/**
* <p>Estimates module size based on two finder patterns -- it uses
* {@link #sizeOfBlackWhiteBlackRunBothWays(int, int, int, int)} to figure the
* width of each, measuring along the axis between their centers.</p>
*/
private float calculateModuleSizeOneWay(ResultPoint pattern, ResultPoint otherPattern)
{
float moduleSizeEst1 = sizeOfBlackWhiteBlackRunBothWays((int) pattern.getX(),
(int) pattern.getY(),
(int) otherPattern.getX(),
(int) otherPattern.getY());
float moduleSizeEst2 = sizeOfBlackWhiteBlackRunBothWays((int) otherPattern.getX(),
(int) otherPattern.getY(),
(int) pattern.getX(),
(int) pattern.getY());
if (Single.IsNaN(moduleSizeEst1)) {
return moduleSizeEst2;
}
if (Single.IsNaN(moduleSizeEst2))
{
return moduleSizeEst1;
}
// Average them, and divide by 7 since we've counted the width of 3 black modules,
// and 1 white and 1 black module on either side. Ergo, divide sum by 14.
return (moduleSizeEst1 + moduleSizeEst2) / 14.0f;
}
/**
* Counts the number of black/white transitions between two points, using something like Bresenham's algorithm.
*/
private ResultPointsAndTransitions transitionsBetween(ResultPoint from, ResultPoint to) {
// See QR Code Detector, sizeOfBlackWhiteBlackRun()
int fromX = (int) from.getX();
int fromY = (int) from.getY();
int toX = (int) to.getX();
int toY = (int) to.getY();
bool steep = Math.Abs(toY - fromY) > Math.Abs(toX - fromX);
if (steep) {
int temp = fromX;
fromX = fromY;
fromY = temp;
temp = toX;
toX = toY;
toY = temp;
}
int dx = Math.Abs(toX - fromX);
int dy = Math.Abs(toY - fromY);
int error = -dx >> 1;
int ystep = fromY < toY ? 1 : -1;
int xstep = fromX < toX ? 1 : -1;
int transitions = 0;
bool inBlack = image.isBlack(steep ? fromY : fromX, steep ? fromX : fromY);
for (int x = fromX, y = fromY; x != toX; x += xstep) {
bool isBlack = image.isBlack(steep ? y : x, steep ? x : y);
if (isBlack == !inBlack) {
transitions++;
inBlack = isBlack;
}
error += dy;
if (error > 0) {
y += ystep;
error -= dx;
}
}
return new ResultPointsAndTransitions(from, to, transitions);
}
private static BitMatrix sampleGrid(MonochromeBitmapSource image,
ResultPoint topLeft,
ResultPoint topRight,
ResultPoint bottomLeft,
ResultPoint alignmentPattern,
int dimension)
{
float dimMinusThree = (float) dimension - 3.5f;
float bottomRightX;
float bottomRightY;
float sourceBottomRightX;
float sourceBottomRightY;
if (alignmentPattern != null) {
bottomRightX = alignmentPattern.getX();
bottomRightY = alignmentPattern.getY();
sourceBottomRightX = sourceBottomRightY = dimMinusThree - 3.0f;
} else {
// Don't have an alignment pattern, just make up the bottom-right point
bottomRightX = (topRight.getX() - topLeft.getX()) + bottomLeft.getX();
bottomRightY = (topRight.getY() - topLeft.getY()) + bottomLeft.getY();
sourceBottomRightX = sourceBottomRightY = dimMinusThree;
}
GridSampler sampler = GridSampler.Instance;
return sampler.sampleGrid(
image,
dimension,
3.5f,
3.5f,
dimMinusThree,
3.5f,
sourceBottomRightX,
sourceBottomRightY,
3.5f,
dimMinusThree,
topLeft.getX(),
topLeft.getY(),
topRight.getX(),
topRight.getY(),
bottomRightX,
bottomRightY,
bottomLeft.getX(),
bottomLeft.getY());
}
private static BitMatrix sampleGrid(MonochromeBitmapSource image,
ResultPoint topLeft,
ResultPoint bottomLeft,
ResultPoint bottomRight,
int dimension) {
// We make up the top right point for now, based on the others.
// TODO: we actually found a fourth corner above and figured out which of two modules
// it was the corner of. We could use that here and adjust for perspective distortion.
float topRightX = (bottomRight.getX() - bottomLeft.getX()) + topLeft.getX();
float topRightY = (bottomRight.getY() - bottomLeft.getY()) + topLeft.getY();
// Note that unlike in the QR Code sampler, we didn't find the center of modules, but the
// very corners. So there is no 0.5f here; 0.0f is right.
GridSampler sampler = GridSampler.Instance;
return sampler.sampleGrid(
image,
dimension,
0.0f,
0.0f,
dimension,
0.0f,
dimension,
dimension,
0.0f,
dimension,
topLeft.getX(),
topLeft.getY(),
topRightX,
topRightY,
bottomRight.getX(),
bottomRight.getY(),
bottomLeft.getX(),
bottomLeft.getY());
}