Approximate tick fitting. #13.

leather/axis.py

@@ -19,6 +19,18 @@ def __init__(self, ticks=5, tick_width='1px', tick_size=4, tick_color='#eee', la
         self.label_color = label_color
         self.zero_color = zero_color
 
+        self.label_font_family = 'Monaco'
+        self.label_font_size = '14px'
+        self.label_font_char_height = 14
+        self.label_font_char_width = 8
+
+    def compute_text_margin(self, scale, orient):
+        if orient == 'left':
+            max_len = max(len(six.text_type(t)) for t in scale.ticks(self.ticks))
+            return max_len * self.label_font_char_width
+        elif orient == 'bottom':
+            return self.label_font_char_height
+
     def to_svg(self, width, height, scale, orient):
         """
         Render this axis to SVG elements.
@@ -84,8 +96,8 @@ def to_svg(self, width, height, scale, orient):
                 dy=dy,
                 fill=self.label_color
             )
-
             label.set('text-anchor', text_anchor)
+            label.set('font-family', 'Monaco')
             label.text = six.text_type(value)
 
             tick_group.append(tick)

leather/chart.py

@@ -145,18 +145,25 @@ def to_svg_group(self, width, height, margin=None):
         elif not isinstance(margin, Box):
             margin = Box(*margin)
 
-        canvas_width = width - (margin.left + margin.right)
-        canvas_height = height - (margin.top + margin.bottom)
+        root_width = width - (margin.left + margin.right)
+        root_height = height - (margin.top + margin.bottom)
 
         root_group = ET.Element('g')
         root_group.set('transform', svg.translate(margin.left, margin.top))
 
         # Axes
-        axes_group = ET.Element('g')
-
         x_scale, x_axis = self._validate_dimension(X)
         y_scale, y_axis = self._validate_dimension(Y)
 
+        bottom_margin = x_axis.compute_text_margin(x_scale, 'bottom')
+        left_margin = y_axis.compute_text_margin(y_scale, 'left')
+
+        canvas_width = root_width - left_margin
+        canvas_height = root_height - bottom_margin
+
+        axes_group = ET.Element('g')
+        axes_group.set('transform', svg.translate(left_margin, 0))
+
         axes_group.append(x_axis.to_svg(canvas_width, canvas_height, x_scale, 'bottom'))
         axes_group.append(y_axis.to_svg(canvas_width, canvas_height, y_scale, 'left'))
 
@@ -166,8 +173,8 @@ def to_svg_group(self, width, height, margin=None):
         for series in self._layers:
             series_group.append(series.to_svg(canvas_width, canvas_height, x_scale, y_scale))
 
+        axes_group.append(series_group)
         root_group.append(axes_group)
-        root_group.append(series_group)
 
         return root_group