The article introduces how to display an image by OpenCV in CPlusPlus and Python language. The user can exit the whole program when he presses the ESC key. CPP CMakeLists.txt macro(use_cxx11) if (CMAKE_VERSION VERSION_LESS “3.1”) if (CMAKE_CXX_COMPILER_ID STREQUAL “GNU”) set (CMAKE_CXX_FLAGS “${CMAKE_CXX_FLAGS} -std=gnu++11”) endif () else () set (CMAKE_CXX_STANDARD 11) Read more…
Downloaded the announcement of a listed company from cninfo.com.cn and saved it as a PDF file. The relevant title about it is 国泰君安 – 关于独立董事公开征集投票权的公告. Let’s extract text and table on the PDF file by python. We have to make sure the library pdfplumber had been installed. Use the command Read more…
The article introduces a way to reduce the size of the gif file. The python script analysis gif file and generate many png files from multiple frames. Then it takes a few png files to combine a new smaller gif file. In addition, You can use OpenCV to convert the Read more…
The instance of vtkImporter contains vtkRenderWindow and vtkRenderer objects. It supports to recover original scene including lights, cameras, actors, etc. Here is a simple example which imports 3D studio file and shows the whole scene. import vtk DataRoot = “/Users/weiyang/Downloads/VTKData” importer = vtk.vtk3DSImporter() importer.ComputeNormalsOn() importer.SetFileName( DataRoot + “/Data/iflamigm.3ds” ) importer.Read() Read more…
I want to get the solution of the equation Bisection Method The first algorithm for the problem is bisection method. The algorithm bisection method doesn’t require derivation for the equation. It just needs a possible solution range [l, r], then calculates the variable mid as , compares the result of Read more…
There are three examples using views displaying relations of vtk classes. The article learned from VTKUsersGuide vtkTreeRingView Python #!/usr/bin/env python from vtk import * def main(): datapath = “/Users/weiyang/Downloads/VTKData” #vtk.util.misc.vtkGetDataRoot() reader1 = vtkXMLTreeReader() reader1.SetFileName(datapath + “/Data/Infovis/XML/vtkclasses.xml”) reader1.SetEdgePedigreeIdArrayName(“tree edge”) reader1.GenerateVertexPedigreeIdsOff(); reader1.SetVertexPedigreeIdArrayName(“id”); reader2 = vtkXMLTreeReader() reader2.SetFileName(datapath + “/Data/Infovis/XML/vtklibrary.xml”) reader2.SetEdgePedigreeIdArrayName(“graph edge”) reader2.GenerateVertexPedigreeIdsOff(); reader2.SetVertexPedigreeIdArrayName(“id”); Read more…
Two ways to add data object for a vtkView. 1) Create a representation object, set the inputs for it by calling SetInputConnection() or SetInput(), then add representation for the view. 2) Use AddRepresentationFromInputConnection or AddRepresentationFromInput to create representation automatically. 1) Python from vtk import * surfaceRepresentation = vtkRenderedSurfaceRepresentation() sphere = Read more…
vtkGraphLayoutView is a subclass of vtkGraphLayoutView which has own renderer, renderWindow, command observer, actor and etc. The following code shows how to use it to display a 2D image. from vtk import * def main(): # create a random graph source = vtkRandomGraphSource() source.SetNumberOfVertices(100) source.SetNumberOfEdges(110) source.StartWithTreeOn() source.Update() arcParallelStrategy = vtkArcParallelEdgeStrategy() Read more…
The article shows how to clip a cone by a plane. The vtkClipPolyData object provides a major algorithm to process the 3D model. Here is python script that describes all details about it. #!/usr/bin/env python import vtk cone = vtk.vtkConeSource() coneMapper = vtk.vtkPolyDataMapper() coneMapper.SetInputConnection( cone.GetOutputPort() ) coneActor = vtk.vtkActor() coneActor.SetMapper( Read more…