原文链接：https://www.jianshu.com/p/d3ef5a9902b7
物理分辨率是硬件所支持的，逻辑分辨率是软件可以达到的。

2517412-08bd9e1ae9b7c303.png
2517412-4c60254266a1216b.png
2517412-8024495486992c0c.png
宏定义
//获得屏幕的宽高

define kScreenWidth ([UIScreen mainScreen].bounds.size.width)

define kScreenHeight ([UIScreen mainScreen].bounds.size.height)

//iPhoneX / iPhoneXS

define isIphoneX_XS (kScreenWidth == 375.f && kScreenHeight == 812.f ? YES : NO)

//iPhoneXR / iPhoneXSMax

define isIphoneXR_XSMax (kScreenWidth == 414.f && kScreenHeight == 896.f ? YES : NO)

//异性全面屏

define isFullScreen (isIphoneX_XS || isIphoneXR_XSMax)

// Status bar height.

define StatusBarHeight (isFullScreen ? 44.f : 20.f)

// Navigation bar height.

define NavigationBarHeight 44.f

// Tabbar height.

define TabbarHeight (isFullScreen ? (49.f+34.f) : 49.f)

// Tabbar safe bottom margin.

define TabbarSafeBottomMargin (isFullScreen ? 34.f : 0.f)

// Status bar & navigation bar height.

define StatusBarAndNavigationBarHeight (isFullScreen ? 88.f : 64.f)