bench/bench_graph_svg.py

'''
Created on May 16, 2011

@author: bungeman
'''
import sys
import getopt
import re
import os
import bench_util
import json
import xml.sax.saxutils

# We throw out any measurement outside this range, and log a warning.
MIN_REASONABLE_TIME = 0
MAX_REASONABLE_TIME = 99999

def usage():
    """Prints simple usage information."""
    
    print '-d <dir> a directory containing bench_r<revision>_<scalar> files.'
    print '-b <bench> the bench to show.'
    print '-c <config> the config to show (GPU, 8888, 565, etc).'
    print '-t <time> the time to show (w, c, g, etc).'
    print '-s <setting>[=<value>] a setting to show (alpha, scalar, etc).'
    print '-r <revision>[:<revision>] the revisions to show.'
    print '   Negative <revision> is taken as offset from most recent revision.'
    print '-f <revision>[:<revision>] the revisions to use for fitting.'
    print '   Negative <revision> is taken as offset from most recent revision.'
    print '-x <int> the desired width of the svg.'
    print '-y <int> the desired height of the svg.'
    print '-l <title> title to use for the output graph'
    print '--default-setting <setting>[=<value>] setting for those without.'
    

class Label:
    """The information in a label.
    
    (str, str, str, str, {str:str})"""
    def __init__(self, bench, config, time_type, settings):
        self.bench = bench
        self.config = config
        self.time_type = time_type
        self.settings = settings
    
    def __repr__(self):
        return "Label(%s, %s, %s, %s)" % (
                   str(self.bench),
                   str(self.config),
                   str(self.time_type),
                   str(self.settings),
               )
    
    def __str__(self):
        return "%s_%s_%s_%s" % (
                   str(self.bench),
                   str(self.config),
                   str(self.time_type),
                   str(self.settings),
               )
    
    def __eq__(self, other):
        return (self.bench == other.bench and
                self.config == other.config and
                self.time_type == other.time_type and
                self.settings == other.settings)
    
    def __hash__(self):
        return (hash(self.bench) ^
                hash(self.config) ^
                hash(self.time_type) ^
                hash(frozenset(self.settings.iteritems())))

def get_latest_revision(directory):
    """Returns the latest revision number found within this directory.
    """
    latest_revision_found = -1
    for bench_file in os.listdir(directory):
        file_name_match = re.match('bench_r(\d+)_(\S+)', bench_file)
        if (file_name_match is None):
            continue
        revision = int(file_name_match.group(1))
        if revision > latest_revision_found:
            latest_revision_found = revision
    if latest_revision_found < 0:
        return None
    else:
        return latest_revision_found

def parse_dir(directory, default_settings, oldest_revision, newest_revision):
    """Parses bench data from files like bench_r<revision>_<scalar>.
    
    (str, {str, str}, Number, Number) -> {int:[BenchDataPoints]}"""
    revision_data_points = {} # {revision : [BenchDataPoints]}
    for bench_file in os.listdir(directory):
        file_name_match = re.match('bench_r(\d+)_(\S+)', bench_file)
        if (file_name_match is None):
            continue

        revision = int(file_name_match.group(1))
        scalar_type = file_name_match.group(2)

        if (revision < oldest_revision or revision > newest_revision):
            continue

        file_handle = open(directory + '/' + bench_file, 'r')

        if (revision not in revision_data_points):
            revision_data_points[revision] = []
        default_settings['scalar'] = scalar_type
        revision_data_points[revision].extend(
                        bench_util.parse(default_settings, file_handle))
        file_handle.close()
    return revision_data_points

def add_to_revision_data_points(new_point, revision, revision_data_points):
    """Add new_point to set of revision_data_points we are building up.
    """
    if (revision not in revision_data_points):
        revision_data_points[revision] = []
    revision_data_points[revision].append(new_point)

def filter_data_points(unfiltered_revision_data_points):
    """Filter out any data points that are utterly bogus.

