It is necessary to generate a QR code from the text. I'm using the ZXing.unity.dll library

using ZXing;
using ZXing.QrCode;

Generating QR code

private static Color32[] Encode(string textForEncoding, int width, int height) {
    var writer = new BarcodeWriter {
        Format = BarcodeFormat.QR_CODE,

        Options = new QrCodeEncodingOptions{
            Height = height,
            Width = width
        }
    };
return writer.Write(textForEncoding);
}
public Texture2D generateQR(string text) {
    var encoded = new Texture2D (256, 256);
    var color32 = Encode(text, encoded.width, encoded.height);
    encoded.SetPixels32(color32);
    encoded.Apply();
    return encoded;
}

Applying the generated QR to the RawImage filled in the field

public RawImage RI;
...
RI.texture = generateQR("https://test.link/123");

The output is a picture with large white edges.

QR code preview pic

• Q1 - How to remove white edges;
• Q2 - How to make a transparent background;
• Q3 - How to change black color to any other

CodePudding user response：

Q3: Sample for changing foreground and background color:

private static Color32[] Encode(string textForEncoding, int width, int height)
{
    var writer = new BarcodeWriter
    {
        Format = BarcodeFormat.QR_CODE,

        Options = new QrCodeEncodingOptions
        {
            Height = height,
            Width = width
        },
        Renderer = new Color32Renderer
        {
            Background = new Color32(255, 0, 0, 0),
            Foreground = new Color32(0, 255, 0, 0)
        }
    };
    return writer.Write(textForEncoding);
}

Q2: I' not absolutely sure, but the following sample should create a transparent background:

private static Color32[] Encode(string textForEncoding, int width, int height)
{
    var writer = new BarcodeWriter
    {
        Format = BarcodeFormat.QR_CODE,

        Options = new QrCodeEncodingOptions
        {
            Height = height,
            Width = width
        },
        Renderer = new Color32Renderer
        {
            Background = new Color32(0, 0, 0, 255)
        }
    };
    return writer.Write(textForEncoding);
}

Q1: create the image as small as possible without a border and resize it manually

private static Color32[] Encode(string textForEncoding, int width, int height)
{
    var writer = new BarcodeWriter
    {
        Format = BarcodeFormat.QR_CODE,

        Options = new QrCodeEncodingOptions
        {
            Height = width,
            Width = height,
            Margin = 0
        }
    };
    return writer.Write(textForEncoding);
}
public Texture2D generateQR(string text)
{
    // create the image as small as possible without a white border by setting width an height to 1
    var color32 = Encode(text, 1, 1);
    var widthAndHeight = color32.Length / 2;
    var encoded = new Texture2D(widthAndHeight, widthAndHeight);
    encoded.SetPixels32(color32);
    encoded.Apply();
    //
    // Attention: insert code for resizing to the desired size here
    // I didn't try it myself. Not sure if it works.
    //
    encoded.Resize(256, 256);
    return encoded;
}