OK, in the three instances you posted, the plots were bad, but the incoming
label is correct. So, we know the problem lies somewhere in the image
generation, and not in the weeWX configuration.

Try this version of genplot.py. Same drill: run wee_reports, check for a
bad image, post the log that goes along with that bad image.

-tk

On Thu, Jan 25, 2018 at 9:46 AM, k_herriage via weewx-user <
[email protected]> wrote:

> at 10:45 correct.
>
>
> On Thursday, January 25, 2018 at 10:43:18 AM UTC-6, [email protected]
> wrote:
>>
>> The one I just looked at 10:40 was correct.
>>
>>
>> On Thursday, January 25, 2018 at 10:03:32 AM UTC-6, gjr80 wrote:
>>>
>>> This couldn't be an Apple PIL or pillow thing could it? Having watched
>>> these plots on and off for a couple of days almost all have some extra text
>>> in the outHumidity label. Given the number of instrumented outputs posted
>>> by Keith I am sure at least one must have been from a 'bad' plot. Mind you
>>> when I had a look last night when Keith posted his first log, the plot I
>>> happened to look at was perfect (some 45 minutes after Keith's log).
>>>
>>> Gary
>>>
>> --
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#
#    Copyright (c) 2009-2016 Tom Keffer <[email protected]>
#
#    See the file LICENSE.txt for your full rights.
#
"""Routines for generating image plots.
"""
import syslog
import colorsys
import locale
import time
try:
    from PIL import Image, ImageDraw
except ImportError:
    import Image, ImageDraw

import weeplot.utilities
import weeutil.weeutil
from weeutil.weeutil import to_unicode

# NB: All labels passed in should be in UTF-8. They are then converted to Unicode, which
# some fonts support, others don't. If the chosen font does not support Unicode, then the label
# will be changed back to UTF-8, then tried again.        

class GeneralPlot(object):
    """Holds various parameters necessary for a plot. It should be specialized by the type of plot.
    
    """
    def __init__(self, config_dict):
        """Initialize an instance of GeneralPlot.
        
        config_dict: an instance of ConfigObj, or something that looks like it.
        
        """
        
        self.line_list = []
        
        self.xscale = (None, None, None)
        self.yscale = (None, None, None)

        self.anti_alias             = int(config_dict.get('anti_alias',  1))

        self.image_width            = int(config_dict.get('image_width',  300)) * self.anti_alias
        self.image_height           = int(config_dict.get('image_height', 180)) * self.anti_alias
        self.image_background_color = weeplot.utilities.tobgr(config_dict.get('image_background_color', '0xf5f5f5'))

        self.chart_background_color = weeplot.utilities.tobgr(config_dict.get('chart_background_color', '0xd8d8d8'))
        self.chart_gridline_color   = weeplot.utilities.tobgr(config_dict.get('chart_gridline_color',   '0xa0a0a0'))
        color_list                  = config_dict.get('chart_line_colors', ['0xff0000', '0x00ff00', '0x0000ff'])
        fill_color_list             = config_dict.get('chart_fill_colors', color_list)
        width_list                  = config_dict.get('chart_line_width',  [1, 1, 1])
        self.chart_line_colors      = [weeplot.utilities.tobgr(v) for v in color_list]
        self.chart_fill_colors      = [weeplot.utilities.tobgr(v) for v in fill_color_list]
        self.chart_line_widths      = [int(v) for v in width_list]

        
        self.top_label_font_path    = config_dict.get('top_label_font_path')
        self.top_label_font_size    = int(config_dict.get('top_label_font_size', 10)) * self.anti_alias

        self.unit_label             = None
        self.unit_label_font_path   = config_dict.get('unit_label_font_path')
        self.unit_label_font_color  = weeplot.utilities.tobgr(config_dict.get('unit_label_font_color', '0x000000'))
        self.unit_label_font_size   = int(config_dict.get('unit_label_font_size', 10)) * self.anti_alias
        self.unit_label_position    = (10 * self.anti_alias, 0)
        
