initial commit, 4.5 stable

thirdparty/msdfgen/core/edge-segments.h

@@ -0,0 +1,146 @@
+
+#pragma once
+
+#include "Vector2.hpp"
+#include "SignedDistance.hpp"
+#include "EdgeColor.h"
+
+namespace msdfgen {
+
+// Parameters for iterative search of closest point on a cubic Bezier curve. Increase for higher precision.
+#define MSDFGEN_CUBIC_SEARCH_STARTS 4
+#define MSDFGEN_CUBIC_SEARCH_STEPS 4
+
+/// An abstract edge segment.
+class EdgeSegment {
+
+public:
+    EdgeColor color;
+
+    static EdgeSegment *create(Point2 p0, Point2 p1, EdgeColor edgeColor = WHITE);
+    static EdgeSegment *create(Point2 p0, Point2 p1, Point2 p2, EdgeColor edgeColor = WHITE);
+    static EdgeSegment *create(Point2 p0, Point2 p1, Point2 p2, Point2 p3, EdgeColor edgeColor = WHITE);
+
+    EdgeSegment(EdgeColor edgeColor = WHITE) : color(edgeColor) { }
+    virtual ~EdgeSegment() { }
+    /// Creates a copy of the edge segment.
+    virtual EdgeSegment *clone() const = 0;
+    /// Returns the numeric code of the edge segment's type.
+    virtual int type() const = 0;
+    /// Returns the array of control points.
+    virtual const Point2 *controlPoints() const = 0;
+    /// Returns the point on the edge specified by the parameter (between 0 and 1).
+    virtual Point2 point(double param) const = 0;
+    /// Returns the direction the edge has at the point specified by the parameter.
+    virtual Vector2 direction(double param) const = 0;
+    /// Returns the change of direction (second derivative) at the point specified by the parameter.
+    virtual Vector2 directionChange(double param) const = 0;
+    /// Returns the minimum signed distance between origin and the edge.
+    virtual SignedDistance signedDistance(Point2 origin, double &param) const = 0;
+    /// Converts a previously retrieved signed distance from origin to perpendicular distance.
+    virtual void distanceToPerpendicularDistance(SignedDistance &distance, Point2 origin, double param) const;
+    /// Outputs a list of (at most three) intersections (their X coordinates) with an infinite horizontal scanline at y and returns how many there are.
+    virtual int scanlineIntersections(double x[3], int dy[3], double y) const = 0;
+    /// Adjusts the bounding box to fit the edge segment.
+    virtual void bound(double &l, double &b, double &r, double &t) const = 0;
+
+    /// Reverses the edge (swaps its start point and end point).
+    virtual void reverse() = 0;
+    /// Moves the start point of the edge segment.
+    virtual void moveStartPoint(Point2 to) = 0;
+    /// Moves the end point of the edge segment.
+    virtual void moveEndPoint(Point2 to) = 0;
+    /// Splits the edge segments into thirds which together represent the original edge.
+    virtual void splitInThirds(EdgeSegment *&part0, EdgeSegment *&part1, EdgeSegment *&part2) const = 0;
+
+};
+
+/// A line segment.
+class LinearSegment : public EdgeSegment {
+
+public:
+    enum EdgeType {
+        EDGE_TYPE = 1
+    };
+
+    Point2 p[2];
+
+    LinearSegment(Point2 p0, Point2 p1, EdgeColor edgeColor = WHITE);
+    LinearSegment *clone() const;
+    int type() const;
+    const Point2 *controlPoints() const;
+    Point2 point(double param) const;
+    Vector2 direction(double param) const;
+    Vector2 directionChange(double param) const;
+    double length() const;
+    SignedDistance signedDistance(Point2 origin, double &param) const;
+    int scanlineIntersections(double x[3], int dy[3], double y) const;
+    void bound(double &l, double &b, double &r, double &t) const;
+
+    void reverse();
+    void moveStartPoint(Point2 to);
+    void moveEndPoint(Point2 to);
+    void splitInThirds(EdgeSegment *&part0, EdgeSegment *&part1, EdgeSegment *&part2) const;
+
+};
+
+/// A quadratic Bezier curve.
+class QuadraticSegment : public EdgeSegment {
+
+public:
+    enum EdgeType {
+        EDGE_TYPE = 2
+    };
+
+    Point2 p[3];
+
+    QuadraticSegment(Point2 p0, Point2 p1, Point2 p2, EdgeColor edgeColor = WHITE);
+    QuadraticSegment *clone() const;
+    int type() const;
+    const Point2 *controlPoints() const;
+    Point2 point(double param) const;
+    Vector2 direction(double param) const;
+    Vector2 directionChange(double param) const;
+    double length() const;
+    SignedDistance signedDistance(Point2 origin, double &param) const;
+    int scanlineIntersections(double x[3], int dy[3], double y) const;
+    void bound(double &l, double &b, double &r, double &t) const;
+
+    void reverse();
+    void moveStartPoint(Point2 to);
+    void moveEndPoint(Point2 to);
+    void splitInThirds(EdgeSegment *&part0, EdgeSegment *&part1, EdgeSegment *&part2) const;
+
+    EdgeSegment *convertToCubic() const;
+
+};
+
+/// A cubic Bezier curve.
+class CubicSegment : public EdgeSegment {
+
+public:
+    enum EdgeType {
+        EDGE_TYPE = 3
+    };
+
+    Point2 p[4];
+
+    CubicSegment(Point2 p0, Point2 p1, Point2 p2, Point2 p3, EdgeColor edgeColor = WHITE);
+    CubicSegment *clone() const;
+    int type() const;
+    const Point2 *controlPoints() const;
+    Point2 point(double param) const;
+    Vector2 direction(double param) const;
+    Vector2 directionChange(double param) const;
+    SignedDistance signedDistance(Point2 origin, double &param) const;
+    int scanlineIntersections(double x[3], int dy[3], double y) const;
+    void bound(double &l, double &b, double &r, double &t) const;
+
+    void reverse();
+    void moveStartPoint(Point2 to);
+    void moveEndPoint(Point2 to);
+    void splitInThirds(EdgeSegment *&part0, EdgeSegment *&part1, EdgeSegment *&part2) const;
+
+};
+
+}