gplots.py

gplots.py

"""
Make plots with the "Google Image Charts" API.
The functions here return a URL.  That URL will then throw a PNG back at you.
So embed them in <img src=...> or whatever.

This uses the "Google Image Charts API," formerly known as "Google Charts API",
which is officially deprecated and has been since 2012, I guess:
https://en.wikipedia.org/wiki/Google_Chart_API
https://developers.google.com/chart/image/
So look out I guess.  But it is a MUCH better quick-and-simple API than their
complicated javascript thing they say you should now use.  I like to use it to
embed plots inside static HTML when doing data analysis, especially if I need
to make hundreds of plots all on a page together.

This script uses the python 'GChartWrapper' package, but only for a utility
function.  That library does lots of other stuff too.

Last checked: 2017-11-14 it seemed to work:

>>> import gplots
>>> print gplots.barplot([3,3,4,4,4,5,8,3,3,3,4])
http://chart.apis.google.com/chart?chd=e:TlTlaHaHaHgp0PTlTlTlaH&chxt=x,y&chxs=0,676767,11.5,0,lt,676767&chxr=0,0,11|1,0,9.8&chbh=15,1&chs=300x100&cht=bvs&chma=30
"""

from __future__ import division
import math,os


## Google chart library

import GChartWrapper
def extended_encoding(vals, lower, upper, encoding):
    encoder = GChartWrapper.encoding.codeset[encoding]
    def scale(x):
        if not (lower <= x <= upper):
            return None
        N = encoder['max_value'] + 1  ## um not sure about the +1
        scale_on_01 = (x-lower) / (upper - lower)
        scaled = math.floor(scale_on_01 * N)
        scaled = min(scaled, encoder['max_value'])
        assert 0 <= scaled <= encoder['max_value']
        return scaled
    vals_scaled = [scale(x) for x in vals]
    vals_encoded = [encoder['value'](x) if x is not None else encoder['none'] for x in vals_scaled]
    return ''.join(vals_encoded)

def barplot(ys1, xmax=None, ymin=0, ymax=None, width=300, height=100, time_labels=None):
    ymax = max(ys1)*1.1 + 1 if ymax is None else ymax
    params = {}
    params['chs'] = '{width}x{height}'.format(**locals())
    params['cht'] = 'bvs'
    params['chd'] = 'e:' + extended_encoding(ys1, ymin, ymax, 'extended')
    params['chbh'] = '15,1'
    # axes and stuff
    params['chxt'] = 'x,y'
    # x-axis
    xmax = len(ys1) if xmax is None else xmax
    params['chxr'] = '0,0,{xmax}'.format(**locals())
    #if time_labels: params['chxl'] = '0:|' + '|'.join(code for num,code in time_labels)
    if time_labels: params['chxl'] = '0:|' + '|'.join(time_labels)
    params['chxs'] = '0,676767,11.5,0,lt,676767'  # tick marks
    # y-axis
    params['chxr'] += '|1,{ymin},{ymax}'.format(**locals())
    params['chma'] = 30

    # url
    items = [('chd',params['chd'])]
    del params['chd']
    items += params.items()
    return 'http://chart.apis.google.com/chart?' + '&'.join('%s=%s' % kv for kv in items)

def barplot2(ys1, xmax=None, ymin=0, ymax=None, width=300, height=100, time_labels=None, **kwargs):
    ymax = max(ys1)*1.1 + 1 if ymax is None else ymax
    params = {}
    params['chs'] = '{width}x{height}'.format(**locals())
    params['cht'] = 'bvs'
    params['chd'] = 'e:' + extended_encoding(ys1, ymin, ymax, 'extended')
    params['chbh'] = '15,1'
    # axes and stuff
    params['chxt'] = 'x'
    # x-axis
    xmax = len(ys1) if xmax is None else xmax
    params['chxr'] = '0,0,{xmax}'.format(**locals())
    #if time_labels: params['chxl'] = '0:|' + '|'.join(code for num,code in time_labels)
    if time_labels: params['chxl'] = '0:|' + '|'.join(time_labels)
    params['chxs'] = '0,676767,11.5,0,lt,676767'  # tick marks
    # y-axis
    params['chxr'] += '|1,{ymin},{ymax}'.format(**locals())
    #params['chma'] = 30

    params.update(kwargs)

    # url
    items = [('chd',params['chd'])]
    del params['chd']
    items += params.items()
    return 'http://chart.apis.google.com/chart?' + '&'.join('%s=%s' % kv for kv in items)

def circle(diameter=50):
    diameter = int(diameter)
    return """
    <div style="
        display: block;
        width: {diameter}px;
        height: {diameter}px;
        background: #333;
        -moz-border-radius: 40px;
        -webkit-border-radius: 40px;
    "></div>
  """.format(**locals()).replace("\n"," ").strip()


## jquery sparklines library

def get_js(outputfile):
    global __file__
    here = os.path.abspath(os.path.dirname(__file__))
    there= os.path.abspath(os.path.dirname(outputfile))
    os.system("cp {here}/sparks/*.js {there}".format(**locals()))

def spark_js():
    """ header stuff for js using jquery-sparklines """

    return """
    <script type="text/javascript" src="jquery.min.js"></script>
    <script type="text/javascript" src="jquery.sparkline.min.js"></script>

    <script type="text/javascript">
        $(function() {
            $('.barplot').sparkline('html', {enableTagOptions:true, type:'bar'});
        });
    </script>
    """

def spark(klass, data, **opts):
    bads = [k for k in opts if not k.startswith('spark')]
    for k in bads: 
        opts['spark'+k[0].upper() + k[1:]] = opts[k]
        del opts[k]
    opts['class'] = klass
    opts_h = ' '.join('{}="{}"'.format(k,v) for k,v in opts.items())
    data_h = ','.join(str(x) for x in data)
    return "<span {}>{}</span>".format(opts_h, data_h)