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Never pass ISO-8859-1 as encode hint #2934

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Merged
TheLastProject merged 1 commit into from
Jan 4, 2026
+26 −15
Merged

Never pass ISO-8859-1 as encode hint #2934

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41 changes: 26 additions & 15 deletions app/src/main/java/protect/card_locker/BarcodeImageWriterTask.java
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@

import java.lang.ref.WeakReference;
import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Map;
import java.util.Objects;

Expand Down Expand Up @@ -184,23 +185,33 @@ private Bitmap generate() {
MultiFormatWriter writer = new MultiFormatWriter();

Map<EncodeHintType, Object> encodeHints = new ArrayMap<>();
Charset chosenEncoding = encoding;
// Use charset if defined or guess otherwise
if (encoding != null) {
Log.d(TAG, "Encoding explicitly set, " + encoding.name());
encodeHints.put(EncodeHintType.CHARACTER_SET, encoding);
if (chosenEncoding != null) {
Log.d(TAG, "Encoding explicitly set, " + chosenEncoding.name());
} else {
String guessedEncoding = StringUtils.guessEncoding(cardId.getBytes(), new ArrayMap<>());
Log.d(TAG, "Guessed encoding: " + guessedEncoding);

// We don't want to pass the guessed encoding as an encoding hint unless it is UTF-8 as
// zxing is likely to add the mentioned encoding hint as ECI inside the barcode.
//
// Due to many barcode scanners in the wild being badly coded they may trip over ECI
// info existing and fail to scan, such as in https://github.com/CatimaLoyalty/Android/issues/2921
if (Objects.equals(guessedEncoding, "UTF8")) {
Log.d(TAG, "Guessed encoding is UTF8, so passing as encoding hint");
encodeHints.put(EncodeHintType.CHARACTER_SET, Charset.forName(guessedEncoding));
}
chosenEncoding = Charset.forName(StringUtils.guessEncoding(cardId.getBytes(), new ArrayMap<>()));
Log.d(TAG, "Guessed encoding: " + chosenEncoding.name());
}

// We don't want to pass the ISO-8859-1 as an encoding hint as zxing may add this as ECI
// inside the barcode.
//
// Due to many barcode scanners in the wild being badly coded they may trip over ECI
// info existing and fail to scan.
// See:
// - https://github.com/CatimaLoyalty/Android/issues/2921
// - https://github.com/CatimaLoyalty/Android/issues/2932
//
// Just not always passing the encoding hint is slightly hacky, but in 5+ years of Catima
// cards without encode hints have never caused any issues (unless they were UTF-8), yet
// just days after passing ISO-8859-1 as CHARACTER_SET in the encode hints already 2
// scan failures were reported (one for QR, one for Aztec).
if (!Objects.equals(chosenEncoding.name(), StandardCharsets.ISO_8859_1.name())) {
Log.d(TAG, "Chosen encoding is not ISO_8859_1, so passing as encoding hint");
encodeHints.put(EncodeHintType.CHARACTER_SET, chosenEncoding);
} else {
Log.d(TAG, "Not passing encoding as encoding hint");
}

BitMatrix bitMatrix;
Expand Down