just to save

merge.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"image"
+	_ "image/png"
+	_ "image/jpeg"
+	"image/color"
+	"image/png"
+	"os"
+)
+
+type Merge struct {
+	first, second image.Image
+}
+
+func (m Merge) ColorModel() color.Model { return m.first.ColorModel() }
+func (m Merge) Bounds() image.Rectangle { return m.first.Bounds() }
+
+func (m Merge) At(x, y int) color.Color {
+	if (x%2 != 0) && (y%2 != 0) {
+		return m.second.At(x, y)
+	}
+	return m.first.At(x, y)
+}
+
+func main() {
+	f1, err := os.Open(os.Args[1])
+	if err != nil {
+		panic(err)
+	}
+	f2, err := os.Open(os.Args[2])
+	if err != nil {
+		panic(err)
+	}
+	img1, _, err := image.Decode(f1)
+	if err != nil {
+		panic(err)
+	}
+	img2, _, err := image.Decode(f2)
+	if err != nil {
+		panic(err)
+	}
+	png.Encode(os.Stdout, Merge{img1, img2})
+}