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Fix centroid and interior algorithms (#3771)

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* fix interior algorithm - closing segment handling

* fix centroid algorithm - closing segment handling

* update visual tests
This commit is contained in:
talaj 2017-09-25 15:45:02 +02:00 committed by Artem Pavlenko
parent 304cce8efa
commit f3cf1ad388
2 changed files with 70 additions and 61 deletions
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97
include/mapnik/geom_util.hpp
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@ -28,6 +28,8 @@
#include <mapnik/coord.hpp>
#include <mapnik/vertex.hpp>
#include <mapnik/geometry/geometry_types.hpp>
#include <mapnik/geometry/point.hpp>
// stl
#include <cmath>
#include <vector>
@ -329,56 +331,60 @@ bool middle_point(PathType & path, double & x, double & y)
template <typename PathType>
bool centroid(PathType & path, double & x, double & y)
{
double x0 = 0.0;
double y0 = 0.0;
double x1 = 0.0;
double y1 = 0.0;
double start_x;
double start_y;
geometry::point<double> p0, p1, move_to, start;
path.rewind(0);
unsigned command = path.vertex(&x0, &y0);
unsigned command = path.vertex(&p0.x, &p0.y);
if (command == SEG_END) return false;
start_x = x0;
start_y = y0;
start = move_to = p0;
double atmp = 0.0;
double xtmp = 0.0;
double ytmp = 0.0;
unsigned count = 1;
while (SEG_END != (command = path.vertex(&x1, &y1)))
while (SEG_END != (command = path.vertex(&p1.x, &p1.y)))
{
if (command == SEG_CLOSE) continue;
double dx0 = x0 - start_x;
double dy0 = y0 - start_y;
double dx1 = x1 - start_x;
double dy1 = y1 - start_y;
switch (command)
{
case SEG_MOVETO:
move_to = p1;
break;
case SEG_CLOSE:
p1 = move_to;
case SEG_LINETO:
double dx0 = p0.x - start.x;
double dy0 = p0.y - start.y;
double dx1 = p1.x - start.x;
double dy1 = p1.y - start.y;
double ai = dx0 * dy1 - dx1 * dy0;
atmp += ai;
xtmp += (dx1 + dx0) * ai;
ytmp += (dy1 + dy0) * ai;
x0 = x1;
y0 = y1;
break;
}
p0 = p1;
++count;
}
if (count <= 2) {
x = (start_x + x0) * 0.5;
y = (start_y + y0) * 0.5;
if (count <= 2)
{
x = (start.x + p0.x) * 0.5;
y = (start.y + p0.y) * 0.5;
return true;
}
if (atmp != 0)
{
x = (xtmp/(3*atmp)) + start_x;
y = (ytmp/(3*atmp)) + start_y;
x = (xtmp / (3 * atmp)) + start.x;
y = (ytmp / (3 * atmp)) + start.y;
}
else
{
x = x0;
y = y0;
x = p0.x;
y = p0.y;
}
return true;
}
@ -532,47 +538,50 @@ bool interior_position(PathType & path, double & x, double & y)
// center of the widest intersection between the polygon and the line.
std::vector<double> intersections; // only need to store the X as we know the y
geometry::point<double> p0, p1, move_to;
unsigned command = SEG_END;
double x0 = 0;
double y0 = 0;
path.rewind(0);
unsigned command = path.vertex(&x0, &y0);
double x1 = 0;
double y1 = 0;
while (SEG_END != (command = path.vertex(&x1, &y1)))
while (SEG_END != (command = path.vertex(&p0.x, &p0.y)))
{
if (command == SEG_CLOSE)
continue;
if (command != SEG_MOVETO)
switch (command)
{
case SEG_MOVETO:
move_to = p0;
break;
case SEG_CLOSE:
p0 = move_to;
case SEG_LINETO:
// if the segments overlap
if (y0==y1)
if (p0.y == p1.y)
{
if (y0==y)
if (p0.y == y)
{
double xi = (x0+x1)/2.0;
double xi = (p0.x + p1.x) / 2.0;
intersections.push_back(xi);
}
}
// if the path segment crosses the bisector
else if ((y0 <= y && y1 >= y) ||
(y0 >= y && y1 <= y))
else if ((p0.y <= y && p1.y >= y) ||
(p0.y >= y && p1.y <= y))
{
// then calculate the intersection
double xi = x0;
if (x0 != x1)
double xi = p0.x;
if (p0.x != p1.x)
{
double m = (y1-y0)/(x1-x0);
double c = y0 - m*x0;
double m = (p1.y - p0.y) / (p1.x - p0.x);
double c = p0.y - m * p0.x;
xi = (y - c) / m;
}
intersections.push_back(xi);
}
break;
}
x0 = x1;
y0 = y1;
p1 = p0;
}
// no intersections we just return the default
if (intersections.empty())
return true;

2
test/data-visual

@ -1 +1 @@
Subproject commit 0af6da2ce95b9b5a06b79a18c4b00ee114ca8efc
Subproject commit c02a08b045197fc0a7b28ac060cf74b58cfb3a2b