Work on log scale + minor fixes

demo/simple_test.py

@@ -32,7 +32,7 @@ bar.add('inc', [None, 1, None, 2])
 bar.x_labels = map(str, rng)
 
 bar.fill = True
-bar.render_to_file('out-bar.svg')
+# bar.render_to_file('out-bar.svg')
 
 hbar = HorizontalBar()
 rng = [18, 9, 7, 3, 1, None, -5]
@@ -44,7 +44,7 @@ hbar.add('test3', rng3)
 hbar.x_labels = map(
     lambda x: '%s / %s' % x, zip(map(str, rng), map(str, rng2)))
 hbar.title = "Horizontal Bar test"
-hbar.render_to_file('out-horizontalbar.svg')
+# hbar.render_to_file('out-horizontalbar.svg')
 
 rng = [3, -32, 39, 12]
 rng2 = [24, -8, 18, 12]
@@ -63,18 +63,18 @@ stackedbar.add('@@@@@@@', rng)
 stackedbar.add('++++++', rng2)
 stackedbar.add('--->', rng3)
 stackedbar.add('None', [None, 42, 42])
-stackedbar.render_to_file('out-stackedbar.svg')
+# stackedbar.render_to_file('out-stackedbar.svg')
 
 config.title = "Horizontal Stacked Bar test"
 hstackedbar = HorizontalStackedBar(config)
 hstackedbar.add('@@@@@@@', rng)
 hstackedbar.add('++++++', rng2)
 hstackedbar.add('--->', rng3)
-hstackedbar.render_to_file('out-horizontalstackedbar.svg')
+# hstackedbar.render_to_file('out-horizontalstackedbar.svg')
 
 line = Line(Config(style=NeonStyle,
-                   zero=1, fill=True,
-                   human_readable=True, logarithmic=True))
+                   zero=.0001, fill=True,
+                   human_readable=not True, logarithmic=True))
 rng = range(-30, 31, 1)
 
 # line.add('test1', [1000 ** cos(x / 10.) for x in rng])
@@ -88,7 +88,10 @@ rng = range(-30, 31, 1)
 # line.add('2', [None, None, 2, 4, 8, None, 14, 10, None])
 # line.add('1', [1, 5, 3, 4, 6, 12, 13, 7, 2])
 # line.add('1', [.000000091, .000000094, .000092])
-line.add('_', [12, 200001, 12])
+# line.add('_', [2 ** -3, 2.9 ** -8, 2])
+# line.add('_', [.001, .0001, .00001])
+# line.add('_', [1 + 10 ** 10, 3 + 10 ** 10, 2 + 10 ** 10])
+line.add('_', [1, -4, 2, 8, -2])
 line.x_labels = map(str, rng)
 line.title = "Line test"
 # line.interpolate = "cubic"
@@ -102,7 +105,7 @@ stackedline.add('test3', [9, 3, 2, 10,  8,  2])
 stackedline.x_labels = ['a', 'b', 'c', 'd', 'e', 'f', 'g']
 stackedline.title = "Stackedline test"
 stackedline.interpolate = "cubic"
-stackedline.render_to_file('out-stackedline.svg')
+# stackedline.render_to_file('out-stackedline.svg')
 
 xy = XY(Config(fill=True, style=NeonStyle, interpolate='cubic'))
 xy.add('test1', [(1981, 1), (1999, -4), (2001, 2), (2003, 10), (2012, 8)])
@@ -111,7 +114,7 @@ xy.add('test2', [(None, None), (None, 12), (2007, None), (2002.3, 12)])
 # xy.add('test2', [(1980, 0), (1985, 2), (1995, -2), (2005, 4), (2020, -4)])
                  # (2005, 6), (2010, -6), (2015, 3), (2020, -3), (2025, 0)])
 xy.title = "XY test"
-xy.render_to_file('out-xy.svg')
+# xy.render_to_file('out-xy.svg')
 
 pie = Pie(Config(style=NeonStyle))
 pie.add('test', [11, 8, 21])
@@ -121,7 +124,7 @@ pie.add('test4', [20, 18, 9])
 pie.add('test5', [17, 5, 10])
 pie.add('test6', [None, None, 10])
 pie.title = "Pie test"
-pie.render_to_file('out-pie.svg')
+# pie.render_to_file('out-pie.svg')
 
 config = Config()
 config.fill = True
@@ -135,4 +138,4 @@ radar.add('test2', [10, 2, 0, 5, 1, 9, 4])
 
 radar.title = "Radar test"
 
