assets-for-lmika.org/cmd/fetch-header-image/main.go

package main

import (
	"bytes"
	"flag"
	"io"
	"log"
	"net/http"
	"os"
	"path/filepath"

	"github.com/disintegration/imaging"
)

func main() {
	targetFile := flag.String("o", "out.jpg", "target file")
	flag.Parse()

	var bfr bytes.Buffer

	if err := fetchHeaderImage(&bfr, "https://lmika.org/uploads/2025/pxl-20251120-083552448.jpg"); err != nil {
		log.Fatal(err)
	}

	img, err := imaging.Decode(&bfr, imaging.AutoOrientation(true))
	if err != nil {
		log.Fatal(err)
	}

	rImg := imaging.Resize(img, 1280, 0, imaging.Lanczos)

	if err := os.MkdirAll(filepath.Dir(*targetFile), 0755); err != nil {
		log.Fatal(err)
	}

	if err := imaging.Save(rImg, *targetFile, imaging.JPEGQuality(70)); err != nil {
		log.Fatal(err)
	}
}

func fetchHeaderImage(w io.Writer, url string) error {
	r, err := http.Get(url)
	if err != nil {
		return err
	}
	defer r.Body.Close()

	_, err = io.Copy(w, r.Body)
	return err
}