Back to project page flash-your-qr.
The source code is released under:
Apache License
If you think the Android project flash-your-qr listed in this page is inappropriate, such as containing malicious code/tools or violating the copyright, please email info at java2s dot com, thanks.
/* * Copyright 2008 ZXing authors/*ww w . j a va 2 s . com*/ * * 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.encoder; import com.google.zxing.WriterException; import com.google.zxing.common.BitArray; import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel; /** * @author satorux@google.com (Satoru Takabayashi) - creator * @author dswitkin@google.com (Daniel Switkin) - ported from C++ */ public final class MatrixUtil { private MatrixUtil() { // do nothing } private static final int[][] POSITION_DETECTION_PATTERN = { {1, 1, 1, 1, 1, 1, 1}, {1, 0, 0, 0, 0, 0, 1}, {1, 0, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 1, 0, 1}, {1, 0, 1, 1, 1, 0, 1}, {1, 0, 0, 0, 0, 0, 1}, {1, 1, 1, 1, 1, 1, 1}, }; private static final int[][] HORIZONTAL_SEPARATION_PATTERN = { {0, 0, 0, 0, 0, 0, 0, 0}, }; private static final int[][] VERTICAL_SEPARATION_PATTERN = { {0}, {0}, {0}, {0}, {0}, {0}, {0}, }; private static final int[][] POSITION_ADJUSTMENT_PATTERN = { {1, 1, 1, 1, 1}, {1, 0, 0, 0, 1}, {1, 0, 1, 0, 1}, {1, 0, 0, 0, 1}, {1, 1, 1, 1, 1}, }; // From Appendix E. Table 1, JIS0510X:2004 (p 71). The table was double-checked by komatsu. private static final int[][] POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE = { {-1, -1, -1, -1, -1, -1, -1}, // Version 1 { 6, 18, -1, -1, -1, -1, -1}, // Version 2 { 6, 22, -1, -1, -1, -1, -1}, // Version 3 { 6, 26, -1, -1, -1, -1, -1}, // Version 4 { 6, 30, -1, -1, -1, -1, -1}, // Version 5 { 6, 34, -1, -1, -1, -1, -1}, // Version 6 { 6, 22, 38, -1, -1, -1, -1}, // Version 7 { 6, 24, 42, -1, -1, -1, -1}, // Version 8 { 6, 26, 46, -1, -1, -1, -1}, // Version 9 { 6, 28, 50, -1, -1, -1, -1}, // Version 10 { 6, 30, 54, -1, -1, -1, -1}, // Version 11 { 6, 32, 58, -1, -1, -1, -1}, // Version 12 { 6, 34, 62, -1, -1, -1, -1}, // Version 13 { 6, 26, 46, 66, -1, -1, -1}, // Version 14 { 6, 26, 48, 70, -1, -1, -1}, // Version 15 { 6, 26, 50, 74, -1, -1, -1}, // Version 16 { 6, 30, 54, 78, -1, -1, -1}, // Version 17 { 6, 30, 56, 82, -1, -1, -1}, // Version 18 { 6, 30, 58, 86, -1, -1, -1}, // Version 19 { 6, 34, 62, 90, -1, -1, -1}, // Version 20 { 6, 28, 50, 72, 94, -1, -1}, // Version 21 { 6, 26, 50, 74, 98, -1, -1}, // Version 22 { 6, 30, 54, 78, 102, -1, -1}, // Version 23 { 6, 28, 54, 80, 106, -1, -1}, // Version 24 { 6, 32, 58, 84, 110, -1, -1}, // Version 25 { 6, 30, 58, 86, 114, -1, -1}, // Version 26 { 6, 34, 62, 90, 118, -1, -1}, // Version 27 { 6, 26, 50, 74, 98, 122, -1}, // Version 28 { 6, 30, 54, 78, 102, 126, -1}, // Version 29 { 6, 26, 52, 78, 104, 130, -1}, // Version 30 { 6, 30, 56, 82, 108, 134, -1}, // Version 31 { 6, 34, 60, 86, 112, 138, -1}, // Version 32 { 6, 30, 58, 86, 114, 142, -1}, // Version 33 { 6, 34, 62, 90, 118, 146, -1}, // Version 34 { 6, 30, 54, 78, 102, 126, 150}, // Version 35 { 6, 24, 50, 76, 102, 128, 154}, // Version 36 { 6, 28, 54, 80, 106, 132, 158}, // Version 37 { 6, 32, 58, 84, 110, 136, 162}, // Version 38 { 6, 26, 54, 82, 110, 138, 166}, // Version 39 { 6, 30, 58, 86, 114, 142, 170}, // Version 40 }; // Type info cells at the left top corner. private static final int[][] TYPE_INFO_COORDINATES = { {8, 0}, {8, 1}, {8, 2}, {8, 3}, {8, 4}, {8, 5}, {8, 7}, {8, 8}, {7, 