docs » hs.screen

Manipulate screens (i.e. monitors)

The macOS coordinate system used by Hammerspoon assumes a grid that spans all the screens (positioned as per System Preferences->Displays->Arrangement). The origin 0,0 is at the top left corner of the primary screen. (Screens to the left of the primary screen, or above it, and windows on these screens, will have negative coordinates)

Submodules

API Overview

API Documentation

Variables

strictScreenInDirection
Signature hs.screen.strictScreenInDirection
Type Variable
Description If set to `true`, the methods `hs.screen:toEast()`, `:toNorth()` etc. will disregard screens that lie perpendicularly to the desired axis
Source extensions/screen/init.lua

Functions

accessibilitySettings
Signature hs.screen.accessibilitySettings() -> table
Type Function
Description Gets the current state of the screen-related accessibility settings
Parameters
  • None
Returns
  • A table containing the following keys, and corresponding boolean values for whether the user has enabled these options:
    • ReduceMotion (only available on macOS 10.12 or later)
    • ReduceTransparency
    • IncreaseContrast
    • InvertColors (only available on macOS 10.12 or later)
    • DifferentiateWithoutColor
Source extensions/screen/internal.m
find
Signature hs.screen.find(hint) -> hs.screen object(s)
Type Function
Description Finds screens
Parameters
  • hint - search criterion for the desired screen(s); it can be:
    • a number as per hs.screen:id()
    • a string containing the UUID of the desired screen
    • a string pattern that matches (via string.match) the screen name as per hs.screen:name() (for convenience, the matching will be done on lowercased strings)
    • an hs.geometry point object, or constructor argument, with the x and y position of the screen in the current layout as per hs.screen:position()
    • an hs.geometry size object, or constructor argument, with the resolution of the screen as per hs.screen:fullFrame()
    • an hs.geometry rect object, or constructor argument, with an arbitrary rect in absolute coordinates; the screen containing the largest part of the rect will be returned
Returns
  • one or more hs.screen objects that match the supplied search criterion, or nil if none found
Notes
  • for convenience you call call this as hs.screen(hint)
Source extensions/screen/init.lua
restoreGamma
Signature hs.screen.restoreGamma()
Type Function
Description Restore the gamma settings to defaults
Parameters
  • None
Returns
  • None
Notes
  • This returns all displays to the gamma tables specified by the user's selected ColorSync display profiles
Source extensions/screen/internal.m
screenPositions
Signature hs.screen.screenPositions() -> table
Type Function
Description Returns a list of all connected and enabled screens, along with their "position" relative to the primary screen
Parameters
  • None
Returns
  • a table where each key is an hs.screen object, and the corresponding value is a table {x=X,y=Y}, where X and Y attempt to indicate each screen's position relative to the primary screen (which is at {x=0,y=0}); so e.g. a value of {x=-1,y=0} indicates a screen immediately to the left of the primary screen, and a value of {x=0,y=2} indicates a screen positioned below the primary screen, with another screen inbetween.
Notes
  • grid-like arrangements of same-sized screens should behave consistently; but there's no guarantee of a consistent result for more "exotic" screen arrangements
Source extensions/screen/init.lua

Constructors

allScreens
Signature hs.screen.allScreens() -> hs.screen[]
Type Constructor
Description Returns all the screens
Parameters
  • None
Returns
  • A table containing one or more hs.screen objects
Source extensions/screen/internal.m
mainScreen
Signature hs.screen.mainScreen() -> screen
Type Constructor
Description Returns the 'main' screen, i.e. the one containing the currently focused window
Parameters
  • None
Returns
  • An hs.screen object
Source extensions/screen/internal.m
primaryScreen
Signature hs.screen.primaryScreen() -> screen
Type Constructor
Description Gets the primary screen
Parameters
  • None
Returns
  • An hs.screen object
Source extensions/screen/init.lua

