// make-tile creates a tileable image from an input image.
// ( +clone -flop ) +append ( +clone -flip ) -append -resize 50%
func make_tile(mw *imagick.MagickWand, outfile string) {
mwc := mw.Clone()
mwc.FlopImage()
mw.AddImage(mwc)
mwc.Destroy()
mwc = mw.AppendImages(false)
mwf := mwc.Clone()
mwf.FlipImage()
mwc.AddImage(mwf)
mwf.Destroy()
mwf = mwc.AppendImages(true)
w := mwf.GetImageWidth()
h := mwf.GetImageHeight()
// 1 = Don't blur or sharpen image
mwf.ResizeImage(w/2, h/2, imagick.FILTER_LANCZOS, 1)
mwf.WriteImage(outfile)
mwf.Destroy()
mwc.Destroy()
}