Trait rxing::Binarizer

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pub trait Binarizer {
    type Source: LuminanceSource;

    // Required methods
    fn get_luminance_source(&self) -> &Self::Source;
    fn get_black_row(&self, y: usize) -> Result<Cow<'_, BitArray>>;
    fn get_black_matrix(&self) -> Result<&BitMatrix>;
    fn create_binarizer(&self, source: Self::Source) -> Self
       where Self: Sized;
    fn get_width(&self) -> usize;
    fn get_height(&self) -> usize;
}

Expand description

This class hierarchy provides a set of methods to convert luminance data to 1 bit data. It allows the algorithm to vary polymorphically, for example allowing a very expensive thresholding technique for servers and a fast one for mobile. It also permits the implementation to vary, e.g. a JNI version for Android and a Java fallback version for other platforms.

@author dswitkin@google.com (Daniel Switkin)

Required Associated Types§

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type Source: LuminanceSource

Required Methods§

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fn get_luminance_source(&self) -> &Self::Source

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fn get_black_row(&self, y: usize) -> Result<Cow<'_, BitArray>>

Converts one row of luminance data to 1 bit data. May actually do the conversion, or return cached data. Callers should assume this method is expensive and call it as seldom as possible. This method is intended for decoding 1D barcodes and may choose to apply sharpening. For callers which only examine one row of pixels at a time, the same BitArray should be reused and passed in with each call for performance. However it is legal to keep more than one row at a time if needed.

@param y The row to fetch, which must be in [0, bitmap height) @param row An optional preallocated array. If null or too small, it will be ignored. If used, the Binarizer will call BitArray.clear(). Always use the returned object. @return The array of bits for this row (true means black). @throws NotFoundException if row can’t be binarized

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fn get_black_matrix(&self) -> Result<&BitMatrix>

Converts a 2D array of luminance data to 1 bit data. As above, assume this method is expensive and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or may not apply sharpening. Therefore, a row from this matrix may not be identical to one fetched using getBlackRow(), so don’t mix and match between them.

@return The 2D array of bits for the image (true means black). @throws NotFoundException if image can’t be binarized to make a matrix

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fn create_binarizer(&self, source: Self::Source) -> Self
where Self: Sized,

Creates a new object with the same type as this Binarizer implementation, but with pristine state. This is needed because Binarizer implementations may be stateful, e.g. keeping a cache of 1 bit data. See Effective Java for why we can’t use Java’s clone() method.

@param source The LuminanceSource this Binarizer will operate on. @return A new concrete Binarizer implementation object.

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