    Returns (allowed_revision_data_points, ignored_revision_data_points):
        allowed_revision_data_points: points that survived the filter
        ignored_revision_data_points: points that did NOT survive the filter
    """
    allowed_revision_data_points = {} # {revision : [BenchDataPoints]}
    ignored_revision_data_points = {} # {revision : [BenchDataPoints]}
    revisions = unfiltered_revision_data_points.keys()
    revisions.sort()
    for revision in revisions:
        for point in unfiltered_revision_data_points[revision]:
            if point.time < MIN_REASONABLE_TIME or point.time > MAX_REASONABLE_TIME:
                add_to_revision_data_points(point, revision, ignored_revision_data_points)
            else:
                add_to_revision_data_points(point, revision, allowed_revision_data_points)
    return (allowed_revision_data_points, ignored_revision_data_points)

def create_lines(revision_data_points, settings
               , bench_of_interest, config_of_interest, time_of_interest):
    """Convert revision data into sorted line data.
    
    ({int:[BenchDataPoints]}, {str:str}, str?, str?, str?)
        -> {Label:[(x,y)] | [n].x <= [n+1].x}"""
    revisions = revision_data_points.keys()
    revisions.sort()
    lines = {} # {Label:[(x,y)] | x[n] <= x[n+1]}
    for revision in revisions:
        for point in revision_data_points[revision]:
            if (bench_of_interest is not None and
                not bench_of_interest == point.bench):
                continue
            
            if (config_of_interest is not None and
                not config_of_interest == point.config):
                continue
            
            if (time_of_interest is not None and
                not time_of_interest == point.time_type):
                continue
            
            skip = False
            for key, value in settings.items():
                if key in point.settings and point.settings[key] != value:
                    skip = True
                    break
            if skip:
                continue
            
            line_name = Label(point.bench
                            , point.config
                            , point.time_type
                            , point.settings)
            
            if line_name not in lines:
                lines[line_name] = []
            
            lines[line_name].append((revision, point.time))
            
    return lines

def bounds(lines):
    """Finds the bounding rectangle for the lines.
    
    {Label:[(x,y)]} -> ((min_x, min_y),(max_x,max_y))"""
    min_x = bench_util.Max
    min_y = bench_util.Max
    max_x = bench_util.Min
    max_y = bench_util.Min
    
    for line in lines.itervalues():
        for x, y in line:
            min_x = min(min_x, x)
            min_y = min(min_y, y)
            max_x = max(max_x, x)
            max_y = max(max_y, y)
            
    return ((min_x, min_y), (max_x, max_y))

def create_regressions(lines, start_x, end_x):
    """Creates regression data from line segments.
    
    ({Label:[(x,y)] | [n].x <= [n+1].x}, Number, Number)
        -> {Label:LinearRegression}"""
    regressions = {} # {Label : LinearRegression}
    
    for label, line in lines.iteritems():
        regression_line = [p for p in line if start_x <= p[0] <= end_x]
        
        if (len(regression_line) < 2):
            continue
        regression = bench_util.LinearRegression(regression_line)
        regressions[label] = regression
    
    return regressions

def bounds_slope(regressions):
    """Finds the extreme up and down slopes of a set of linear regressions.
    
    ({Label:LinearRegression}) -> (max_up_slope, min_down_slope)"""
    max_up_slope = 0
    min_down_slope = 0
    for regression in regressions.itervalues():
        min_slope = regression.find_min_slope()
        max_up_slope = max(max_up_slope, min_slope)
        min_down_slope = min(min_down_slope, min_slope)
    
    return (max_up_slope, min_down_slope)

def main():
    """Parses command line and writes output."""
    
