m_base_length(0.0),

m_kindex(0.0),

m_status(initial),

m_preserve_x_scale(true)

{

{

m_src_vertices.remove_all();

m_kindex = 0.0;

m_status = initial;

{

if(m_status == initial)

{

m_src_vertices.modify_last(vertex_dist(x, y));

m_status = making_path;

}

else

{

line_to(x, y);

}

{

if(m_status == making_path)

{

m_src_vertices.add(vertex_dist(x, y));

}

{

if(m_status == making_path && m_src_vertices.size() > 1)

{

unsigned i;

double dist;

double d;

m_src_vertices.close(false);

if(m_src_vertices.size() > 2)

{

if(m_src_vertices[m_src_vertices.size() - 2].dist * 10.0 <

m_src_vertices[m_src_vertices.size() - 3].dist)

{

d = m_src_vertices[m_src_vertices.size() - 3].dist +

m_src_vertices[m_src_vertices.size() - 2].dist;

m_src_vertices[m_src_vertices.size() - 2] =

m_src_vertices[m_src_vertices.size() - 1];

m_src_vertices.remove_last();

m_src_vertices[m_src_vertices.size() - 2].dist = d;

}

}

dist = 0.0;

for(i = 0; i < m_src_vertices.size(); i++)

{

vertex_dist& v = m_src_vertices[i];

double d = v.dist;

v.dist = dist;

dist += d;

}

m_kindex = (m_src_vertices.size() - 1) / dist;

m_status = ready;

}

{

if(m_base_length >= 1e-10) return m_base_length;

return (m_status == ready) ?

m_src_vertices[m_src_vertices.size() - 1].dist :

0.0;

{

if(m_status == ready)

{

if(m_base_length > 1e-10)

{

*x *= m_src_vertices[m_src_vertices.size() - 1].dist /

m_base_length;

}

double x1 = 0.0;

double y1 = 0.0;

double dx = 1.0;

double dy = 1.0;

double d = 0.0;

double dd = 1.0;

if(*x < 0.0)

{

// Extrapolation on the left

//--------------------------

x1 = m_src_vertices[0].x;

y1 = m_src_vertices[0].y;

dx = m_src_vertices[1].x - x1;

dy = m_src_vertices[1].y - y1;

dd = m_src_vertices[1].dist - m_src_vertices[0].dist;

d = *x;

}

else

if(*x > m_src_vertices[m_src_vertices.size() - 1].dist)

{

// Extrapolation on the right

//--------------------------

unsigned i = m_src_vertices.size() - 2;

unsigned j = m_src_vertices.size() - 1;

x1 = m_src_vertices[j].x;

y1 = m_src_vertices[j].y;

dx = x1 - m_src_vertices[i].x;

dy = y1 - m_src_vertices[i].y;

dd = m_src_vertices[j].dist - m_src_vertices[i].dist;

d = *x - m_src_vertices[j].dist;

}

else

{

// Interpolation

//--------------------------

unsigned i = 0;

unsigned j = m_src_vertices.size() - 1;

if(m_preserve_x_scale)

{

unsigned k;

for(i = 0; (j - i) > 1; )

{

if(*x < m_src_vertices[k = (i + j) >> 1].dist)

{

j = k;

}

else

{

i = k;

}

}

d = m_src_vertices[i].dist;

dd = m_src_vertices[j].dist - d;

d = *x - d;

}

else

{

i = unsigned(*x * m_kindex);

j = i + 1;

dd = m_src_vertices[j].dist - m_src_vertices[i].dist;

d = ((*x * m_kindex) - i) * dd;

}

x1 = m_src_vertices[i].x;

y1 = m_src_vertices[i].y;

dx = m_src_vertices[j].x - x1;

dy = m_src_vertices[j].y - y1;

}

double x2 = x1 + dx * d / dd;

double y2 = y1 + dy * d / dd;

*x = x2 - *y * dy / dd;

*y = y2 + *y * dx / dd;

}