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. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Formats;
import com.chilkatsoft.chilkat2.JsonObject;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

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

        // Dark blue modules on a pale yellow background.
        JsonObject json = new 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");
        try {
            fmt.qrCode("generate", json, jsonOut);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            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.
        JsonObject json2 = new 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");
        try {
            fmt.qrCode("generate", json2, jsonOut);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            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
    }
}