Go Graphics

gg is a library for rendering 2D graphics in pure Go.

Installation

go get github.com/fogleman/gg

Hello, Circle!

Look how easy!

package main

import "github.com/fogleman/gg"

func main() {
    dc := gg.NewContext(1000, 1000)
    dc.DrawCircle(500, 500, 400)
    dc.SetRGB(0, 0, 0)
    dc.SetLineWidth(10)
    dc.Stroke()
    dc.SavePNG("out.png")
}

Drawing Functions

Ever used a graphics library that didn't have functions for drawing rectangles or circles? What a pain!

DrawLine(x1, y1, x2, y2 float64)
DrawRectangle(x, y, w, h float64)
DrawCircle(x, y, r float64)
DrawArc(x, y, r, angle1, angle2 float64)
DrawEllipse(x, y, rx, ry float64)
DrawEllipticalArc(x, y, rx, ry, angle1, angle2 float64)
DrawImage(im image.Image, x, y int)
DrawString(x, y float64, s string)

MoveTo(x, y float64)
LineTo(x, y float64)
QuadraticTo(x1, y1, x2, y2 float64)
ClosePath()
ClearPath()

Clear()
Stroke()
Fill()
StrokePreserve()
FillPreserve()

Color Functions

Colors can be set in several different ways for your convenience.

SetRGB(r, g, b float64)
SetRGBA(r, g, b, a float64)
SetRGB255(r, g, b int)
SetRGBA255(r, g, b, a int)
SetColor(c color.Color)
SetHexColor(x string)

Transformation Functions

All the usual matrix transformations are available too.

Identity()
Translate(x, y float64)
Scale(x, y float64)
Rotate(angle float64)
RotateAbout(angle, x, y float64)
Shear(x, y float64)
TransformPoint(x, y float64) (tx, ty float64)
Push()
Pop()

What's Missing?

If you need any of the features below, I recommend using cairo instead.

• Clipping Regions
• Gradients / Patterns
• Cubic Beziers
• Dashed Lines