How to determine the scale of an Image - ios

I have an image that I'm using which is 960x1280. I have coordinates for a rectangle of x:391 y:772, x:574 y:772, x:574 y:870, x:391 y:870 which allows me to put the rectangle in the proper spot IF the image is still 960x1280. Of course, when I'm in Xcode, the screen size is 375x667.
When drawing the rectangle with the above coordinates, the rectangle is no longer visible. If just use the screen scale of 3 (UIScreen.main.scale) it's not accurate either.
I create a UIImageView that has constraints of 0 for all four sides and using aspect .fit or .fill. How do I now know the proper scale of the image so the rectangle is drawn in the right spot?
Thanks

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I have added an icon to my assets to be used in an image view. However, When I put it in an image view the outer edges seem to be larger than the image itself. Is there any way I can fully fill the image. Even when I try scale to fill or aspect fill, fit options still there remains a margin in between.
In other words I want my circular image to be tangent to the image view rectangle
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Stick 2 Image views dimensions in all iOS devices

I want to thank anyone of you who is contributing to this community, and i which to find a solution to the issue that is presented below:
this is a capture of my xcode project Main Storyboard:
it contains a background image view with a grid picture and a small image view over it with a cercle picture.the content mode is the same for both views is aspect fit.
what i am trying to achieve here is to get the same combination between the two images, as in this picture, on all devices.
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I grabbed your image and clipped out the circle.
The "grid" actual pixels are 312 x 324. The "circle" is 30 x 30.
I set the grid imageView to fill, with a width-to-height ratio of 312:324 and a width of 0.75 to superview.
I set the circle imageView to fill, with a width-to-height ratio of 1:1 and a width constraint of 30:312 of the grid imageView.
Here is the result:
You would need to calculate the run-time" ratio for placement, but that's pretty straight-forward.
Edit:
I whipped up a simple example - has buttons to move the circle based on the intersection points: https://github.com/DonMag/GridScale

How to slicing image and make it stretchable with image assets

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centre arrow remain as it is
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You can't do this with sliced images.
The area between the edges will stretch or repeat in order to fill the area. You can't also preserver the centre section of an image this way.
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Detail:
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EDIT
Please Find out the Attached Image for understanding
I think there's a little ambiguity in the question: a frame must be specified in a coordinate system. But I think you're looking for a rect relative to the original, unclipped image.
If that's right, then the rect can be computed as follows. Say the image is called image, and the image view is imageView. The size of the rect is the size of the image view:
imageView.bounds.size
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