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/*
* Copyright (C) 1999-2011 Insight Software Consortium
* Copyright (C) 2005-2022 Centre National d'Etudes Spatiales (CNES)
*
* This file is part of Orfeo Toolbox
*
* https://www.orfeo-toolbox.org/
*
* 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
*
* 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.
*/
// Many image processing tasks require images of non-scalar pixel type. A
// typical example is a multispectral image. The following code illustrates
// how to instantiate and use an image whose pixels are of vector type.
//
// We could use the \doxygen{itk}{Vector} class to define the pixel
// type. The Vector class is intended to represent a geometrical vector in
// space. It is not intended to be used as an array container like the
// \href{http://www.sgi.com/tech/stl/Vector.html}{\code{std::vector}} in
// \href{http://www.sgi.com/tech/stl/}{STL}. If you are interested in
// containers, the \doxygen{itk}{VectorContainer} class may provide the
// functionality you want.
//
// \index{itk::Vector}
// \index{itk::Vector!header}
//
// However, the \doxygen{itk}{Vector} is a fixed size array and it
// assumes that the number of channels of the image is known at
// compile time. Therefore, we prefer to use the
// \doxygen{otb}{VectorImage} class which allows choosing the number
// of channels of the image at runtime. The pixels will be of type
// \doxygen{itk}{VariableLengthVector}.
//
// The first step is to include the header file of the VectorImage class.
#include "otbVectorImage.h"
int main(int, char* [])
{
// The VectorImage class is templated over the type used to represent
// the coordinate in space and over the dimension of the space. In
// this example,
// we want to represent Pl\'eiades images which have 4 bands.
//
// \index{otb::VectorImage!Instantiation}
using PixelType = unsigned char;
using ImageType = otb::VectorImage<PixelType, 2>;
// Then the image object can be created
ImageType::Pointer image = ImageType::New();
// The image region should be initialized
ImageType::IndexType start;
ImageType::SizeType size;
size[0] = 200; // size along X
size[1] = 200; // size along Y
start[0] = 0; // first index on X
start[1] = 0; // first index on Y
ImageType::RegionType region;
region.SetSize(size);
region.SetIndex(start);
// Pixel data is allocated
image->SetRegions(region);
// Since the pixel dimensionality is chosen at runtime, one has to
// pass this parameter to the image before memory allocation.
image->SetNumberOfComponentsPerPixel(4);
image->Allocate();
ImageType::IndexType pixelIndex;
pixelIndex[0] = 27; // x position
pixelIndex[1] = 29; // y position
// The VariableLengthVector class overloads the operator
// \code{[]}. This makes it possible to access the
// Vector's components using index notation. The user must not
// forget to allocate the memory for each individual pixel by using
// the \code{Reserve} method.
ImageType::PixelType pixelValue;
pixelValue.Reserve(4);
pixelValue[0] = 1; // Blue component
pixelValue[1] = 6; // Green component
pixelValue[2] = 100; // Red component
pixelValue[3] = 100; // NIR component
// We can now store this vector in one of the image pixels by defining an
// index and invoking the \code{SetPixel()} method.
image->SetPixel(pixelIndex, pixelValue);
// The GetPixel method can also be used to read Vectors
// pixels from the image
ImageType::PixelType value = image->GetPixel(pixelIndex);
// Lets repeat that both \code{SetPixel()} and \code{GetPixel()} are
// inefficient and should only be used for debugging purposes or for
// implementing interactions with a graphical user interface such as
// querying pixel value by clicking with the mouse.
return EXIT_SUCCESS;
}
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