What is pixel density?
Pixel density to the concentration of pixels on a particular display, measured in pixels per inch (ppi). Pixel density is calculated by dividing the diagonal pixel resolution of a display by its diagonal size.
What is PPI?
PPI is the acronym from Pixels Per Inch. It is a unit of measure used to quantify the number of pixels found on a square inch surface. To get a clear idea of what it means, imagine a square inch that’s divided and organized in a grid of cells. Each and every cell in that grid has a pixel inside. The number of cells inside the grid, also known as pixels, tells you the PPI.
See also: Mobile Application