mirror of https://github.com/Chlumsky/msdfgen.git
82 lines
2.5 KiB
C++
82 lines
2.5 KiB
C++
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#include "Contour.h"
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#include "arithmetics.hpp"
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namespace msdfgen {
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static double shoelace(const Point2 &a, const Point2 &b) {
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return (b.x-a.x)*(a.y+b.y);
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}
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void Contour::addEdge(const EdgeHolder &edge) {
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edges.push_back(edge);
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}
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#ifdef MSDFGEN_USE_CPP11
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void Contour::addEdge(EdgeHolder &&edge) {
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edges.push_back((EdgeHolder &&) edge);
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}
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#endif
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EdgeHolder & Contour::addEdge() {
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edges.resize(edges.size()+1);
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return edges.back();
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}
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static void pointBounds(Point2 p, double &l, double &b, double &r, double &t) {
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if (p.x < l) l = p.x;
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if (p.y < b) b = p.y;
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if (p.x > r) r = p.x;
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if (p.y > t) t = p.y;
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}
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void Contour::bounds(double &l, double &b, double &r, double &t) const {
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for (std::vector<EdgeHolder>::const_iterator edge = edges.begin(); edge != edges.end(); ++edge)
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(*edge)->bounds(l, b, r, t);
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}
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void Contour::miterBounds(double &l, double &b, double &r, double &t, double border, double miterLimit) const {
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if (edges.empty())
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return;
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Vector2 prevDir = edges.back()->direction(1).normalize(true);
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for (std::vector<EdgeHolder>::const_iterator edge = edges.begin(); edge != edges.end(); ++edge) {
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Vector2 dir = -(*edge)->direction(0).normalize(true);
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double miterLength = miterLimit;
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double q = .5*(1-dotProduct(prevDir, dir));
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if (q > 0)
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miterLength = min(1/sqrt(q), miterLimit);
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Point2 miter = (*edge)->point(0)+border*miterLength*(prevDir+dir).normalize(true);
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pointBounds(miter, l, b, r, t);
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prevDir = (*edge)->direction(1).normalize(true);
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}
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}
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int Contour::winding() const {
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if (edges.empty())
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return 0;
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double total = 0;
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if (edges.size() == 1) {
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Point2 a = edges[0]->point(0), b = edges[0]->point(1/3.), c = edges[0]->point(2/3.);
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total += shoelace(a, b);
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total += shoelace(b, c);
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total += shoelace(c, a);
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} else if (edges.size() == 2) {
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Point2 a = edges[0]->point(0), b = edges[0]->point(.5), c = edges[1]->point(0), d = edges[1]->point(.5);
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total += shoelace(a, b);
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total += shoelace(b, c);
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total += shoelace(c, d);
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total += shoelace(d, a);
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} else {
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Point2 prev = edges.back()->point(0);
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for (std::vector<EdgeHolder>::const_iterator edge = edges.begin(); edge != edges.end(); ++edge) {
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Point2 cur = (*edge)->point(0);
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total += shoelace(prev, cur);
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prev = cur;
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}
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}
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return sign(total);
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}
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}
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