How to get UV coordinate area of rendered material

Hi everyone,

Is it possible to know what area of the material is rendered on the display? I think Three.js already doing this right?

I trying to make Zoom level. When someone zooming it will become a good resolution.
I making CUBE using 6 planes and I’m trying to know the coordinate of the material and which areas are rendered on display.

The below example shows on the display only some areas of TOP, some areas of RIGHT and FRONT.
If I know which coordinate of material is rendered on the display, I’ll draw a good resolution of the image on the canvas.

Thank you,