plt

README

Data Plotter in Go

I am designing a data plotter with only Go dependencies to learn and study about Go. The current state of this package in not ready for usage. You may use it at your own discretion.

Testing the code

To test the code, run: go run example/png/main.go

or build: go build example/png/main.go

This will generate an out.png file. Then, the default image viewer will open out.png.

Usage

Import this package as:

import "github.com/cgxeiji/plt"

Extra features under:

import "github.com/cgxeiji/plt/canvas"

Basic Bar Chart

// Load some values
x := []string{"Jan", "Feb", "Mar", "Apr", "May", "Jun"}
y := []float64{1, 1, 2, 4, 1, 10}

// Create default Bar Chart and return plot (draw.Image)
plot, err := plt.Bar(x, y)
if err != nil {
	log.Panic(err)
}

// Export with your favourite encoder
png.Encode(w, plot)

Multiple Charts

// Load some values
x := []string{"Jan", "Feb", "Mar", "Apr", "May", "Jun"}
y := []float64{1, 1, 2, 4, 1, 10}

// Create a Figure struct to start plotting
fig, err := plt.Figure(1080, 1920)
if err != nil {
	log.Panic(err)
}

// Create a 3x1 plot
axes, err := fig.SubAxes(3, 1)
if err != nil {
	log.Panic(err)
}

// Access top most plot and make a Bar Chart
axes[0].BarPlot(x, y)

// Load some more values
sx := []float64{0.0, 1.1, 2.0, 3.0, 3.5, 4.3, 5.0}
sy := []float64{1.6, 2.2, 3.4, 0.2, 0.0, 0.2, 0.5}

// Access middle plot and make a Bar Chart with no labels
axes[1].BarPlot(nil, sy)

// Access bottom plot and make a Scatter Chart
axes[2].ScatterPlot(sx, sy)

// Render Figure into plot (draw.Image)
plot := plt.Render(fig)

// Export with your favourite encoder
png.Encode(w, plot)

Example Chart

Documentation

Overview

Package plt provides functions to plot data as draw.Image struct.

Index

• func Bar(X []string, Y []float64) (draw.Image, error)
• func Figure(w, h int) (*canvas.Figure, error)
• func Render(f *canvas.Figure) draw.Image

Functions

func Bar

func Bar(X []string, Y []float64) (draw.Image, error)

Bar creates a draw.Image struct given X and Y slices of []string and []float64 respectively. X and Y must have the same length.

func Figure

func Figure(w, h int) (*canvas.Figure, error)

Figure returns a *canvas.Figure struct with a size of w and h in pixels (int).

func Render

func Render(f *canvas.Figure) draw.Image

Render draws a Figure with all its children into a draw.Image interface.