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Port Java qr detector changes

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re-port
Detector::sizeOfBlackWhiteBlackRunBothWays
and
Detector::sizeOfBlackWhiteBlackRun
to reflect changes from r1820 and earlier.

git-svn-id: https://zxing.googlecode.com/svn/trunk@1838 59b500cc-1b3d-0410-9834-0bbf25fbcc57
This commit is contained in:
smparkes@smparkes.net 2011-06-28 15:59:45 +00:00
parent 10065f8c1c
commit 0d4ae9fef6
1 changed files with 72 additions and 64 deletions
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136
cpp/core/src/zxing/qrcode/detector/Detector.cpp
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@ -181,84 +181,92 @@ float Detector::calculateModuleSizeOneWay(Ref<ResultPoint> pattern, Ref<ResultPo
float Detector::sizeOfBlackWhiteBlackRunBothWays(int fromX, int fromY, int toX, int toY) {
float result = sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
float result = sizeOfBlackWhiteBlackRun(fromX, fromY, toX, toY);
// Now count other way -- don't run off image though of course
float scale = 1.0f;
int otherToX = fromX - (toX - fromX);
if (otherToX < 0) {
scale = (float) fromX / (float) (fromX - otherToX);
otherToX = 0;
} else if (otherToX > (int)image_->getWidth()) {
scale = (float) (image_->getWidth() - fromX) / (float) (otherToX - fromX);
otherToX = image_->getWidth();
}
int otherToY = (int) (fromY - (toY - fromY) * scale);
// Now count other way -- don't run off image though of course
float scale = 1.0f;
int otherToX = fromX - (toX - fromX);
if (otherToX < 0) {
scale = (float) fromX / (float) (fromX - otherToX);
otherToX = 0;
} else if (otherToX >= (int)image_->getWidth()) {
scale = (float) (image_->getWidth() - 1 - fromX) / (float) (otherToX - fromX);
otherToX = image_->getWidth() - 1;
}
int otherToY = (int) (fromY - (toY - fromY) * scale);
scale = 1.0f;
if (otherToY < 0) {
scale = (float) fromY / (float) (fromY - otherToY);
otherToY = 0;
} else if (otherToY > (int)image_->getHeight()) {
scale = (float) (image_->getHeight() - fromY) / (float) (otherToY - fromY);
otherToY = image_->getHeight();
}
otherToX = (int) (fromX + (otherToX - fromX) * scale);
scale = 1.0f;
if (otherToY < 0) {
scale = (float) fromY / (float) (fromY - otherToY);
otherToY = 0;
} else if (otherToY >= (int)image_->getHeight()) {
scale = (float) (image_->getHeight() - 1 - fromY) / (float) (otherToY - fromY);
otherToY = image_->getHeight() - 1;
}
otherToX = (int) (fromX + (otherToX - fromX) * scale);
result += sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
return result;
result += sizeOfBlackWhiteBlackRun(fromX, fromY, otherToX, otherToY);
// Middle pixel is double-counted this way; subtract 1
return result - 1.0f;
}
float Detector::sizeOfBlackWhiteBlackRun(int fromX, int fromY, int toX, int toY) {
// Mild variant of Bresenham's algorithm;
// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
bool steep = abs(toY - fromY) > abs(toX - fromX);
if (steep) {
int temp = fromX;
fromX = fromY;
fromY = temp;
temp = toX;
toX = toY;
toY = temp;
}
// Mild variant of Bresenham's algorithm;
// see http://en.wikipedia.org/wiki/Bresenham's_line_algorithm
bool steep = abs(toY - fromY) > abs(toX - fromX);
if (steep) {
int temp = fromX;
fromX = fromY;
fromY = temp;
temp = toX;
toX = toY;
toY = temp;
}
int dx = abs(toX - fromX);
int dy = abs(toY - fromY);
int error = -dx >> 1;
int ystep = fromY < toY ? 1 : -1;
int xstep = fromX < toX ? 1 : -1;
int state = 0; // In black pixels, looking for white, first or second time
for (int x = fromX, y = fromY; x != toX; x += xstep) {
int dx = abs(toX - fromX);
int dy = abs(toY - fromY);
int error = -dx >> 1;
int xstep = fromX < toX ? 1 : -1;
int ystep = fromY < toY ? 1 : -1;
int realX = steep ? y : x;
int realY = steep ? x : y;
if (state == 1) { // In white pixels, looking for black
if (image_->get(realX, realY)) {
// In black pixels, looking for white, first or second time.
int state = 0;
// Loop up until x == toX, but not beyond
int xLimit = toX + xstep;
for (int x = fromX, y = fromY; x != xLimit; x += xstep) {
int realX = steep ? y : x;
int realY = steep ? x : y;
// Does current pixel mean we have moved white to black or vice versa?
if (!(state == 1 ^ image_->get(realX, realY))) {
if (state == 2) {
int diffX = x - fromX;
int diffY = y - fromY;
return (float) sqrt((double) (diffX * diffX + diffY * diffY));
}
state++;
}
} else {
if (!image_->get(realX, realY)) {
state++;
}
}
if (state == 3) { // Found black, white, black, and stumbled back onto white; done
int diffX = x - fromX;
int diffY = y - fromY;
if (xstep < 0) {
diffX++;
error += dy;
if (error > 0) {
if (y == toY) {
break;
}
y += ystep;
error -= dx;
}
return (float)sqrt((double)(diffX * diffX + diffY * diffY));
}
error += dy;
if (error > 0) {
y += ystep;
error -= dx;
// Found black-white-black; give the benefit of the doubt that the next pixel outside the image
// is "white" so this last point at (toX+xStep,toY) is the right ending. This is really a
// small approximation; (toX+xStep,toY+yStep) might be really correct. Ignore this.
if (state == 2) {
int diffX = toX + xstep - fromX;
int diffY = toY - fromY;
return (float) sqrt((double) (diffX * diffX + diffY * diffY));
}
}
int diffX = toX - fromX;
int diffY = toY - fromY;
return (float)sqrt((double)(diffX * diffX + diffY * diffY));
// else we didn't find even black-white-black; no estimate is really possible
return NAN;
}
Ref<AlignmentPattern> Detector::findAlignmentInRegion(float overallEstModuleSize, int estAlignmentX, int estAlignmentY,