        self.bottom_label_font_path = config_dict.get('bottom_label_font_path')
        self.bottom_label_font_color= weeplot.utilities.tobgr(config_dict.get('bottom_label_font_color', '0x000000'))
        self.bottom_label_font_size = int(config_dict.get('bottom_label_font_size', 10)) * self.anti_alias
        self.bottom_label_offset    = int(config_dict.get('bottom_label_offset', 3))

        self.axis_label_font_path   = config_dict.get('axis_label_font_path')
        self.axis_label_font_color  = weeplot.utilities.tobgr(config_dict.get('axis_label_font_color', '0x000000'))
        self.axis_label_font_size   = int(config_dict.get('axis_label_font_size', 10)) * self.anti_alias

        self.x_label_format         = to_unicode(config_dict.get('x_label_format'))
        self.y_label_format         = to_unicode(config_dict.get('y_label_format'))
        
        self.x_nticks               = int(config_dict.get('x_nticks', 10))
        self.y_nticks               = int(config_dict.get('y_nticks', 10))

        self.x_label_spacing        = int(config_dict.get('x_label_spacing', 2))
        self.y_label_spacing        = int(config_dict.get('y_label_spacing', 2))
        
        # Calculate sensible margins for the given image and font sizes.
        self.lmargin = int(4.0 * self.axis_label_font_size)
        self.rmargin = 20 * self.anti_alias
        self.bmargin = int(1.5 * (self.bottom_label_font_size + self.axis_label_font_size) + 0.5)
        self.tmargin = int(1.5 * self.top_label_font_size + 0.5)
        self.tbandht = int(1.2 * self.top_label_font_size + 0.5)
        self.padding =  3 * self.anti_alias

        self.render_rose            = False
        self.rose_width             = int(config_dict.get('rose_width', 21))
        self.rose_height            = int(config_dict.get('rose_height', 21))
        self.rose_diameter          = int(config_dict.get('rose_diameter', 10))
        self.rose_position          = (self.lmargin + self.padding + 5, self.image_height - self.bmargin - self.padding - self.rose_height)
        self.rose_rotation          = None
        self.rose_label             = to_unicode(config_dict.get('rose_label', 'N'))
        self.rose_label_font_path   = config_dict.get('rose_label_font_path', self.bottom_label_font_path)
        self.rose_label_font_size   = int(config_dict.get('rose_label_font_size', 10))  
        self.rose_label_font_color  = weeplot.utilities.tobgr(config_dict.get('rose_label_font_color', '0x000000'))
        self.rose_color             = config_dict.get('rose_color')
        if self.rose_color is not None:
            self.rose_color = weeplot.utilities.tobgr(self.rose_color)

        # Show day/night transitions
        self.show_daynight          = weeutil.weeutil.tobool(config_dict.get('show_daynight', False))
        self.daynight_day_color     = weeplot.utilities.tobgr(config_dict.get('daynight_day_color', '0xffffff'))
        self.daynight_night_color   = weeplot.utilities.tobgr(config_dict.get('daynight_night_color', '0xf0f0f0'))
        self.daynight_edge_color    = weeplot.utilities.tobgr(config_dict.get('daynight_edge_color', '0xefefef'))
        self.daynight_gradient      = int(config_dict.get('daynight_gradient', 20))

    def setBottomLabel(self, bottom_label):
        """Set the label to be put at the bottom of the plot.
        
        """
        self.bottom_label = to_unicode(bottom_label)
        
    def setUnitLabel(self, unit_label):
        """Set the label to be used to show the units of the plot.
        
        """
        self.unit_label = to_unicode(unit_label)
        
    def setXScaling(self, xscale):
        """Set the X scaling.
        
        xscale: A 3-way tuple (xmin, xmax, xinc)
        """
        self.xscale = xscale
        
    def setYScaling(self, yscale):
        """Set the Y scaling.
        
        yscale: A 3-way tuple (ymin, ymax, yinc)
        """
        self.yscale = yscale
        
    def addLine(self, line):
        """Add a line to be plotted.
        
        line: an instance of PlotLine
        
        """
        if None in line.x:
            raise weeplot.ViolatedPrecondition, "X vector cannot have any values 'None' "
        self.line_list.append(line)

    def setLocation(self, lat, lon):
        self.latitude  = lat
        self.longitude = lon
        
    def setDayNight(self, showdaynight, daycolor, nightcolor, edgecolor):
        """Configure day/night bands.

        showdaynight: Boolean flag indicating whether to draw day/night bands

        daycolor: color for day bands

        nightcolor: color for night bands

        edgecolor: color for transition between day and night
        """
        self.show_daynight = showdaynight
        self.daynight_day_color = daycolor
        self.daynight_night_color = nightcolor
        self.daynight_edge_color = edgecolor

    def render(self):
        """Traverses the universe of things that have to be plotted in this image, rendering
        them and returning the results as a new Image object.
        
