From da743e0e16f93475da650878c1aaed36cfd3d2a4 Mon Sep 17 00:00:00 2001
From: nedko <nedko@internedko.net>
Date: Tue, 13 Sep 2022 17:54:19 +0300
Subject: [PATCH] Added initial path implementation. Needs stroke width fixing

---
 .gitignore    |   1 +
 main_path.cpp | 177 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 178 insertions(+)
 create mode 100644 main_path.cpp

diff --git a/.gitignore b/.gitignore
index 6c08583..953d70e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,4 @@ polygon
 polygon.exe
 path
 path.exe
+.vscode/*
diff --git a/main_path.cpp b/main_path.cpp
new file mode 100644
index 0000000..3986b01
--- /dev/null
+++ b/main_path.cpp
@@ -0,0 +1,177 @@
+#include <iostream>
+#include <string>
+#include <vector>
+#include <utility>
+
+#include <math.h>
+
+using namespace std;
+
+struct Point
+{
+	double x;
+	double y;
+
+	Point& operator/=(const double& val)
+	{
+		x /= val;
+		y /= val;
+		return *this;
+	}
+};
+
+Point operator-(const Point& p1, const Point& p2)
+{
+	return Point{.x = p1.x - p2.x, .y = p1.y - p2.y};
+}
+
+Point operator+(const Point& p1, const Point& p2)
+{
+	return Point{.x = p1.x + p2.x, .y = p1.y + p2.y};
+}
+
+double radians(double degrees)
+{
+	return degrees * M_PI / 180.0;
+}
+
+double degrees(double radians)
+{
+	return radians * 180.0 / M_PI;
+}
+
+Point& vec_normalize(Point& vec)
+{
+	double len = sqrt(vec.x * vec.x + vec.y * vec.y);
+	vec /= len;
+	return vec;
+}
+
+double get_angle(Point start, Point end)
+{
+	double angle;
+	Point vec;
+	double dot;
+
+	vec = end - start;
+	vec_normalize(vec);
+
+	angle = degrees(acos(vec.x));
+
+	if (vec.y < 0)
+	{
+		angle += 180.0;
+	}
+
+	return angle;
+}
+
+double get_stroke_angle(double prev_angle, double curr_angle)
+{
+	double angle;
+
+	angle = (curr_angle - prev_angle) / 2 + prev_angle + 90;
+
+	return angle;
+}
+
+pair<Point, Point> perform_stroke(double stroke_size, double stroke_angle, Point point)
+{
+	pair<Point, Point> result;
+	Point add;
+
+	add.x = cos(radians(stroke_angle)) * stroke_size / 2;
+	add.y = sin(radians(stroke_angle)) * stroke_size / 2;
+
+	result.first = point + add;
+	result.second = point - add;
+
+	return result;
+}
+
+void usage(const string& name)
+{
+	cout << "Usage: " << name << "<stroke size> <x1> <y1> <x2> <y2> [<xN> <yN> ...]" << endl;
+	cout << "\tstroke size - how big the stroke should be" << endl;
+	cout << "\tx1 - x coordinate of first point" << endl;
+	cout << "\ty1 - y coordinate of first point" << endl;
+}
+
+void get_polygon(double stroke_size, const vector<Point>& points)
+{
+	double prev_angle;
+	double curr_angle;
+	vector<Point> forward;
+	vector<Point> backward;
+	pair<Point, Point> tmp;
+
+	for (int i = 1; i < points.size(); ++i)
+	{
+		prev_angle = curr_angle;
+		curr_angle = get_angle(points[i - 1], points[i]);
+
+		if (1 == i)
+		{
+			// First angle is end cap
+			tmp = perform_stroke(stroke_size, curr_angle + 90, points[i - 1]);
+		}
+		else
+		{
+			tmp = perform_stroke(stroke_size, get_stroke_angle(prev_angle, curr_angle), points[i - 1]);
+		}
+
+		forward.push_back(tmp.first);
+		backward.push_back(tmp.second);
+	}
+
+	// Last angle is end cap
+	tmp = perform_stroke(stroke_size, curr_angle + 90, points[points.size() - 1]);
+	forward.push_back(tmp.first);
+	backward.push_back(tmp.second);
+
+	for (int i = 0; i < forward.size(); ++i)
+	{
+		cout << forward[i].x << "," << forward[i].y << " ";
+	}
+
+	for (int i = backward.size() - 1; i >= 0; --i)
+	{
+		cout << backward[i].x << "," << backward[i].y << " ";
+	}
+
+	cout << endl;
+}
+
+int main(int argc, char **argv)
+{
+	double stroke_size;
+	Point tmp;
+	vector<Point> points;
+	int last_idx;
+
+	if (argc < 5)
+	{
+		usage(argv[0]);
+		cout << "Insufficient arguments" << endl;
+		return -1;
+	}
+
+	stroke_size = stod(argv[1]);
+
+	last_idx = argc;
+	if (0 != last_idx % 2)
+	{
+		--last_idx;
+	}
+
+	for (int i = 2; i < last_idx; i += 2)
+	{
+		tmp.x = stod(argv[i]);
+		tmp.y = stod(argv[i + 1]);
+		points.push_back(tmp);
+	}
+
+	get_polygon(stroke_size, points);
+
+	return 0;
+}