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#pragma once
#include <vector>
namespace msdfgen {
/// Fill rule dictates how intersection total is interpreted during rasterization.
enum FillRule {
FILL_NONZERO,
FILL_ODD, // "even-odd"
FILL_POSITIVE,
FILL_NEGATIVE
};
/// Resolves the number of intersection into a binary fill value based on fill rule.
bool interpretFillRule(int intersections, FillRule fillRule);
/// Represents a horizontal scanline intersecting a shape.
class Scanline {
public:
/// An intersection with the scanline.
struct Intersection {
/// X coordinate.
double x;
/// Normalized Y direction of the oriented edge at the point of intersection.
int direction;
};
static double overlap(const Scanline &a, const Scanline &b, double xFrom, double xTo, FillRule fillRule);
Scanline();
/// Populates the intersection list.
void setIntersections(const std::vector<Intersection> &intersections);
#ifdef MSDFGEN_USE_CPP11
void setIntersections(std::vector<Intersection> &&intersections);
#endif
/// Returns the number of intersections left of x.
int countIntersections(double x) const;
/// Returns the total sign of intersections left of x.
int sumIntersections(double x) const;
/// Decides whether the scanline is filled at x based on fill rule.
bool filled(double x, FillRule fillRule) const;
private:
std::vector<Intersection> intersections;
mutable int lastIndex;
void preprocess();
int moveTo(double x) const;
};
}
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