56 lines
1.5 KiB
C++
56 lines
1.5 KiB
C++
|
|
||
|
|
#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;
|
||
|
|
|
||
|
|
};
|
||
|
|
|
||
|
|
}
|