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Diffstat (limited to 'libraries/zxing/src/com/google/zxing/qrcode/encoder/MatrixUtil.java')
| -rw-r--r-- | libraries/zxing/src/com/google/zxing/qrcode/encoder/MatrixUtil.java | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/libraries/zxing/src/com/google/zxing/qrcode/encoder/MatrixUtil.java b/libraries/zxing/src/com/google/zxing/qrcode/encoder/MatrixUtil.java new file mode 100644 index 000000000..3d434e675 --- /dev/null +++ b/libraries/zxing/src/com/google/zxing/qrcode/encoder/MatrixUtil.java @@ -0,0 +1,524 @@ +/* + * Copyright 2008 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.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); + } + } + } + } + +} |