        """

        # NB: In what follows the variable 'draw' is an instance of an ImageDraw object and is in pixel units.
        # The variable 'sdraw' is an instance of ScaledDraw and its units are in the "scaled" units of the plot
        # (e.g., the horizontal scaling might be for seconds, the vertical for degrees Fahrenheit.)
        image = Image.new("RGB", (self.image_width, self.image_height), self.image_background_color)
        draw = self._getImageDraw(image)
        draw.rectangle(((self.lmargin,self.tmargin), 
                        (self.image_width - self.rmargin, self.image_height - self.bmargin)), 
                        fill=self.chart_background_color)
        
        self._renderBottom(draw)
        self._renderTopBand(draw)
        
        self._calcXScaling()
        self._calcYScaling()
        self._calcXLabelFormat()
        self._calcYLabelFormat()
        
        sdraw = self._getScaledDraw(draw)
        if self.show_daynight:
            self._renderDayNight(sdraw)
        self._renderXAxes(sdraw)
        self._renderYAxes(sdraw)
        self._renderPlotLines(sdraw)
        if self.render_rose:
            self._renderRose(image, draw)

        if self.anti_alias != 1:
            image.thumbnail((self.image_width / self.anti_alias, self.image_height / self.anti_alias), Image.ANTIALIAS)

        return image
    
    def _getImageDraw(self, image):
        """Returns an instance of ImageDraw with the proper dimensions and background color"""
        draw = UniDraw(image)
        return draw
    
    def _getScaledDraw(self, draw):
        """Returns an instance of ScaledDraw, with the appropriate scaling.
        
        draw: An instance of ImageDraw
        """
        sdraw = weeplot.utilities.ScaledDraw(draw, ((self.lmargin + self.padding, self.tmargin + self.padding),
                                                    (self.image_width - self.rmargin - self.padding, self.image_height - self.bmargin - self.padding)),
                                                    ((self.xscale[0], self.yscale[0]), (self.xscale[1], self.yscale[1])))
        return sdraw
        
    def _renderDayNight(self, sdraw):
        """Draw vertical bands for day/night."""
        (first, transitions) = weeutil.weeutil.getDayNightTransitions(
            self.xscale[0], self.xscale[1], self.latitude, self.longitude)
        color = self.daynight_day_color \
            if first == 'day' else self.daynight_night_color
        xleft = self.xscale[0]
        for x in transitions:
            sdraw.rectangle(((xleft,self.yscale[0]),
                             (x,self.yscale[1])), fill=color)
            xleft = x
            color = self.daynight_night_color \
                if color == self.daynight_day_color else self.daynight_day_color
        sdraw.rectangle(((xleft,self.yscale[0]),
                         (self.xscale[1],self.yscale[1])), fill=color)
        if self.daynight_gradient:
            if first == 'day':
                color1 = self.daynight_day_color
                color2 = self.daynight_night_color
            else:
                color1 = self.daynight_night_color
                color2 = self.daynight_day_color
            nfade = self.daynight_gradient
            # gradient is longer at the poles than the equator
            d = 120 + 300 * (1 - (90.0 - abs(self.latitude)) / 90.0)
            for i in range(len(transitions)):
                last_ = self.xscale[0] if i == 0 else transitions[i-1]
                next_ = transitions[i+1] if i < len(transitions)-1 else self.xscale[1]
                for z in range(1,nfade):
                    c = blend_hls(color2, color1, float(z)/float(nfade))
                    rgbc = int2rgbstr(c)
                    x1 = transitions[i]-d*(nfade+1)/2+d*z
                    if last_ < x1 < next_:
                        sdraw.rectangle(((x1, self.yscale[0]),
                                         (x1+d, self.yscale[1])),
                                        fill=rgbc)
                if color1 == self.daynight_day_color:
                    color1 = self.daynight_night_color
                    color2 = self.daynight_day_color
                else:
                    color1 = self.daynight_day_color
                    color2 = self.daynight_night_color
        # draw a line at the actual sunrise/sunset
        for x in transitions:
            sdraw.line((x,x),(self.yscale[0],self.yscale[1]),
                       fill=self.daynight_edge_color)

