1 /*

     2  *  CGPointUtils.c

     3  *  PinchMe

     4  *

     5  *  Created by Jeff LaMarche on 8/2/08.

     6  *  Copyright 2008 __MyCompanyName__. All rights reserved.

     7  *

     8  */

     9 

    10 #include "CGPointUtils.h"

    11 #include <math.h>

    12 

    13 #define degreesToRadian(x) (M_PI * x / 180.0)

    14 #define radiansToDegrees(x) (180.0 * x / M_PI)

    15 

    16 CGFloat distanceBetweenPoints (CGPoint first, CGPoint second) {

    17 	CGFloat deltaX = second.x - first.x;

    18 	CGFloat deltaY = second.y - first.y;

    19 	return sqrt(deltaX*deltaX + deltaY*deltaY );

    20 };

    21 

    22 CGFloat angleBetweenPoints(CGPoint first, CGPoint second) {

    23 	CGFloat height = second.y - first.y;

    24 	CGFloat width = first.x - second.x;

    25 	CGFloat rads = atan(height/width);

    26 	return radiansToDegrees(rads);

    27 	//degs = degrees(atan((top - bottom)/(right - left)))

    28 }

    29 

    30 CGFloat angleBetweenLines(CGPoint line1Start, CGPoint line1End, CGPoint line2Start, CGPoint line2End) {

    31 	

    32 	CGFloat a = line1End.x - line1Start.x;

    33 	CGFloat b = line1End.y - line1Start.y;

    34 	CGFloat c = line2End.x - line2Start.x;

    35 	CGFloat d = line2End.y - line2Start.y;

    36 	

    37 	CGFloat rads = acos(((a*c) + (b*d)) / ((sqrt(a*a + b*b)) * (sqrt(c*c + d*d))));

    38 	

    39 	return radiansToDegrees(rads);

    40 }