    try:
        opts, _ = getopt.getopt(sys.argv[1:]
                                 , "d:b:c:l:t:s:r:f:x:y:"
                                 , "default-setting=")
    except getopt.GetoptError, err:
        print str(err) 
        usage()
        sys.exit(2)
    
    directory = None
    config_of_interest = None
    bench_of_interest = None
    time_of_interest = None
    revision_range = '0:'
    regression_range = '0:'
    latest_revision = None
    requested_height = None
    requested_width = None
    title = 'Bench graph'
    settings = {}
    default_settings = {}

    def parse_range(range):
        """Takes '<old>[:<new>]' as a string and returns (old, new).
        Any revision numbers that are dependent on the latest revision number
        will be filled in based on latest_revision.
        """
        old, _, new = range.partition(":")
        old = int(old)
        if old < 0:
            old += latest_revision;
        if not new:
            new = latest_revision;
        new = int(new)
        if new < 0:
            new += latest_revision;
        return (old, new)

    def add_setting(settings, setting):
        """Takes <key>[=<value>] adds {key:value} or {key:True} to settings."""
        name, _, value = setting.partition('=')
        if not value:
            settings[name] = True
        else:
            settings[name] = value
        
    try:
        for option, value in opts:
            if option == "-d":
                directory = value
            elif option == "-b":
                bench_of_interest = value
            elif option == "-c":
                config_of_interest = value
            elif option == "-t":
                time_of_interest = value
            elif option == "-s":
                add_setting(settings, value)
            elif option == "-r":
                revision_range = value
            elif option == "-f":
                regression_range = value
            elif option == "-x":
                requested_width = int(value)
            elif option == "-y":
                requested_height = int(value)
            elif option == "-l":
                title = value
            elif option == "--default-setting":
                add_setting(default_settings, value)
            else:
                usage()
                assert False, "unhandled option"
    except ValueError:
        usage()
        sys.exit(2)

    if directory is None:
        usage()
        sys.exit(2)

    latest_revision = get_latest_revision(directory)
    oldest_revision, newest_revision = parse_range(revision_range)
    oldest_regression, newest_regression = parse_range(regression_range)

    unfiltered_revision_data_points = parse_dir(directory
                                   , default_settings
                                   , oldest_revision
                                   , newest_revision)

    # Filter out any data points that are utterly bogus... make sure to report
    # that we did so later!
    (allowed_revision_data_points, ignored_revision_data_points) = filter_data_points(
        unfiltered_revision_data_points)

    # Update oldest_revision and newest_revision based on the data we could find
    all_revision_numbers = allowed_revision_data_points.keys()
    oldest_revision = min(all_revision_numbers)
    newest_revision = max(all_revision_numbers)

    lines = create_lines(allowed_revision_data_points
                   , settings
                   , bench_of_interest
                   , config_of_interest
                   , time_of_interest)

    regressions = create_regressions(lines
                                   , oldest_regression
                                   , newest_regression)

    output_xhtml(lines, oldest_revision, newest_revision, ignored_revision_data_points,
                 regressions, requested_width, requested_height, title)

def qa(out):
    """Stringify input and quote as an xml attribute."""
    return xml.sax.saxutils.quoteattr(str(out))
def qe(out):
    """Stringify input and escape as xml data."""
    return xml.sax.saxutils.escape(str(out))

def create_select(qualifier, lines, select_id=None):
    """Output select with options showing lines which qualifier maps to it.
    
    ((Label) -> str, {Label:_}, str?) -> _"""
    options = {} #{ option : [Label]}
    for label in lines.keys():
        option = qualifier(label)
        if (option not in options):
            options[option] = []
        options[option].append(label)
    option_list = list(options.keys())
    option_list.sort()
    print '<select class="lines"',
    if select_id is not None:
        print 'id=%s' % qa(select_id)
    print 'multiple="true" size="10" onchange="updateSvg();">'
    for option in option_list:
        print '<option value=' + qa('[' + 
        reduce(lambda x,y:x+json.dumps(str(y))+',',options[option],"")[0:-1]
        + ']') + '>'+qe(option)+'</option>'
    print '</select>'

