minilineplot 0.0.1

A single Python module, with no dependencies, producing an SVG image of a chart with one or more plotted lines

minilineplot

minilineplot.py is a single Python module, with no dependencies, producing an SVG image of a chart with one or more plotted lines.

The chart has a left vertical axis and a bottom horizontal axis, grid lines are possible,

Two classes are defined.

Line, containing x,y points which creates a line to be plotted

Axis which creates the axis, and to which Line objects can be added.

The Axis class has methods to create an svg string suitable for embedding in an html document it can also create an svg image, either as a bytes object, or saved to a file.

Line

Arguments

values a list of x,y tuples

color an SVG color of the line

stroke line width, 1 for a thin line.

label A label string for a key, if not given, the key will not be drawn

If the Axis 'xstrings' argument is set as strings along the x axis, for example months of the year, then the Line values tuples should be: x is a percentage along the x axis, y is the actual value.

so [(0,59), (100,28)] is a line from

the extreme left (0%) value 59 to the extreme right (100%) value 28

If the Axis x axis is defined as numbers rather than strings then each (x,y) tuple should be the numeric values to be plotted.

color is an SVG color, using standard strings such as

Color Names: "red", "blue" etc.

Hex Codes: "#FF0000" for red.

RGB/RGBA: "rgb(255,0,0)" or "rgba(255,0,0,0.5)" (with opacity).

HSL/HSLA: "hsl(0,100%,50%)" or "hsla(0,100%,50%,0.5)" (hue, saturation, lightness, alpha)

Axis

Arguments

lines list of Line objects

fontsize default 24

imagewidth default 800

imageheight default 600

xstrings A list of strings used as the x axis values, use for text values such as months, etc.,

If any strings are set in xstrings, the following xaxis numbers are ignored

xformat default string ".2f" Sets how the x axis numbers are formatted.

xmin default 0, the minimum x value

xmax default 10, the maximum x value

xintervals default 5, the interval spacing of values along the x axis, 5 would be five intervals and six values.

The y axis is always just numbers

yformat default string ".2f" Sets how the y axis numbers are formatted.

ymin default 0, the minimum y value

ymax default 10, the maximum y value

yintervals default 5, the interval spacing of values along the y axis, 5 would be five intervals and six values.

title default "", A string printed at the top of the chart

description default "", A string printed at the bottom of the chart

verticalgrid default 1

0 is no vertical grid lines, 1 is a line for every x axis interval, 2 is a line for every second interval etc.,

horzontalgrid default 1

0 is no horizontal grid lines, 1 is a line for every y axis interval, 2 is a line for every second interval etc.,

The following colors are SVG colors, using standard strings

gridcol default "grey" Color of the chart grid

axiscol default "black" Color of axis, title and description

chartbackcol default "white" the background colour of the chart

backcol default "white" The background colour of the whole image

xformat and yformat are strings describing how numbers are printed, for example the string ".2f" gives a number to two decimal places

Methods

to_string(xml_declaration = False)

Return a string SVG object. If xml_declaration is True, an xml tag will be included in the returned string which is usually required when creating an svg image file but not required if embedding the code directly into an html document,

to_bytes(xml_declaration = True)

Return a bytes SVG object.

to_file(filepath)

Save the plot to an svg image file

To install, simply copy minilineplot.py to your own project files, or just cut and paste the contents. The code is public domain.

Note, to keep things simple there is no data validation, so lines with values outside the axis will not be caught, it is rubbish in = rubbish out.