bars

A Go library to generate simple character based graphs inspired by Spark.

Use

The MakeBar function is the foundation of the package and is the function that generates the graph. MakeBar will take two arguments. The first one is the set of values to generate the graph from. The second argument must be an instance of the BarSet struct. Each BarSet instance holds the runes that will be used to render the graph.

type BarSet struct {
    // Near zero values
    Zero rune
    // Values from 1/16 to 3/16
    Eighth rune
    // Values from 3/16 to 5/16
    Quarter rune
    // Values from 5/16 to 7/16
    ThreeEighths rune
    // Values from 7/16 to 9/16
    Half rune
    // Values from 9/16 to 11/16
    FiveEighths rune
    // Values from 11/16 to 13/16
    ThreeQuarters rune
    // Values from 13/16 to 15/16
    SevenEighths rune
    // Values near One
    One rune
}

Two instances of BarSet are provided. NiceBarSet will display the graph with ▁▂▃▄▅▆▇█, while BraileBarSet will display the graph with ⣀⣤⣶⣿.

You can, of course, create your own graphs with other characters by creating a new instance of BarSet with the characters you desire.

Example

Here is a very simple example of how to use the library. It creates a program very similar to Spark.

package main

import (
    "fmt"
    "github.com/maurodec/bars"
    "os"
    "strconv"
)

func main() {
    args := os.Args[1:]

    numbers := make([]float64, len(args))
    for i := 0; i < len(numbers); i++ {
        if n, err := strconv.ParseFloat(args[i], 64); err == nil {
            numbers[i] = n
        } else {
            fmt.Printf("Invalid argument: %s\n", args[i])
            os.Exit(1)
        }
    }

    lines := bars.MakeBar(numbers, bars.NiceBarSet)
    fmt.Println(string(lines))
}

Run it:

go run fauxspark.go 3 2 2 1 4 8 3 3 9 4 4 7 6 2

> "▂▁▁ ▃▇▂▂█▃▃▆▅▁"

NOTE: Your browser may display some of the characters in a slightly different manner than you browser.