mirror of
https://gitlab.kitware.com/vtk/vtk-m
synced 2024-09-08 13:23:51 +00:00
92 lines
2.8 KiB
C++
92 lines
2.8 KiB
C++
//============================================================================
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// Copyright (c) Kitware, Inc.
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// All rights reserved.
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// See LICENSE.txt for details.
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//
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// This software is distributed WITHOUT ANY WARRANTY; without even
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// the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
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// PURPOSE. See the above copyright notice for more information.
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//============================================================================
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#include <vtkm/io/ImageReaderPNM.h>
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#include <vtkm/io/PixelTypes.h>
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VTKM_THIRDPARTY_PRE_INCLUDE
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#include <vtkm/thirdparty/lodepng/vtkmlodepng/lodepng.h>
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VTKM_THIRDPARTY_POST_INCLUDE
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namespace vtkm
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{
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namespace io
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{
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ImageReaderPNM::~ImageReaderPNM() noexcept {}
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VTKM_CONT
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void ImageReaderPNM::Read()
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{
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std::ifstream inStream(this->FileName.c_str(), std::ios_base::binary | std::ios_base::in);
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// Currently, the only magic number supported is P6
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std::string magicNum;
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inStream >> magicNum;
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if (magicNum != "P6")
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{
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throw vtkm::cont::ErrorBadValue("MagicNumber: " + magicNum + " in file: " + this->FileName +
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" did not match: P6");
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}
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vtkm::Id width;
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vtkm::Id height;
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vtkm::Id maxColorValue;
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inStream >> width >> height >> maxColorValue;
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inStream.get();
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if ((maxColorValue > 0) && (maxColorValue <= 255))
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{
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this->DecodeFile<vtkm::io::RGBPixel_8>(inStream, width, height);
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}
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else if ((maxColorValue > 255) && (maxColorValue <= 65535))
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{
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this->DecodeFile<vtkm::io::RGBPixel_16>(inStream, width, height);
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}
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else
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{
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throw vtkm::cont::ErrorBadValue("MaxColorValue: " + std::to_string(maxColorValue) +
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" from file: " + this->FileName +
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" is not in valid range of [1, 65535]");
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}
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}
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VTKM_CONT
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template <typename PixelType>
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void ImageReaderPNM::DecodeFile(std::ifstream& inStream,
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const vtkm::Id& width,
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const vtkm::Id& height)
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{
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vtkm::UInt32 imageSize = static_cast<vtkm::UInt32>(width * height * PixelType::BYTES_PER_PIXEL);
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std::vector<unsigned char> imageData(imageSize);
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inStream.read(reinterpret_cast<char*>(imageData.data()), imageSize);
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// Fill in the data starting from the end (Images are read Top-Left to Bottom-Right,
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// but are stored from Bottom-Left to Top-Right)
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vtkm::io::ImageReaderBase::ColorArrayType array;
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array.Allocate(width * height);
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auto portal = array.WritePortal();
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vtkm::Id vtkmIndex = 0;
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for (vtkm::Id yIndex = height - 1; yIndex >= 0; yIndex--)
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{
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for (vtkm::Id xIndex = 0; xIndex < width; xIndex++)
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{
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vtkm::Id pnmIndex = yIndex * width + xIndex;
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portal.Set(vtkmIndex, PixelType(imageData.data(), pnmIndex).ToVec4f());
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vtkmIndex++;
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}
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}
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this->InitializeImageDataSet(width, height, array);
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}
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}
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} // namespace vtkm::io
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