Merge pull request #254 from tbirdso/scale-an-image

ENH: `ScaleAnImage` Python example and input data update

Author: tbirdso

src/Core/Transform/CMakeLists.txt

@@ -15,7 +15,7 @@ compare_to_baseline(
 
 add_example(ScaleAnImage)
 compare_to_baseline(EXAMPLE_NAME ScaleAnImage
-  BASELINE_PREFIX ScaleAnImageOutput
+  BASELINE_PREFIX ScaleAnImageOutputBaseline
   )
 
 add_example(TranslateAVectorImage)

src/Core/Transform/ScaleAnImage/CMakeLists.txt

@@ -13,21 +13,24 @@ install(TARGETS ScaleAnImage
   DESTINATION bin/ITKSphinxExamples/Core/Transform
   COMPONENT Runtime
   )
-
-install(FILES Code.cxx CMakeLists.txt
+  
+install(FILES Code.cxx Code.py CMakeLists.txt
   DESTINATION share/ITKSphinxExamples/Code/Core/Transform/ScaleAnImage/
   COMPONENT Code
   )
 
 
 enable_testing()
-set(input_image ${CMAKE_CURRENT_BINARY_DIR}/input.png)
-set(output_image Output.png)
-set(test_options)
 
 add_test(NAME ScaleAnImageTest
   COMMAND ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/ScaleAnImage
-    ${input_image}
-    ${output_image}
-    ${test_options}
+    ${CMAKE_CURRENT_BINARY_DIR}/ScaleAnImageInput.png
+    ${CMAKE_CURRENT_BINARY_DIR}/ScaleAnImageOutput.png
   )
+
+if(ITK_WRAP_PYTHON)
+add_test(NAME ScaleAnImageTestPython
+COMMAND ${PYTHON_EXECUTABLE} ${CMAKE_CURRENT_SOURCE_DIR}/Code.py
+    ${CMAKE_CURRENT_BINARY_DIR}/ScaleAnImageInput.png
+    ${CMAKE_CURRENT_BINARY_DIR}/ScaleAnImageOutputPython.png)
+endif()

src/Core/Transform/ScaleAnImage/Code.cxx

@@ -17,25 +17,25 @@
  *=========================================================================*/
 #include "itkImage.h"
 #include "itkScaleTransform.h"
+#include "itkImageFileReader.h"
 #include "itkImageFileWriter.h"
 #include "itkResampleImageFilter.h"
 
-using ImageType = itk::Image<unsigned char, 2>;
-
-static void
-CreateImage(ImageType::Pointer image);
-
 int
-main()
+main(int argc, char * argv[])
 {
-  auto image = ImageType::New();
-  CreateImage(image);
+  if (argc < 3)
+  {
+    std::cerr << "Usage: " << argv[0] << " inputFile outputFile" << std::endl;
+  }
 
-  itk::WriteImage(image, "input.png");
+  using PixelType = unsigned char;
+  constexpr unsigned int ImageDimension = 2;
+  using ImageType = itk::Image<PixelType, ImageDimension>;
+  auto image = itk::ReadImage<ImageType>(argv[1]);
 
-  // using TransformType = itk::ScaleTransform<float, 2>; // If you want to use float here, you must use:
-  // using ResampleImageFilterType = itk::ResampleImageFilter<ImageType, ImageType, float>; later.
-  using TransformType = itk::ScaleTransform<double, 2>;
+  using MetricValueType = double;
+  using TransformType = itk::ScaleTransform<MetricValueType, 2>;
   auto                      scaleTransform = TransformType::New();
   itk::FixedArray<float, 2> scale;
   scale[0] = 1.5; // newWidth/oldWidth
@@ -48,57 +48,14 @@ main()
 
   scaleTransform->SetCenter(center);
 
-  using ResampleImageFilterType = itk::ResampleImageFilter<ImageType, ImageType>;
+  using ResampleImageFilterType = itk::ResampleImageFilter<ImageType, ImageType, MetricValueType>;
   auto resampleFilter = ResampleImageFilterType::New();
   resampleFilter->SetTransform(scaleTransform);
   resampleFilter->SetInput(image);
   resampleFilter->SetSize(image->GetLargestPossibleRegion().GetSize());
   resampleFilter->Update();
 