8}, {5, 8}, {4, 8}, {3, 8}, {2, 8}, {1, 8}, {0, 8}, }; // From Appendix D in JISX0510:2004 (p. 67) private static final int VERSION_INFO_POLY = 0x1f25; // 1 1111 0010 0101 // From Appendix C in JISX0510:2004 (p.65). private static final int TYPE_INFO_POLY = 0x537; private static final int TYPE_INFO_MASK_PATTERN = 0x5412; // Set all cells to -1. -1 means that the cell is empty (not set yet). // // JAVAPORT: We shouldn't need to do this at all. The code should be rewritten to begin encoding // with the ByteMatrix initialized all to zero. public static void clearMatrix(ByteMatrix matrix) { matrix.clear((byte) -1); } // Build 2D matrix of QR Code from "dataBits" with "ecLevel", "version" and "getMaskPattern". On // success, store the result in "matrix" and return true. public static void buildMatrix(BitArray dataBits, ErrorCorrectionLevel ecLevel, int version, int maskPattern, ByteMatrix matrix) throws WriterException { clearMatrix(matrix); embedBasicPatterns(version, matrix); // Type information appear with any version. embedTypeInfo(ecLevel, maskPattern, matrix); // Version info appear if version >= 7. maybeEmbedVersionInfo(version, matrix); // Data should be embedded at end. embedDataBits(dataBits, maskPattern, matrix); } // Embed basic patterns. On success, modify the matrix and return true. // The basic patterns are: // - Position detection patterns // - Timing patterns // - Dark dot at the left bottom corner // - Position adjustment patterns, if need be public static void embedBasicPatterns(int version, ByteMatrix matrix) throws WriterException { // Let's get started with embedding big squares at corners. embedPositionDetectionPatternsAndSeparators(matrix); // Then, embed the dark dot at the left bottom corner. embedDarkDotAtLeftBottomCorner(matrix); // Position adjustment patterns appear if version >= 2. maybeEmbedPositionAdjustmentPatterns(version, matrix); // Timing patterns should be embedded after position adj. patterns. embedTimingPatterns(matrix); } // Embed type information. On success, modify the matrix. public static void embedTypeInfo(ErrorCorrectionLevel ecLevel, int maskPattern, ByteMatrix matrix) throws WriterException { BitArray typeInfoBits = new BitArray(); makeTypeInfoBits(ecLevel, maskPattern, typeInfoBits); for (int i = 0; i < typeInfoBits.getSize(); ++i) { // Place bits in LSB to MSB order. LSB (least significant bit) is the last value in // "typeInfoBits". boolean bit = typeInfoBits.get(typeInfoBits.getSize() - 1 - i); // Type info bits at the left top corner. See 8.9 of JISX0510:2004 (p.46). int x1 = TYPE_INFO_COORDINATES[i][0]; int y1 = TYPE_INFO_COORDINATES[i][1]; matrix.set(x1, y1, bit); if (i < 8) { // Right top corner. int x2 = matrix.getWidth() - i - 1; int y2 = 8; matrix.set(x2, y2, bit); } else { // Left bottom corner. int x2 = 8; int y2 = matrix.getHeight() - 7 + (i - 8); matrix.set(x2, y2, bit); } } } // Embed version information if need be. On success, modify the matrix and return true. // See 8.10 of JISX0510:2004 (p.47) for how to embed version information. public static void maybeEmbedVersionInfo(int version, ByteMatrix matrix) throws WriterException { if (version < 7) { // Version info is necessary if version >= 7. return; // Don't need version info. } BitArray versionInfoBits = new BitArray(); makeVersionInfoBits(version, versionInfoBits); int bitIndex = 6 * 3 - 1; // It will decrease from 17 to 0. for (int i = 0; i < 6; ++i) { for (int j = 0; j < 3; ++j) { // Place bits in LSB (least