Image scaling test

srgb/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"image"
+	"image/png"
+	"log"
+	"os"
+
+	"golang.org/x/image/draw"
+)
+
+func main() {
+	var err error
+
+	flag.Usage = func() {
+		fmt.Fprintf(os.Stderr, "Usage: %s input output\n", os.Args[0])
+	}
+	flag.Parse()
+	if flag.NArg() != 2 {
+		flag.Usage()
+		os.Exit(2)
+	}
+
+	// Read input file.
+	f, err := os.Open(os.Args[1])
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	src, _, err := image.Decode(f)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Scale down by a factor of 2.
+	sb := src.Bounds()
+	dst := image.NewRGBA(image.Rect(0, 0, sb.Dx()/2, sb.Dy()/2))
+	draw.BiLinear.Scale(dst, dst.Bounds(), src, sb, draw.Over, nil)
+
+	// Write output file.
+	if f, err = os.Create(os.Args[2]); err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+	if err := png.Encode(f, dst); err != nil {
+		log.Fatal(err)
+	}
+}