package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"log"

	"github.com/chai2010/webp"
)

func main() {
	var buf bytes.Buffer
	var width, height int
	var data []byte
	var err error

	// Load file data
	if data, err = ioutil.ReadFile("./testdata/1_webp_ll.webp"); err != nil {
		log.Println(err)
	}

	// GetInfo
	if width, height, _, err = webp.GetInfo(data); err != nil {
		log.Println(err)
	}
	fmt.Printf("width = %d, height = %d\n", width, height)

	// GetMetadata
	if metadata, err := webp.GetMetadata(data, "ICCP"); err != nil {
		fmt.Printf("Metadata: err = %v\n", err)
	} else {
		fmt.Printf("Metadata: %s\n", string(metadata))
	}

	// Decode webp
	m, err := webp.Decode(bytes.NewReader(data))
	if err != nil {
		log.Println(err)
	}

	// Encode lossless webp
	if err = webp.Encode(&buf, m, &webp.Options{Lossless: true}); err != nil {
		log.Println(err)
	}
	if err = ioutil.WriteFile("output.webp", buf.Bytes(), 0666); err != nil {
		log.Println(err)
	}
}

m, err := webp.DecodeRGB(data)
if err != nil {
	log.Fatal(err)
}

data, err := webp.EncodeRGB(m)
if err != nil {
	log.Fatal(err)
}

m, _ := webp.DecodeRGB(data)
rgb := m.(webp.Image)
b := rgb.Bounds()

for y := b.Min.Y; y < b.Max.Y; y++ {
	off := (y-b.Min.Y)*rgb.Stride()
	pix := rgb.Pix()[off:][:rgb.Stride()]
	for i := 0; i < len(pix); i += 3 {
		R := pix[i+0]
		G := pix[i+1]
		B := pix[i+2]
		...
	}
}