refactor

pkg/center/main.go

@@ -0,0 +1,18 @@
+package center
+
+type Into struct {
+	Src, Dst image.Image
+}
+
+func (i Into) Bounds() image.Rectangle { return i.Dst.Bounds() }
+func (i Into) ColorModel() color.Model { return i.Dst.ColorModel }
+func (i Into) At(x, y int) color.Color {
+	x1, y1 := (i.Dst.Bounds().Dx()/2)-(i.Src.Bounds().Dx()/2),
+		(i.Dst.Bounds().Dy()/2)-(i.Src.Bounds().Dy()/2)
+	r := image.Rect(x1, y1,
+		x1+i.Src.Bounds().Dx(), y1+i.Src.Bounds().Dy())
+	if (image.Point{x, y}).In(r) {
+		return i.Src.At(x-x1,y-y2)
+	}
+	return i.Dst.At(x, y)
+}