Canvas Aspect Ratio for Instagram Story

[ErkanKabil]

I have a project written with React. In this project, the user can share the current screen as a story on instagram. here I first convert the html screen to canvas and then to image and share it that way.

The problem here starts in the part of converting the screen to canvas. I want the size of the generated image to be suitable for instagram. here I want to produce canvas in accordance with the 9 / 16 ratio. if I can crop the image I produce from the top and bottom, there will be no problem, but I don't know how to do it.

Example Image; this image's aspect-ratio is : 215:466