Class MultiFormatReader

core/src/main/java/com/google/zxing/MultiFormatReader.java:38–199

MultiFormatReader is a convenience class and the main entry point into the library for most uses. By default it attempts to decode all barcode formats that the library supports. Optionally, you can provide a hints object to request different behavior, for example only decoding QR codes. @author Sea

 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class MultiFormatReader implements Reader {

  private static final Reader[] EMPTY_READER_ARRAY = new Reader[0];

  private Map<DecodeHintType,?> hints;
  private Reader[] readers;

  /**
   * This version of decode honors the intent of Reader.decode(BinaryBitmap) in that it
   * passes null as a hint to the decoders. However, that makes it inefficient to call repeatedly.
   * Use setHints() followed by decodeWithState() for continuous scan applications.
   *
   * @param image The pixel data to decode
   * @return The contents of the image
   * @throws NotFoundException Any errors which occurred
   */
  @Override
  public Result decode(BinaryBitmap image) throws NotFoundException {
    setHints(null);
    return decodeInternal(image);
  }

  /**
   * Decode an image using the hints provided. Does not honor existing state.
   *
   * @param image The pixel data to decode
   * @param hints The hints to use, clearing the previous state.
   * @return The contents of the image
   * @throws NotFoundException Any errors which occurred
   */
  @Override
  public Result decode(BinaryBitmap image, Map<DecodeHintType,?> hints) throws NotFoundException {
    setHints(hints);
    return decodeInternal(image);
  }

  /**
   * Decode an image using the state set up by calling setHints() previously. Continuous scan
   * clients will get a <b>large</b> speed increase by using this instead of decode().
   *
   * @param image The pixel data to decode
   * @return The contents of the image
   * @throws NotFoundException Any errors which occurred
   */
  public Result decodeWithState(BinaryBitmap image) throws NotFoundException {
    // Make sure to set up the default state so we don't crash
    if (readers == null) {
      setHints(null);
    }
    return decodeInternal(image);
  }

  /**
   * This method adds state to the MultiFormatReader. By setting the hints once, subsequent calls
   * to decodeWithState(image) can reuse the same set of readers without reallocating memory. This
   * is important for performance in continuous scan clients.
   *
   * @param hints The set of hints to use for subsequent calls to decode(image)