Crystal Plotting Shard

Cryplot is Crystal plotting library powered by gnuplot. The goal of the Cryplot is to enable you, Crystal programmer, to conveniently plot beautiful graphs as easy as in other high-level programming languages.

The only external runtime dependencies is gnuplot executable and it need to be in your system path.

gnuplot-palettes color palettes are downloaded at shard installation and made available to your use via simply invoking the plot#palette and passing in any available palette enum Cryplot::Palette.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     cryplot:
       github: naqvis/cryplot
   

2. Run shards install

Example 1

require "cryplot"

# Create a vector with values from 0 to 5 divived into 100 uniform intervals
x = Cryplot.linspace(0.0, 5.0, 100)

# Create a plot object
Cryplot.plot {
  # set color palette
  palette(:set2)

  # Draw a sine graph putting x on the x-axis and sin(x) on the y-axis
  draw_curve(x, x.map { |v| Math.sin(v) }).label("sin(x)").line_width(4)

  # Draw a cosine graph putting x on the x-axis and cos(x) on the y-axis
  draw_curve(x, x.map { |v| Math.cos(v) }).label("cos(x)").line_width(4)

  # Show the plot in a pop-up window
  show

  # Save the plot a PDF file
  save("plot.pdf")
}

Running above sample code will produce and show you following plot:

Example 2 (Use custom gnuplot commands)

require "cryplot"

time = [0.0, 1.0, 2.1, 3.1, 4.2, 5.2, 6.2, 7.2, 8.2, 9.1, 10.0, 11.0, 12.0,
        12.9, 13.8, 14.9, 15.9, 17.0, 17.9, 18.9, 20.0, 21.0, 22.0, 23.0, 24.0, 25.0,
        26.0, 27.0, 28.0, 29.0, 30.0, 31.0, 32.0, 32.9, 33.8, 34.7, 35.7, 36.6, 37.7]

angle = [-14.7, 8.6, 28.8, 46.7, 47.4, 36.5, 37.0, 5.1, -11.2, -22.4, -35.5, -33.6, -21.1,
         -15.0, -1.6, 19.5, 27.5, 32.6, 27.5, 20.2, 13.8, -1.3, -24.5, -25.0, -25.0, -20.2,
         -9.9, 5.8, 14.7, 21.8, 29.8, 21.4, 24.6, 25.8, 0.6, -16.6, -24.0, -24.6, -19.8]

stdvar = [3.6, 3.6, 3.0, 3.4, 3.5, 3.4, 10.3, 3.4, 3.4, 3.5, 3.6, 3.9, 3.9,
          4.2, 2.7, 3.2, 2.8, 3.5, 2.7, 3.3, 3.4, 4.2, 6.7, 3.3, 3.1, 3.6,
          3.2, 3.2, 3.0, 3.5, 2.7, 4.1, 2.7, 12.0, 2.9, 3.2, 3.7, 3.8, 3.5]

Cryplot.plot {
  # Set the Title of the plort
  title("Cavendish Data").title_font_size(20).title_text_color("blue")

  # Set x-axix and y-axis labels
  xlabel("Time (s)")
  ylabel("Angle (mrad)")

  # Adjust the Legend position
  legend.at_top_right

  # Adjust grid , border, style, tics settings
  grid
    .show
    .back
    .line_width(1)
  border.none
  style_fill.border_show
  tics.hide
  border.left.right.top.bottom.back

  # Draw Error Bars
  draw_error_bars_y(time, angle, stdvar).line_width(2).line_color("purple").label_none

  # Draw raw-data line by using the same dataset
  draw("1:2", "lines").line_color("green").line_width(2).label("raw data")

  # custom gnuplot commands (these commands are passed as-is to gnuplot)
  gnuplot("theta(t) = theta0 + a * exp(-t / tau) * sin(2 * pi * t / T + phi)")
  gnuplot("fit theta(x) '#{data_filename}' using 1:2:3 via a, tau, phi, T, theta0")

  # draw best fit curve
  draw("theta(x)", "", "").label("best-fit curve").line_width(3).line_color("orange")

  # Set the size
  size(480, 380)

  # Show the plot in a pop-up window
  show

  # Save the plot in PNG file
  save("best-fit-curve.png")
}

Running above sample code will produce and show you following plot:

Refer to specs or examples folder for further samples.

Available Color Palettes

Do you want to change the colors?

All available color palettes and their names can be found here.

Development

To run all tests:

crystal spec

Contributing

1. Fork it (https://github.com/naqvis/cryplot/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Ali Naqvi - creator and maintainer