Worst quality perspective image on canvas

I have a problem on my project.

I am developing a perspective mockup creating module for designers. Users upload images and i get them for placing in mockups with making some perspective calculations. Then users can download this image. I made all of this on clientside with js.

But there is a problem for images which are drawn on canvas with perspective calculations like this;

Sample img: http://ift.tt/17rVnXp

orginal image size: 6500 x 3592 and you can see spread edges on image...

I tried a few technics like ctx.imageSmoothingEnabled true etc.. But result was always same.

What can i do for solve this problem? What do you think about this?

edit

For more detail;

I get an image (Resolution free) from user then crop it for mockup ratio. For example in my sample image, user image was cropped for imac ratio 16:9 then making calculation with four dot of screen. By the way, my mockup image size is 6500 x 3592. so i made scale, transform etc this cropped image and put it in mockup on canvas. And then use blob to download this image to client...

Thanks.