def output_ignored_data_points_warning(ignored_revision_data_points):
    """Write description of ignored_revision_data_points to stdout as xhtml.
    """
    num_ignored_points = 0
    description = ''
    revisions = ignored_revision_data_points.keys()
    if revisions:
        revisions.sort()
        revisions.reverse()
        for revision in revisions:
            num_ignored_points += len(ignored_revision_data_points[revision])
            points_at_this_revision = []
            for point in ignored_revision_data_points[revision]:
                points_at_this_revision.append(point.bench)
            points_at_this_revision.sort()
            description += 'r%d: %s\n' % (revision, points_at_this_revision)
    if num_ignored_points == 0:
        print 'Did not discard any data points; all were within the range [%d-%d]' % (
            MIN_REASONABLE_TIME, MAX_REASONABLE_TIME)
    else:
        print '<table width="100%" bgcolor="ff0000"><tr><td align="center">'
        print 'Discarded %d data points outside of range [%d-%d]' % (
            num_ignored_points, MIN_REASONABLE_TIME, MAX_REASONABLE_TIME)
        print '</td></tr><tr><td width="100%" align="center">'
        print ('<textarea rows="4" style="width:97%" readonly="true" wrap="off">'
            + qe(description) + '</textarea>')
        print '</td></tr></table>'

def output_xhtml(lines, oldest_revision, newest_revision, ignored_revision_data_points,
                 regressions, requested_width, requested_height, title):
    """Outputs an svg/xhtml view of the data."""
    print '<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"',
    print '"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">'
    print '<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">'
    print '<head>'
    print '<title>%s</title>' % qe(title)
    print '</head>'
    print '<body>'
    
    output_svg(lines, regressions, requested_width, requested_height)

    #output the manipulation controls
    print """
<script type="text/javascript">//<![CDATA[
    function getElementsByClass(node, searchClass, tag) {
        var classElements = new Array();
        var elements = node.getElementsByTagName(tag);
        var pattern = new RegExp("^|\\s"+searchClass+"\\s|$");
        for (var i = 0, elementsFound = 0; i < elements.length; ++i) {
            if (pattern.test(elements[i].className)) {
                classElements[elementsFound] = elements[i];
                ++elementsFound;
            }
        }
        return classElements;
    }
    function getAllLines() {
        var selectElem = document.getElementById('benchSelect');
        var linesObj = {};
        for (var i = 0; i < selectElem.options.length; ++i) {
            var lines = JSON.parse(selectElem.options[i].value);
            for (var j = 0; j < lines.length; ++j) {
                linesObj[lines[j]] = true;
            }
        }
        return linesObj;
    }
    function getOptions(selectElem) {
        var linesSelectedObj = {};
        for (var i = 0; i < selectElem.options.length; ++i) {
            if (!selectElem.options[i].selected) continue;
            
            var linesSelected = JSON.parse(selectElem.options[i].value);
            for (var j = 0; j < linesSelected.length; ++j) {
                linesSelectedObj[linesSelected[j]] = true;
            }
        }
        return linesSelectedObj;
    }
    function objectEmpty(obj) {
        for (var p in obj) {
            return false;
        }
        return true;
    }
    function markSelectedLines(selectElem, allLines) {
        var linesSelected = getOptions(selectElem);
        if (!objectEmpty(linesSelected)) {
            for (var line in allLines) {
                allLines[line] &= (linesSelected[line] == true);
            }
        }
    }
    function updateSvg() {
        var allLines = getAllLines();
        
        var selects = getElementsByClass(document, 'lines', 'select');
        for (var i = 0; i < selects.length; ++i) {
            markSelectedLines(selects[i], allLines);
        }
        
        for (var line in allLines) {
            var svgLine = document.getElementById(line);
            var display = (allLines[line] ? 'inline' : 'none');
            svgLine.setAttributeNS(null,'display', display);
        }
    }
    
