This article is a sequel to the previous one https://www.weiy.city/2023/04/draw-a-circle-around-mouse-postion-on-screen/. Let’s check if the vertex of cone is inside the red circle when we move mouse. CustomIteractorStyle.cpp UPaintBrush.cpp UPaintBrush.h Output:
The example draws a red circle around mouse position by vtkContextItem, vtkContext2D and vtkContextActor. When moving mouse, the red circle following it. CMakeLists.txt CustomIteractorStyle.h: CustomIteractorStyle.cpp UPaintBrush.h UPaintBrush.cpp main.cpp
This post is based on an old project Use ITK And VTK To Show DICOM Image. We want to add an above layer which drawed translucent red color on the gray image. Use alpha blend algorithm to merge two different color: origin color = $(R_1, G_1, B_1, 255)$ canvas color Read more…
Environment: VTK8.2.0, ITK5.0.0 Here is a demo project to display DICOM data by ITK and VTK. CMakeLists.txt main.cpp The folder contains a series of dcm files.Run it. Convert it to RGBA Image crudely.
Make canvas response to key press event We often create our custom iteractor style object to define our interactive behaviors.Write some debug code in OnKeyPress event.For web page, the element canvas is like Qt’s widget. Set property tabindex for responsing to user key press event. Asynchronous call It’s synchronous for JS code call wasm Read more…
The post shows how to use difference matrix to let two camera have same action. We can get the following relationship between viewUp vector and view plane normal. The view transform matrix can be generated from camera focal point, postion and view up vector. Matrix of camera’s view transform: Read more…
Set An Image As Render Background std::string bgImgPath = “./resource/bg.png”; vtkNew<vtkPNGReader> imgReader; imgReader->SetFileName(bgImgPath.c_str()); vtkNew<vtkTexture> backgroundTexture; backgroundTexture->SetInputConnection(imgReader->GetOutputPort()); m_Renderer->GradientBackgroundOff(); backgroundTexture->Update(); m_Renderer->SetBackgroundTexture(backgroundTexture); m_Renderer->SetTexturedBackground(true); Save 3D Model Screen Shot With Transparent Background Don’t set textured background for renderer object. Then set alpha bits for renderer window object, read RGBA information from back buffer when Read more…
I’m assuming we’re using a parallel projection for 3D environment. We can find the project transform matrix logic at VTK code source. The ParallelScale is bigger, xmax – xmin and ymax – ymin is bigger, matrix[0][0] and matrix[1][1] is smaller. So we can get that the display length of model Read more…
PreserveColorBuffer You can see the following effect after preserving color buffer for renderer object. Download 3D Model With WASM From Web Pabge The browser will download the VTP file automatically when your web page run to the above logic.