chartty

Pure JS library for making scatter plots in the terminal with braille dots

API

function plot(
    x: number[],
    y: number[],
    options?: Options,
): string;

interface Options {
    // minimum x value on plot
    xmin?: number;
    // maximum x value on plot
    xmax?: number;
    // minimum y value on plot
    ymin?: number;
    // maximum y value on plot
    ymax?: number;
    // width of plot in terminal characters [80]
    width?: number;
    // height of plot in terminal characters [24]
    height?: number;
    // whether to draw the x-axis as a line of hyphens [false]
    xaxis?: boolean;
    // whether to draw the y-axis as a line of bars [false]
    yaxis?: boolean; 
    // whether to draw the origin as a '+' [false]
    origin?: boolean; 
    // whether to draw a rectangle around the entire plot [false]
    border?: boolean;
    // number of x-axis labels to display (default 0)
    xlabels?: number;
    // number of y-axis labels to display (default 0)
    ylabels?: number; 
    // plot title centered on top line
    title?: string; 
    // name for x axis, printed on bottom of chart
    xname?: string;
    // name for y axis, printed vertically on left edge
    yname?: string
}

Vertical text is added as appropriate for x-tick labels or y-axis name by stacking characters on top of each other. Labels will all cut into the width/height dimensions of the chart, so it is recommended to use larger than the default if including labels.

Actually drawing the axes has the significant drawback that it will be impossible to draw dots on the same character as the axis lines.

The actual scatter plot is done with Braille characters, so that each character in the string can plot up to 8 different points, in a 4 (high) by 2 (wide) grid. If multiple points fall onto the same dot, it is still only drawn once - there is no way to represent more than one point in a single dot.