1 /*=========================================================================
2  *
3  *  Copyright Insight Software Consortium
4  *
5  *  Licensed under the Apache License, Version 2.0 (the "License");
6  *  you may not use this file except in compliance with the License.
7  *  You may obtain a copy of the License at
8  *
9  *         http://www.apache.org/licenses/LICENSE-2.0.txt
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11  *  Unless required by applicable law or agreed to in writing, software
12  *  distributed under the License is distributed on an "AS IS" BASIS,
13  *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  *  See the License for the specific language governing permissions and
15  *  limitations under the License.
16  *
17  *=========================================================================*/
18 /*=========================================================================
19  *
20  *  Portions of this file are subject to the VTK Toolkit Version 3 copyright.
21  *
22  *  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
23  *
24  *  For complete copyright, license and disclaimer of warranty information
25  *  please refer to the NOTICE file at the top of the ITK source tree.
26  *
27  *=========================================================================*/
28 #ifndef itkInPlaceImageFilter_h
29 #define itkInPlaceImageFilter_h
30 
31 #include "itkImageToImageFilter.h"
32 #include "itkIsSame.h"
33 
34 namespace itk
35 {
36 /** \class InPlaceImageFilter
37  * \brief Base class for filters that take an image as input and overwrite that image as the output
38  *
39  * InPlaceImageFilter is the base class for all process objects whose
40  * output image data is constructed by overwriting the input image
41  * data. In other words, the output bulk data is the same block of
42  * memory as the input bulk data.  This filter provides the mechanisms
43  * for in place image processing while maintaining general pipeline
44  * mechanics. InPlaceImageFilters use less memory than standard
45  * ImageToImageFilters because the input buffer is reused as the
46  * output buffer.  However, this benefit does not come without a cost.
47  * Since the filter overwrites its input, the ownership of the bulk
48  * data is transitioned from the input data object to the output data
49  * object.  When a data object has multiple consumers with one
50  * of the consumers being an in place filter, the in place filter
51  * effectively destroys the bulk data for the data object. Upstream
52  * filters will then have to re-execute to regenerate the data object's
53  * bulk data for the remaining consumers.
54  *
55  * Since an InPlaceImageFilter reuses the input bulk data memory for the
56  * output bulk data memory, the input image type must match the output
57  * image type.  If the input and output image types are not identical,
58  * the filter reverts to a traditional ImageToImageFilter behaviour
59  * where an output image is allocated. Additionally, the requested
60  * region of the output must match that of the input. In place
61  * operation can also be controlled (when the input and output image
62  * type match) via the methods InPlaceOn() and InPlaceOff().
63  *
64  * Subclasses of InPlaceImageFilter must take extra care in how they
65  * manage memory using (and perhaps overriding) the implementations of
66  * ReleaseInputs() and AllocateOutputs() provided here.
67  *
68  * \ingroup ImageFilters
69  * \ingroup ITKCommon
70  */
71 template< typename TInputImage, typename TOutputImage = TInputImage >
72 class ITK_TEMPLATE_EXPORT InPlaceImageFilter:public ImageToImageFilter< TInputImage, TOutputImage >
73 {
74 public:
75   ITK_DISALLOW_COPY_AND_ASSIGN(InPlaceImageFilter);
76 
77   /** Standard class type aliases. */
78   using Self = InPlaceImageFilter;
79   using Superclass = ImageToImageFilter< TInputImage, TOutputImage >;
80   using Pointer = SmartPointer< Self >;
81   using ConstPointer = SmartPointer< const Self >;
82 
83   /** Run-time type information (and related methods). */
84   itkTypeMacro(InPlaceImageFilter, ImageToImageFilter);
85 
86   /** Superclass type alias. */
87   using OutputImageType = typename Superclass::OutputImageType;
88   using OutputImagePointer = typename Superclass::OutputImagePointer;
89   using OutputImageRegionType = typename Superclass::OutputImageRegionType;
90   using OutputImagePixelType = typename Superclass::OutputImagePixelType;
91 
92   /** Some convenient type alias. */
93   using InputImageType = TInputImage;
94   using InputImagePointer = typename InputImageType::Pointer;
95   using InputImageConstPointer = typename InputImageType::ConstPointer;
96   using InputImageRegionType = typename InputImageType::RegionType;
97   using InputImagePixelType = typename InputImageType::PixelType;
98 
99   /** ImageDimension constants */
100   static constexpr unsigned int InputImageDimension = TInputImage::ImageDimension;
101   static constexpr unsigned int OutputImageDimension = TOutputImage::ImageDimension;
102 
103   /** In place operation can be turned on and off. Asking for
104    * in-place operation, i.e. calling SetInplace(true) or InplaceOn(),
105    * will be effective only if CanRunInPlace also returns true.
