Beispiel #1
0
func loadSize(ctxt *fs.Context, name string, max int) *image.RGBA {
	data, _, err := ctxt.Read("qr/upload/" + name + ".png")
	if err != nil {
		panic(err)
	}
	i, _, err := image.Decode(bytes.NewBuffer(data))
	if err != nil {
		panic(err)
	}
	b := i.Bounds()
	dx, dy := max, max
	if b.Dx() > b.Dy() {
		dy = b.Dy() * dx / b.Dx()
	} else {
		dx = b.Dx() * dy / b.Dy()
	}
	var irgba *image.RGBA
	switch i := i.(type) {
	case *image.RGBA:
		irgba = resize.ResizeRGBA(i, i.Bounds(), dx, dy)
	case *image.NRGBA:
		irgba = resize.ResizeNRGBA(i, i.Bounds(), dx, dy)
	}
	return irgba
}
Beispiel #2
0
func upload(w http.ResponseWriter, req *http.Request, link string) {
	// Upload of a new image.
	// Copied from Moustachio demo.
	f, _, err := req.FormFile("image")
	if err != nil {
		fmt.Fprintf(w, "You need to select an image to upload.\n")
		return
	}
	defer f.Close()

	i, _, err := image.Decode(f)
	if err != nil {
		panic(err)
	}

	// Convert image to 128x128 gray+alpha.
	b := i.Bounds()
	const max = 128
	// If it's gigantic, it's more efficient to downsample first
	// and then resize; resizing will smooth out the roughness.
	var i1 *image.RGBA
	if b.Dx() > 4*max || b.Dy() > 4*max {
		w, h := 2*max, 2*max
		if b.Dx() > b.Dy() {
			h = b.Dy() * h / b.Dx()
		} else {
			w = b.Dx() * w / b.Dy()
		}
		i1 = resize.Resample(i, b, w, h)
	} else {
		// "Resample" to same size, just to convert to RGBA.
		i1 = resize.Resample(i, b, b.Dx(), b.Dy())
	}
	b = i1.Bounds()

	// Encode to PNG.
	dx, dy := 128, 128
	if b.Dx() > b.Dy() {
		dy = b.Dy() * dx / b.Dx()
	} else {
		dx = b.Dx() * dy / b.Dy()
	}
	i128 := resize.ResizeRGBA(i1, i1.Bounds(), dx, dy)

	var buf bytes.Buffer
	if err := png.Encode(&buf, i128); err != nil {
		panic(err)
	}

	h := md5.New()
	h.Write(buf.Bytes())
	tag := fmt.Sprintf("%x", h.Sum(nil))[:32]

	ctxt := fs.NewContext(req)
	if err := ctxt.Write("qr/upload/"+tag+".png", buf.Bytes()); err != nil {
		panic(err)
	}

	// Redirect with new image tag.
	// Redirect to draw with new image tag.
	http.Redirect(w, req, req.URL.Path+"?"+url.Values{"i": {tag}, "url": {link}}.Encode(), 302)
}