ImageDataToQImage
VTKExamples/Cxx/Qt/ImageDataToQImage
Description¶
This example shows how a vtkImageData can be converted into a QImage.
See also the QImageToImageSource example.
Code¶
ImageDataToQImage.cxx
#include <vtkVersion.h> #include <vtkImageData.h> #include <vtkSmartPointer.h> #include <QImage> #include <QColor> #include <QApplication> // Create a green 50x50 imageData for demonstration purposes vtkSmartPointer<vtkImageData> createDemoImageData() { vtkSmartPointer<vtkImageData> image = vtkSmartPointer<vtkImageData>::New(); image->SetDimensions( 50, 50, 1 ); #if VTK_MAJOR_VERSION <= 5 #pragma message( VTK_MAJOR_VERSION ) image->SetNumberOfScalarComponents( 3 ); image->SetScalarTypeToUnsignedChar(); image->AllocateScalars(); #else image->AllocateScalars( VTK_UNSIGNED_CHAR, 3 ); #endif int width = image->GetDimensions()[0]; int height = image->GetDimensions()[1]; for ( int y = 0; y < height; y++ ) { for ( int x = 0; x < width; x++ ) { unsigned char *pixel = static_cast<unsigned char *>( image->GetScalarPointer( x, y, 0 ) ); pixel[0] = 0; pixel[1] = 255; pixel[2] = 0; } } return image; } // The actual conversion code QImage vtkImageDataToQImage( vtkSmartPointer<vtkImageData> imageData ) { if ( !imageData ) { return QImage(); } /// \todo retrieve just the UpdateExtent int width = imageData->GetDimensions()[0]; int height = imageData->GetDimensions()[1]; QImage image( width, height, QImage::Format_RGB32 ); QRgb *rgbPtr = reinterpret_cast<QRgb *>( image.bits() ) + width * ( height - 1 ); unsigned char *colorsPtr = reinterpret_cast<unsigned char *>( imageData->GetScalarPointer() ); // Loop over the vtkImageData contents. for ( int row = 0; row < height; row++ ) { for ( int col = 0; col < width; col++ ) { // Swap the vtkImageData RGB values with an equivalent QColor *( rgbPtr++ ) = QColor( colorsPtr[0], colorsPtr[1], colorsPtr[2] ).rgb(); colorsPtr += imageData->GetNumberOfScalarComponents(); } rgbPtr -= width * 2; } return image; } int main( int argc, char *argv[] ) { QApplication app( argc, argv ); QImage qimage = vtkImageDataToQImage( createDemoImageData() ); qimage.save( "qimage.png" ); return EXIT_SUCCESS; }
CMakeLists.txt¶
cmake_minimum_required(VERSION 2.8) PROJECT(ImageDataToQImage) find_package(VTK REQUIRED) include(${VTK_USE_FILE}) add_executable(ImageDataToQImage MACOSX_BUNDLE ImageDataToQImage.cxx) target_link_libraries(ImageDataToQImage ${VTK_LIBRARIES})
Download and Build ImageDataToQImage¶
Danger
The generation of tar files has not been ported to the new VTKExamples. Some tarballs may be missing or out-of-date.
Click here to download ImageDataToQImage and its CMakeLists.txt file. Once the tarball ImageDataToQImage.tar has been downloaded and extracted,
cd ImageDataToQImage/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:
./ImageDataToQImage
WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.