106    * By default CanRunInPlace checks whether the input and output
107    * image type match. */
108   itkSetMacro(InPlace, bool);
109   itkGetConstMacro(InPlace, bool);
110   itkBooleanMacro(InPlace);
111 
112   /** Can the filter run in place? To do so, the filter's first input
113    * and output must have the same dimension and pixel type. This
114    * method can be used in conjunction with the InPlace ivar to
115    * determine whether a particular use of the filter is really
116    * running in place. Some filters may be able to optimize their
117    * operation if the InPlace is true and CanRunInPlace is true.
118    * CanRunInPlace may also be overridded by InPlaceImageFilter
119    * subclasses to fine tune its behavior. */
120   virtual bool CanRunInPlace() const;
121 
122 protected:
123   InPlaceImageFilter() = default;
124   ~InPlaceImageFilter() override = default;
125 
126   void PrintSelf(std::ostream & os, Indent indent) const override;
127 
128   /** The GenerateData method normally allocates the buffers for all
129    * of the outputs of a filter. Since InPlaceImageFilter's can use an
130    * overwritten version of the input for its output, the output
131    * buffer should not be allocated. When possible, we graft the input
132    * to the filter to the output.  If an InPlaceFilter has multiple
133    * outputs, then it would need to override this method to graft one
134    * of its outputs and allocate the remaining. If a filter is
135    * threaded (i.e. it provides an implementation of
136    * ThreadedGenerateData()), this method is called automatically. If
137    * an InPlaceFilter is not threaded (i.e. it provides an
138    * implementation of GenerateData()), then this method (or
139    * equivalent) must be called in GenerateData(). */
AllocateOutputs()140   void AllocateOutputs() override
141   {
142     this->InternalAllocateOutputs(IsSame<TInputImage, TOutputImage>());
143   }
144 
145   /** InPlaceImageFilter may transfer ownership of the input bulk data
146    * to the output object.  Once the output object owns the bulk data
147    * (done in AllocateOutputs()), the input object must release its
148    * hold on the bulk data.  ProcessObject::ReleaseInputs() only
149    * releases the input bulk data when the user has set the
150    * ReleaseDataFlag.  InPlaceImageFilter::ReleaseInputs() also
151    * releases the input that it has overwritten.
152    *
153    * \sa ProcessObject::ReleaseInputs() */
154   void ReleaseInputs() override;
155 
156   /** This methods should only be called during the GenerateData phase
157    *  of the pipeline. This method return true if the input image's
158    *  bulk data is the same as the output image's data.
159    */
160   itkGetConstMacro(RunningInPlace,bool);
161 
162 private:
163   // the type are different we can't run in place
InternalAllocateOutputs(const FalseType &)164   void InternalAllocateOutputs( const FalseType& )
165   {
166     this->m_RunningInPlace = false;
167     this->Superclass::AllocateOutputs();
168   }
169 
170   void InternalAllocateOutputs( const TrueType& );
171 
172   bool m_InPlace{true}; // enable the possibility of in-place
173   bool m_RunningInPlace{false};
174 
175 };
176 } // end namespace itk
177 
178 #ifndef ITK_MANUAL_INSTANTIATION
179 #include "itkInPlaceImageFilter.hxx"
180 #endif
181 
182 #endif
183