com.google.zxing.multi

## Class ByQuadrantReader

- java.lang.Object
- - com.google.zxing.multi.ByQuadrantReader

- All Implemented Interfaces:
    Reader

      public final class ByQuadrantReader
      extends Object
      implements Reader

  This class attempts to decode a barcode from an image, not by scanning the whole image, but by scanning subsets of the image. This is important when there may be multiple barcodes in an image, and detecting a barcode may find parts of multiple barcode and fail to decode (e.g. QR Codes). Instead this scans the four quadrants of the image -- and also the center 'quadrant' to cover the case where a barcode is found in the center.
  See Also:
    `GenericMultipleBarcodeReader`

- - ### Constructor Summary

    Constructors
    Constructor and Description
    `ByQuadrantReader(Reader delegate)`

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `Result` | `decode(BinaryBitmap image)` Locates and decodes a barcode in some format within an image.
    `Result` | `decode(BinaryBitmap image, Map<DecodeHintType,?> hints)` Locates and decodes a barcode in some format within an image.
    `void` | `reset()` Resets any internal state the implementation has after a decode, to prepare it for reuse.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Constructor Detail

    - #### ByQuadrantReader

          public ByQuadrantReader(Reader delegate)

  - ### Method Detail

    - #### decode

          public Result decode(BinaryBitmap image)
                        throws NotFoundException,
                               ChecksumException,
                               FormatException

      Description copied from interface: `Reader`
      Locates and decodes a barcode in some format within an image.
      Specified by:
        `decode` in interface `Reader`
      Parameters:
        `image` - image of barcode to decode
      Returns:
        String which the barcode encodes
      Throws:
        `NotFoundException` - if no potential barcode is found
        `ChecksumException` - if a potential barcode is found but does not pass its checksum
        `FormatException` - if a potential barcode is found but format is invalid

    - #### decode

          public Result decode(BinaryBitmap image,
                               Map<DecodeHintType,?> hints)
                        throws NotFoundException,
                               ChecksumException,
                               FormatException

      Description copied from interface: `Reader`
      Locates and decodes a barcode in some format within an image. This method also accepts hints, each possibly associated to some data, which may help the implementation decode.
      Specified by:
        `decode` in interface `Reader`
      Parameters:
        `image` - image of barcode to decode
        `hints` - passed as a `Map` from `DecodeHintType` to arbitrary data. The meaning of the data depends upon the hint type. The implementation may or may not do anything with these hints.
      Returns:
        String which the barcode encodes
      Throws:
        `NotFoundException` - if no potential barcode is found
        `ChecksumException` - if a potential barcode is found but does not pass its checksum
        `FormatException` - if a potential barcode is found but format is invalid

    - #### reset

          public void reset()

      Description copied from interface: `Reader`
      Resets any internal state the implementation has after a decode, to prepare it for reuse.
      Specified by:
        `reset` in interface `Reader`

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