Pixels per inch (PPI) is a measurement of the pixel density (resolution) defined as the number of horizontal or vertical pixel found in an inch.
Pixels per inch (PPI) is a measurement of the pixel density (resolution) of devices in various contexts: typically computer displays, image scanners, and digital camera image sensors. It is defined as the horizontal or vertical density (for square pixels) as those are the same but the density on along the diagonal is lower.
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