/usr/include/InsightToolkit/Review/itkBresenhamLine.txx is in libinsighttoolkit3-dev 3.20.1-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | /*=========================================================================
Program: Insight Segmentation & Registration Toolkit
Module: itkBresenhamLine.txx
Language: C++
Date: $Date$
Version: $Revision$
Copyright (c) Insight Software Consortium. All rights reserved.
See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notices for more information.
=========================================================================*/
#ifndef __itkBresenhamLine_txx
#define __itkBresenhamLine_txx
#include "itkBresenhamLine.h"
namespace itk {
template<unsigned int VDimension>
typename BresenhamLine<VDimension>::OffsetArray BresenhamLine<VDimension>
::BuildLine(LType Direction, unsigned int length)
{
// copied from the line iterator
/** Variables that drive the Bresenham-Algorithm */
// The dimension with the largest difference between start and end
unsigned int m_MainDirection;
// Accumulated error for the other dimensions
IndexType m_AccumulateError;
// Increment for the error for each step. Two times the difference between
// start and end
IndexType m_IncrementError;
// If enough is accumulated for a dimension, the index has to be
// incremented. Will be the number of pixels in the line
IndexType m_MaximalError;
// Direction of increment. -1 or 1
IndexType m_OverflowIncrement;
// After an overflow, the accumulated error is reduced again. Will be
// two times the number of pixels in the line
IndexType m_ReduceErrorAfterIncrement;
OffsetArray result(length);
IndexType m_CurrentImageIndex, StartIndex, LastIndex;
Direction.Normalize();
// we are going to start at 0
m_CurrentImageIndex.Fill(0);
StartIndex.Fill(0);
for (unsigned i = 0; i<VDimension;i++)
{
LastIndex[i] = (IndexValueType)(length*Direction[i]);
}
// Find the dominant direction
IndexValueType maxDistance = 0;
unsigned int maxDistanceDimension = 0;
for (unsigned i = 0; i<VDimension;i++)
{
IndexValueType distance = abs(LastIndex[i]);
if (distance > maxDistance)
{
maxDistance = distance;
maxDistanceDimension = i;
}
m_IncrementError[i] = 2*distance;
m_OverflowIncrement[i] = (LastIndex[i] < 0 ? -1 : 1);
}
m_MainDirection = maxDistanceDimension;
m_MaximalError.Fill(maxDistance);
m_ReduceErrorAfterIncrement.Fill(2*maxDistance);
m_AccumulateError.Fill(0);
unsigned int steps = 1;
result[0] = m_CurrentImageIndex - StartIndex;
while (steps < length)
{
// This part is from ++ in LineConstIterator
// We need to modify m_AccumulateError, m_CurrentImageIndex, m_IsAtEnd
for (unsigned int i = 0; i < VDimension; ++i)
{
if (i == m_MainDirection)
{
m_CurrentImageIndex[i] += m_OverflowIncrement[i];
}
else
{
m_AccumulateError[i] += m_IncrementError[i];
if (m_AccumulateError[i] >= m_MaximalError[i])
{
m_CurrentImageIndex[i] += m_OverflowIncrement[i];
m_AccumulateError[i] -= m_ReduceErrorAfterIncrement[i];
}
}
}
result[steps] = m_CurrentImageIndex - StartIndex; // produce an offset
++steps;
}
return(result);
}
} // namespace itk
#endif
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