mygpo/publisher/templatetags/pcharts.py

   1 from django import template
   2 from django.utils.safestring import mark_safe
   3 from django.utils.translation import ugettext as _
   4 from mygpo.publisher.utils import colour_repr
   5 from mygpo.utils import format_time
   6 import hashlib
   7 import math
   8
   9 register = template.Library()
  10
  11 @register.filter
  12 def bar_chart(parts):
  13
  14     maxv = max([ int(x['y']) for x in parts ])
  15     bar_width = 15
  16     bar_space = 15
  17     group_space = 20
  18
  19     parts = [
  20         'cht=bvg',     # Vertical bar chart with grouped bars.
  21         'chs=%dx100' % ((bar_space + group_space) * (len(parts) + 1)),
  22         'chl=%s' % '|'.join([x['x'] for x in parts]),
  23         'chd=t:%s' % ','.join([ repr(int(x['y'])) for x in parts ]),
  24         'chxt=x,y', # visible axes
  25         'chbh=%d,%d,%d' % (bar_width, bar_space, group_space),
  26         'chds=0,%d' % maxv, # avis scaling from 0 to max
  27         'chxr=1,0,%d' % maxv, # labeling for axis 1 (y) from 0 to max
  28         ]
  29
  30     s = '<img src="http://chart.apis.google.com/chart?%s"' % '&'.join(parts)
  31
  32     return mark_safe(s)
  33
  34 @register.filter
  35 def episode_heatmap_visualization(heatmap_data, step_length):
  36     """
  37     display a visual heatmap using the Google Charts API
  38
  39     heatmap_data is expected as an array of numbers of users that have
  40     played this part part of the episode. the length of the parts is
  41     indicated by step_length; the duration of the whole episode is
  42     therefore approximated by len(heatmap_data) * step_length
  43     """
  44     label_steps = 2
  45     #               red            yellow         green
  46     colours = ( (210, 54, 28), (239, 236, 22), (15, 212, 18) )
  47
  48     max_val = max(heatmap_data)
  49     axis_pos = []
  50     axis_label = []
  51     part_colours = []
  52     duration = len(heatmap_data) * step_length
  53
  54     n=0
  55     for part in heatmap_data:
  56         if n % label_steps == 0:
  57             axis_pos.append(n*step_length)
  58             axis_label.append(format_time(n*step_length))
  59         rgb = colour_repr(part, max_val, colours)
  60         part_colours.append('%02x%02x%02x' % rgb)
  61         n += 1
  62
  63     parts = [
  64         'cht=bhs',                           #bar chart
  65         'chco=%s' % ','.join(part_colours),  #colors
  66         'chs=760x50',                        #width corresponds to length, arbitrary height
  67         'chds=0,%s' % duration,              #axis scaling from 0 to maximum duration
  68         'chd=t:%s' % '|'.join([repr(step_length)] * len(heatmap_data)),  # all block have the same width
  69         'chxt=x',                            #visible axes
  70         'chxr=0,0,%s' % duration,            #axis range for axis 0 (x): 0 - duration
  71         'chxl=0:|%s' % '|'.join(axis_label), #axis labels
  72         'chxp=0,%s' % ','.join([repr(x) for x in axis_pos]),             #axis label positions
  73         ]
  74
  75     s = '<img src="http://chart.apis.google.com/chart?%s"' % '&'.join(parts)
  76
  77     return mark_safe(s)
  78
  79