significant bit) to MSB order. boolean bit = versionInfoBits.get(bitIndex); bitIndex--; // Left bottom corner. matrix.set(i, matrix.getHeight() - 11 + j, bit); // Right bottom corner. matrix.set(matrix.getHeight() - 11 + j, i, bit); } } } // Embed "dataBits" using "getMaskPattern". On success, modify the matrix and return true. // For debugging purposes, it skips masking process if "getMaskPattern" is -1. // See 8.7 of JISX0510:2004 (p.38) for how to embed data bits. public static void embedDataBits(BitArray dataBits, int maskPattern, ByteMatrix matrix) throws WriterException { int bitIndex = 0; int direction = -1; // Start from the right bottom cell. int x = matrix.getWidth() - 1; int y = matrix.getHeight() - 1; while (x > 0) { // Skip the vertical timing pattern. if (x == 6) { x -= 1; } while (y >= 0 && y < matrix.getHeight()) { for (int i = 0; i < 2; ++i) { int xx = x - i; // Skip the cell if it's not empty. if (!isEmpty(matrix.get(xx, y))) { continue; } boolean bit; if (bitIndex < dataBits.getSize()) { bit = dataBits.get(bitIndex); ++bitIndex; } else { // Padding bit. If there is no bit left, we'll fill the left cells with 0, as described // in 8.4.9 of JISX0510:2004 (p. 24). bit = false; } // Skip masking if mask_pattern is -1. if (maskPattern != -1) { if (MaskUtil.getDataMaskBit(maskPattern, xx, y)) { bit = !bit; } } matrix.set(xx, y, bit); } y += direction; } direction = -direction; // Reverse the direction. y += direction; x -= 2; // Move to the left. } // All bits should be consumed. if (bitIndex != dataBits.getSize()) { throw new WriterException("Not all bits consumed: " + bitIndex + '/' + dataBits.getSize()); } } // Return the position of the most significant bit set (to one) in the "value". The most // significant bit is position 32. If there is no bit set, return 0. Examples: // - findMSBSet(0) => 0 // - findMSBSet(1) => 1 // - findMSBSet(255) => 8 public static int findMSBSet(int value) { int numDigits = 0; while (value != 0) { value >>>= 1; ++numDigits; } return numDigits; } // Calculate BCH (Bose-Chaudhuri-Hocquenghem) code for "value" using polynomial "poly". The BCH // code is used for encoding type information and version information. // Example: Calculation of version information of 7. // f(x) is created from 7. // - 7 = 000111 in 6 bits // - f(x) = x^2 + x^1 + x^0 // g(x) is given by the standard (p. 67) // - g(x) = x^12 + x^11 + x^10 + x^9 + x^8 + x^5 + x^2 + 1 // Multiply f(x) by x^(18 - 6) // - f'(x) = f(x) * x^(18 - 6) // - f'(x) = x^14 + x^13 + x^12 // Calculate the remainder of f'(x) / g(x) // x^2 // __________________________________________________ // g(x) )x^14 + x^13 + x^12 // x^14 + x^13 + x^12 + x^11 + x^10 + x^7 + x^4 + x^2 // -------------------------------------------------- // x^11 + x^10 + x^7 + x^4 + x^2 // // The remainder is x^11 + x^10 + x^7 + x^4 + x^2 // Encode it in binary: 110010010100 // The return value is 0xc94 (1100 1001 0100) // // Since all coefficients in the polynomials are 1 or 0, we can do the calculation by bit // operations. We don't care if cofficients are positive or negative. public static int calculateBCHCode(int value, int poly) { // If poly is "1 1111 0010 0101" (version info poly), msbSetInPoly is 13. We'll subtract 1 // from 13 to make it 12. int msbSetInPoly = findMSBSet(poly); value <<= msbSetInPoly - 1; // Do the division business using exclusive-or operations. while (findMSBSet(value) >= msbSetInPoly) { value ^= poly << (findMSBSet(value) - msbSetInPoly); } // Now