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+ add middle_point() method

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+ fixed 'point' positioning
  in shield_symbolizer
This commit is contained in:
Artem Pavlenko 2010-06-10 16:34:52 +00:00
parent e634c06c17
commit b1b730d94c
2 changed files with 54 additions and 1 deletions
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52
include/mapnik/geometry.hpp
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@ -251,6 +251,58 @@ public:
*y=y0;
}
void middle_point(double *x, double *y) const
{
// calculate mid point on path
double x0=0;
double y0=0;
double x1=0;
double y1=0;
unsigned size = cont_.size();
if (size == 1)
{
cont_.get_vertex(0,x,y);
}
else if (size == 2)
{
cont_.get_vertex(0,&x0,&y0);
cont_.get_vertex(1,&x1,&y1);
*x = 0.5 * (x1 + x0);
*y = 0.5 * (y1 + y0);
}
else
{
double len=0.0;
for (unsigned pos = 1; pos < size; ++pos)
{
cont_.get_vertex(pos-1,&x0,&y0);
cont_.get_vertex(pos,&x1,&y1);
double dx = x1 - x0;
double dy = y1 - y0;
len += std::sqrt(dx * dx + dy * dy);
}
double midlen = 0.5 * len;
double dist = 0.0;
for (unsigned pos = 1; pos < size;++pos)
{
cont_.get_vertex(pos-1,&x0,&y0);
cont_.get_vertex(pos,&x1,&y1);
double dx = x1 - x0;
double dy = y1 - y0;
double seg_len = std::sqrt(dx * dx + dy * dy);
if (( dist + seg_len) >= midlen)
{
double r = (midlen - dist)/seg_len;
*x = x0 + (x1 - x0) * r;
*y = y0 + (y1 - y0) * r;
break;
}
dist += seg_len;
}
}
}
void line_to(value_type x,value_type y)
{
cont_.push_back(x,y,SEG_LINETO);

3
src/agg/process_shield_symbolizer.cpp
View file

@ -154,7 +154,8 @@ void agg_renderer<T>::process(shield_symbolizer const& sym,
if( how_placed == VERTEX_PLACEMENT )
geom.vertex(&label_x,&label_y); // by vertex
else
geom.label_position(&label_x, &label_y); // by middle of line or by point
geom.middle_point(&label_x, &label_y); // by middle of line
prj_trans.backward(label_x,label_y, z);
t_.forward(&label_x,&label_y);