BackgroundImage
Repository source: BackgroundImage
Description¶
This example displays an image as the "background" of a scene, and renders a superquadric in front of it.
The example accepts a jpeg file on the command line to use as a background image. If there is no file, it generates a simple background.
Other languages
See (Python), (PythonicAPI)
Question
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Code¶
BackgroundImage.cxx
#include <vtkActor.h>
#include <vtkCamera.h>
#include <vtkImageActor.h>
#include <vtkImageCanvasSource2D.h>
#include <vtkImageData.h>
#include <vtkImageReader2.h>
#include <vtkImageReader2Factory.h>
#include <vtkNamedColors.h>
#include <vtkNew.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkRenderer.h>
#include <vtkSmartPointer.h>
#include <vtkSuperquadricSource.h>
#include <array>
int main(int argc, char* argv[])
{
vtkNew<vtkNamedColors> colors;
vtkSmartPointer<vtkImageData> imageData;
// Verify input arguments.
if (argc > 1)
{
// Read the image
vtkNew<vtkImageReader2Factory> readerFactory;
vtkSmartPointer<vtkImageReader2> imageReader;
imageReader.TakeReference(readerFactory->CreateImageReader2(argv[1]));
imageReader->SetFileName(argv[1]);
imageReader->Update();
imageData = imageReader->GetOutput();
}
else
{
std::array<double, 3> drawColor1{0, 0, 0};
std::array<double, 3> drawColor2{0, 0, 0};
std::array<double, 3> drawColor3{0, 0, 0};
auto color1 = colors->GetColor3ub("warm_grey").GetData();
auto color2 = colors->GetColor3ub("DarkCyan").GetData();
auto color3 = colors->GetColor3ub("LightCoral").GetData();
for (auto i = 0; i < 3; ++i)
{
drawColor1[i] = color1[i];
drawColor2[i] = color2[i];
drawColor3[i] = color3[i];
}
vtkNew<vtkImageCanvasSource2D> canvasSource;
canvasSource->SetExtent(0, 100, 0, 100, 0, 0);
canvasSource->SetScalarTypeToUnsignedChar();
canvasSource->SetNumberOfScalarComponents(3);
canvasSource->SetDrawColor(drawColor1.data());
canvasSource->FillBox(0, 100, 0, 100);
canvasSource->SetDrawColor(drawColor2.data());
canvasSource->FillTriangle(10, 10, 25, 10, 25, 25);
canvasSource->SetDrawColor(drawColor3.data());
canvasSource->FillTube(75, 75, 0, 75, 5.0);
canvasSource->Update();
imageData = canvasSource->GetOutput();
}
// Create an image actor to display the image.
vtkNew<vtkImageActor> imageActor;
imageActor->SetInputData(imageData);
// Create a renderer to display the image in the background.
vtkNew<vtkRenderer> backgroundRenderer;
// Create a superquadric.
vtkNew<vtkSuperquadricSource> superquadricSource;
superquadricSource->SetPhiRoundness(1.1);
superquadricSource->SetThetaRoundness(.2);
// Create a mapper and actor.
vtkNew<vtkPolyDataMapper> superquadricMapper;
superquadricMapper->SetInputConnection(superquadricSource->GetOutputPort());
vtkNew<vtkActor> superquadricActor;
superquadricActor->SetMapper(superquadricMapper);
superquadricActor->GetProperty()->SetColor(
colors->GetColor3d("NavajoWhite").GetData());
vtkNew<vtkRenderer> sceneRenderer;
vtkNew<vtkRenderWindow> renderWindow;
// Set up the render window and renderers such that there is
// a background layer and a foreground layer.
backgroundRenderer->SetLayer(0);
backgroundRenderer->InteractiveOff();
sceneRenderer->SetLayer(1);
renderWindow->SetNumberOfLayers(2);
renderWindow->AddRenderer(backgroundRenderer);
renderWindow->AddRenderer(sceneRenderer);
renderWindow->SetWindowName("BackgroundImage");
vtkNew<vtkRenderWindowInteractor> renderWindowInteractor;
renderWindowInteractor->SetRenderWindow(renderWindow);
// Add actors to the renderers
sceneRenderer->AddActor(superquadricActor);
backgroundRenderer->AddActor(imageActor);
// Render once to figure out where the background camera will be.
renderWindow->Render();
// Set up the background camera to fill the renderer with the image.
double origin[3];
double spacing[3];
int extent[6];
imageData->GetOrigin(origin);
imageData->GetSpacing(spacing);
imageData->GetExtent(extent);
vtkCamera* camera = backgroundRenderer->GetActiveCamera();
camera->ParallelProjectionOn();
double xc = origin[0] + 0.5 * (extent[0] + extent[1]) * spacing[0];
double yc = origin[1] + 0.5 * (extent[2] + extent[3]) * spacing[1];
// double xd = (extent[1] - extent[0] + 1)*spacing[0];
double yd = (extent[3] - extent[2] + 1) * spacing[1];
double d = camera->GetDistance();
camera->SetParallelScale(0.5 * yd);
camera->SetFocalPoint(xc, yc, 0.0);
camera->SetPosition(xc, yc, d);
// Render again to set the correct view.
renderWindow->Render();
// Interact with the window.
renderWindowInteractor->Start();
return EXIT_SUCCESS;
}
CMakeLists.txt¶
cmake_minimum_required(VERSION 3.12 FATAL_ERROR)
project(BackgroundImage)
find_package(VTK COMPONENTS
CommonColor
CommonCore
CommonDataModel
FiltersSources
IOImage
ImagingSources
InteractionStyle
RenderingContextOpenGL2
RenderingCore
RenderingFreeType
RenderingGL2PSOpenGL2
RenderingOpenGL2
)
if (NOT VTK_FOUND)
message(FATAL_ERROR "BackgroundImage: Unable to find the VTK build folder.")
endif()
# Prevent a "command line is too long" failure in Windows.
set(CMAKE_NINJA_FORCE_RESPONSE_FILE "ON" CACHE BOOL "Force Ninja to use response files.")
add_executable(BackgroundImage MACOSX_BUNDLE BackgroundImage.cxx )
target_link_libraries(BackgroundImage PRIVATE ${VTK_LIBRARIES}
)
# vtk_module_autoinit is needed
vtk_module_autoinit(
TARGETS BackgroundImage
MODULES ${VTK_LIBRARIES}
)
Download and Build BackgroundImage¶
Click here to download BackgroundImage and its CMakeLists.txt file. Once the tarball BackgroundImage.tar has been downloaded and extracted,
cd BackgroundImage/build
If VTK is installed:
cmake ..
If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:
cmake -DVTK_DIR:PATH=/home/me/vtk_build ..
Build the project:
make
and run it:
./BackgroundImage
WINDOWS USERS
Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.