/* * Copyright 2007 ZXing authors * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ // package com::google::zxing::qrcode::decoder; /** *

Encapsulates data masks for the data bits in a QR code, per ISO 18004:2006 6.8. Implementations * of this class can un-mask a raw BitMatrix. For simplicity, they will unmask the entire BitMatrix, * including areas used for finder patterns, timing patterns, etc. These areas should be unused * after the point they are unmasked anyway.

* *

Note that the diagram in section 6.8.1 is misleading since it indicates that i is column position * and j is row position. In fact, as the text says, i is row position and j is column position.

* * @author Sean Owen */ enum DataMask { /** * 000: mask bits for which (x + y) mod 2 == 0 */ DATA_MASK_000() { fn is_masked(&self, i: i32, j: i32) -> bool { return ((i + j) & 0x01) == 0; } } , /** * 001: mask bits for which x mod 2 == 0 */ DATA_MASK_001() { fn is_masked(&self, i: i32, j: i32) -> bool { return (i & 0x01) == 0; } } , /** * 010: mask bits for which y mod 3 == 0 */ DATA_MASK_010() { fn is_masked(&self, i: i32, j: i32) -> bool { return j % 3 == 0; } } , /** * 011: mask bits for which (x + y) mod 3 == 0 */ DATA_MASK_011() { fn is_masked(&self, i: i32, j: i32) -> bool { return (i + j) % 3 == 0; } } , /** * 100: mask bits for which (x/2 + y/3) mod 2 == 0 */ DATA_MASK_100() { fn is_masked(&self, i: i32, j: i32) -> bool { return (((i / 2) + (j / 3)) & 0x01) == 0; } } , /** * 101: mask bits for which xy mod 2 + xy mod 3 == 0 * equivalently, such that xy mod 6 == 0 */ DATA_MASK_101() { fn is_masked(&self, i: i32, j: i32) -> bool { return (i * j) % 6 == 0; } } , /** * 110: mask bits for which (xy mod 2 + xy mod 3) mod 2 == 0 * equivalently, such that xy mod 6 < 3 */ DATA_MASK_110() { fn is_masked(&self, i: i32, j: i32) -> bool { return ((i * j) % 6) < 3; } } , /** * 111: mask bits for which ((x+y)mod 2 + xy mod 3) mod 2 == 0 * equivalently, such that (x + y + xy mod 3) mod 2 == 0 */ DATA_MASK_111() { fn is_masked(&self, i: i32, j: i32) -> bool { return ((i + j + ((i * j) % 3)) & 0x01) == 0; } } ; // End of enum constants. /** *

Implementations of this method reverse the data masking process applied to a QR Code and * make its bits ready to read.

* * @param bits representation of QR Code bits * @param dimension dimension of QR Code, represented by bits, being unmasked */ fn unmask_bit_matrix(&self, bits: &BitMatrix, dimension: i32) { { let mut i: i32 = 0; while i < dimension { { { let mut j: i32 = 0; while j < dimension { { if self.is_masked(i, j) { bits.flip(j, i); } } j += 1; } } } i += 1; } } } fn is_masked(&self, i: i32, j: i32) -> bool ; }