http://www.woshipm.com/pmd/176328.html
respective definitions:
- px: pixel, pixel, the most basic unit of a picture or photo on an electronic screen
- pt: point, point, a common unit in the printing industry, equal to 1/72 of an inch
- ppi: pixel per inch, the number of pixels per inch, the higher the value, the finer the screen
- dpi: dot per inch, how many dots per inch, the higher the value, the finer the picture
- dp: dip, Density-independent pixel, is the length unit for Android development, 1dp means 1px length when the screen pixel density is 160ppi
- sp: scale-independent pixel, the font size unit for Android development.
Conversion formula:
1pt= (DPI / 72) px
dpi=ppi
ppi= the number of pixels on the diagonal of the screen / the length of the diagonal line = √ (the horizontal pixels of the screen^2 + the vertical pixels of the screen^2) / the length of the diagonal
1dp=(screen ppi/160)px
When the text size is "Normal", 1sp=1dp, and when the text size is "Large" or "Extra Large", 1sp>1dp.
In general, it can be considered that sp=dp.
Replenish:
dp is the unit of length in Android development, and it has a different correspondence with px according to different screen resolutions.
Android screens vary in size, and are divided into the following specifications according to their pixel density:
1dp is defined as 1px at a screen density value of 160ppi, i.e., at mdpi, 1dp = 1px. Taking mdpi as the standard, the density value ratio of these screens is: ldpi : mdpi : hdpi : xhdpi : xxhdpi = 0.75 : 1 : 1.5 : 2 : 3; that is, under the density of xhdpi, 1dp=2px; in the case of hdpi, 1dp=1.5px. Other analogies.