Java Requires Chilkat v11.7.0+

QR Code Error Correction Levels

See more QR Code Examples

Demonstrates the four QR error-correction levels. L, M, Q and H allow a reader to recover the data when about 7%, 15%, 25% and 30% of the symbol is damaged or covered. More error correction leaves less room for data, so the same text needs a larger symbol at a higher level. The default is M. The example also shows boostErrorCorrection, which raises the level for free when the chosen version has room to spare. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Formats;
import com.chilkatsoft.chilkat2.JsonArray;
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 json = new JsonObject();
        JsonObject jsonOut = new JsonObject();
        json.updateString("payload.text", "https://www.chilkatsoft.com/barcode_overview.asp");

        // Encode the same text at each level.
        JsonArray levels = new JsonArray();
        levels.load("[\"L\",\"M\",\"Q\",\"H\"]");
        for (int i = 0; i <= 3; i++) {
            json.updateString("encoding.qr.errorCorrection", levels.stringAt(i));
            try {
                fmt.qrCode("generate", json, jsonOut);
            } catch (ChilkatException e) {
                System.out.println(e.getLastErrorText());
                return;
            }

            System.out.println("level " + levels.stringAt(i) + ": version " + jsonOut.intOf("symbols[0].selectedEncoding.version") + ", " + jsonOut.intOf("symbols[0].dimensions.modulesWide") + " modules wide");
        }

        // The four symbols.  They hold the same text, and the higher the level, the larger the symbol:

        // 

        // A symbol often has room left over.  boostErrorCorrection uses it: the level is raised
        // as far as the same version allows, so the symbol is no larger but is more robust.
        JsonObject json2 = new JsonObject();
        json2.updateString("payload.text", "https://chilkatsoft.com");
        json2.updateString("encoding.qr.errorCorrection", "L");
        try {
            fmt.qrCode("generate", json2, jsonOut);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("level L requested: version " + jsonOut.intOf("symbols[0].selectedEncoding.version") + ", level " + jsonOut.stringOf("symbols[0].selectedEncoding.errorCorrection"));

        json2.updateBool("encoding.qr.boostErrorCorrection", true);
        try {
            fmt.qrCode("generate", json2, jsonOut);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("level L with boost: version " + jsonOut.intOf("symbols[0].selectedEncoding.version") + ", level " + jsonOut.stringOf("symbols[0].selectedEncoding.errorCorrection"));

        // Level L, and level M reached by the boost.  The two symbols are the same size:

        // 

        // Sample output:

        // level L: version 3, 29 modules wide
        // level M: version 4, 33 modules wide
        // level Q: version 5, 37 modules wide
        // level H: version 6, 41 modules wide
        // level L requested: version 2, level L
        // level L with boost: version 2, level M
    }
}