gogal

Pure Go SVG chart library with CSS-only interactivity and HTMX integration.

Go Version License: MIT

Overview

gogal generates pure SVG charts server-side with zero JavaScript. Interactivity is provided through CSS (hover tooltips, transitions) and HTMX (legend toggling, axis switching, live updates).

Designed for use with lofigui and server-rendered web applications.

Key Features

  • Pure Go: Zero dependencies, no cgo, gokrazy compatible
  • Pure SVG: Server-side rendered, clean markup, responsive viewBox
  • CSS interactivity: Hover tooltips, transitions, animations — no JavaScript
  • HTMX integration: Legend toggling, axis switching, zoom controls, SSE live updates
  • Dual axis modes: Time-proportional and event-proportional X axes
  • Four variants: Sparkline, Static, Interactive, Live
  • Accessible: ARIA labels, <title>, <desc> by default
  • Testable: Layout computation separated from SVG rendering

Quick Start

package main

import (
    "os"
    "codeberg.org/hum3/gogal"
)

func main() {
    chart := gogal.NewLineChart(
        gogal.WithTitle("Temperature"),
        gogal.WithSize(800, 400),
    )
    chart.Add("Sensor A", []gogal.DataPoint{
        {X: 0, Y: 20.1},
        {X: 1, Y: 21.3},
        {X: 2, Y: 19.8},
        {X: 3, Y: 22.5},
    })
    chart.Render(os.Stdout)
}

Chart Types

Type Sparkline Static Interactive Live
Line Yes Yes Yes Yes
Bar Yes Yes Yes Yes
Scatter Yes Yes Yes Yes

Examples

See the examples/ directory for progressively complex demos.
Source (Codeberg) https://codeberg.org/hum3/gogal
Mirror (GitHub) https://github.com/drummonds/gogal