// Apply mask penalty rule 3 and return the penalty. Find consecutive cells of 00001011101 or
// 10111010000, and give penalty to them. If we find patterns like 000010111010000, we give
// penalties twice (i.e. 40 * 2).
public static int applyMaskPenaltyRule3(ByteMatrix matrix)
{
int penalty = 0;
sbyte[][] array = matrix.getArray();
int width = matrix.width();
int height = matrix.height();
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
// Tried to simplify following conditions but failed.
if (x + 6 < width &&
array[y][x] == 1 &&
array[y][x + 1] == 0 &&
array[y][x + 2] == 1 &&
array[y][x + 3] == 1 &&
array[y][x + 4] == 1 &&
array[y][x + 5] == 0 &&
array[y][x + 6] == 1 &&
((x + 10 < width &&
array[y][x + 7] == 0 &&
array[y][x + 8] == 0 &&
array[y][x + 9] == 0 &&
array[y][x + 10] == 0) ||
(x - 4 >= 0 &&
array[y][x - 1] == 0 &&
array[y][x - 2] == 0 &&
array[y][x - 3] == 0 &&
array[y][x - 4] == 0)))
{
penalty += 40;
}
if (y + 6 < height &&
array[y][x] == 1 &&
array[y + 1][x] == 0 &&
array[y + 2][x] == 1 &&
array[y + 3][x] == 1 &&
array[y + 4][x] == 1 &&
array[y + 5][x] == 0 &&
array[y + 6][x] == 1 &&
((y + 10 < height &&
array[y + 7][x] == 0 &&
array[y + 8][x] == 0 &&
array[y + 9][x] == 0 &&
array[y + 10][x] == 0) ||
(y - 4 >= 0 &&
array[y - 1][x] == 0 &&
array[y - 2][x] == 0 &&
array[y - 3][x] == 0 &&
array[y - 4][x] == 0)))
{
penalty += 40;
}
}
}
return penalty;
}
// Apply mask penalty rule 2 and return the penalty. Find 2x2 blocks with the same color and give
// penalty to them.
public static int applyMaskPenaltyRule2(ByteMatrix matrix)
{
int penalty = 0;
sbyte[][] array = matrix.getArray();
int width = matrix.width();
int height = matrix.height();
for (int y = 0; y < height - 1; ++y)
{
for (int x = 0; x < width - 1; ++x)
{
int value = array[y][x];
if (value == array[y][x + 1] && value == array[y + 1][x] && value == array[y + 1][x + 1])
{
penalty += 3;
}
}
}
return penalty;
}
// Note that the input matrix uses 0 == white, 1 == black, while the output matrix uses
// 0 == black, 255 == white (i.e. an 8 bit greyscale bitmap).
private static ByteMatrix renderResult(QRCode code, int width, int height)
{
ByteMatrix input = code.getMatrix();
int inputWidth = input.width();
int inputHeight = input.height();
int qrWidth = inputWidth + (QUIET_ZONE_SIZE << 1);
int qrHeight = inputHeight + (QUIET_ZONE_SIZE << 1);
int outputWidth = Math.Max(width, qrWidth);
int outputHeight = Math.Max(height, qrHeight);
int multiple = Math.Min(outputWidth / qrWidth, outputHeight / qrHeight);
// Padding includes both the quiet zone and the extra white pixels to accomodate the requested
// dimensions. For example, if input is 25x25 the QR will be 33x33 including the quiet zone.
