Displays¶

Reading a device's displays: list_displays enumerates every logical display from adb shell dumpsys display, and get_display_size / get_display_density read one display's pixel dimensions and dpi from adb shell wm size / adb shell wm density, including any active override. The display_id values list_displays returns are the ones -d / --display on the screenshot, input, and activity-launch tools expect.

`get_display_density` ¶

Get a display's density in dpi: adb shell wm density [-d display_id].

Record this before a density-override test so you can restore it after, or to convert between dp and px for layout assertions. Returns the panel's physical density and, when a wm density N override is in effect, the override too — plus the effective density apps see. Setting or resetting the density isn't implemented here.

Parameters:

Name	Type	Description	Default
`serial`	`str`	The target device's adb serial (see list_connected_devices).	required
`display_id`	`int \| None`	Which logical display to query (see list_displays). Omit for the device's default display. Must be non-negative.	`None`

Returns:

Type	Description
`DisplayDensity`	The serial, the display_id queried (None for the default display), physical_density, override_density (None when no override is set), and effective_density (the override if set, else physical).

Error handling

A negative display_id raises INVALID_ARGUMENT before any adb call. An unknown serial or unresponsive adb binary raises DEVICE_NOT_FOUND/ ADB_UNAVAILABLE; a permission rejection raises PERMISSION_DENIED. A display_id that doesn't exist (wm reports "-1") and output with no recognizable "Physical density:" line both raise DISPLAY_INFO_UNAVAILABLE.

Example

Called with serial="emulator-5554". A typical response:

{
  "status": "success",
  "message": "default display on emulator-5554: 160dpi.",
  "data": {
    "serial": "emulator-5554",
    "display_id": null,
    "physical_density": 160,
    "override_density": null,
    "effective_density": 160
  },
  "error": null
}

`get_display_size` ¶

Get a display's pixel dimensions: adb shell wm size [-d display_id].

Read this before coordinate-based tap/swipe automation so taps land where you expect. Returns the panel's physical resolution and, when a wm size WxH override is currently in effect, the override too — plus the effective resolution apps actually see (the override if set, else physical). Setting or resetting the size isn't implemented here.

Parameters:

Name	Type	Description	Default
`serial`	`str`	The target device's adb serial (see list_connected_devices).	required
`display_id`	`int \| None`	Which logical display to query (see list_displays). Omit for the device's default display. Must be non-negative.	`None`

Returns:

Type	Description
`DisplaySize`	The serial, the display_id queried (None for the default display), physical_width/physical_height, override_width/override_height (None when no override is set), and effective_width/effective_height.

Error handling

A negative display_id raises INVALID_ARGUMENT before any adb call. An unknown serial or unresponsive adb binary raises DEVICE_NOT_FOUND/ ADB_UNAVAILABLE; a permission rejection raises PERMISSION_DENIED. A display_id that doesn't exist (wm reports "0x0") and output with no recognizable "Physical size:" line both raise DISPLAY_INFO_UNAVAILABLE.

Example

Called with serial="emulator-5554". A typical response:

{
  "status": "success",
  "message": "default display on emulator-5554: 1408x792.",
  "data": {
    "serial": "emulator-5554",
    "display_id": null,
    "physical_width": 1408,
    "physical_height": 792,
    "override_width": null,
    "override_height": null,
    "effective_width": 1408,
    "effective_height": 792
  },
  "error": null
}

`list_displays` ¶

Enumerate a device's logical displays: adb shell dumpsys display.

This is the display-discovery anchor for the rest of the server — the display_id values it returns are what -d / --display on the screenshot, input, and activity-launch tools expect. dumpsys display is large and mostly unstable internal state; this reads only two curated markers (the mViewports=[...] line and the Display States: section) and parses them in Python. Changing display state (size, density, rotation) isn't implemented here.

Parameters:

Name	Type	Description	Default
`serial`	`str`	The target device's adb serial (see list_connected_devices).	required

Returns:

Type Description

DisplayList

The serial and displays: a list (ordered by display_id, always at least one entry) of {display_id, state ("ON"/"OFF"/"DOZE"/…), type ("INTERNAL"/"EXTERNAL"/"VIRTUAL"/"OVERLAY"), width, height, density_dpi, rotation (0-3 quarter-turns), unique_id}. Every field except display_id may be None when dumpsys display didn't report it (e.g. dimensions/density/type are None for a powered-off display with no active viewport).

Error handling

An unknown serial or unresponsive adb binary raises DEVICE_NOT_FOUND/ADB_UNAVAILABLE. A permission rejection raises PERMISSION_DENIED. If dumpsys display runs but its output has no recognizable display records at all (format drift, truncated output), this raises DISPLAY_INFO_UNAVAILABLE rather than returning an empty list. Any other non-zero exit raises BACKEND_ERROR.

Example

Called with serial="emulator-5554". A typical response:

{
  "status": "success",
  "message": "1 display on emulator-5554: 0.",
  "data": {
    "serial": "emulator-5554",
    "displays": [
      {
        "display_id": 0,
        "state": "ON",
        "type": "INTERNAL",
        "width": 1408,
        "height": 792,
        "density_dpi": 160,
        "rotation": 0,
        "unique_id": "local:4619827259835644672"
      }
    ]
  },
  "error": null
}

Displays¶

get_display_density ¶

get_display_size ¶

list_displays ¶

`get_display_density` ¶

`get_display_size` ¶

`list_displays` ¶