    function mark(markerId) {
        for (var line in getAllLines()) {
            var svgLineGroup = document.getElementById(line);
            var display = svgLineGroup.getAttributeNS(null,'display');
            if (display == null || display == "" || display != "none") {
                var svgLine = document.getElementById(line+'_line');
                if (markerId == null) {
                    svgLine.removeAttributeNS(null,'marker-mid');
                } else {
                    svgLine.setAttributeNS(null,'marker-mid', markerId);
                }
            }
        }
    }
//]]></script>"""

    print '<table border="0" width="%s">' % requested_width
    print """
<tr valign="top"><td width="50%">
<table border="0" width="100%">
<tr><td align="center"><table border="0">
<form>
<tr valign="bottom" align="center">
<td width="1">Bench&nbsp;Type</td>
<td width="1">Bitmap Config</td>
<td width="1">Timer&nbsp;Type (Cpu/Gpu/wall)</td>
<td width="1"><!--buttons--></td>
</tr><tr valign="top" align="center">
"""
    print '<td width="1">'
    create_select(lambda l: l.bench, lines, 'benchSelect')
    print '</td><td width="1">'
    create_select(lambda l: l.config, lines)
    print '</td><td width="1">'
    create_select(lambda l: l.time_type, lines)

    all_settings = {}
    variant_settings = set()
    for label in lines.keys():
        for key, value  in label.settings.items():
            if key not in all_settings:
                all_settings[key] = value
            elif all_settings[key] != value:
                variant_settings.add(key)

    for k in variant_settings:
        create_select(lambda l: l.settings[k], lines)

    print '</td><td width="1"><button type="button"',
    print 'onclick=%s' % qa("mark('url(#circleMark)'); return false;"),
    print '>Mark Points</button>'
    print '<button type="button" onclick="mark(null);">Clear Points</button>'
    print '</td>'
    print """
</tr>
</form>
</table></td></tr>
<tr><td align="center">
<hr />
"""

    output_ignored_data_points_warning(ignored_revision_data_points)
    print '</td></tr></table>'
    print '</td><td width="2%"><!--gutter--></td>'

    print '<td><table border="0">'
    print '<tr><td align="center">%s<br></br>revisions r%s - r%s</td></tr>' % (
        qe(title),
        bench_util.CreateRevisionLink(oldest_revision),
        bench_util.CreateRevisionLink(newest_revision))
    print """
<tr><td align="left">
<p>Brighter red indicates tests that have gotten worse; brighter green
indicates tests that have gotten better.</p>
<p>To highlight individual tests, hold down CONTROL and mouse over
graph lines.</p>
<p>To highlight revision numbers, hold down SHIFT and mouse over
the graph area.</p>
<p>To only show certain tests on the graph, select any combination of
tests in the selectors at left.  (To show all, select all.)</p>
<p>Use buttons at left to mark/clear points on the lines for selected
benchmarks.</p>
</td></tr>
</table>

</td>
</tr>
</table>
</body>
</html>"""
    
def compute_size(requested_width, requested_height, rev_width, time_height):
    """Converts potentially empty requested size into a concrete size.
    
    (Number?,  Number?) -> (Number, Number)"""
    pic_width = 0
    pic_height = 0
    if (requested_width is not None and requested_height is not None):
        pic_height = requested_height
        pic_width = requested_width
    
    elif (requested_width is not None):
        pic_width = requested_width
        pic_height = pic_width * (float(time_height) / rev_width)
        
    elif (requested_height is not None):
        pic_height = requested_height
        pic_width = pic_height * (float(rev_width) / time_height)
        
    else:
        pic_height = 800
        pic_width = max(rev_width*3
                      , pic_height * (float(rev_width) / time_height))
    
    return (pic_width, pic_height)

def output_svg(lines, regressions, requested_width, requested_height):
    """Outputs an svg view of the data."""
    
