MacBook Pro M1 Video Output using DVI Adaptor

On the MacBook Pro M1 screen the grayscale is achieved by partly turning on the pixels. I say this because under a magnifying glass there are no gaps between the pixels meaning that it is NOT a case of turning on alternate pixels.

Given that the video available from a USBC-to-DVI adaptor is digital, i.e. with no partly illuminated pixels (they are either full ON or full OFF) how will the DVI signals deliver this?

DVI being a digital interface does not mean that pixels on the display have to be either fully on or fully off because of the digital "zeroes and ones".

Using DVI, a number of bits are transferred for each pixel to represent what we would like the display to show. The actual number of bits per pixels varies depending on your configuration - but it can be up to 48 bits in a dual-link DVI setup, but is typically 24 bits per pixels in many setups. It can also be fewer than that.

In a typical 24 bits per pixel setup, you would find that the intensity of the red, green and blue colors are described for each as a number from 0-254. I.e. 8 bit per color, 24 bits per pixel for a RGB setup.

Note that the above is a simplified explanation of how DVI works on a conceptual level. The actual signal transferred over the wire actually uses 10 bits symbols to transfer 8 bit worth of payload data.