Pixel Mobile development pixel knowledge

640*1136 pictures cannot be fully displayed on the Ipone?

Iphone5 Resolution: 640*1136 (claimed--device independent pixels)

Why Iphone5 is 320px*568px?

Px:css pixels logical pixels, abstract units used by the browser (can be larger and smaller depending on the device)

Dp,pt:device indipendent pixels device independent pixels (physical pixels fixed, not larger and smaller as logical pixels)

Dpr:devicepixelratio Device pixel scaling ratio

Calculation formula: 1px= (DPR) 2*DP

iphone5 Pixel Explanation: (Iphone5 's dpr=2)

Flat: 1px= (2) 2*DP 640DP*1136DP

Dimensions: 1PX=2*DP 320px*568px

DPI: Ink dots (printing) that can be sprayed every inch of the printer

PPI: The number of pixels per inch of the screen, which is the pixel density in units of inches

At present, in the computer display device parameter description, the two meanings are the same

Calculation formula: Move Iphone5 as an example (Iphone5 is 4 inches)

Ppi=√ (11362+6402)/4=326ppi

Note: The unit is a physical pixel, not the larger PX PPI, the higher the number of pixels, the more clear the image

But the lower the visibility (small), the larger the system default setting scaling ratio

Retina (Gaoqing): DPR are greater than or equal to 2

Pixel Mobile development pixel knowledge