link

ppi Pixel Per Inch 像素密度 物理参数 538
dpi Dot Per Inch 像素密度 软件指定的，可能人为修改，不同ppi的手机譬如430、440、450，系统能指定dpi都为480 640
dp/dip Density-independent Pixels 抽象单位 1 dp = 1 pixel, — in 160 dpi screen 1 dp = 4 pixels
density density = dpi /160 每 dp 占当前设备屏幕多少像素 4
sp scale-independent pixels specifying font sizes, so they will be adjusted for both the screen density and user’s preference.
mate 20 pro

inch, 1 inch = 2.54 centimeters, 就是和键盘的shift的按键差不多长度，但是稍微短一点 ppi等于或者约等于dpi

  1. +----------------+----------------+---------------+-------------------------------+
  2. | Density Bucket | Screen Density | Physical Size | Pixel Size                    | 
  3. +----------------+----------------+---------------+-------------------------------+
  4. | ldpi           | 120 dpi        | 0.5 x 0.5 in  | 0.5 in * 120 dpi = 60x60 px   | 
  5. +----------------+----------------+---------------+-------------------------------+
  6. | mdpi           | 160 dpi        | 0.5 x 0.5 in  | 0.5 in * 160 dpi = 80x80 px   | 
  7. +----------------+----------------+---------------+-------------------------------+
  8. | hdpi           | 240 dpi        | 0.5 x 0.5 in  | 0.5 in * 240 dpi = 120x120 px | 
  9. +----------------+----------------+---------------+-------------------------------+
  10. | xhdpi          | 320 dpi        | 0.5 x 0.5 in  | 0.5 in * 320 dpi = 160x160 px | 
  11. +----------------+----------------+---------------+-------------------------------+
  12. | xxhdpi         | 480 dpi        | 0.5 x 0.5 in  | 0.5 in * 480 dpi = 240x240 px | 
  13. +----------------+----------------+---------------+-------------------------------+
  14. | xxxhdpi        | 640 dpi        | 0.5 x 0.5 in  | 0.5 in * 640 dpi = 320x320 px | 
  15. +----------------+----------------+---------------+-------------------------------+
  1. +---------+-------------+---------------+-------------+--------------------+
  2. | Unit    | Description | Units Per     | Density     | Same Physical Size | 
  3. |         |             | Physical Inch | Independent | On Every Screen    | 
  4. +---------+-------------+---------------+-------------+--------------------+
  5. | px      | Pixels      | Varies        | No          | No                 | 
  6. +---------+-------------+---------------+-------------+--------------------+
  7. | in      | Inches      | 1             | Yes         | Yes                | 
  8. +---------+-------------+---------------+-------------+--------------------+
  9. | mm      | Millimeters | 25.4          | Yes         | Yes                | 
  10. +---------+-------------+---------------+-------------+--------------------+
  11. | pt      | Points      | 72            | Yes         | Yes                | 
  12. +---------+-------------+---------------+-------------+--------------------+
  13. | dp      | Density     | ~160          | Yes         | No                 | 
  14. |         | Independent |               |             |                    | 
  15. |         | Pixels      |               |             |                    | 
  16. +---------+-------------+---------------+-------------+--------------------+
  17. | sp      | Scale       | ~160          | Yes         | No                 | 
  18. |         | Independent |               |             |                    | 
  19. |         | Pixels      |               |             |                    | 
  20. +---------+-------------+---------------+-------------+--------------------+

屏幕适配方案

  • 限定符适配方案—reference
  • 今日头条适配方案-反射修正系统的density值—reference