From fcc313fcaa2b4820103fd7d771bebaac03e0aaba Mon Sep 17 00:00:00 2001
From: boyska <piuttosto@logorroici.org>
Date: Fri, 6 Jan 2017 04:05:18 +0100
Subject: [PATCH] similar_fit much improved

get the inner angle
---
 lines.cpp | 22 ++++++++++++++--------
 lines.h   |  9 +++++++++
 2 files changed, 23 insertions(+), 8 deletions(-)
 create mode 100644 lines.h

diff --git a/lines.cpp b/lines.cpp
index fad7fa1..baaecc1 100644
--- a/lines.cpp
+++ b/lines.cpp
@@ -13,6 +13,15 @@ double dist(cv::Point a, cv::Point b)
 {
 		return sqrt((double)pow(a.x-b.x,2)+pow(a.y-b.y,2));
 }
+
+double inner_angle(cv::Point a, cv::Point middle, cv::Point b)
+{
+	cv::Point v1 = a - middle;
+	cv::Point v2 = b - middle;
+	double v1_length = dist(cv::Point(0, 0), v1);
+	double v2_length = dist(cv::Point(0, 0), v2);
+	return acos( (v1.x*v2.x + v1.y*v2.y) / (v1_length*v2_length) );
+}
 // takes the two points that are more distant from the next, ie:
 // i st distance(hull[i], hull[i+1]) is maximum and 2nd maximum
 int* max2_distance(std::vector<cv::Point> hull)
@@ -51,16 +60,13 @@ int* max2_distance(std::vector<cv::Point> hull)
 
 /* check if a,b,newpoint belong to the same line (with minor approximation) */
 bool similar_fit(cv::Point a, cv::Point b, cv::Point newpoint) {
-	if( newpoint.x==b.x && newpoint.y==b.y )
-		return true;
-	if( a.x==b.x || b.x==newpoint.x )
-		return a.x==b.x && b.x==newpoint.x; // TODO: this is just too harsh, there is no tolerance!
+	return similar_fit(a, b, newpoint, 5);
+}
 
-	double coeff1 = ((double)a.y-b.y) / (a.x-b.x);
-	double coeff2 = ((double)b.y-newpoint.y) / (b.x-newpoint.x);
+bool similar_fit(cv::Point a, cv::Point b, cv::Point newpoint, float tolerance_degrees) {
+	double angle = inner_angle(a, b, newpoint) * 180 / M_PI;
 
-	if( abs(std::max(coeff1,coeff2)/std::min(coeff1,coeff2)) < 2 ) {
-		std::cout << "No fit " << b << newpoint << " " << coeff1 << " " << coeff2 << std::endl;
+	if( angle > (180-tolerance_degrees) &&  angle < (180+tolerance_degrees) ) {
 		return true;
 	}
 	return false;
diff --git a/lines.h b/lines.h
new file mode 100644
index 0000000..55858ea
--- /dev/null
+++ b/lines.h
@@ -0,0 +1,9 @@
+#include<algorithm>
+
+#include<opencv2/opencv.hpp>
+
+std::vector<std::vector<cv::Point>> simplify_hull(std::vector<cv::Point> hull);
+std::vector<std::vector<cv::Point>> simplify_hull(std::vector<cv::Point> hull, double mindistance);
+
+bool similar_fit(cv::Point a, cv::Point b, cv::Point newpoint);
+bool similar_fit(cv::Point a, cv::Point b, cv::Point newpoint, float tolerance_degrees);