How to render each pixel of a bitmap texture to each native physical pixel of the screen on macOS?

Question

As modern macOS devices choose to use a scaled HiDPI resolution by default, bitmap images get blurred on screen. Is there a way to render a bitmap pixel by pixel to the true na

Answer 1

If these are resource images, use asset catalogs to provide x2 and x3 resolution version of your images, icons, etc. Classes like NSImageView will automatically select the best version for the display resolution.

If you just have some random image and you want it draw at the resolution of the display, get the backingScaleFactor of the view's window. If it's 2.0 then drawing a 200 x 200 pixel image into a 100 x 100 coordinate point rectangle will draw it at 1:1 native resolution. Similarly, if the scale factor is 3.0, a 300 x 300 pixel image will draw into a 100 x 100 coordinate point rectangle.

Not surprisingly, Apple has an extensive guide on this subject: High Resolution Guidelines for OS X

Answer 2

Your best bet is probably Metal. MTKView's drawableSize claims that the default is the view's size "in native pixels". I'm not certain if that means device pixels or backing store pixels. If the latter, you could turn off autoResizeDrawable and set drawableSize directly.

To obtain the display's physical pixel count, you can use my answer here.

You can also try using Core Graphics with a CGImage of that size drawn to a rect of the screen size in backing store pixels. It's possible that all of the scaling will be internally cancelled out.