// Encode encodes a string using the given version, level, and mask.
func Encode(w http.ResponseWriter, req *http.Request) {
val := func(s string) int {
v, _ := strconv.Atoi(req.FormValue(s))
return v
}
l := coding.Level(val("l"))
v := coding.Version(val("v"))
enc := coding.String(req.FormValue("t"))
m := coding.Mask(val("m"))
p, err := coding.NewPlan(v, l, m)
if err != nil {
panic(err)
}
cc, err := p.Encode(enc)
if err != nil {
panic(err)
}
c := &qr.Code{Bitmap: cc.Bitmap, Size: cc.Size, Stride: cc.Stride, Scale: 8}
w.Header().Set("Content-Type", "image/png")
w.Header().Set("Cache-Control", "public, max-age=3600")
w.Write(c.PNG())
}
func makeMask(req *http.Request, font string, pt int, vers, mask, scale int) image.Image {
p, err := coding.NewPlan(coding.Version(vers), coding.L, coding.Mask(mask))
if err != nil {
panic(err)
}
m := makeImage(req, maskName[mask], font, pt, len(p.Pixel), 0, scale, func(x, y int) uint32 {
pix := p.Pixel[y][x]
switch pix.Role() {
case coding.Data, coding.Check:
if pix&coding.Invert != 0 {
return 0x000000ff
}
}
return 0xffffffff
})
return m
}
// Encode returns an encoding of text at the given error correction level.
func Encode(text string, level Level) (*Code, error) {
// Pick data encoding, smallest first.
// We could split the string and use different encodings
// but that seems like overkill for now.
var enc coding.Encoding
switch {
case coding.Num(text).Check() == nil:
enc = coding.Num(text)
case coding.Alpha(text).Check() == nil:
enc = coding.Alpha(text)
default:
enc = coding.String(text)
}
// Pick size.
l := coding.Level(level)
var v coding.Version
for v = coding.MinVersion; ; v++ {
if v > coding.MaxVersion {
return nil, errors.New("text too long to encode as QR")
}
if enc.Bits(v) <= v.DataBytes(l)*8 {
break
}
}
// Build and execute plan.
p, err := coding.NewPlan(v, l, 0)
if err != nil {
return nil, err
}
cc, err := p.Encode(enc)
if err != nil {
return nil, err
}
// TODO: Pick appropriate mask.
return &Code{cc.Bitmap, cc.Size, cc.Stride, 8}, nil
}
func makeFrame(req *http.Request, font string, pt, vers, l, scale, dots int) image.Image {
lev := coding.Level(l)
p, err := coding.NewPlan(coding.Version(vers), lev, 0)
if err != nil {
panic(err)
}
nd := p.DataBytes / p.Blocks
nc := p.CheckBytes / p.Blocks
extra := p.DataBytes - nd*p.Blocks
cap := fmt.Sprintf("QR v%d, %s", vers, lev)
if dots > 0 {
cap = fmt.Sprintf("QR v%d order, from bottom right", vers)
}
m := makeImage(req, cap, font, pt, len(p.Pixel), 0, scale, func(x, y int) uint32 {
pix := p.Pixel[y][x]
switch pix.Role() {
case coding.Data:
if dots > 0 {
return 0xffffffff
}
off := int(pix.Offset() / 8)
nd := nd
var i int
for i = 0; i < p.Blocks; i++ {
if i == extra {
nd++
}
if off < nd {
break
}
off -= nd
}
return blockColors[i%len(blockColors)]
case coding.Check:
if dots > 0 {
return 0xffffffff
}
i := (int(pix.Offset()/8) - p.DataBytes) / nc
return dark(blockColors[i%len(blockColors)])
}
if pix&coding.Black != 0 {
return 0x000000ff
}
return 0xffffffff
})
if dots > 0 {
b := m.Bounds()
for y := 0; y <= len(p.Pixel); y++ {
for x := 0; x < b.Dx(); x++ {
m.SetRGBA(x, y*scale-(y/len(p.Pixel)), color.RGBA{127, 127, 127, 255})
}
}
for x := 0; x <= len(p.Pixel); x++ {
for y := 0; y < b.Dx(); y++ {
m.SetRGBA(x*scale-(x/len(p.Pixel)), y, color.RGBA{127, 127, 127, 255})
}
}
order := make([]image.Point, (p.DataBytes+p.CheckBytes)*8+1)
for y, row := range p.Pixel {
for x, pix := range row {
if r := pix.Role(); r != coding.Data && r != coding.Check {
continue
}
// draw.Draw(m, m.Bounds().Add(image.Pt(x*scale, y*scale)), dot, image.ZP, draw.Over)
order[pix.Offset()] = image.Point{x*scale + scale/2, y*scale + scale/2}
}
}
for mode := 0; mode < 2; mode++ {
for i, p := range order {
q := order[i+1]
if q.X == 0 {
break
}
line(m, p, q, mode)
}
}
}
return m
}