石の上にも三年

Graph plotting package with a small API powered by gnuplot.

Requires gnuplot.

Installation

1. Add the dependency to your shard.yml:

dependencies:
  ishi:
    github: toddsundsted/ishi

2. Run shards install

Usage

To display a line chart of the data points in xdata (the x values) and ydata (the corresponding y values):

require "ishi"

ishi = Ishi.new
ishi.plot(xdata, ydata)
ishi.show

Or, if you prefer command-style:

require "ishi"

Ishi.new do
  plot(xdata, ydata)
end

plot accepts data points in several formats:

• plot(ydata) - y values in ydata with x values ranging from 0 to ydata.size - 1
• plot(xdata, ydata) - x values in xdata and corresponding y values in ydata
• plot(xdata, ydata, zdata) - x values from xdata, y values from ydata, and z values from zdata
• plot(expression) - any gnuplot-supported mathematical expression

xdata, ydata and zdata may be any data type that implements Indexable(Number). Chart dimensionality (2D or 3D) is inferred from the data.

All plot methods/commands accept the optional named arguments title and style. title specifies the title of the plot displayed in the chart key. style specifies the style of the plot (line, points, etc.). See the API documentation for details.

By default, Ishi pops open a window to display charts. However, Ishi comes with extensions that display plots as text, HTML or images in the terminal, or render plots to other IO destinations. Note: inline image display only works with ITerm2.

To plot the sin(x) function as text:

require "ishi/text" # or "ishi/html" or "ishi/iterm2"

Ishi.new do
  plot("sin(x)")
end

This produces:

    1 +--------------------------------------------------------------------+
      |                *  *              +  *  **         +       *  *     |
  0.8 |-+             *   *                 *    *          sin(x* *******-|
      |              *     *                *    *               *    *    |
  0.6 |-+            *      *              *     *               *     * +-|
      |              *      *             *       *             *       *  |
  0.4 |*+            *      *             *       *             *       *+-|
      |*            *        *            *        *           *        *  |
  0.2 |*+           *        *            *        *           *        *+-|
      | *          *          *          *         *          *          * |
    0 |-*          *          *          *         *          *          *-|
      |  *         *          *         *           *         *           *|
 -0.2 |-+*         *          *         *           *         *          +*|
      |  *        *            *       *             *       *            *|
 -0.4 |-+*        *            *       *             *       *           +*|
      |   *      *              *      *             *      *              |
 -0.6 |-+ *     *               *     *              *      *            +-|
      |    *    *               *     *               *     *              |
 -0.8 |-+   *   *                *   *                 *   *             +-|
      |     *  *       +         **  *   +             *  *                |
   -1 +--------------------------------------------------------------------+
     -10              -5                 0                5                10

Contributors

• Todd Sundsted - creator and maintainer