defmodule Contex do
  @moduledoc """
  Contex is a pure Elixir server-side data-plotting / charting system that generates SVG output.

  Contex is designed to be simple to use and extensible, relying on common core components, such
  as `Contex.Axis` and `Contex.Scale`, to create new plot types.

  The typical usage pattern is to wrap your data in a `Contex.Dataset`, pass that into a
  specific chart type (e.g. `Contex.BarChart`) to build the `Contex.PlotContent`, and then
  to lay that out using `Contex.Plot`, finally calling `Contex.Plot.to_svg(plot)` to create
  the SVG output.

  A minimal example might look like:
  ```
    data = [["Apples", 10], ["Bananas", 12], ["Pears", 2]]
    dataset = Contex.Dataset.new(data)
    plot_content = Contex.BarChart.new(dataset)
    plot = Contex.Plot.new(600, 400, plot_content)
    output = Contex.Plot.to_svg(plot)
  ```

  ## CSS Styling
  Various CSS classes are used to style the output. Sample CSS is shown below
  ```css
  /* Styling for tick line */
  .exc-tick {
    stroke: grey;
  }

  /* Styling for tick text */
  .exc-tick text {
    fill: grey;
    stroke: none;
  }

  /* Styling for axis line */
  .exc-domain {
    stroke:  rgb(207, 207, 207);
  }

  /* Styling for grid line */
  .exc-grid {
    stroke: lightgrey;
  }

  /* Styling for outline of colours in legend */
  .exc-legend {
    stroke: black;
  }

  /* Styling for text of colours in legend */
  .exc-legend text {
    fill: grey;
    font-size: 0.8rem;
    stroke: none;
  }

  /* Styling for title & subtitle of any plot */
  .exc-title {
    fill: darkslategray;
    font-size: 2.3rem;
    stroke: none;
  }
  .exc-subtitle {
    fill: darkgrey;
    font-size: 1.0rem;
    stroke: none;
  }

  /* Styling for label printed inside a bar on a barchart */
  .exc-barlabel-in {
    fill: white;
    font-size: 0.7rem;
  }

  /* Styling for label printed outside of a bar (e.g. if bar is too small) */
  .exc-barlabel-out {
    fill: grey;
    font-size: 0.7rem;
  }
  ```

  """
end