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
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.