mirror of https://github.com/Kozea/pygal.git
Python to generate nice looking SVG graph
http://pygal.org/
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277 lines
7.4 KiB
277 lines
7.4 KiB
import math |
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from operator import add |
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from lxml import etree |
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from svg.charts.graph import Graph |
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def robust_add(a,b): |
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"Add numbers a and b, treating None as 0" |
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if a is None: a = 0 |
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if b is None: b = 0 |
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return a+b |
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RADIANS = math.pi/180 |
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class Pie(Graph): |
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""" |
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A presentation-quality SVG pie graph |
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Synopsis |
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======== |
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from svg.charts.pie import Pie |
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fields = ['Jan', 'Feb', 'Mar'] |
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data_sales_02 = [12, 45, 21] |
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graph = Pie(dict( |
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height = 500, |
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width = 300, |
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fields = fields)) |
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graph.add_data({'data': data_sales_02, 'title': 'Sales 2002'}) |
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print "Content-type" image/svg+xml\r\n\r\n' |
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print graph.burn() |
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Description |
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=========== |
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This object aims to allow you to easily create high quality |
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SVG pie graphs. You can either use the default style sheet |
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or supply your own. Either way there are many options which can |
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be configured to give you control over how the graph is |
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generated - with or without a key, display percent on pie chart, |
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title, subtitle etc. |
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""" |
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"if true, displays a drop shadow for the chart" |
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show_shadow = True |
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"Sets the offset of the shadow from the pie chart" |
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shadow_offset = 10 |
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show_data_labels = False |
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"If true, display the actual field values in the data labels" |
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show_actual_values = False |
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"If true, display the percentage value of each pie wedge in the data labels" |
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show_percent = True |
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"If true, display the labels in the key" |
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show_key_data_labels = True |
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"If true, display the actual value of the field in the key" |
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show_key_actual_values = True |
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"If true, display the percentage value of the wedges in the key" |
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show_key_percent = False |
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"If true, explode the pie (put space between the wedges)" |
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expanded = False |
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"If true, expand the largest pie wedge" |
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expand_greatest = False |
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"The amount of space between expanded wedges" |
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expand_gap = 10 |
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show_x_labels = False |
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show_y_labels = False |
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"The font size of the data point labels" |
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datapoint_font_size = 12 |
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stylesheet_names = Graph.stylesheet_names + ['pie.css'] |
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def add_data(self, data_descriptor): |
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""" |
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Add a data set to the graph |
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>>> graph.add_data({data:[1,2,3,4]}) # doctest: +SKIP |
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Note that a 'title' key is ignored. |
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Multiple calls to add_data will sum the elements, and the pie will |
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display the aggregated data. e.g. |
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>>> graph.add_data({data:[1,2,3,4]}) # doctest: +SKIP |
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>>> graph.add_data({data:[2,3,5,7]}) # doctest: +SKIP |
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is the same as: |
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graph.add_data({data:[3,5,8,11]}) # doctest: +SKIP |
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""" |
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self.data = map(robust_add, self.data, data_descriptor['data']) |
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def add_defs(self, defs): |
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"Add svg definitions" |
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etree.SubElement( |
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defs, |
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'filter', |
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id='dropshadow', |
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width='1.2', |
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height='1.2', |
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) |
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etree.SubElement( |
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defs, |
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'feGaussianBlur', |
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stdDeviation='4', |
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result='blur', |
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) |
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def draw_graph(self): |
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"Here we don't need the graph (consider refactoring)" |
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pass |
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def get_y_labels(self): |
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"Definitely consider refactoring" |
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return [''] |
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def get_x_labels(self): |
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"Okay. I'll refactor after this" |
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return [''] |
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def keys(self): |
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total = reduce(add, self.data) |
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percent_scale = 100.0 / total |
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def key(field, value): |
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result = [field] |
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result.append('[%s]' % value) |
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if self.show_key_percent: |
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percent = str(round((v/total*100))) + '%' |
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result.append(percent) |
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return ' '.join(result) |
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return map(key, self.fields, self.data) |
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def draw_data(self): |
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self.graph = etree.SubElement(self.root, 'g') |
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background = etree.SubElement(self.graph, 'g') |
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# midground is somewhere between the background and the foreground |
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midground = etree.SubElement(self.graph, 'g') |
