With any electronically created image there is a grid, or an array made of dots or squares that are called pixels. This is true for a live dot flip board, a direct view LED display, OLED, LCD, DLP, D-ILA, Micro LED quantum dots, or any other technology. This pixel structure is the base component of the image. An image (size?) is simply a sum of many pixels that each light up to a specific brightness or color to create a completed image. Pixels have a few major things they all share regardless of technology.
Today I am talking about relative position i.e. how close each pixel is from a center line to the next pixel’s center line. This pixel to pixel distance or space is the display pixel density and is calculated using a variable that have labelled P because it also equal to the total pixel size. The closer the pixels are the more density there is in a display. The closer the pixels are the more pixels there are per square meter or foot. But P isn’t relative and can be found two ways.
First, you can find P by array total. For total pixel count you solve for the new pixel count first in the X, Y direction, then simply multiply the answer out. So, if 4 by 4 image is 4x4=16 pixels and you double the density to get 8 by 8 which is 8x8=64 pixels.
The second way to find P is by the combined difference multiplier in each direction. For doubling a display’s density, the distance X increased by a factor of 2. So, 2 x 2 = 4 and using the prior total of 16, multiply that by the difference factor which is 4. 16 x 4 = 64. Same answer.
Shown both ways if you triple the density, 12 x 12 pixels you have 144 pixels or 3x3 = 9. 16 x 9 = 144. But why do a difference rather than an array you may ask? Well, the answer is that if you have a display that is not a complete array, when you calculate the pixels you have to subtract out the non-full array section. In a difference if there were 100 pixels before and you double the pixel density you have 400 pixels regardless of where they are. So, it can be easier at times to use a total pixel count difference rather than using a X, Y axis count. It depends on what you are solving for.