vtk用数组、迭代器访问元素

~~迭代器这货我写控制台的时候就没用明白过==~~

先说用数组直接访问的实现的功能是将左下角的区域变黑

#include <vtkSmartPointer.h>
#include <vtkImageViewer2.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkBMPReader.h>
#include <vtkImageData.h>

int main(int argc, char* argv[])
{
	
	vtkSmartPointer<vtkBMPReader> reader =
		vtkSmartPointer<vtkBMPReader>::New();
	reader->SetFileName(",,/tmp.bmp");
	reader->Update();

	int dims[3];
	reader->GetOutput()->GetDimensions(dims);

	int nbOfComp;
	nbOfComp = reader->GetOutput()->GetNumberOfScalarComponents();

	for(int k=0; k<dims[2]; k++)
	{
		for(int j=0; j<dims[1]; j++)
		{
			for(int i=0; i<dims[0]; i++)
			{
				if(i<100 && j<100)
				{
					unsigned char * pixel = 
						(unsigned char *) ( reader->GetOutput()->GetScalarPointer(i, j, k) );
					*pixel = 0;
					*(pixel+1) = 0;
					*(pixel+2) = 0;
				}
			}
		}
	}

	vtkSmartPointer<vtkImageViewer2> imageViewer =
		vtkSmartPointer<vtkImageViewer2>::New();
	imageViewer->SetInputConnection(reader->GetOutputPort());

	vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
		vtkSmartPointer<vtkRenderWindowInteractor>::New();
	imageViewer->SetupInteractor(renderWindowInteractor);
	imageViewer->Render();
	imageViewer->GetRenderer()->ResetCamera();
	imageViewer->Render();

	imageViewer->GetRenderer()->SetBackground(1.0, 1.0, 1.0);
	imageViewer->SetSize(640, 480);
	imageViewer->GetRenderWindow()->SetWindowName("VisitImagePixelDirectlyExample");


	renderWindowInteractor->Start();

	return EXIT_SUCCESS;
}

再说用迭代器的

#include <vtkSmartPointer.h>
#include <vtkImageViewer2.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkBMPReader.h>
#include <vtkImageData.h>
#include <vtkImageIterator.h>

//测试图像：../lena.bmp
int main(int argc, char* argv[])
{
	//依旧是正常的读入
	vtkSmartPointer<vtkBMPReader> reader =
		vtkSmartPointer<vtkBMPReader>::New();
	reader->SetFileName("../lena.bmp");
	reader->Update();

	//设置变换的子区域 六个值分别代表x,y,z的最小值最大值
	int subRegion[6] = { 0, 300, 0, 300, 0, 0 };
	//两个参数：要访问的图像和访问区域
	vtkImageIterator<unsigned char> it(reader->GetOutput(), subRegion);
	//注意这里两个while循环
	while (!it.IsAtEnd())
	{
		unsigned char *inSI = it.BeginSpan();
		unsigned char *inSIEnd = it.EndSpan();

		while (inSI != inSIEnd)//组内
		{
			*inSI = 255 - *inSI;
			++inSI;
		}
		it.NextSpan();
	}

	vtkSmartPointer<vtkImageViewer2> imageViewer =
		vtkSmartPointer<vtkImageViewer2>::New();
	imageViewer->SetInputConnection(reader->GetOutputPort());

	vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
		vtkSmartPointer<vtkRenderWindowInteractor>::New();
	imageViewer->SetupInteractor(renderWindowInteractor);
	imageViewer->Render();
	imageViewer->GetRenderer()->ResetCamera();
	imageViewer->Render();

	imageViewer->GetRenderer()->SetBackground(1.0, 1.0, 1.0);
	imageViewer->SetSize(640, 480);
	imageViewer->GetRenderWindow()->SetWindowName("VisitImagePixelIterativelyExample");

	renderWindowInteractor->Start();

	return EXIT_SUCCESS;
}

效果：