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is_expanded = (self.expanded or self.expand_greatest) |
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diameter = min(self.graph_width, self.graph_height) |
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# the following assumes int(True)==1 and int(False)==0 |
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diameter -= self.expand_gap * int(is_expanded) |
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diameter -= self.datapoint_font_size * int(self.show_data_labels) |
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diameter -= 10 * int(self.show_shadow) |
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radius = diameter / 2.0 |
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xoff = (self.width - diameter) / 2 |
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yoff = (self.height - self.border_bottom - diameter) |
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yoff -= 10 * int(self.show_shadow) |
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transform = 'translate(%(xoff)s %(yoff)s)' % vars() |
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self.graph.set('transform', transform) |
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wedge_text_pad = 5 |
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wedge_text_pad = 20 * int(self.show_percent) * int(self.show_data_labels) |
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total = reduce(add, self.data) |
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max_value = max(self.data) |
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percent_scale = 100.0 / total |
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prev_percent = 0 |
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rad_mult = 3.6 * RADIANS |
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for index, (field, value) in enumerate(zip(self.fields, self.data)): |
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percent = percent_scale * value |
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radians = prev_percent * rad_mult |
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x_start = radius+(math.sin(radians) * radius) |
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y_start = radius-(math.cos(radians) * radius) |
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radians = (prev_percent+percent) * rad_mult |
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x_end = radius+(math.sin(radians) * radius) |
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y_end = radius-(math.cos(radians) * radius) |
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percent_greater_fifty = int(percent>=50) |
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path = ' '.join(( |
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"M%(radius)s,%(radius)s", |
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"L%(x_start)s,%(y_start)s", |
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"A%(radius)s,%(radius)s", |
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"0,", |
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"%(percent_greater_fifty)s,1,", |
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"%(x_end)s %(y_end)s Z")) |
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path = path % vars() |
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wedge = etree.SubElement( |
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self.foreground, |
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'path', |
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{ |
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'd': path, |
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'class': 'fill%s' % (index+1), |
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} |
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) |
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translate = None |
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tx = 0 |
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ty = 0 |
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half_percent = prev_percent + percent / 2 |
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radians = half_percent * rad_mult |
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if self.show_shadow: |
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shadow = etree.SubElement( |
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background, |
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'path', |
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d=path, |
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filter='url(#dropshadow)', |
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style='fill: #ccc; stroke: none', |
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) |
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clear = etree.SubElement( |
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midground, |
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'path', |
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d=path, |
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# note, this probably only works when the background |
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# is also #fff |
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# consider getting the style from the stylesheet |
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style="fill:#fff; stroke:none;", |
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) |
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if self.expanded or (self.expand_greatest and value == max_value): |
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tx = (math.sin(radians) * self.expand_gap) |
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ty = -(math.cos(radians) * self.expand_gap) |
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translate = "translate(%(tx)s %(ty)s)" % vars() |
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wedge.set('transform', translate) |
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clear.set('transform', translate) |
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if self.show_shadow: |
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shadow_tx = self.shadow_offset + tx |
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shadow_ty = self.shadow_offset + ty |
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translate = 'translate(%(shadow_tx)s %(shadow_ty)s)' % vars() |
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shadow.set('transform', translate) |
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if self.show_data_labels and value != 0: |
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label = [] |
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if self.show_key_data_labels: |
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label.append(field) |
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if self.show_actual_values: |
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label.append('[%s]' % value) |
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if self.show_percent: |
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label.append('%d%%' % round(percent)) |
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label = ' '.join(label) |
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msr = math.sin(radians) |
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mcr = math.cos(radians) |
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tx = radius + (msr * radius) |
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ty = radius -(mcr * radius) |
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if self.expanded or (self.expand_greatest and value == max_value): |
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tx += (msr * self.expand_gap) |
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ty -= (mcr * self.expand_gap) |
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label_node = etree.SubElement( |
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self.foreground, |
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'text', |
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{ |
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'x':str(tx), |
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'y':str(ty), |
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'class':'dataPointLabel', |
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'style':'stroke: #fff; stroke-width: 2;', |
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} |
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) |
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label_node.text = label |
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label_node = etree.SubElement( |
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self.foreground, |
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'text', |
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{ |
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'x':str(tx), |
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'y':str(ty), |
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'class': 'dataPointLabel', |
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} |
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) |
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label_node.text = label |
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prev_percent += percent |
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def round(self, val, to): |
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return round(val,to)
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