    def _renderXAxes(self, sdraw):
        """Draws the x axis and vertical constant-x lines, as well as the labels.
        
        """

        axis_label_font = weeplot.utilities.get_font_handle(self.axis_label_font_path,
                                                            self.axis_label_font_size)

        drawlabelcount = 0
        for x in weeutil.weeutil.stampgen(self.xscale[0], self.xscale[1], self.xscale[2]) :
            sdraw.line((x, x), (self.yscale[0], self.yscale[1]), fill=self.chart_gridline_color,
                       width=self.anti_alias)
            if drawlabelcount % self.x_label_spacing == 0 :
                xlabel = self._genXLabel(x)
                axis_label_size = sdraw.draw.textsize(xlabel, font=axis_label_font)
                xpos = sdraw.xtranslate(x)
                sdraw.draw.text((xpos - axis_label_size[0]/2, self.image_height - self.bmargin + 2),
                                xlabel, fill=self.axis_label_font_color, font=axis_label_font)
            drawlabelcount += 1

    def _renderYAxes(self, sdraw):
        """Draws the y axis and horizontal constant-y lines, as well as the labels.
        Should be sufficient for most purposes.
        
        """
        nygridlines     = int((self.yscale[1] - self.yscale[0]) / self.yscale[2] + 1.5)
        axis_label_font = weeplot.utilities.get_font_handle(self.axis_label_font_path,
                                                                self.axis_label_font_size)
        
        # Draw the (constant y) grid lines 
        for i in xrange(nygridlines) :
            y = self.yscale[0] + i * self.yscale[2]
            sdraw.line((self.xscale[0], self.xscale[1]), (y, y), fill=self.chart_gridline_color,
                       width=self.anti_alias)
            # Draw a label on every other line:
            if i % self.y_label_spacing == 0 :
                ylabel = self._genYLabel(y)
                axis_label_size = sdraw.draw.textsize(ylabel, font=axis_label_font)
                ypos = sdraw.ytranslate(y)
                sdraw.draw.text((self.lmargin - axis_label_size[0] - 2, ypos - axis_label_size[1]/2),
                                ylabel, fill=self.axis_label_font_color, font=axis_label_font)

    def _renderPlotLines(self, sdraw):
        """Draw the collection of lines, using a different color for each one. Because there is
        a limited set of colors, they need to be recycled if there are very many lines.
        
        """
        nlines = len(self.line_list)
        ncolors = len(self.chart_line_colors)
        nfcolors = len(self.chart_fill_colors)
        nwidths = len(self.chart_line_widths)

        # Draw them in reverse order, so the first line comes out on top of the image
        for j, this_line in enumerate(self.line_list[::-1]):
            
            iline=nlines-j-1
            color = self.chart_line_colors[iline%ncolors] if this_line.color is None else this_line.color
            fill_color = self.chart_fill_colors[iline%nfcolors] if this_line.fill_color is None else this_line.fill_color
            width = (self.chart_line_widths[iline%nwidths] if this_line.width is None else this_line.width) * self.anti_alias

