LCOV - code coverage report
Current view: directory - objdir/dist/include - gfxLineSegment.h (source / functions) Found Hit Coverage
Test: app.info Lines: 23 0 0.0 %
Date: 2012-06-02 Functions: 3 0 0.0 %

       1                 : /* -*- Mode: C++; tab-width: 20; indent-tabs-mode: nil; c-basic-offset: 4 -*-
       2                 :  * ***** BEGIN LICENSE BLOCK *****
       3                 :  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
       4                 :  *
       5                 :  * The contents of this file are subject to the Mozilla Public License Version
       6                 :  * 1.1 (the "License"); you may not use this file except in compliance with
       7                 :  * the License. You may obtain a copy of the License at
       8                 :  * http://www.mozilla.org/MPL/
       9                 :  *
      10                 :  * Software distributed under the License is distributed on an "AS IS" basis,
      11                 :  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
      12                 :  * for the specific language governing rights and limitations under the
      13                 :  * License.
      14                 :  *
      15                 :  * The Original Code is Mozilla Corporation code.
      16                 :  *
      17                 :  * The Initial Developer of the Original Code is Oracle Corporation.
      18                 :  * Portions created by the Initial Developer are Copyright (C) 2005
      19                 :  * the Initial Developer. All Rights Reserved.
      20                 :  *
      21                 :  * Contributor(s):
      22                 :  *   Matt Woodrow <mwoodrow@mozilla.com>
      23                 :  *
      24                 :  * Alternatively, the contents of this file may be used under the terms of
      25                 :  * either the GNU General Public License Version 2 or later (the "GPL"), or
      26                 :  * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
      27                 :  * in which case the provisions of the GPL or the LGPL are applicable instead
      28                 :  * of those above. If you wish to allow use of your version of this file only
      29                 :  * under the terms of either the GPL or the LGPL, and not to allow others to
      30                 :  * use your version of this file under the terms of the MPL, indicate your
      31                 :  * decision by deleting the provisions above and replace them with the notice
      32                 :  * and other provisions required by the GPL or the LGPL. If you do not delete
      33                 :  * the provisions above, a recipient may use your version of this file under
      34                 :  * the terms of any one of the MPL, the GPL or the LGPL.
      35                 :  *
      36                 :  * ***** END LICENSE BLOCK ***** */
      37                 : 
      38                 : #ifndef GFX_LINESEGMENT_H
      39                 : #define GFX_LINESEGMENT_H
      40                 : 
      41                 : #include "gfxTypes.h"
      42                 : #include "gfxPoint.h"
      43                 : 
      44                 : struct THEBES_API gfxLineSegment {
      45               0 :   gfxLineSegment(const gfxPoint &aStart, const gfxPoint &aEnd) 
      46                 :     : mStart(aStart)
      47               0 :     , mEnd(aEnd)
      48               0 :   {}
      49                 : 
      50               0 :   bool PointsOnSameSide(const gfxPoint& aOne, const gfxPoint& aTwo)
      51                 :   {
      52                 :     // Solve the equation y - mStart.y - ((mEnd.y - mStart.y)/(mEnd.x - mStart.x))(x - mStart.x) for both points 
      53                 :   
      54               0 :     gfxFloat deltaY = (mEnd.y - mStart.y);
      55               0 :     gfxFloat deltaX = (mEnd.x - mStart.x);
      56                 :   
      57               0 :     gfxFloat one = deltaX * (aOne.y - mStart.y) - deltaY * (aOne.x - mStart.x);
      58               0 :     gfxFloat two = deltaX * (aTwo.y - mStart.y) - deltaY * (aTwo.x - mStart.x);
      59                 : 
      60                 :     // If both results have the same sign, then we're on the correct side of the line.
      61                 :     // 0 (on the line) is always considered in.
      62                 : 
      63               0 :     if ((one >= 0 && two >= 0) || (one <= 0 && two <= 0))
      64               0 :       return true;
      65               0 :     return false;
      66                 :   }
      67                 : 
      68                 :   /**
      69                 :    * Determines if two line segments intersect, and returns the intersection
      70                 :    * point in aIntersection if they do.
      71                 :    *
      72                 :    * Coincident lines are considered not intersecting as they don't have an
      73                 :    * intersection point.
      74                 :    */
      75               0 :   bool Intersects(const gfxLineSegment& aOther, gfxPoint& aIntersection)
      76                 :   {
      77                 :     gfxFloat denominator = (aOther.mEnd.y - aOther.mStart.y) * (mEnd.x - mStart.x ) - 
      78               0 :                            (aOther.mEnd.x - aOther.mStart.x ) * (mEnd.y - mStart.y);
      79                 : 
      80                 :     // Parallel or coincident. We treat coincident as not intersecting since
      81                 :     // these lines are guaranteed to have corners that intersect instead.
      82               0 :     if (!denominator) {
      83               0 :       return false;
      84                 :     }
      85                 : 
      86                 :     gfxFloat anumerator = (aOther.mEnd.x - aOther.mStart.x) * (mStart.y - aOther.mStart.y) -
      87               0 :                          (aOther.mEnd.y - aOther.mStart.y) * (mStart.x - aOther.mStart.x);
      88                 :   
      89                 :     gfxFloat bnumerator = (mEnd.x - mStart.x) * (mStart.y - aOther.mStart.y) -
      90               0 :                          (mEnd.y - mStart.y) * (mStart.x - aOther.mStart.x);
      91                 : 
      92               0 :     gfxFloat ua = anumerator / denominator;
      93               0 :     gfxFloat ub = bnumerator / denominator;
      94                 : 
      95               0 :     if (ua <= 0.0 || ua >= 1.0 ||
      96                 :         ub <= 0.0 || ub >= 1.0) {
      97                 :       //Intersection is outside of the segment
      98               0 :       return false;
      99                 :     }
     100                 : 
     101               0 :     aIntersection = mStart + (mEnd - mStart) * ua;  
     102               0 :     return true;
     103                 :   }
     104                 : 
     105                 :   gfxPoint mStart;
     106                 :   gfxPoint mEnd;
     107                 : };
     108                 : 
     109                 : #endif /* GFX_LINESEGMENT_H */

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