PHP 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 PHP

<?php

use Chilkat2\Formats;
use Chilkat2\JsonArray;
use Chilkat2\JsonObject;

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

$fmt = new Formats();
$json = new JsonObject();
$jsonOut = new JsonObject();
$json->UpdateString('payload.text', 'https://www.chilkatsoft.com/barcode_overview.asp');

// Encode the same text at each level.
$levels = new JsonArray();
$levels->Load('["L","M","Q","H"]');
for ($i = 0; $i <= 3; $i++) {
    $json->UpdateString('encoding.qr.errorCorrection', $levels->StringAt($i));
    try {
        $fmt->QrCode('generate', $json, $jsonOut);
    } catch (\Chilkat2\Exception $e) {
        echo $e->getMessage(), "\n";
        exit;
    }

    echo 'level ', $levels->StringAt($i), ': version ', $jsonOut->IntOf('symbols[0].selectedEncoding.version'), ', ', $jsonOut->IntOf('symbols[0].dimensions.modulesWide'), " modules wide\n";
}

// 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.
$json2 = new JsonObject();
$json2->UpdateString('payload.text', 'https://chilkatsoft.com');
$json2->UpdateString('encoding.qr.errorCorrection', 'L');
try {
    $fmt->QrCode('generate', $json2, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'level L requested: version ', $jsonOut->IntOf('symbols[0].selectedEncoding.version'), ', level ', $jsonOut->StringOf('symbols[0].selectedEncoding.errorCorrection'), "\n";

$json2->UpdateBool('encoding.qr.boostErrorCorrection', true);
try {
    $fmt->QrCode('generate', $json2, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'level L with boost: version ', $jsonOut->IntOf('symbols[0].selectedEncoding.version'), ', level ', $jsonOut->StringOf('symbols[0].selectedEncoding.errorCorrection'), "\n";

// 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