Go Requires Chilkat v11.7.0+

QR Code Colors and Transparent Background

See more QR Code Examples

Demonstrates colored QR codes. render.foreground is the color of the dark modules and render.background the color behind them, each as #RRGGBB. Either can instead be an object with a color and an opacity from 0 to 1, and a background opacity of 0 gives a PNG with a transparent background to place over a page or a design. Readers need contrast: keep the modules clearly darker than whatever ends up behind them. Go

    success := false

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    fmt := chilkat.NewFormats()
    jsonOut := chilkat.NewJsonObject()

    //  Dark blue modules on a pale yellow background.
    json := chilkat.NewJsonObject()
    json.UpdateString("payload.text","https://www.chilkatsoft.com/")
    json.UpdateInt("render.moduleSize",6)
    json.UpdateString("render.foreground","#1B3A6B")
    json.UpdateString("render.background","#FFF8DC")
    json.UpdateString("output.path","qa_output/qr_blue.png")
    json.UpdateBool("output.overwrite",true)
    json.UpdateString("output.return","none")
    success = fmt.QrCode("generate",json,jsonOut)
    if success == false {
        fmt.Println(fmt.LastErrorText())
        fmt.DisposeFormats()
        jsonOut.DisposeJsonObject()
        json.DisposeJsonObject()
        return
    }

    fmt.Println("colored: ", *jsonOut.StringOf("outputs[0].path"), ", ", jsonOut.IntOf("outputs[0].byteCount"), " bytes")

    //  The image written to qa_output/qr_blue.png:

    //  

    //  The same modules on a fully transparent background.
    json2 := chilkat.NewJsonObject()
    json2.UpdateString("payload.text","https://www.chilkatsoft.com/")
    json2.UpdateInt("render.moduleSize",6)
    json2.UpdateString("render.foreground","#1B3A6B")
    json2.UpdateString("render.background.color","#FFFFFF")
    json2.UpdateNumber("render.background.opacity","0")
    json2.UpdateString("output.path","qa_output/qr_transparent.png")
    json2.UpdateBool("output.overwrite",true)
    json2.UpdateString("output.return","none")
    success = fmt.QrCode("generate",json2,jsonOut)
    if success == false {
        fmt.Println(fmt.LastErrorText())
        fmt.DisposeFormats()
        jsonOut.DisposeJsonObject()
        json.DisposeJsonObject()
        json2.DisposeJsonObject()
        return
    }

    fmt.Println("transparent: ", *jsonOut.StringOf("outputs[0].path"), ", ", jsonOut.IntOf("outputs[0].byteCount"), " bytes")

    //  qa_output/qr_transparent.png, placed here over a checkerboard and over a colored page
    //  to show that whatever is behind the image shows through:

    //  

    //  Sample output:

    //  colored: qa_output/qr_blue.png, 1345 bytes
    //  transparent: qa_output/qr_transparent.png, 1377 bytes

    fmt.DisposeFormats()
    jsonOut.DisposeJsonObject()
    json.DisposeJsonObject()
    json2.DisposeJsonObject()