scale(position, self.scale))
+        position = round_to_scale(ymin, step)
+        while position < ymax:
+            rounded = round_to_scale(position, self.scale)
+            if ymin <= rounded <= ymax:
+                positions.add(rounded)
             position += step
+        if not positions:
+            return [ymin]
         return positions
 
     def _compute_margin(self, x_labels, y_labels):

pygal/config.py

@@ -5,10 +5,13 @@ class Config(object):
     width = 800
     height = 600
     scale = 1
-    max_scale_step = 20
+    max_scale_step = 10
     base_css = None
     style = DefaultStyle
     label_font_size = 12
     x_labels = None
     y_labels = None
     title = None
+
+    def __init__(self, **kwargs):
+        self.__dict__.update(kwargs)

pygal/test/test_bar.py

@@ -4,8 +4,8 @@ from math import cos, sin
 
 def test_simple_bar():
     bar = Bar()
-    rng = [12, 3, 30, 4, 40, 10, 9, 2]
+    rng = [12, 3, 30, -5, 40, 10, 9, 2]
     bar.add('test1', rng)
     bar.x_labels = map(str, rng)
     bar.title = "Bar test"
-    bar.render()
+    bar._in_browser()

pygal/test/test_line.py

@@ -1,9 +1,10 @@
 from pygal.line import Line
+from pygal.config import Config
 from math import cos, sin
 
 
 def test_simple_line():
-    line = Line()
+    line = Line(Config(scale=.5))
     rng = range(-30, 31, 5)
     line.add('test1', [cos(x / 10.) for x in rng])
     line.add('test2', [sin(x / 10.) for x in rng])
@@ -13,6 +14,15 @@ def test_simple_line():
     line._in_browser()
 
 
+def test_line():
+    line = Line()
+    rng = [8, 12, 23, 73, 39, 57]
+    line.add('-_-', rng)
+    line.x_labels = map(str, rng)
+    line.title = "cos sin and cos - sin"
+    line._in_browser()
+
+
 def test_one_dot():
     line = Line()
     line.add('one dot', [12])

pygal/util.py

@@ -3,6 +3,7 @@ from math import floor
 
 
 def round_to_int(number, precision):
+    precision = int(precision)
     rounded = (int(number) + precision / 2) / precision * precision
     return rounded