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 

    14 CGFloat distanceBetweenPoints (CGPoint first, CGPoint second) {

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

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

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

    18 }

    19 

    20 CGFloat angleBetweenPoints(CGPoint first, CGPoint second) {

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

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

    23 	CGFloat rads = atan(height/width);

    24 	return radiansToDegrees(rads);

    25 }

    26 

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

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

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

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

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

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

    33 	return radiansToDegrees(rads);

    34 }