gopaper/image.go

package main

import (
	"image"
	"log"
	"os"

	"github.com/disintegration/gift"

	_ "image/jpeg"
	"image/png"
)

type ImageFilters struct {
	Colorize [3]float32
	Contrast int
	Gamma    float64
}

func loadImage(filename string) image.Image {
	f, err := os.Open(filename)
	log.Println("filename: ", filename)
	if err != nil {
		log.Fatalf("os.Open failed: %v", err)
	}
	defer f.Close()
	img, _, err := image.Decode(f)
	if err != nil {
		log.Fatalf("image.Decode failed: %v", err)
	}
	return img
}

func saveImage(filename string, img image.Image) {
	log.Println("new filename: ", filename)
	f, err := os.Create(filename)
	if err != nil {
		log.Fatalf("os.Create failed: %v", err)
	}
	defer f.Close()
	err = png.Encode(f, img)
	if err != nil {
		log.Fatalf("png.Encode failed: %v", err)
	}
}

func processImage(img image.Image, config Config) image.Image {

	cArgs := config.Colorize
	g := gift.New(
		gift.Colorize(cArgs[0], cArgs[1], cArgs[2]),
		gift.Contrast(float32(config.Contrast)),
		gift.Gamma(float32(config.Gamma)),
	)

	dst := image.NewRGBA(g.Bounds(img.Bounds()))
	g.Draw(dst, img)

	return dst
}