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Added support for maps with only 2 reference points

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This commit is contained in:
Martin Tůma 2017-08-14 23:57:53 +02:00
parent afe9a14d5b
commit a7154988ab
1 changed files with 31 additions and 7 deletions
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36
src/offlinemap.cpp
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@ -248,20 +248,44 @@ bool OfflineMap::computeTransformation(const QList<ReferencePoint> &points)
{
Q_ASSERT(points.size() >= 2);
// translate + scale
if (points.size() == 2) {
if (points.at(0).xy.x() == points.at(1).xy.x()
|| points.at(0).xy.y() == points.at(1).xy.y()) {
_errorString = "Invalid reference points tuple";
return false;
}
QPointF p0(_projection->ll2xy(points.at(0).ll));
QPointF p1(_projection->ll2xy(points.at(1).ll));
qreal dX, dY, lat0, lon0;
dX = (p0.x() - p1.x()) / (points.at(0).xy.x() - points.at(1).xy.x());
dY = (p1.y() - p0.y()) / (points.at(1).xy.y() - points.at(0).xy.y());
lat0 = p0.y() - points.at(0).xy.y() * dY;
lon0 = p1.x() - points.at(1).xy.x() * dX;
_transform = QTransform(1.0/dX, 0, 0, 1.0/dY, -lon0/dX, -lat0/dY);
_inverted = _transform.inverted();
return true;
}
// full affine transformation (least squares method)
Matrix c(3, 2);
c.zeroize();
for (size_t i = 0; i < c.h(); i++) {
for (size_t j = 0; j < c.w(); j++) {
for (size_t k = 0; k < c.h(); k++) {
for (int i = 0; i < points.size(); i++) {
for (int k = 0; k < points.size(); k++) {
double f[3], t[2];
QPointF p = _projection->ll2xy(points.at(i).ll);
QPointF p = _projection->ll2xy(points.at(k).ll);
f[0] = p.x();
f[1] = p.y();
f[2] = 1.0;
t[0] = points.at(i).xy.x();
t[1] = points.at(i).xy.y();
c.m(k,j) += f[k] * t[j];
t[0] = points.at(k).xy.x();
t[1] = points.at(k).xy.y();
c.m(i,j) += f[i] * t[j];
}
}
}