// If the requested size is 200x160, the multiple will be 4, for a QR of 132x132. These will
// handle all the padding from 100x100 (the actual QR) up to 200x160.
int leftPadding = (outputWidth - (inputWidth * multiple)) / 2;
int topPadding = (outputHeight - (inputHeight * multiple)) / 2;
ByteMatrix output = new ByteMatrix(outputHeight, outputWidth);
sbyte[][] outputArray = output.getArray();
// We could be tricky and use the first row in each set of multiple as the temporary storage,
// instead of allocating this separate array.
sbyte[] row = new sbyte[outputWidth];
// 1. Write the white lines at the top
for (int y = 0; y < topPadding; y++) {
setRowColor(outputArray[y], unchecked((sbyte)255));
}
// 2. Expand the QR image to the multiple
sbyte[][] inputArray = input.getArray();
for (int y = 0; y < inputHeight; y++) {
// a. Write the white pixels at the left of each row
for (int x = 0; x < leftPadding; x++) {
row[x] = unchecked((sbyte) 255);
}
// b. Write the contents of this row of the barcode
int offset = leftPadding;
for (int x = 0; x < inputWidth; x++) {
sbyte value = (inputArray[y][x] == 1) ? (sbyte) 0 : unchecked((sbyte) 255);
for (int z = 0; z < multiple; z++) {
row[offset + z] = value;
}
offset += multiple;
}
// c. Write the white pixels at the right of each row
offset = leftPadding + (inputWidth * multiple);
for (int x = offset; x < outputWidth; x++) {
row[x] = unchecked((sbyte) 255);
}
// d. Write the completed row multiple times
offset = topPadding + (y * multiple);
for (int z = 0; z < multiple; z++) {
System.Array.Copy(row, 0, outputArray[offset + z], 0, outputWidth);
}
}
// 3. Write the white lines at the bottom
int offset2 = topPadding + (inputHeight * multiple);
for (int y = offset2; y < outputHeight; y++)
{
setRowColor(outputArray[y], unchecked((sbyte) 255));
}
return output;
}
// Helper function for applyMaskPenaltyRule1. We need this for doing this calculation in both
// vertical and horizontal orders respectively.
private static int applyMaskPenaltyRule1Internal(ByteMatrix matrix, bool isHorizontal)
{
int penalty = 0;
int numSameBitCells = 0;
int prevBit = -1;
// Horizontal mode:
// for (int i = 0; i < matrix.height(); ++i) {
// for (int j = 0; j < matrix.width(); ++j) {
// int bit = matrix.get(i, j);
// Vertical mode:
// for (int i = 0; i < matrix.width(); ++i) {
// for (int j = 0; j < matrix.height(); ++j) {
// int bit = matrix.get(j, i);
int iLimit = isHorizontal ? matrix.height() : matrix.width();
int jLimit = isHorizontal ? matrix.width() : matrix.height();
sbyte[][] array = matrix.getArray();
for (int i = 0; i < iLimit; ++i)
{
for (int j = 0; j < jLimit; ++j)
{
int bit = isHorizontal ? array[i][j] : array[j][i];
if (bit == prevBit)
{
numSameBitCells += 1;
// Found five repetitive cells with the same color (bit).
// We'll give penalty of 3.
if (numSameBitCells == 5)
{
penalty += 3;
}
else if (numSameBitCells > 5)
{
// After five repetitive cells, we'll add the penalty one
// by one.
penalty += 1;
}
}
else
{
numSameBitCells = 1; // Include the cell itself.
prevBit = bit;
}
}
numSameBitCells = 0; // Clear at each row/column.
}
return penalty;
}
// Apply mask penalty rule 4 and return the penalty. Calculate the ratio of dark cells and give
// penalty if the ratio is far from 50%. It gives 10 penalty for 5% distance. Examples:
// - 0% => 100
// - 40% => 20
// - 45% => 10
// - 50% => 0
// - 55% => 10
// - 55% => 20
// - 100% => 100
public static int applyMaskPenaltyRule4(ByteMatrix matrix)
{
int numDarkCells = 0;
sbyte[][] array = matrix.getArray();
int width = matrix.width();
int height = matrix.height();
for (int y = 0; y < height; ++y)
{
for (int x = 0; x < width; ++x)
{
if (array[y][x] == 1)
{
numDarkCells += 1;
}
}
}
int numTotalCells = matrix.height() * matrix.width();
double darkRatio = (double)numDarkCells / numTotalCells;
return Math.Abs((int)(darkRatio * 100 - 50)) / 5 * 10;
}