    (global_min_x, _), (global_max_x, global_max_y) = bounds(lines)
    max_up_slope, min_down_slope = bounds_slope(regressions)
    
    #output
    global_min_y = 0
    x = global_min_x
    y = global_min_y
    w = global_max_x - global_min_x
    h = global_max_y - global_min_y
    font_size = 16
    line_width = 2
    
    pic_width, pic_height = compute_size(requested_width, requested_height
                                       , w, h)
    
    def cw(w1):
        """Converts a revision difference to display width."""
        return (pic_width / float(w)) * w1
    def cx(x):
        """Converts a revision to a horizontal display position."""
        return cw(x - global_min_x)

    def ch(h1):
        """Converts a time difference to a display height."""
        return -(pic_height / float(h)) * h1
    def cy(y):
        """Converts a time to a vertical display position."""
        return pic_height + ch(y - global_min_y)
    
    print '<svg',
    print 'width=%s' % qa(str(pic_width)+'px')
    print 'height=%s' % qa(str(pic_height)+'px')
    print 'viewBox="0 0 %s %s"' % (str(pic_width), str(pic_height))
    print 'onclick=%s' % qa(
            "var event = arguments[0] || window.event;"
            " if (event.shiftKey) { highlightRevision(null); }"
            " if (event.ctrlKey) { highlight(null); }"
            " return false;")
    print 'xmlns="http://www.w3.org/2000/svg"'
    print 'xmlns:xlink="http://www.w3.org/1999/xlink">'
    
    print """
<defs>
    <marker id="circleMark"
      viewBox="0 0 2 2" refX="1" refY="1"
      markerUnits="strokeWidth"
      markerWidth="2" markerHeight="2"
      orient="0">
      <circle cx="1" cy="1" r="1"/>
    </marker>
</defs>"""
    
    #output the revisions
    print """
<script type="text/javascript">//<![CDATA[
    var previousRevision;
    var previousRevisionFill;
    var previousRevisionStroke
    function highlightRevision(id) {
        if (previousRevision == id) return;

        document.getElementById('revision').firstChild.nodeValue = 'r' + id;
        document.getElementById('rev_link').setAttribute('xlink:href',
            'http://code.google.com/p/skia/source/detail?r=' + id);
        
        var preRevision = document.getElementById(previousRevision);
        if (preRevision) {
            preRevision.setAttributeNS(null,'fill', previousRevisionFill);
            preRevision.setAttributeNS(null,'stroke', previousRevisionStroke);
        }
        
        var revision = document.getElementById(id);
        previousRevision = id;
        if (revision) {
            previousRevisionFill = revision.getAttributeNS(null,'fill');
            revision.setAttributeNS(null,'fill','rgb(100%, 95%, 95%)');
            
            previousRevisionStroke = revision.getAttributeNS(null,'stroke');
            revision.setAttributeNS(null,'stroke','rgb(100%, 90%, 90%)');
        }
    }
//]]></script>"""
    
    def print_rect(x, y, w, h, revision):
        """Outputs a revision rectangle in display space,
           taking arguments in revision space."""
        disp_y = cy(y)
        disp_h = ch(h)
        if disp_h < 0:
            disp_y += disp_h
            disp_h = -disp_h
        
        print '<rect id=%s x=%s y=%s' % (qa(revision), qa(cx(x)), qa(disp_y),),
        print 'width=%s height=%s' % (qa(cw(w)), qa(disp_h),),
        print 'fill="white"',
        print 'stroke="rgb(98%%,98%%,88%%)" stroke-width=%s' % qa(line_width),
        print 'onmouseover=%s' % qa(
                "var event = arguments[0] || window.event;"
                " if (event.shiftKey) {"
                    " highlightRevision('"+str(revision)+"');"
                    " return false;"
                " }"),
        print ' />'
    
    xes = set()
    for line in lines.itervalues():
        for point in line:
            xes.add(point[0])
    revisions = list(xes)
    revisions.sort()
    
    left = x
    current_revision = revisions[0]
    for next_revision in revisions[1:]:
        width = (((next_revision - current_revision) / 2.0)
                 + (current_revision - left))
        print_rect(left, y, width, h, current_revision)
        left += width
        current_revision = next_revision
    print_rect(left, y, x+w - left, h, current_revision)

