/usr/include/ITK-4.9/itkBresenhamLine.hxx is in libinsighttoolkit4-dev 4.9.0-4ubuntu1.
This file is owned by root:root, with mode 0o644.
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*
* Copyright Insight Software Consortium
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0.txt
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*=========================================================================*/
#ifndef itkBresenhamLine_hxx
#define itkBresenhamLine_hxx
#include "itkBresenhamLine.h"
#include "itkPoint.h"
#include "itkMath.h"
#include "vnl/vnl_math.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 = static_cast<long>(vnl_math_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 );
}
template< unsigned int VDimension >
typename BresenhamLine< VDimension >::IndexArray BresenhamLine< VDimension >
::BuildLine(IndexType p0, IndexType p1)
{
itk::Point<float,VDimension> point0;
itk::Point<float,VDimension> point1;
for(unsigned int i = 0; i < VDimension; i++)
{
point0[i] = p0[i];
point1[i] = p1[i];
}
const unsigned int distance = itk::Math::RoundHalfIntegerToEven<unsigned int, double>( point0.EuclideanDistanceTo(point1) );
OffsetArray offsets = this->BuildLine(point1-point0, distance);
IndexArray indices(offsets.size());
for(unsigned int i = 0; i < offsets.size(); i++)
{
indices[i] = p0 + offsets[i];
}
return indices;
}
} // namespace itk
#endif
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