kiten

kiten

Simple and fast 2D graphics library for Go.

Examples

Create a new canvas

width := 1280
height := 720
canvas := kiten.NewCanvas(width, height, kiten.BlendAdd)

Create a new canvas from an RGBA image

(you can use this later to overlay or draw on images, for example)

canvas := kiten.CanvasFromImageRGBA(image, kiten.BlendAdd)

Real time example

Fill the whole canvas with a black color

If you're rendering multiple frames, remember to clear the canvas when drawing a new frame

canvas.Fill(color.RGBA{0, 0, 0, 255})

Draw a red line from 100,100 to 500,700

canvas.Line(100, 100, 500, 700, color.RGBA{255, 0, 0, 255})

Draw a blue circle at 150,150 with the radius of 70

canvas.Circle(150, 150, 70, color.RGBA{0, 0, 255, 255})

Draw a filled blue circle at 150,150 with the radius of 70

canvas.CircleFilled(150, 150, 70, color.RGBA{0, 0, 255, 255})

Draw a filled blue circle with a green outline at 150,150 with the radius of 70

canvas.CircleOutline(150, 150, 70, color.RGBA{0, 0, 255, 255}, color.RGBA{0, 255, 0, 255})

Set the pixel at 500,500 to white

This will do nothing if the coordinates are invalid

canvas.SetPixel(500, 500, color.RGBA{255, 255, 255, 255})

Get the pixel value at 170,300

This will return a transparent color if the coordinates are invalid

canvas.PixelAt(170, 300) // Returns color.RGBA

Draw a green rectangle from 100,100 to 200,200 (not filled)

canvas.Rect(100, 100, 200, 200, color.RGBA{0, 255, 0, 255})

Draw a green rectangle from 100,100 to 200,200 (filled)

canvas.RectFilled(100, 100, 200, 200, color.RGBA{0, 255, 0, 255})

Draw a canvas on top of another canvas at 450,300 and resize it to 100 by 150 pixels

canvas.PutCanvas(450, 300, 100, 150, canvas2)

Connect a path with white lines

import (
    "rand"
    "image"
)

// Generate a path
path := []image.Point{}
for i := 0; i < 100; i++ {
    path = append(path, image.Pt(i*30, canvas.Height/2-rand.Intn(100)))
}

// Draw it
canvas.DrawPath(path, color.RGBA{255, 255, 255, 255})

Draw text at 500,500

import "golang.org/x/image/font/inconsolata"
canvas.Text("Hello World!", 500, 500, inconsolata.Regular8x16, color.RGBA{255, 255, 255, 255})

Export canvas to PNG

import "os"
file, err := os.Create("output.png")
if err != nil {
    panic(err)
}
defer file.Close()

err := canvas.WritePNG(file)
if err != nil {
    panic(err)
}

Draw a white (not filled) triangle (500,500 -> 500,700 -> 600,700)

canvas.Triangle(500, 500, 500, 700, 600, 700, color.RGBA{255, 255, 255, 255})

Draw a white filled triangle (500,500 -> 500,700 -> 600,700)

canvas.TriangleFilled(500, 500, 500, 700, 600, 700, color.RGBA{255, 255, 255, 255})

Draw a white filled triangle with a red outline (500,500 -> 500,700 -> 600,700)

canvas.TriangleOutline(500, 500, 500, 700, 600, 700, color.RGBA{255, 255, 255, 255}, color.RGBA{255, 0, 0, 255})