141 lines
3.1 KiB
C++
141 lines
3.1 KiB
C++
#ifndef VEC2D_H_INCLUDED
|
|
#define VEC2D_H_INCLUDED
|
|
|
|
#include "cairo.h"
|
|
|
|
#include <cmath>
|
|
#include <iostream>
|
|
#include <ostream>
|
|
|
|
class vec2d {
|
|
public:
|
|
double x;
|
|
double y;
|
|
|
|
vec2d& operator=(const vec2d& other) {
|
|
x = other.x;
|
|
y = other.y;
|
|
return *this;
|
|
}
|
|
|
|
vec2d& operator+=(const vec2d& other) {
|
|
x += other.x;
|
|
y += other.y;
|
|
return *this;
|
|
}
|
|
|
|
vec2d& operator-=(const vec2d& other) {
|
|
x -= other.x;
|
|
y -= other.y;
|
|
return *this;
|
|
}
|
|
|
|
vec2d& operator*=(double l) {
|
|
x *= l;
|
|
y *= l;
|
|
return *this;
|
|
}
|
|
|
|
vec2d operator+(const vec2d& other) const {
|
|
return vec2d{x + other.x, y + other.y};
|
|
}
|
|
|
|
vec2d operator-(const vec2d& other) const {
|
|
return vec2d{x - other.x, y - other.y};
|
|
}
|
|
|
|
vec2d operator-() const {
|
|
return vec2d{-x, -y};
|
|
}
|
|
|
|
vec2d operator*(double l) const {
|
|
return vec2d{x * l, y * l};
|
|
}
|
|
|
|
vec2d operator/(double a) const {
|
|
return vec2d{x / a, y / a};
|
|
}
|
|
|
|
bool operator==(vec2d& o) const {
|
|
return x == o.x && y == o.y;
|
|
}
|
|
|
|
vec2d& rotate(double angle) {
|
|
double sin_a = sin(angle);
|
|
double cos_a = cos(angle);
|
|
double x1 = x;
|
|
double y1 = y;
|
|
x = cos_a * x1 - sin_a * y1;
|
|
y = sin_a * x1 + cos_a * y1;
|
|
return *this;
|
|
}
|
|
|
|
vec2d orthogonal() {
|
|
return {-y, x};
|
|
}
|
|
|
|
void draw(cairo_t* cr, vec2d p) const {
|
|
double arrow_lenght_ = 10 * vec2d::norm(*this);
|
|
double arrow_degrees_ = .5;
|
|
|
|
// see
|
|
// http://kapo-cpp.blogspot.com/2008/10/drawing-arrows-with-cairo.html
|
|
double angle = atan2(y, x) + M_PI;
|
|
|
|
vec2d end = p + (*this) * 30;
|
|
|
|
double x1 = end.x + arrow_lenght_ * cos(angle - arrow_degrees_);
|
|
double y1 = end.y + arrow_lenght_ * sin(angle - arrow_degrees_);
|
|
double x2 = end.x + arrow_lenght_ * cos(angle + arrow_degrees_);
|
|
double y2 = end.y + arrow_lenght_ * sin(angle + arrow_degrees_);
|
|
|
|
cairo_set_source_rgb(cr, 255, 0, 0);
|
|
|
|
cairo_move_to(cr, p.x, p.y);
|
|
cairo_line_to(cr, end.x, end.y);
|
|
cairo_stroke(cr);
|
|
|
|
cairo_move_to(cr, end.x, end.y);
|
|
cairo_line_to(cr, x1, y1);
|
|
cairo_stroke(cr);
|
|
|
|
cairo_move_to(cr, end.x, end.y);
|
|
cairo_line_to(cr, x2, y2);
|
|
cairo_stroke(cr);
|
|
}
|
|
|
|
static double dot(const vec2d& a, const vec2d& b) {
|
|
return a.x * b.x + a.y * b.y;
|
|
}
|
|
|
|
static double cross(const vec2d& a, const vec2d& b) {
|
|
return a.x * b.y - a.y * b.x;
|
|
}
|
|
|
|
static vec2d cross(const double omega, const vec2d& v) {
|
|
return {-omega * v.y, omega * v.x};
|
|
}
|
|
|
|
static double norm2(const vec2d& v) {
|
|
return vec2d::dot(v, v);
|
|
}
|
|
|
|
static double norm(const vec2d& v) {
|
|
return std::sqrt(dot(v, v));
|
|
}
|
|
|
|
static vec2d normalize(const vec2d& v) {
|
|
return v / norm(v);
|
|
}
|
|
};
|
|
|
|
static inline std::ostream& operator<<(std::ostream& os, vec2d& p) {
|
|
return os << '(' << p.x << ", " << p.y << ')';
|
|
}
|
|
|
|
static inline vec2d operator*(double l, const vec2d& v) {
|
|
return vec2d{v.x * l, v.y * l};
|
|
}
|
|
|
|
#endif
|