80 lines
2.4 KiB
Go
80 lines
2.4 KiB
Go
package mujica
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import (
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"cmp"
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"log/slog"
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"math"
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"github.com/egoist/mygo/ui"
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"mujicaui/theme"
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)
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// QRCodeOptions configure a QRCode.
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type QRCodeOptions struct {
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Level QRLevel
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// Size is the side in DIPs with the quiet zone; zero is 160.
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Size float32
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// Label names the code for assistive technology; empty uses "QR code".
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Label string
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}
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// qrCodeCache keeps the last encoding so it runs only when the text or level changes.
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type qrCodeCache struct {
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text string
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level QRLevel
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m QRMatrix
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err error
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done bool
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}
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// QRCode draws text as a QR code, encoded offline; too long a text shows an error.
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func QRCode(c *ui.Context, text string, opts QRCodeOptions) *ui.Element {
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_ = opts.Level.String()
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if !(opts.Size >= 0) || math.IsInf(float64(opts.Size), 1) {
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panic("mujica: QRCode Size must be finite and >= 0")
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}
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size := opts.Size
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if size == 0 {
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size = 160
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}
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k := Tokens(c)
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e := ui.Box(c).Size(size, size).Shrink(0).Role(ui.RoleImage).Label(cmp.Or(opts.Label, msg(c, "qr_code.label")))
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cache := ui.Local(e, "qr_code", func() qrCodeCache { return qrCodeCache{} })
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if !cache.done || cache.text != text || cache.level != opts.Level {
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m, err := EncodeQR([]byte(text), opts.Level)
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*cache = qrCodeCache{text: text, level: opts.Level, m: m, err: err, done: true}
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slog.Debug("mujica: qr_code encoded", "version", m.Version, "level", opts.Level, "err", err)
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}
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if cache.err != nil {
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e.Center().Padding(Density(c).Unit()*2).Background(k.Surface).Border(theme.BorderWidth, k.Danger).Radius(theme.CardRadius).
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Description(cache.err.Error())
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e.Children(func() {
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ui.Text(c, msg(c, "qr_code.too_long")).TextColor(k.Danger).FontSize(FontSize(c, theme.CaptionSize)).TextAlign(ui.Center)
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})
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return e
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}
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m := cache.m
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// Scanners need dark modules on a light field, in either theme.
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light, dark := theme.Light().Surface, theme.Light().Text
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e.Draw(func(p *ui.Painter, r ui.Rect) {
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n := m.Size() + 8
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s := p.Scale()
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mod := float32(math.Floor(float64(r.W*s)/float64(n))) / s
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if mod <= 0 {
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return
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}
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ox := float32(math.Round(float64((r.X+(r.W-mod*float32(n))/2)*s))) / s
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oy := float32(math.Round(float64((r.Y+(r.H-mod*float32(n))/2)*s))) / s
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p.Fill(r, light, theme.ControlRadius)
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for y, row := range m.Modules {
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for x, on := range row {
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if on {
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p.Fill(ui.Rect{X: ox + float32(x+4)*mod, Y: oy + float32(y+4)*mod, W: mod, H: mod}, dark, 0)
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}
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}
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}
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})
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return e
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}
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