95 lines
2.5 KiB
Python
95 lines
2.5 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 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 Line(Shape):
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"""
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Render a series of data as a line.
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:param stroke_color:
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The color to stroke the lines. If not provided, default chart colors
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will be used.
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:param width:
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The width of the lines. Defaults to :data:`.theme.default_line_width`.
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"""
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def __init__(self, stroke_color=None, width=None):
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self._stroke_color = stroke_color
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self._width = width or theme.default_line_width
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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('Line can not be used to render CategorySeries.')
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if series.data_type(X) is Text or series.data_type(Y) is Text:
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raise ValueError('Line does not support Text values.')
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def _new_path(self, stroke_color):
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"""
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Start a new path.
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"""
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path = ET.Element('path',
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stroke=stroke_color,
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fill='none'
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)
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path.set('stroke-width', six.text_type(self._width))
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return path
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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 lines to SVG elements.
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"""
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group = ET.Element('g')
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group.set('class', 'series lines')
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if self._stroke_color:
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stroke_color = self._stroke_color
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else:
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stroke_color = next(palette)
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path = self._new_path(stroke_color)
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path_d = []
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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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if path_d:
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path.set('d', ' '.join(path_d))
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group.append(path)
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path_d = []
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path = self._new_path(stroke_color)
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continue
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proj_x = x_scale.project(d.x, 0, width)
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proj_y = y_scale.project(d.y, height, 0)
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if not path_d:
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command = 'M'
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else:
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command = 'L'
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path_d.extend([
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command,
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six.text_type(proj_x),
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six.text_type(proj_y)
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])
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if path_d:
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path.set('d', ' '.join(path_d))
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group.append(path)
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return group
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