            # Calculate the size of a gap in data
            maxdx = None
            if this_line.gap_fraction is not None:
                maxdx = this_line.gap_fraction * (self.xscale[1] - self.xscale[0])

            if this_line.plot_type == 'line' :
                ms = this_line.marker_size
                if ms is not None:
                    ms *= self.anti_alias
                sdraw.line(this_line.x, 
                           this_line.y, 
                           line_type=this_line.line_type,
                           marker_type=this_line.marker_type,
                           marker_size=ms,
                           fill  = color,
                           width = width,
                           maxdx = maxdx)
            elif this_line.plot_type == 'bar' :
                for x, y, bar_width in zip(this_line.x, this_line.y, this_line.bar_width):
                    if y is None:
                        continue
                    sdraw.rectangle(((x - bar_width, self.yscale[0]), (x, y)), fill=fill_color, outline=color)
            elif this_line.plot_type == 'vector' :
                for (x, vec) in zip(this_line.x, this_line.y):
                    sdraw.vector(x, vec,
                                 vector_rotate = this_line.vector_rotate,
                                 fill  = color,
                                 width = width)
                self.render_rose = True
                self.rose_rotation = this_line.vector_rotate
                if self.rose_color is None:
                    self.rose_color = color

    def _renderBottom(self, draw):
        """Draw anything at the bottom (just some text right now).
        
        """
        bottom_label_font = weeplot.utilities.get_font_handle(self.bottom_label_font_path, self.bottom_label_font_size)
        bottom_label_size = draw.textsize(self.bottom_label, font=bottom_label_font)
        
        draw.text(((self.image_width - bottom_label_size[0])/2, 
                   self.image_height - bottom_label_size[1] - self.bottom_label_offset),
                  self.bottom_label, 
                  fill=self.bottom_label_font_color,
                  font=bottom_label_font)
        
    def _renderTopBand(self, draw):
        """Draw the top band and any text in it.
        
        """
        # Draw the top band rectangle
        draw.rectangle(((0,0), 
                        (self.image_width, self.tbandht)), 
                        fill = self.chart_background_color)

        # Put the units in the upper left corner
        unit_label_font = weeplot.utilities.get_font_handle(self.unit_label_font_path, self.unit_label_font_size)
        if self.unit_label:
            draw.text(self.unit_label_position,
                      self.unit_label,
                      fill=self.unit_label_font_color,
                      font=unit_label_font)

        top_label_font = weeplot.utilities.get_font_handle(self.top_label_font_path, self.top_label_font_size)
        
        # The top label is the appended label_list. However, it has to be drawn in segments 
        # because each label may be in a different color. For now, append them together to get
        # the total width
        top_label = ' '.join([line.label for line in self.line_list])
        top_label_size = draw.textsize(top_label, font=top_label_font)
        
        x = (self.image_width - top_label_size[0])/2
        y = 0
        
        ncolors = len(self.chart_line_colors)
        for i, this_line in enumerate(self.line_list):
            color = self.chart_line_colors[i%ncolors] if this_line.color is None else this_line.color
            syslog.syslog(syslog.LOG_ERR, "Rendering label %s" % this_line.label)
            # Draw a label
            draw.text( (x,y), this_line.label, fill = color, font = top_label_font)
            # Now advance the width of the label we just drew, plus a space:
            label_size = draw.textsize(this_line.label + ' ', font= top_label_font)
            x += label_size[0]

    def _renderRose(self, image, draw):
        """Draw a compass rose."""
        
        rose_center_x = self.rose_width/2  + 1
        rose_center_y = self.rose_height/2 + 1
        barb_width  = 3
        barb_height = 3
        # The background is all white with a zero alpha (totally transparent)
        rose_image = Image.new("RGBA", (self.rose_width, self.rose_height), (0x00, 0x00, 0x00, 0x00))
        rose_draw = ImageDraw.Draw(rose_image)
 
        fill_color = add_alpha(self.rose_color)
        # Draw the arrow straight up (North). First the shaft:
        rose_draw.line( ((rose_center_x, 0), (rose_center_x, self.rose_height)), width = 1, fill = fill_color)
        # Now the left barb:
        rose_draw.line( ((rose_center_x - barb_width, barb_height), (rose_center_x, 0)), width = 1, fill = fill_color)
        # And the right barb:
        rose_draw.line( ((rose_center_x, 0), (rose_center_x + barb_width, barb_height)), width = 1, fill = fill_color)
        
        rose_draw.ellipse(((rose_center_x - self.rose_diameter/2,
                            rose_center_y - self.rose_diameter/2),
                           (rose_center_x + self.rose_diameter/2,
                            rose_center_y + self.rose_diameter/2)),
                          outline = fill_color)

