Java 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. Java

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

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

    CkFormats fmt = new CkFormats();
    CkJsonObject jsonOut = new CkJsonObject();

    //  Dark blue modules on a pale yellow background.
    CkJsonObject json = new CkJsonObject();
    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) {
        System.out.println(fmt.lastErrorText());
        return;
        }

    System.out.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.
    CkJsonObject json2 = new CkJsonObject();
    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) {
        System.out.println(fmt.lastErrorText());
        return;
        }

    System.out.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
  }
}