How to solve the problem of stretching deformation in the captured images of renderwindow

Hi vtk community and maintainers,
I would like to ask for help with the captureImages API.The model elements I rendered using vtk.js look good on the page. I use the renderwindow captureImages method to obtain a screenshot of the canvas. But the screenshot obtained shows that the model element on it has been stretched and deformed, and it has been stretched in the y-axis direction.
is there a way to solve this problem?
thank you