        # Rotate if necessary:
        if self.rose_rotation:
            rose_image = rose_image.rotate(self.rose_rotation)
            rose_draw = ImageDraw.Draw(rose_image)
        
        # Calculate the position of the "N" label:
        rose_label_font = weeplot.utilities.get_font_handle(self.rose_label_font_path, self.rose_label_font_size)
        rose_label_size = draw.textsize(self.rose_label, font=rose_label_font)
        
        # Draw the label in the middle of the (possibly) rotated arrow
        rose_draw.text((rose_center_x - rose_label_size[0]/2 - 1,
                        rose_center_y - rose_label_size[1]/2 - 1),
                        self.rose_label,
                        fill = add_alpha(self.rose_label_font_color),
                        font = rose_label_font)

        # Paste the image of the arrow on to the main plot. The alpha
        # channel of the image will be used as the mask.
        # This will cause the arrow to overlay the background plot
        image.paste(rose_image, self.rose_position, rose_image)
        

    def _calcXScaling(self):
        """Calculates the x scaling. It will probably be specialized by
        plots where the x-axis represents time.
        
        """
        (xmin, xmax) = self._calcXMinMax()

        self.xscale = weeplot.utilities.scale(xmin, xmax, self.xscale, nsteps=self.x_nticks)
            
    def _calcYScaling(self):
        """Calculates y scaling. Can be used 'as-is' for most purposes."""
        # The filter is necessary because unfortunately the value 'None' is not
        # excluded from min and max (i.e., min(None, x) is not necessarily x). 
        # The try block is necessary because min of an empty list throws a
        # ValueError exception.
        ymin = ymax = None
        for line in self.line_list:
            if line.plot_type == 'vector':
                try:
                    # For progressive vector plots, we want the magnitude of the complex vector
                    yline_max = max(abs(c) for c in filter(lambda v : v is not None, line.y))
                except ValueError:
                    yline_max = None
                yline_min = - yline_max if yline_max is not None else None
            else:
                yline_min = weeutil.weeutil.min_with_none(line.y)
                yline_max = weeutil.weeutil.max_with_none(line.y)
            ymin = weeutil.weeutil.min_with_none([ymin, yline_min])
            ymax = weeutil.weeutil.max_with_none([ymax, yline_max])

        if ymin is None and ymax is None :
            # No valid data. Pick an arbitrary scaling
            self.yscale=(0.0, 1.0, 0.2)
        else:
            self.yscale = weeplot.utilities.scale(ymin, ymax, self.yscale, nsteps=self.y_nticks)

    def _calcXLabelFormat(self):
        if self.x_label_format is None:
            self.x_label_format = weeplot.utilities.pickLabelFormat(self.xscale[2])

    def _calcYLabelFormat(self):
        if self.y_label_format is None:
            self.y_label_format = weeplot.utilities.pickLabelFormat(self.yscale[2])
        
    def _genXLabel(self, x):
        xlabel = locale.format(self.x_label_format, x)
        return xlabel
    
    def _genYLabel(self, y):
        ylabel = locale.format(self.y_label_format, y)
        return ylabel
    
    def _calcXMinMax(self):
        xmin = xmax = None
        for line in self.line_list:
            xline_min = weeutil.weeutil.min_with_none(line.x)
            xline_max = weeutil.weeutil.max_with_none(line.x)
            # If the line represents a bar chart, then the actual minimum has to
            # be adjusted for the bar width of the first point
            if line.plot_type == 'bar':
                xline_min = xline_min - line.bar_width[0]
            xmin = weeutil.weeutil.min_with_none([xmin, xline_min])
            xmax = weeutil.weeutil.max_with_none([xmax, xline_max])
        return (xmin, xmax)

class TimePlot(GeneralPlot) :
    """Class that specializes GeneralPlot for plots where the x-axis is time."""
    
