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/* MiscTDUtils.m
Copyright 1996 Uwe Hoffmann.
This notice may not be removed from this source code.
The use and distribution of this software is governed by the
terms of the MiscKit license agreement. Refer to the license
document included with the MiscKit distribution for the terms.
Version 2 (August 1996)
*/
#import <Foundation/Foundation.h>
BOOL miscTD_straddles(NSPoint p1, NSPoint p2, NSPoint p3, NSPoint p4)
{
float crossP1, crossP2;
crossP1 = (p3.x - p1.x) * (p2.y - p1.y) - (p2.x - p1.x) * (p3.y - p1.y);
crossP2 = (p4.x - p1.x) * (p2.y - p1.y) - (p2.x - p1.x) * (p4.y - p1.y);
if((crossP1 > 0 && crossP2 < 0) || (crossP1 < 0 && crossP2 > 0)){
crossP1 = (p1.x - p3.x) * (p4.y - p3.y) - (p4.x - p3.x) * (p1.y - p3.y);
crossP2 = (p2.x - p3.x) * (p4.y - p3.y) - (p4.x - p3.x) * (p2.y - p3.y);
if((crossP1 > 0 && crossP2 < 0) || (crossP1 < 0 && crossP2 > 0))
return YES;
else
return NO;
} else
return NO;
}
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