// getStreams opens ands returns the input and output streams.
func getImages(input string) (draw.Image, draw.Image) {
var fd io.ReadCloser
var err error
if len(input) == 0 {
fd = os.Stdin
} else {
fd, err = os.Open(input)
defer fd.Close()
}
if err != nil {
fmt.Fprintf(os.Stderr, "Open input file: %v\n", err)
os.Exit(1)
}
img, _, err := lib.Decode(fd)
if err != nil {
fmt.Fprintf(os.Stderr, "Decode image: %v\n", err)
os.Exit(1)
}
dimg, ok := img.(draw.Image)
if !ok {
fmt.Fprintf(os.Stderr, "Decode image: %T is not draw.Image; missing Set method.\n", img)
os.Exit(1)
}
return dimg, image.NewRGBA(img.Bounds())
}
// load loads the given image.
func load(input string) image.Image {
var fd io.ReadCloser
var err error
if len(input) == 0 {
fd = os.Stdin
} else {
fd, err = os.Open(input)
defer fd.Close()
}
if err != nil {
fmt.Fprintf(os.Stderr, "Open input file: %v\n", err)
os.Exit(1)
}
img, _, err := lib.Decode(fd)
if err != nil {
fmt.Fprintf(os.Stderr, "Decode image: %v\n", err)
os.Exit(1)
}
return img
}