mirror of https://github.com/h44z/wg-portal.git
89 lines
2.0 KiB
Go
89 lines
2.0 KiB
Go
package configfile
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// waiting for https://github.com/yeqown/go-qrcode/pull/85 to get merged
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// meanwhile we use our own writer implementation
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import (
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"image"
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"image/color"
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"image/png"
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"io"
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"github.com/yeqown/go-qrcode/v2"
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)
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type Option struct {
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Padding int
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BlockSize int
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}
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// compressedWriter implements issue#69, generating compressed images
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// in some special situations, such as, network transferring.
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// https://github.com/yeqown/go-qrcode/issues/69
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type compressedWriter struct {
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fd io.WriteCloser
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option *Option
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}
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var (
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backgroundColor = color.Gray{Y: 0xff}
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foregroundColor = color.Gray{Y: 0x00}
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)
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func NewCompressedWriter(writer io.WriteCloser, opt *Option) qrcode.Writer {
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return compressedWriter{fd: writer, option: opt}
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}
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func (w compressedWriter) Write(mat qrcode.Matrix) error {
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padding := w.option.Padding
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blockWidth := w.option.BlockSize
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width := mat.Width()*blockWidth + 2*padding
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height := width
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img := image.NewPaletted(
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image.Rect(0, 0, width, height),
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color.Palette([]color.Color{backgroundColor, foregroundColor}),
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)
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bgColor := uint8(img.Palette.Index(backgroundColor))
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fgColor := uint8(img.Palette.Index(foregroundColor))
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rectangle := func(x1, y1 int, x2, y2 int, img *image.Paletted, color uint8) {
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for x := x1; x < x2; x++ {
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for y := y1; y < y2; y++ {
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pos := img.PixOffset(x, y)
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img.Pix[pos] = color
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}
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}
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}
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// background
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rectangle(0, 0, width, height, img, bgColor)
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mat.Iterate(qrcode.IterDirection_COLUMN, func(x int, y int, v qrcode.QRValue) {
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sx := x*blockWidth + padding
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sy := y*blockWidth + padding
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es := (x+1)*blockWidth + padding
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ey := (y+1)*blockWidth + padding
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if v.IsSet() {
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rectangle(sx, sy, es, ey, img, fgColor)
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}
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//switch v.IsSet() {
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//case false:
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// gray = backgroundColor
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//default:
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// gray = foregroundColor
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//}
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})
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encoder := png.Encoder{CompressionLevel: png.BestCompression}
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return encoder.Encode(w.fd, img)
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}
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func (w compressedWriter) Close() error {
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return w.fd.Close()
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}
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