We can use XML to store the OpenCV matrix and read it to recover the whole image. A simple example is in the following code snippet. We write an original image data to Untitled1.xml, then read it to generate another Mat object and show it. #include <stdio.h> #include <opencv2/opencv.hpp> #include Read more…
We can find that vtkOrientedGlyphContourRepresentation supports to set 3D model always above other objects. // Create the contour widget vtkSmartPointer<vtkContourWidget> contourWidget = vtkSmartPointer<vtkContourWidget>::New(); // Override the default representation for the contour widget to customize its look vtkSmartPointer<vtkOrientedGlyphContourRepresentation> contourRepresentation = vtkSmartPointer<vtkOrientedGlyphContourRepresentation>::New(); // … contourWidget->SetRepresentation(contourRepresentation); contourRepresentation->SetAlwaysOnTop( true ); I readed the code Read more…
We want to know the height of the above cone, there is the precondition that there is a red sphere in the center of the cone and we assume that we can’t get the height from multiplying the length of the vector both red spheres forms by 2. The original Read more…
The article shows a way to calculate the length between two points on a curve. We create a ring and put axis actor in the center to show the ring’s orientation and size. Here are implementation details, the data file curve.vtp can be downloaded from my github repository documents. #define Read more…
How to set different colors for different parts of a single 3D model? The article introduces a way that set scalars for pointData and map the information by vtkColorTransferFunction object, then vtkPolyDataMapper object configure a correct scalar mode and use vtkColorTransferFunction object as its lookupTable. The code snippet shows all Read more…
Git stash has many common operations that can be represented by following commands. git stash git stash list git stash pop [–index] [stash_id] git stash apply [–index] [stash_id] git stash drop [stash_id] git stash clear Now we will learn a few other powerful options. git stash push After October 2017, Read more…
I want to rotate the curve to be close to both points, the rotate axis is vector( 0, 0, 1 ) which is Z-axis in VTK’s world coordinate system. We can use the summary of distance squares to indicate the match level, the value is bigger means the curve is Read more…
We can use vtkCoordinate and vtkRenderer objects to convert point’s coordinate from a system to another one. I found vtkCoordinate called the functions of vtkViewport (vtkRenderer is child class of vtkViewport) to accomplish coordinate transformation. class vtkViewport: virtual void LocalDisplayToDisplay(double &x, double &y); virtual void DisplayToNormalizedDisplay(double &u, double &v); virtual 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…