rxing/
binarizer.rs

1/*
2 * Copyright 2009 ZXing authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17//package com.google.zxing;
18
19use std::borrow::Cow;
20
21use crate::{
22    common::{BitArray, BitMatrix, LineOrientation, Result},
23    LuminanceSource,
24};
25
26/**
27 * This class hierarchy provides a set of methods to convert luminance data to 1 bit data.
28 * It allows the algorithm to vary polymorphically, for example allowing a very expensive
29 * thresholding technique for servers and a fast one for mobile. It also permits the implementation
30 * to vary, e.g. a JNI version for Android and a Java fallback version for other platforms.
31 *
32 * @author dswitkin@google.com (Daniel Switkin)
33 */
34pub trait Binarizer {
35    //private final LuminanceSource source;
36    //fn new(source:dyn LuminanceSource) -> Self;
37
38    type Source: LuminanceSource;
39
40    fn get_luminance_source(&self) -> &Self::Source;
41
42    /**
43     * Converts one row of luminance data to 1 bit data. May actually do the conversion, or return
44     * cached data. Callers should assume this method is expensive and call it as seldom as possible.
45     * This method is intended for decoding 1D barcodes and may choose to apply sharpening.
46     * For callers which only examine one row of pixels at a time, the same BitArray should be reused
47     * and passed in with each call for performance. However it is legal to keep more than one row
48     * at a time if needed.
49     *
50     * @param y The row to fetch, which must be in [0, bitmap height)
51     * @param row An optional preallocated array. If null or too small, it will be ignored.
52     *            If used, the Binarizer will call BitArray.clear(). Always use the returned object.
53     * @return The array of bits for this row (true means black).
54     * @throws NotFoundException if row can't be binarized
55     */
56    fn get_black_row(&self, y: usize) -> Result<Cow<'_, BitArray>>;
57
58    // An alternate version of get_black_row that fetches the line from the matrix if
59    // it has already been generated, falling back to get_black_row if it hasn't.
60    fn get_black_row_from_matrix(&self, y: usize) -> Result<Cow<'_, BitArray>>;
61
62    /**
63     * Converts a 2D array of luminance data to 1 bit data. As above, assume this method is expensive
64     * and do not call it repeatedly. This method is intended for decoding 2D barcodes and may or
65     * may not apply sharpening. Therefore, a row from this matrix may not be identical to one
66     * fetched using getBlackRow(), so don't mix and match between them.
67     *
68     * @return The 2D array of bits for the image (true means black).
69     * @throws NotFoundException if image can't be binarized to make a matrix
70     */
71    fn get_black_matrix(&self) -> Result<&BitMatrix>;
72
73    /// Get a row or column of the image
74    fn get_black_line(&self, l: usize, lt: LineOrientation) -> Result<Cow<'_, BitArray>>;
75
76    /**
77     * Creates a new object with the same type as this Binarizer implementation, but with pristine
78     * state. This is needed because Binarizer implementations may be stateful, e.g. keeping a cache
79     * of 1 bit data. See Effective Java for why we can't use Java's clone() method.
80     *
81     * @param source The LuminanceSource this Binarizer will operate on.
82     * @return A new concrete Binarizer implementation object.
83     */
84    fn create_binarizer(&self, source: Self::Source) -> Self
85    where
86        Self: Sized;
87
88    fn get_width(&self) -> usize;
89
90    fn get_height(&self) -> usize;
91}
rxing/binarizer.rs

rxing/
binarizer.rs
