line_iterator.h
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00001 /*
00002  * Copyright (c) 2012, Willow Garage, Inc.
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions are met:
00007  *
00008  *     * Redistributions of source code must retain the above copyright
00009  *       notice, this list of conditions and the following disclaimer.
00010  *     * Redistributions in binary form must reproduce the above copyright
00011  *       notice, this list of conditions and the following disclaimer in the
00012  *       documentation and/or other materials provided with the distribution.
00013  *     * Neither the name of the Willow Garage, Inc. nor the names of its
00014  *       contributors may be used to endorse or promote products derived from
00015  *       this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
00018  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
00021  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00022  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
00023  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
00024  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
00025  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
00026  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00027  * POSSIBILITY OF SUCH DAMAGE.
00028  */
00029 #ifndef LINE_ITERATOR_H
00030 #define LINE_ITERATOR_H
00031 
00032 #include <stdlib.h>
00033 
00034 namespace base_local_planner
00035 {
00036 
00038 class LineIterator
00039 {
00040 public:
00041   LineIterator( int x0, int y0, int x1, int y1 )
00042     : x0_( x0 )
00043     , y0_( y0 )
00044     , x1_( x1 )
00045     , y1_( y1 )
00046     , x_( x0 ) // X and Y start of at first endpoint.
00047     , y_( y0 )
00048     , deltax_( abs( x1 - x0 ))
00049     , deltay_( abs( y1 - y0 ))
00050     , curpixel_( 0 )
00051   {
00052     if( x1_ >= x0_ )                 // The x-values are increasing
00053     {
00054       xinc1_ = 1;
00055       xinc2_ = 1;
00056     }
00057     else                          // The x-values are decreasing
00058     {
00059       xinc1_ = -1;
00060       xinc2_ = -1;
00061     }
00062 
00063     if( y1_ >= y0_)                 // The y-values are increasing
00064     {
00065       yinc1_ = 1;
00066       yinc2_ = 1;
00067     }
00068     else                          // The y-values are decreasing
00069     {
00070       yinc1_ = -1;
00071       yinc2_ = -1;
00072     }
00073 
00074     if( deltax_ >= deltay_ )         // There is at least one x-value for every y-value
00075     {
00076       xinc1_ = 0;                  // Don't change the x when numerator >= denominator
00077       yinc2_ = 0;                  // Don't change the y for every iteration
00078       den_ = deltax_;
00079       num_ = deltax_ / 2;
00080       numadd_ = deltay_;
00081       numpixels_ = deltax_;         // There are more x-values than y-values
00082     }
00083     else                          // There is at least one y-value for every x-value
00084     {
00085       xinc2_ = 0;                  // Don't change the x for every iteration
00086       yinc1_ = 0;                  // Don't change the y when numerator >= denominator
00087       den_ = deltay_;
00088       num_ = deltay_ / 2;
00089       numadd_ = deltax_;
00090       numpixels_ = deltay_;         // There are more y-values than x-values
00091     }
00092   }
00093     
00094   bool isValid() const
00095   {
00096     return curpixel_ <= numpixels_;
00097   }
00098 
00099   void advance()
00100   {
00101     num_ += numadd_;              // Increase the numerator by the top of the fraction
00102     if( num_ >= den_ )            // Check if numerator >= denominator
00103     {
00104       num_ -= den_;               // Calculate the new numerator value
00105       x_ += xinc1_;               // Change the x as appropriate
00106       y_ += yinc1_;               // Change the y as appropriate
00107     }
00108     x_ += xinc2_;                 // Change the x as appropriate
00109     y_ += yinc2_;                 // Change the y as appropriate
00110 
00111     curpixel_++;
00112   }
00113   
00114   int getX() const { return x_; }
00115   int getY() const { return y_; }
00116 
00117   int getX0() const { return x0_; }
00118   int getY0() const { return y0_; }
00119 
00120   int getX1() const { return x1_; }
00121   int getY1() const { return y1_; }
00122 
00123 private:
00124   int x0_; 
00125   int y0_; 
00126   int x1_; 
00127   int y1_; 
00128 
00129   int x_; 
00130   int y_; 
00131 
00132   int deltax_; 
00133   int deltay_; 
00134 
00135   int curpixel_; 
00136 
00137   int xinc1_, xinc2_, yinc1_, yinc2_;
00138   int den_, num_, numadd_, numpixels_;
00139 };
00140 
00141 } // end namespace base_local_planner
00142 
00143 #endif // LINE_ITERATOR_H


base_local_planner
Author(s): Eitan Marder-Eppstein, Eric Perko, contradict@gmail.com
autogenerated on Wed Aug 2 2017 03:12:38