the "value" is the remainder (i.e. the BCH code) return value; } // Make bit vector of type information. On success, store the result in "bits" and return true. // Encode error correction level and mask pattern. See 8.9 of // JISX0510:2004 (p.45) for details. public static void makeTypeInfoBits(ErrorCorrectionLevel ecLevel, int maskPattern, BitArray bits) throws WriterException { if (!QRCode.isValidMaskPattern(maskPattern)) { throw new WriterException("Invalid mask pattern"); } int typeInfo = (ecLevel.getBits() << 3) | maskPattern; bits.appendBits(typeInfo, 5); int bchCode = calculateBCHCode(typeInfo, TYPE_INFO_POLY); bits.appendBits(bchCode, 10); BitArray maskBits = new BitArray(); maskBits.appendBits(TYPE_INFO_MASK_PATTERN, 15); bits.xor(maskBits); if (bits.getSize() != 15) { // Just in case. throw new WriterException("should not happen but we got: " + bits.getSize()); } } // Make bit vector of version information. On success, store the result in "bits" and return true. // See 8.10 of JISX0510:2004 (p.45) for details. public static void makeVersionInfoBits(int version, BitArray bits) throws WriterException { bits.appendBits(version, 6); int bchCode = calculateBCHCode(version, VERSION_INFO_POLY); bits.appendBits(bchCode, 12); if (bits.getSize() != 18) { // Just in case. throw new WriterException("should not happen but we got: " + bits.getSize()); } } // Check if "value" is empty. private static boolean isEmpty(int value) { return value == -1; } // Check if "value" is valid. private static boolean isValidValue(int value) { return (value == -1 || // Empty. value == 0 || // Light (white). value == 1); // Dark (black). } private static void embedTimingPatterns(ByteMatrix matrix) throws WriterException { // -8 is for skipping position detection patterns (size 7), and two horizontal/vertical // separation patterns (size 1). Thus, 8 = 7 + 1. for (int i = 8; i < matrix.getWidth() - 8; ++i) { int bit = (i + 1) % 2; // Horizontal line. if (!isValidValue(matrix.get(i, 6))) { throw new WriterException(); } if (isEmpty(matrix.get(i, 6))) { matrix.set(i, 6, bit); } // Vertical line. if (!isValidValue(matrix.get(6, i))) { throw new WriterException(); } if (isEmpty(matrix.get(6, i))) { matrix.set(6, i, bit); } } } // Embed the lonely dark dot at left bottom corner. JISX0510:2004 (p.46) private static void embedDarkDotAtLeftBottomCorner(ByteMatrix matrix) throws WriterException { if (matrix.get(8, matrix.getHeight() - 8) == 0) { throw new WriterException(); } matrix.set(8, matrix.getHeight() - 8, 1); } private static void embedHorizontalSeparationPattern(int xStart, int yStart, ByteMatrix matrix) throws WriterException { // We know the width and height. if (HORIZONTAL_SEPARATION_PATTERN[0].length != 8 || HORIZONTAL_SEPARATION_PATTERN.length != 1) { throw new WriterException("Bad horizontal separation pattern"); } for (int x = 0; x < 8; ++x) { if (!isEmpty(matrix.get(xStart + x, yStart))) { throw new WriterException(); } matrix.set(xStart + x, yStart, HORIZONTAL_SEPARATION_PATTERN[0][x]); } } private static void embedVerticalSeparationPattern(int xStart, int yStart, ByteMatrix matrix) throws WriterException { // We know the width and height. if (VERTICAL_SEPARATION_PATTERN[0].length != 1 || VERTICAL_SEPARATION_PATTERN.length != 7) { throw new WriterException("Bad vertical separation pattern"); } for (int y = 0; y < 7; ++y) { if (!isEmpty(matrix.get(xStart, yStart + y))) { throw new WriterException(); } matrix.set(xStart, yStart + y, VERTICAL_SEPARATION_PATTERN[y][0]); } } // Note that we cannot unify the function with embedPositionDetectionPattern() despite they are // almost identical, since we cannot write a function that takes 2D arrays in different sizes in // C/C++. We should live with the fact. private static void embedPositionAdjustmentPattern(int xStart, int yStart, ByteMatrix matrix) throws WriterException { // We know the width and height. if (POSITION_ADJUSTMENT_PATTERN[0].length != 5 || POSITION_ADJUSTMENT_PATTERN.length != 5) { throw new WriterException("Bad position adjustment"); } for (int y = 0; y < 5; ++y) { for (int x = 0; x < 5; ++x) { if (!isEmpty(matrix.get(xStart + x, yStart + y))) { throw new WriterException(); } matrix.set(xStart + x, yStart + y, POSITION_ADJUSTMENT_PATTERN[y][x]); } } } private static void embedPositionDetectionPattern(int xStart, int yStart, ByteMatrix matrix) throws WriterException { // We know the width and height. if (POSITION_DETECTION_PATTERN[0].length != 7 || POSITION_DETECTION_PATTERN.length != 7) { throw new WriterException("Bad position detection pattern"); } for (int y = 0; y < 7; ++y) { for (int x = 0; x < 7; ++x) { if (!isEmpty(matrix.get(xStart + x, yStart + y))) { throw new WriterException(); } matrix.set(xStart + x, yStart + y, POSITION_DETECTION_PATTERN[y][x]); } } } // Embed position detection patterns and surrounding vertical/horizontal separators. private static void embedPositionDetectionPatternsAndSeparators(ByteMatrix matrix) throws WriterException { // Embed three big squares at corners. int pdpWidth = POSITION_DETECTION_PATTERN[0].length; // Left top corner. embedPositionDetectionPattern(0, 0, matrix); // Right top corner. embedPositionDetectionPattern(matrix.getWidth() - pdpWidth, 0, matrix); // Left bottom corner. embedPositionDetectionPattern(0, matrix.getWidth() - pdpWidth, matrix); // Embed horizontal separation patterns around the squares. int hspWidth = HORIZONTAL_SEPARATION_PATTERN[0].length; // Left top corner. embedHorizontalSeparationPattern(0, hspWidth - 1, matrix); // Right top corner. embedHorizontalSeparationPattern(matrix.getWidth() - hspWidth, hspWidth - 1, matrix); // Left bottom corner. embedHorizontalSeparationPattern(0, matrix.getWidth() - hspWidth, matrix); // Embed vertical separation patterns around the squares. int vspSize = VERTICAL_SEPARATION_PATTERN.length; // Left top corner. embedVerticalSeparationPattern(vspSize, 0, matrix); // Right top corner. embedVerticalSeparationPattern(matrix.getHeight() - vspSize - 1, 0, matrix); // Left bottom corner. embedVerticalSeparationPattern(vspSize, matrix.getHeight() - vspSize, matrix); } // Embed position adjustment patterns if need be. private static void maybeEmbedPositionAdjustmentPatterns(int version, ByteMatrix matrix) throws WriterException { if (version < 2) { // The patterns appear if version >= 2 return; } int index = version - 1; int[] coordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index]; int numCoordinates = POSITION_ADJUSTMENT_PATTERN_COORDINATE_TABLE[index].length; for (int i = 0; i < numCoordinates; ++i) { for (int j = 0; j < numCoordinates; ++j) { int y = coordinates[i]; int x = coordinates[j]; if (x == -1 || y == -1) { continue; } // If the cell is unset, we embed the position adjustment pattern here. if (isEmpty(matrix.get(x, y))) { // -2 is necessary since the x/y coordinates point to the center of the pattern, not the // left top corner. embedPositionAdjustmentPattern(x - 2, y - 2, matrix); } } } } }