如何处理图像，尤其是android中的背景图像

Question

我想知道如何处理android中的图像。我如何能够以正确的尺寸放置图像。图像的分辨率是多少？

Answer 1

有关屏幕尺寸，请阅读Android Documentation。

根据基本图像大小，通过DPI可绘制大小的缩放比率为3：4：6：8：12：16。

LDPI - 0.75x 
MDPI - Original size // means 1.0x here 
HDPI - 1.5x 
XHDPI - 2.0x 
XXHDPI - 3x 
XXXHDPI - 4.0x 

例如，MDPI上的100x100px图像与XHDPI屏幕上的200x200px大小相同。

你可以看到这里不同resolations不同尺寸：

xlarge screens are at least 960dp x 720dp 
large screens are at least 640dp x 480dp 
normal screens are at least 470dp x 320dp 
small screens are at least 426dp x 320dp 
Generalised Dpi values for screens: 

ldpi Resources for low-density (ldpi) screens (~120dpi) 
mdpi Resources for medium-density (mdpi) screens (~160dpi). (This is the baseline density.) 
hdpi Resources for high-density (hdpi) screens (~240dpi). 
xhdpi Resources for extra high-density (xhdpi) screens (~320dpi). 
Therefore generalised size of your resources (assuming they are full screen): 

ldpi 
Vertical = 426 * 120/160 = 319.5px 
Horizontal = 320 * 120/160 = 240px 
mdpi 
Vertical = 470 * 160/160 = 470px 
Horizontal = 320 * 160/160 = 320px 
hdpi 
Vertical = 640 * 240/160 = 960px 
Horizontal = 480 * 240/160 = 720px 
xhdpi 
Vertical = 960 * 320/160 = 1920px 
Horizontal = 720 * 320/160 = 1440px 

px = dp*dpi/160