-radar.render_to_file('out-radar.svg')
+# radar.render_to_file('out-radar.svg')

pygal/css/graph.css

@@ -90,7 +90,7 @@ text.no_data {
 }
 
 .axis.y .logarithmic text:not(.major) {
-  opacity: 0;
+  font-size: 50%;
 }
 
 .axis .line {

pygal/graph/base.py

@@ -29,10 +29,19 @@ class BaseGraph(object):
         min_order = int(floor(log10(min_)))
         max_order = int(ceil(log10(max_)))
         positions = []
+        amplitude = max_order - min_order
+        if amplitude <= 1:
+            return []
+        detail = 10.
+        while amplitude * detail < 20:
+            detail *= 2
+        while amplitude * detail > 50:
+            detail /= 2
         for order in range(min_order, max_order + 1):
-            for i in range(10):
-                tick = i * 10 ** order
-                if min_ <= tick <= max_:
+            for i in range(int(detail)):
+                tick = (10 * i / detail or 1.) * 10 ** order
+                tick = round_to_scale(tick, tick)
+                if min_ <= tick <= max_ and tick not in positions:
                     positions.append(tick)
         return positions
 
@@ -42,7 +51,10 @@ class BaseGraph(object):
         if max_ - min_ == 0:
             return [min_]
         if self.logarithmic:
-            return self._compute_logarithmic_scale(min_, max_)
+            log_scale = self._compute_logarithmic_scale(min_, max_)
+            if log_scale:
+                return log_scale
+                # else we fallback to normal scalling
         order = round(log10(max(abs(min_), abs(max_)))) - 1
         while (max_ - min_) / float(10 ** order) < min_scale:
             order -= 1

pygal/graph/line.py

@@ -34,12 +34,12 @@ class Line(Graph):
             return [val[1]
                     for serie in self.series
                     for val in serie.interpolated
-                    if val[1] != None]
+                    if val[1] != None and (not self.logarithmic or val[1] > 0)]
         else:
             return  [val[1]
                      for serie in self.series
                      for val in serie.points
-                    if val[1] != None]
+                    if val[1] != None and (not self.logarithmic or val[1] > 0)]
 
     def _fill(self, values):
         zero = self.view.y(min(max(self.zero, self._box.ymin), self._box.ymax))

pygal/test/test_config.py

@@ -0,0 +1,53 @@
+# -*- coding: utf-8 -*-
+# This file is part of pygal
+#
+# A python svg graph plotting library
+# Copyright © 2012 Kozea
+#
+# This library is free software: you can redistribute it and/or modify it under
+# the terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option) any
+# later version.
+#
+# This library is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with pygal. If not, see <http://www.gnu.org/licenses/>.
+from pygal import Line
+
+
+def test_logarithmic():
+    line = Line(logarithmic=True)
+    line.add('_', [1, 10 ** 10, 1])
+    q = line.render_pyquery()
+    assert len(q(".axis.x")) == 0
+    assert len(q(".axis.y")) == 1
+    assert len(q(".plot .series path")) == 1
+    assert len(q(".legend")) == 1
+    assert len(q(".x.axis .guides")) == 0
+    assert len(q(".y.axis .guides")) == 51
+    assert len(q(".dots")) == 3
+
+
+def test_logarithmic_bad_interpolation():
+    line = Line(logarithmic=True, interpolate='cubic')
+    line.add('_', [.001, .00000001, 1])
+    q = line.render_pyquery()
+    assert len(q(".y.axis .guides")) == 40
+
+
+def test_logarithmic_big_scale():
+    line = Line(logarithmic=True)
+    line.add('_', [10 ** -10, 10 ** 10, 1])
+    q = line.render_pyquery()
+    assert len(q(".y.axis .guides")) == 41
+
+
+def test_logarithmic_small_scale():
+    line = Line(logarithmic=True)
+    line.add('_', [1 + 10 ** 10, 3 + 10 ** 10, 2 + 10 ** 10])
+    q = line.render_pyquery()
+    assert len(q(".y.axis .guides")) == 21

pygal/view.py

@@ -114,7 +114,7 @@ class LogView(View):
         self.box.fix(False)
 
     def y(self, y):
-        if y == None:
+        if y == None or y <= 0:
             return None
         return (self.height - self.height *
                 (log10(y) - self.log10_ymin)