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Factor out copied-and-pasted polygon area calculations

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This commit is contained in:
Eric Fischer 2016-03-28 17:01:17 -07:00
parent 6f5199adc7
commit c404082421
1 changed files with 4 additions and 24 deletions
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28
geometry.cc
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@ -283,12 +283,7 @@ drawvec clean_or_clip_poly(drawvec &geom, int z, int detail, int buffer, bool cl
}
}
double area = 0;
for (size_t k = i; k < j; k++) {
area += (long double) geom[k].x * (long double) geom[i + ((k - i + 1) % (j - i))].y;
area -= (long double) geom[k].y * (long double) geom[i + ((k - i + 1) % (j - i))].x;
}
area = area / 2;
double area = get_area(geom, i, j);
if (area != 0) {
has_area = true;
}
@ -417,12 +412,7 @@ void check_polygon(drawvec &geom) {
}
}
double area = 0;
for (size_t k = i; k < j; k++) {
area += (long double) geom[k].x * (long double) geom[i + ((k - i + 1) % (j - i))].y;
area -= (long double) geom[k].y * (long double) geom[i + ((k - i + 1) % (j - i))].x;
}
area = area / 2;
double area = get_area(geom, i, j);
if (area > 0) {
outer_start = i;
@ -658,12 +648,7 @@ drawvec reduce_tiny_poly(drawvec &geom, int z, int detail, bool *reduced, double
}
}
double area = 0;
for (size_t k = i; k < j; k++) {
area += (long double) geom[k].x * (long double) geom[i + ((k - i + 1) % (j - i))].y;
area -= (long double) geom[k].y * (long double) geom[i + ((k - i + 1) % (j - i))].x;
}
area = area / 2;
double area = get_area(geom, i, j);
// XXX There is an ambiguity here: If the area of a ring is 0 and it is followed by holes,
// we don't know whether the area-0 ring was a hole too or whether it was the outer ring
@ -1044,12 +1029,7 @@ drawvec fix_polygon(drawvec &geom) {
// Reverse ring if winding order doesn't match
// inner/outer expectation
double area = 0;
for (size_t k = 0; k < ring.size(); k++) {
area += (long double) ring[k].x * (long double) ring[(k + 1) % ring.size()].y;
area -= (long double) ring[k].y * (long double) ring[(k + 1) % ring.size()].x;
}
double area = get_area(ring, 0, ring.size());
if ((area > 0) != outer) {
drawvec tmp;
for (int a = ring.size() - 1; a >= 0; a--) {