mygpo/web/templatetags/charts.py

   1 from django import template
   2 from django.utils.safestring import mark_safe
   3 from django.contrib.staticfiles.storage import staticfiles_storage
   4
   5 from mygpo.utils import format_time
   6 from mygpo.publisher.utils import colour_repr
   7
   8
   9 register = template.Library()
  10
  11 @register.simple_tag
  12 def vertical_bar(value, max_value, display=None):
  13     if not max_value:
  14         return ''
  15
  16     if display == 'ratio':
  17         value_str = '%d/%d' % (value, max_value)
  18     else:
  19         value_str = str(value)
  20
  21     # handle value == None
  22     value = value or 0
  23
  24     try:
  25         ratio = min(float(value) / float(max_value), 1) * 100
  26     except ValueError:
  27         return ''
  28
  29     if ratio > 40:
  30         left, right = '<span>'+ value_str +'</span>', ''
  31     else:
  32         left, right = '&nbsp;', '<span>'+ value_str +'</span>'
  33     s = '<div class="barbg"><div class="bar" style="width: %.2d%%">%s</div>%s</div>' % (ratio, left, right)
  34     return s
  35
  36 @register.filter
  37 def timeline(data):
  38     s = '<script type="text/javascript" src="//www.google.com/jsapi"></script>\n'
  39     s += '<script type="text/javascript">\n'
  40     s += 'google.load("visualization", "1", {"packages":["annotatedtimeline"]});\n'
  41     s += 'google.setOnLoadCallback(drawChart);\n'
  42     s += 'function drawChart() {\n'
  43     s += 'var data = new google.visualization.DataTable();\n'
  44     s += 'data.addColumn("date", "Date");\n'
  45     s += 'data.addColumn("number", "Listeners");\n'
  46     s += 'data.addColumn("string", "title1");\n'
  47     s += 'data.addColumn("string", "text1");\n'
  48     s += 'data.addRows([\n'
  49
  50     for r in data:
  51         if 'episode' in r and r['episode']:
  52             episode = '"%s"' % r['episode'].title if r['episode'].title else '"Unnamed Episode"'
  53             episode_ = '"released"'
  54         else:
  55             episode = 'undefined'
  56             episode_ = 'undefined'
  57
  58         s += '[new Date(%d, %d, %d), %d, %s, %s],\n' % (r['date'].year, r['date'].month-1, r['date'].day, r['listeners'], episode, episode_)
  59
  60     s += ']);\n'
  61     s += 'var chart = new google.visualization.AnnotatedTimeLine(document.getElementById("chart_div"));\n'
  62     s += 'chart.draw(data, {displayAnnotations: true});\n'
  63     s += '}\n'
  64     s += '</script>\n'
  65
  66     return mark_safe(s)
  67
  68
  69 @register.filter
  70 def pie_chart(parts):
  71     parts = [
  72         'cht=p',
  73         'chs=250x100',
  74         'chl=%s' % '|'.join(parts.iterkeys()),
  75         'chd=t:%s' % ','.join([ repr(x) for x in parts.itervalues() ])
  76         ]
  77
  78     s = '<img src="http://chart.apis.google.com/chart?%s"' % '&'.join(parts)
  79
  80     return mark_safe(s)
  81
  82
  83 @register.filter
  84 def episode_heatmap_visualization(heatmap):
  85     """
  86     display a visual heatmap using the Google Charts API
  87
  88     heatmap_data is expected as an array of numbers of users that have
  89     played this part part of the episode. the length of the parts is
  90     indicated by step_length; the duration of the whole episode is
  91     therefore approximated by len(heatmap_data) * step_length
  92     """
  93     label_steps = 2
  94
  95     max_plays = heatmap.max_plays
  96
  97     if max_plays == 1:
  98         #              light blue       dark blue
  99         colours = ( (198, 217, 253), (77, 137, 249) )
 100     else:
 101         #               red            yellow         green
 102         colours = ( (210, 54, 28), (239, 236, 22), (15, 212, 18) )
 103
 104     WIDTH=760
 105
 106     # maximum number of labels that will be placed on the visualization
 107     MAX_LABELS=20
 108
 109     axis_pos = []
 110     axis_label = []
 111     part_colours = []
 112     widths = []
 113     duration = max(heatmap.borders)
 114
 115     last_label = None
 116     for start, end, plays in heatmap.sections:
 117
 118         if last_label is None or (end-last_label) > (duration/MAX_LABELS):
 119             axis_pos.append(end)
 120             axis_label.append(format_time(end))
 121             last_label = end
 122
 123         rgb = colour_repr(plays, max_plays, colours)
 124         part_colours.append('%02x%02x%02x' % rgb)
 125         widths.append( end-start )
 126
 127     parts = [
 128         'cht=bhs',                            # bar chart
 129         'chco=%s' % ','.join(part_colours),   # colors
 130         'chs=%dx50' % WIDTH,                  # width corresponds to length, arbitrary height
 131         'chds=0,%s' % duration,               # axis scaling from 0 to maximum duration
 132         'chd=t:%s' % '|'.join([repr(w) for w in widths]),  # all block have the same width
 133         'chxt=x',                             # visible axes
 134         'chxr=0,0,%s' % duration,             # axis range for axis 0 (x): 0 - duration
 135         'chxl=0:|%s' % '|'.join(axis_label),  # axis labels
 136         'chxp=0,%s' % ','.join([repr(x) for x in axis_pos]),   # axis label positions
 137         ]
 138
 139     s = '<img src="http://chart.apis.google.com/chart?%s" />' % '&'.join(parts)
 140
 141     return mark_safe(s)
 142
 143
 144
 145 @register.simple_tag
 146 def subscriber_change(change):
 147
 148     if change > 1:
 149         change -= 1
 150         return '+{0:.1%}'.format(change)
 151
 152     # we don't care about negative changes
 153     return ''