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 }