C# 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. C#

bool success = false;

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

Chilkat.Formats fmt = new Chilkat.Formats();
Chilkat.JsonObject jsonOut = new Chilkat.JsonObject();

//  Dark blue modules on a pale yellow background.
Chilkat.JsonObject json = new Chilkat.JsonObject();
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) {
    Debug.WriteLine(fmt.LastErrorText);
    return;
}

Debug.WriteLine("colored: " + jsonOut.StringOf("outputs[0].path") + ", " + Convert.ToString(jsonOut.IntOf("outputs[0].byteCount")) + " bytes");

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

//  

//  The same modules on a fully transparent background.
Chilkat.JsonObject json2 = new Chilkat.JsonObject();
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) {
    Debug.WriteLine(fmt.LastErrorText);
    return;
}

Debug.WriteLine("transparent: " + jsonOut.StringOf("outputs[0].path") + ", " + Convert.ToString(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