Java Requires Chilkat v11.7.0+

QR Code with a Text Caption

See more QR Code Examples

Demonstrates printing a line of text under a QR code, such as the order number or the address the code holds, so that a person can read it too. render.text turns the caption on and gives its value, which is printable ASCII and is drawn in a built-in font that needs no font files. The caption can go above or below the symbol, be aligned left, center or right, and be scaled. 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.

    CkJsonObject json = new CkJsonObject();
    json.UpdateString("payload.text","https://www.chilkatsoft.com/order/12345");
    json.UpdateInt("render.moduleSize",6);

    //  The caption.  It need not be the same as the text in the QR code.
    json.UpdateBool("render.text.enabled",true);
    json.UpdateString("render.text.value","ORDER 12345");
    //  position is "below" (the default) or "above".  alignment is "center" (the default), "left" or "right".
    json.UpdateString("render.text.position","below");
    //  Each dot of the caption's font is drawn this many pixels wide.
    json.UpdateInt("render.text.scale",3);

    json.UpdateString("output.path","qa_output/qr_caption.png");
    json.UpdateBool("output.overwrite",true);
    json.UpdateString("output.return","none");

    CkFormats fmt = new CkFormats();
    CkJsonObject jsonOut = new CkJsonObject();
    success = fmt.QrCode("generate",json,jsonOut);
    if (success == false) {
        System.out.println(fmt.lastErrorText());
        return;
        }

    System.out.println("caption: " + jsonOut.stringOf("measurements[0].text"));
    System.out.println("caption scale: " + jsonOut.IntOf("measurements[0].textScale"));
    System.out.println("height added for the caption: " + jsonOut.IntOf("measurements[0].textBandPx") + " pixels");
    System.out.println("image: " + jsonOut.IntOf("measurements[0].canvasWidth") + " x " + jsonOut.IntOf("measurements[0].canvasHeight") + " pixels");

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

    //  

    //  Sample output:

    //  caption: ORDER 12345
    //  caption scale: 3
    //  height added for the caption: 21 pixels
    //  image: 222 x 243 pixels
  }
}