VTK/Examples/Cxx/Images/ImageText
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< VTK | Examples | Cxx(Redirected from VTK/Examples/Cxx/Broken/Images/ImageText)
Jump to navigationJump to searchThis example demonstrates how to draw text onto an image (vtkImageData). It uses vtkImageBlend to blend the text and the image. For another example using vtkImageBlend, see VTK/Examples/Cxx/Images/CombineImages.
See also VTK/Examples/Cxx/Visualization/DrawText for an example of drawing text, also in 2D, but into the render window rather than into a vtkImageData object.
Contents
ImageText.cxx
#include <vtkImageBlend.h>
#include <vtkImageData.h>
#include <vtkPointData.h>
#include <vtkPNGWriter.h>
#include <vtkSmartPointer.h>
#include <vtkFreeTypeUtilities.h>
#include <vtkTextProperty.h>
#include <vtkImageCanvasSource2D.h>
// must build VTK with VTK_USE_SYSTEM_FREETYPE=ON
int main(int argc, char* argv[])
{
// Create a black image with a red circle of radius 50 centered at (60, 60)
vtkSmartPointer<vtkImageCanvasSource2D> drawing =
vtkSmartPointer<vtkImageCanvasSource2D>::New();
drawing->SetScalarTypeToUnsignedChar(); // PNGWriter requires unsigned char (or unsigned short)
drawing->SetNumberOfScalarComponents(3);
drawing->SetExtent(0, 150, 0, 120, 0, 0); // xmin, xmax, ymin, ymax, zmin, zmax
drawing->SetDrawColor(255, 0, 0); // red
drawing->DrawCircle(60, 60, 50); // parameters: x, y, radius
// Create an image of text
vtkSmartPointer<vtkFreeTypeUtilities> freeType = vtkSmartPointer<vtkFreeTypeUtilities>::New();
vtkSmartPointer<vtkTextProperty> textProperty = vtkSmartPointer<vtkTextProperty>::New();
textProperty->SetColor(1.0, 1.0, 0.0); // yellow
textProperty->SetFontSize(24);
vtkSmartPointer<vtkImageData> textImage = vtkSmartPointer<vtkImageData>::New();
freeType->RenderString(textProperty, "Test String", textImage);
// Combine the images
vtkSmartPointer<vtkImageBlend> blend =
vtkSmartPointer<vtkImageBlend>::New();
blend->AddInputConnection(drawing->GetOutputPort());
blend->AddInputData(textImage);
blend->SetOpacity(0, 0.5); // background image: 50% opaque
blend->SetOpacity(1, 1.0); // text: 100% opaque
blend->Update();
vtkSmartPointer<vtkPNGWriter> writer =
vtkSmartPointer<vtkPNGWriter>::New();
writer->SetFileName("output.png");
writer->SetInputConnection(blend->GetOutputPort());
writer->Write();
return EXIT_SUCCESS;
}
Please try the new VTKExamples website.
CMakeLists.txt
cmake_minimum_required(VERSION 2.8)
PROJECT(ImageText)
find_package(VTK REQUIRED)
include(${VTK_USE_FILE})
add_executable(ImageText MACOSX_BUNDLE ImageText.cxx)
if(VTK_LIBRARIES)
target_link_libraries(ImageText ${VTK_LIBRARIES})
else()
target_link_libraries(ImageText vtkHybrid vtkWidgets)
endif()
Download and Build ImageText
Click here to download ImageText. and its CMakeLists.txt file.
Once the tarball ImageText.tar has been downloaded and extracted,
cd ImageText/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:
./ImageText
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.