1 /*=========================================================================
2 
3   Program:   Visualization Toolkit
4   Module:    vtkDiscreteFlyingEdgesClipper2D.h
5 
6   Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
7   All rights reserved.
8   See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
9 
10      This software is distributed WITHOUT ANY WARRANTY; without even
11      the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
12      PURPOSE.  See the above copyright notice for more information.
13 
14 =========================================================================*/
15 /**
16  * @class   vtkDiscreteFlyingEdgesClipper2D
17  * @brief   generate filled regions from segmented 2D image data
18  *
19  * vtkDiscreteFlyingEdgesClipper2D creates filled polygons from a label map
20  * (e.g., segmented image) using a variation of the flying edges algorithm
21  * adapted for 2D clipping. The input is a 2D image where each pixel is
22  * labeled (integer labels are preferred to real values), and the output data
23  * is polygonal data representing labeled regions. (Note that on output each
24  * region [corresponding to a different contour value] may share points on a
25  * shared boundary.)
26  *
27  * While this filter is similar to a contouring operation, label maps do not
28  * provide continuous function values meaning that usual interpolation along
29  * edges is not possible. Instead, when the edge endpoints are labeled in
30  * differing regions, the edge is split at its midpoint. In addition, besides
31  * producing intersection points at the mid-point of edges, the filter may
32  * also generate points interior to the pixel cells. For example, if the four
33  * vertices of a pixel cell are labeled with different regions, then an
34  * interior point is created and four rectangular "regions" are produced.
35  *
36  * Note that one nice feature of this filter is that algorithm execution
37  * occurs only one time no matter the number of contour values. In many
38  * contouring-like algorithms, each separate contour value requires an
39  * additional algorithm execution with a new contour value. So in this filter
40  * large numbers of contour values do not significantly affect overall speed.
41  *
42  * @warning This filter is specialized to 2D images.
43  *
44  * @warning
45  * This class has been threaded with vtkSMPTools. Using TBB or other
46  * non-sequential type (set in the CMake variable
47  * VTK_SMP_IMPLEMENTATION_TYPE) may improve performance significantly.
48  *
49  * @sa
50  * vtkDiscreteFlyingEdges2D vtkDiscreteMarchingCubes vtkContourLoopExtraction
51  * vtkFlyingEdges2D vtkFlyingEdges3D
52  */
53 
54 #ifndef vtkDiscreteFlyingEdgesClipper2D_h
55 #define vtkDiscreteFlyingEdgesClipper2D_h
56 
57 #include "vtkFiltersGeneralModule.h" // For export macro
58 #include "vtkPolyDataAlgorithm.h"
59 #include "vtkContourValues.h" // Needed for direct access to ContourValues
60 
61 class vtkImageData;
62 
63 class VTKFILTERSGENERAL_EXPORT vtkDiscreteFlyingEdgesClipper2D : public vtkPolyDataAlgorithm
64 {
65 public:
66   //@{
67   /**
68    * Standard methods for instantiation, printing, and type information.
69    */
70   static vtkDiscreteFlyingEdgesClipper2D *New();
71   vtkTypeMacro(vtkDiscreteFlyingEdgesClipper2D,vtkPolyDataAlgorithm);
72   void PrintSelf(ostream& os, vtkIndent indent) override;
73   //@}
74 
75   /**
76    * The modified time is a function of the contour values because we delegate to
77    * vtkContourValues.
78    */
79   vtkMTimeType GetMTime() override;
80 
81   /**
82    * Set a particular contour value at contour number i. The index i ranges
83    * between 0 <= i <NumberOfContours. (Note: while contour values are
84    * expressed as doubles, the underlying scalar data may be a different
85    * type. During execution the contour values are static cast to the type of
86    * the scalar values.)
87    */
SetValue(int i,double value)88   void SetValue(int i, double value)
89     {this->ContourValues->SetValue(i,value);}
90 
91   /**
92    * Get the ith contour value.
93    */
GetValue(int i)94   double GetValue(int i)
95     {return this->ContourValues->GetValue(i);}
96 
97   /**
98    * Get a pointer to an array of contour values. There will be
99    * GetNumberOfContours() values in the list.
100    */
GetValues()101   double *GetValues()
102     {return this->ContourValues->GetValues();}
103 
104   /**
105    * Fill a supplied list with contour values. There will be
106    * GetNumberOfContours() values in the list. Make sure you allocate
107    * enough memory to hold the list.
108    */
GetValues(double * contourValues)109   void GetValues(double *contourValues)
110     {this->ContourValues->GetValues(contourValues);}
111 
112   /**
113    * Set the number of contours to place into the list. You only really
114    * need to use this method to reduce list size. The method SetValue()
115    * will automatically increase list size as needed.
116    */
SetNumberOfContours(int number)117   void SetNumberOfContours(int number)
118     {this->ContourValues->SetNumberOfContours(number);}
119 
120   /**
121    * Get the number of contours in the list of contour values.
122    */
GetNumberOfContours()123   int GetNumberOfContours()
124     {return this->ContourValues->GetNumberOfContours();}
125 
126   //@{
127   /**
128    * Generate numContours equally spaced contour values between the specified
129    * range. Contour values will include min/max range values.
130    */
GenerateValues(int numContours,double range[2])131   void GenerateValues(int numContours, double range[2])
132     {this->ContourValues->GenerateValues(numContours, range);}
GenerateValues(int numContours,double rangeStart,double rangeEnd)133   void GenerateValues(int numContours, double rangeStart, double rangeEnd)
134     {this->ContourValues->GenerateValues(numContours, rangeStart, rangeEnd);}
135   //@}
136 
137   //@{
138   /**
139    * Option to set the cell scalars of the output. The scalars will be the
140    * contour values. By default this flag is on.
141    */
142   vtkSetMacro(ComputeScalars,int);
143   vtkGetMacro(ComputeScalars,int);
144   vtkBooleanMacro(ComputeScalars,int);
145   //@}
146 
147   //@{
148   /**
149    * Set/get which component of a multi-component scalar array to contour on;
150    * defaults to 0.
151    */
152   vtkSetMacro(ArrayComponent, int);
153   vtkGetMacro(ArrayComponent, int);
154   //@}
155 
156 protected:
157   vtkDiscreteFlyingEdgesClipper2D();
158   ~vtkDiscreteFlyingEdgesClipper2D() override;
159 
160   int RequestData(vtkInformation *, vtkInformationVector **,
161                   vtkInformationVector *) override;
162   int FillInputPortInformation(int port, vtkInformation *info) override;
163 
164   vtkContourValues *ContourValues;
165   int ComputeScalars;
166   int ArrayComponent;
167 
168 private:
169   vtkDiscreteFlyingEdgesClipper2D(const vtkDiscreteFlyingEdgesClipper2D&) = delete;
170   void operator=(const vtkDiscreteFlyingEdgesClipper2D&) = delete;
171 };
172 
173 
174 #endif
175