    def _calcXScaling(self):
        """Specialized version for time plots."""
        if None in self.xscale:
            (xmin, xmax) = self._calcXMinMax()
            self.xscale = weeplot.utilities.scaletime(xmin, xmax)

    def _calcXLabelFormat(self):
        """Specialized version for time plots."""
        if self.x_label_format is None:
            (xmin, xmax) = self._calcXMinMax()
            if xmin is not None and xmax is not None:
                delta = xmax - xmin
                if delta > 30*24*3600:
                    self.x_label_format = u"%x"
                elif delta > 24*3600:
                    self.x_label_format = u"%x %X"
                else:
                    self.x_label_format = u"%X"
        
    def _genXLabel(self, x):
        if self.x_label_format is None:
            return ''
        time_tuple = time.localtime(x)
        # The function time.strftime() still does not support Unicode, so we have to explicitly
        # convert it to UTF8, then back again:
        xlabel = to_unicode(time.strftime(self.x_label_format.encode('utf8'), time_tuple))
        return xlabel
    
class PlotLine(object):
    """Represents a single line (or bar) in a plot.
    
    """
    def __init__(self, x, y, label='', color=None, fill_color=None, width=None, plot_type='line',
                 line_type='solid', marker_type=None, marker_size=10, 
                 bar_width=None, vector_rotate = None, gap_fraction=None):
        self.x               = x
        self.y               = y
        self.label           = to_unicode(label)
        self.plot_type       = plot_type
        self.line_type       = line_type
        self.marker_type     = marker_type
        self.marker_size     = marker_size
        self.color           = color
        self.fill_color      = fill_color
        self.width           = width
        self.bar_width       = bar_width
        self.vector_rotate   = vector_rotate
        self.gap_fraction    = gap_fraction

class UniDraw(ImageDraw.ImageDraw):
    """Supports non-Unicode fonts
    
    Not all fonts support Unicode characters. These will raise a UnicodeEncodeError exception.
    This class subclasses the regular ImageDraw.Draw class, adding overridden functions to
    catch these exceptions. It then tries drawing the string again, this time as a UTF8 string"""
    
    def text(self, position, string, **options):
        try:
            return ImageDraw.ImageDraw.text(self, position, string, **options)
        except UnicodeEncodeError:
            return ImageDraw.ImageDraw.text(self, position, string.encode('utf8'), **options)
        
    def textsize(self, string, **options):
        try:
            return ImageDraw.ImageDraw.textsize(self, string, **options)
        except UnicodeEncodeError:
            return ImageDraw.ImageDraw.textsize(self, string.encode('utf8'), **options)
            
            
def blend_hls(c, bg, alpha):
    """Fade from c to bg using alpha channel where 1 is solid and 0 is
    transparent.  This fades across the hue, saturation, and lightness."""
    return blend(c, bg, alpha, alpha, alpha)

def blend_ls(c, bg, alpha):
    """Fade from c to bg where 1 is solid and 0 is transparent.
    Change only the lightness and saturation, not hue."""
    return blend(c, bg, 1.0, alpha, alpha)

def blend(c, bg, alpha_h, alpha_l, alpha_s):
    """Fade from c to bg in the hue, lightness, saturation colorspace."""
    r1,g1,b1 = int2rgb(c)
    h1,l1,s1 = colorsys.rgb_to_hls(r1/256.0, g1/256.0, b1/256.0)
    r2,g2,b2 = int2rgb(bg)
    h2,l2,s2 = colorsys.rgb_to_hls(r2/256.0, g2/256.0, b2/256.0)
    h = alpha_h * h1 + (1 - alpha_h) * h2
    l = alpha_l * l1 + (1 - alpha_l) * l2
    s = alpha_s * s1 + (1 - alpha_s) * s2
    r,g,b = colorsys.hls_to_rgb(h, l, s)
    r = round(r * 256.0)
    g = round(g * 256.0)
    b = round(b * 256.0)
    t = rgb2int(int(r),int(g),int(b))
    return int(t)

def int2rgb(x):
    b = (x >> 16) & 0xff
    g = (x >> 8) & 0xff
    r = x & 0xff
    return r,g,b

def int2rgbstr(x):
    return '#%02x%02x%02x' % int2rgb(x)

def rgb2int(r,g,b):
    return r + g*256 + b*256*256

def add_alpha(i):
    """Add an opaque alpha channel to an integer RGB value"""
    r = i & 0xff
    g = (i >> 8)  & 0xff
    b = (i >> 16) & 0xff
    a = 0xff    # Opaque alpha
    return (r,g,b,a)

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