-  itk::WriteImage(resampleFilter->GetOutput(), "output.png");
+  itk::WriteImage(resampleFilter->GetOutput(), argv[2]);
 
   return EXIT_SUCCESS;
 }
-
-void
-CreateImage(ImageType::Pointer image)
-{
-  itk::Index<2> start;
-  start.Fill(0);
-
-  itk::Size<2> size;
-  size.Fill(101);
-
-  ImageType::RegionType region(start, size);
-  image->SetRegions(region);
-  image->Allocate();
-  image->FillBuffer(0);
-
-  // Make a white square
-  for (unsigned int r = 40; r < 60; ++r)
-  {
-    for (unsigned int c = 40; c < 60; ++c)
-    {
-      ImageType::IndexType pixelIndex;
-      pixelIndex[0] = r;
-      pixelIndex[1] = c;
-
-      image->SetPixel(pixelIndex, 255);
-    }
-  }
-
-  itk::ImageRegionIterator<ImageType> imageIterator(image, image->GetLargestPossibleRegion());
-
-  // Draw a white border
-  while (!imageIterator.IsAtEnd())
-  {
-    if (imageIterator.GetIndex()[0] == 0 ||
-        imageIterator.GetIndex()[0] == static_cast<int>(image->GetLargestPossibleRegion().GetSize()[0]) - 1 ||
-        imageIterator.GetIndex()[1] == 0 ||
-        imageIterator.GetIndex()[1] == static_cast<int>(image->GetLargestPossibleRegion().GetSize()[1]) - 1)
-    {
-      imageIterator.Set(255);
-    }
-    ++imageIterator;
-  }
-}

src/Core/Transform/ScaleAnImage/Code.py

@@ -0,0 +1,40 @@
+#!/usr/bin/env python
+
+# =========================================================================
+#
+#   Copyright NumFOCUS
+#
+#   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.
+#
+# =========================================================================*/
+
+import sys
+
+import itk
+
+if len(sys.argv) < 3:
+    raise Exception(f"Usage: {sys.argv[0]} inputFile outputFile")
+
+image = itk.imread(sys.argv[1], itk.UC)
+
+image_dimension = image.GetImageDimension()
+
+transform = itk.ScaleTransform[itk.D, 2].New(
+    scale=[1.5] * image_dimension, center=[x / 2 for x in itk.size(image)]
+)
+
+scaled_image = itk.resample_image_filter(
+    image, transform=transform, size=itk.size(image)
+)
+
+itk.imwrite(scaled_image, sys.argv[2])

src/Core/Transform/ScaleAnImage/Documentation.rst

@@ -20,7 +20,7 @@ Results
 
   Input Image
 
-.. figure:: ScaleAnImageOutput.png
+.. figure:: ScaleAnImageOutputBaseline.png
   :scale: 70%
   :alt: Generated Output Image
 
@@ -36,6 +36,12 @@ C++
 .. literalinclude:: Code.cxx
    :lines: 18-
 
+Python
+...
+
+.. literalinclude:: Code.py
+   :lines: 21-
+
 Classes demonstrated
 --------------------
 

src/Core/Transform/ScaleAnImage/ScaleAnImageInput.png.sha512

@@ -1 +1 @@
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+3751db8b668657ed157daa5f7472ba2775feefbed331d8cd45c867089c5b5a535a10d55ec02cbf7c6cf73309f06636bc4001080b8bbc4f53dec205addd0ee41f

src/Core/Transform/ScaleAnImage/ScaleAnImageOutput.png.sha512

@@ -0,0 +1 @@
+7ec9d81518d26754151a112affbe24a0f206b307aaa8c8bf8241a954e0974b6ea31a8b2982ce26d9de8eb4eeacba4003e16badfc9dd39aa7cd8827080360eb39