dumpsys SurfaceFlinger 分析

1. 检索 "DisplayDevice" 看当前系统有几个屏幕

如下，可以看到有2个物理屏，一个虚拟屏。

DisplayDevice{129, primary, "Internal display"}
DisplayDevice{130, "External display"}
DisplayDevice{virtual, "XiaoMaVirtualActivity-App-VD"}

2. 检索 "Display 129 HWC layers:" / "Display 130 HWC layers:" 查看各物理屏对应的图层信息

Android 13开始会在TOP图层对应行的最右侧标记一个"*"号。

Display 130 HWC layers:
-------------------------------------------------------------------------------------------
 Layer name
           Z |  Window Type |  Comp Type |  Transform |   Disp Frame (LTRB) |          Source Crop (LTRB) |   appPid
-------------------------------------------------------------------------------------------
 SurfaceView - #0
  rel     -2 |            0 |     CLIENT |          0 |    0    0 1920  532 |    0.0    0.0 1920.0  532.0 |    1802
- - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - -- - - - - - - - - - - - - - -
 #1
  rel      0 |         2111 |     CLIENT |          0 |    0    0 1920  532 |    0.0    0.0 1920.0  532.0 |    1802
- - - - - - - - - - - - - - - -- - - - - - - - - - - - - - - -- - - - - - - - - - - - - - -