Changing Current Drawable Size

Is there is a way to change the current Drawable size.

I am having a UIImage and I change it to MTLTexture. Then I had a four vertex(Kind of a plane) to draw the texture. Then I zoom the image. I used projection matrix so that plane is zoomed so that MTLTexture get zoomed.

Then I add triangle. When to no scale i replace the region.

When i reduce scale, plane is reduce scaling when i add a triangle and back to normal it is pixellating while replacing the region.

Any Solution to solve this