The transition to high-density pixel displays that began with smartphones and tablets has spread to the computer monitors. 4K PC screens appeared in 2014, and understanding pixel density has become important when choosing a product, along with screen size and resolution. There are two standards for 4K resolution, “DCI 4K” and “UHD 4K”. Question of what is my screen resolution can be answered as: the display resolution of a digital television, computer monitor, tablet, smartphone or display device is the number of distinct pixels in each dimension that can be displayed.
The "native resolution" is written in a monitor's specifications, but what exactly does it mean? What happens if images are displayed at a resolution other than the "native resolution"? In particular, you can't help wondering what happens when an image is displayed in a resolution with a different aspect ratio.
The "number of pixels", or put another way "the number of points that light up", in an LCD screen is decided, and this "number of pixels" is the "native resolution." For example, this means that a monitor with a native resolution of "1920 × 1200" lights up, or turns off, 1920 horizontal rows (dots) and 1200 vertical rows (dots) of pixels to display images.
Then what happens if an image is displayed in a different resolution from the "native resolution," and in particular what happens if that resolution has a different aspect ratio to the "native resolution"? Let's consider a case where a "1280 × 1024" (horizontal : vertical = 5:4) image is displayed on an LCD monitor with a native resolution of "1920 × 1200" (horizontal : vertical = 16:10).