    #output the lines
    print """
<script type="text/javascript">//<![CDATA[
    var previous;
    var previousColor;
    var previousOpacity;
    function highlight(id) {
        if (previous == id) return;

        document.getElementById('label').firstChild.nodeValue = id;

        var preGroup = document.getElementById(previous);
        if (preGroup) {
            var preLine = document.getElementById(previous+'_line');
            preLine.setAttributeNS(null,'stroke', previousColor);
            preLine.setAttributeNS(null,'opacity', previousOpacity);

            var preSlope = document.getElementById(previous+'_linear');
            if (preSlope) {
                preSlope.setAttributeNS(null,'visibility', 'hidden');
            }
        }

        var group = document.getElementById(id);
        previous = id;
        if (group) {
            group.parentNode.appendChild(group);
            
            var line = document.getElementById(id+'_line');
            previousColor = line.getAttributeNS(null,'stroke');
            previousOpacity = line.getAttributeNS(null,'opacity');
            line.setAttributeNS(null,'stroke', 'blue');
            line.setAttributeNS(null,'opacity', '1');
            
            var slope = document.getElementById(id+'_linear');
            if (slope) {
                slope.setAttributeNS(null,'visibility', 'visible');
            }
        }
    }
//]]></script>"""
    for label, line in lines.items():
        print '<g id=%s>' % qa(label)
        r = 128
        g = 128
        b = 128
        a = .10
        if label in regressions:
            regression = regressions[label]
            min_slope = regression.find_min_slope()
            if min_slope < 0:
                d = max(0, (min_slope / min_down_slope))
                g += int(d*128)
                a += d*0.9
            elif min_slope > 0:
                d = max(0, (min_slope / max_up_slope))
                r += int(d*128)
                a += d*0.9
            
            slope = regression.slope
            intercept = regression.intercept
            min_x = regression.min_x
            max_x = regression.max_x
            print '<polyline id=%s' % qa(str(label)+'_linear'),
            print 'fill="none" stroke="yellow"',
            print 'stroke-width=%s' % qa(abs(ch(regression.serror*2))),
            print 'opacity="0.5" pointer-events="none" visibility="hidden"',
            print 'points="',
            print '%s,%s' % (str(cx(min_x)), str(cy(slope*min_x + intercept))),
            print '%s,%s' % (str(cx(max_x)), str(cy(slope*max_x + intercept))),
            print '"/>'
        
        print '<polyline id=%s' % qa(str(label)+'_line'),
        print 'onmouseover=%s' % qa(
                "var event = arguments[0] || window.event;"
                " if (event.ctrlKey) {"
                    " highlight('"+str(label).replace("'", "\\'")+"');"
                    " return false;"
                " }"),
        print 'fill="none" stroke="rgb(%s,%s,%s)"' % (str(r), str(g), str(b)),
        print 'stroke-width=%s' % qa(line_width),
        print 'opacity=%s' % qa(a),
        print 'points="',
        for point in line:
            print '%s,%s' % (str(cx(point[0])), str(cy(point[1]))),
        print '"/>'

        print '</g>'

    #output the labels
    print '<text id="label" x="0" y=%s' % qa(font_size),
    print 'font-size=%s> </text>' % qa(font_size)

    print '<a id="rev_link" xlink:href="" target="_top">'
    print '<text id="revision" x="0" y=%s style="' % qa(font_size*2)
    print 'font-size: %s; ' % qe(font_size)
    print 'stroke: #0000dd; text-decoration: underline; '
    print '"> </text></a>'

    print '</svg>'

if __name__ == "__main__":
    main()