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