80 lines
2.2 KiB
Python
80 lines
2.2 KiB
Python
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#!/usr/bin/env python
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import xml.etree.ElementTree as ET
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import six
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from leather.data_types import Number, Text
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from leather.series import CategorySeries
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from leather.shapes.base import Shape
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from leather import theme
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from leather.utils import X, Y
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class Bars(Shape):
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"""
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Render a series of data as bars.
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:param fill_color:
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The color to fill the bars. You may also specify a
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:func:`.style_function`.
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"""
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def __init__(self, fill_color=None):
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self._fill_color = fill_color
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def validate_series(self, series):
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"""
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Verify this shape can be used to render a given series.
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"""
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if isinstance(series, CategorySeries):
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raise ValueError('Bars can not be used to render CategorySeries.')
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if series.data_type(X) is not Number:
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raise ValueError('Bars only support Number values for the Y axis.')
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if series.data_type(Y) is not Text:
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raise ValueError('Bars only support Text values for the X axis.')
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def to_svg(self, width, height, x_scale, y_scale, series, palette):
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"""
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Render bars to SVG elements.
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"""
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group = ET.Element('g')
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group.set('class', 'series bars')
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zero_x = x_scale.project(0, 0, width)
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if self._fill_color:
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fill_color = self._fill_color
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else:
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fill_color = next(palette)
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for d in series.data():
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if d.x is None or d.y is None:
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continue
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y1, y2 = y_scale.project_interval(d.y, height, 0)
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proj_x = x_scale.project(d.x, 0, width)
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if d.x < 0:
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bar_x = proj_x
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bar_width = zero_x - proj_x
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else:
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bar_x = zero_x
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bar_width = proj_x - zero_x
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if callable(fill_color):
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color = fill_color(d)
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else:
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color = fill_color
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group.append(ET.Element('rect',
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x=six.text_type(bar_x),
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y=six.text_type(y2),
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width=six.text_type(bar_width),
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height=six.text_type(y1 - y2),
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fill=color
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))
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return group
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