Methods

absoluteToLocal
Signature hs.screen:absoluteToLocal(geom) -> hs.geometry object
Type Method
Description Transforms from the absolute coordinate space used by OSX/Hammerspoon to the screen's local coordinate space, where `0,0` is at the screen's top left corner
Parameters
  • geom - an hs.geometry point or rect, or arguments to construct one
Returns
  • an hs.geometry point or rect, transformed to the screen's local coordinate space
Source extensions/screen/init.lua
availableModes
Signature hs.screen:availableModes() -> table
Type Method
Description Returns a table containing the screen modes supported by the screen. A screen mode is a combination of resolution, scaling factor and colour depth
Parameters
  • None
Returns
  • A table containing the supported screen modes. The keys of the table take the form of "1440x900@2x" (for a HiDPI mode) or "1680x1050@1x" (for a native DPI mode). The values are tables which contain the keys:
    • w - A number containing the width of the screen mode in points
    • h - A number containing the height of the screen mode in points
    • scale - A number containing the scaling factor of the screen mode (typically 1 for a native mode, 2 for a HiDPI mode)
    • freq - A number containing the vertical refresh rate in Hz
    • depth - A number containing the bit depth of the display mode
Notes
  • Prior to 0.9.83, only 32-bit colour modes would be returned, but now all colour depths are returned. This has necessitated changing the naming of the modes in the returned table.
  • "points" are not necessarily the same as pixels, because they take the scale factor into account (e.g. "1440x900@2x" is a 2880x1800 screen resolution, with a scaling factor of 2, i.e. with HiDPI pixel-doubled rendering enabled), however, they are far more useful to work with than native pixel modes, when a Retina screen is involved. For non-retina screens, points and pixels are equivalent.
Source extensions/screen/internal.m
currentMode
Signature hs.screen:currentMode() -> table
Type Method
Description Returns a table describing the current screen mode
Parameters
  • None
Returns
  • A table containing the current screen mode. The keys of the table are:
    • w - A number containing the width of the screen mode in points
    • h - A number containing the height of the screen mode in points
    • scale - A number containing the scaling factor of the screen mode (typically 1 for a native mode, 2 for a HiDPI mode)
    • freq - A number containing the vertical refresh rate in Hz
    • depth - A number containing the bit depth
    • desc - A string containing a representation of the mode as used in hs.screen:availableModes() - e.g. "1920x1080@2x 60Hz 4bpp"
Source extensions/screen/internal.m
desktopImageURL
Signature hs.screen:desktopImageURL([imageURL])
Type Method
Description Gets/Sets the desktop background image for a screen
Parameters
  • imageURL - An optional file:// URL to an image file to set as the background. If omitted, the current file URL is returned
Returns
  • the hs.screen object if a new URL was set, otherwise a string containing the current URL
Notes
  • If the user has set a folder of pictures to be alternated as the desktop background, the path to that folder will be returned.
Source extensions/screen/internal.m
frame
Signature hs.screen:frame() -> hs.geometry rect
Type Method
Description Returns the screen frame, without the dock or menu.
Parameters
  • None
Returns
  • an hs.geometry rect describing this screen's "usable" frame (i.e. without the dock and menu bar) in absolute coordinates
Source extensions/screen/init.lua
fromUnitRect
Signature hs.screen:fromUnitRect(unitrect) -> hs.geometry rect
Type Method
Description Returns the absolute rect of a given unit rect within this screen
Parameters
  • unitrect - an hs.geometry unit rect, or arguments to construct one
Returns
  • an hs.geometry rect describing the given unit rect in absolute coordinates
Notes
  • this method is just a convenience wrapper for hs.geometry.fromUnitRect(unitrect,this_screen:frame())
Source extensions/screen/init.lua
fullFrame
Signature hs.screen:fullFrame() -> hs.geometry rect
Type Method
Description Returns the screen frame, including the dock and menu.
Parameters
  • None
Returns
  • an hs.geometry rect describing this screen's frame in absolute coordinates
Source extensions/screen/init.lua
getBrightness
Signature hs.screen:getBrightness() -> number or nil
Type Method
Description Gets the screen's brightness
Parameters
  • None
Returns
  • A floating point number between 0 and 1, containing the current brightness level, or nil if the display does not support brightness queries
Source extensions/screen/internal.m
getForceToGray
Signature hs.screen.getForceToGray() -> boolean
Type Method
Description Gets the screen's ForceToGray setting
Parameters
  • None
Returns
  • A boolean, true if the ForceToGray mode is set, otherwise false
Source extensions/screen/internal.m
getGamma
Signature hs.screen:getGamma() -> [whitepoint, blackpoint] or nil
Type Method
Description Gets the current whitepoint and blackpoint of the screen
Parameters
  • None
Returns
  • A table containing the white point and black point of the screen, or nil if an error occurred. The keys whitepoint and blackpoint each have values of a table containing the following keys, with corresponding values between 0.0 and 1.0:
    • red
    • green
    • blue
Source extensions/screen/internal.m
getInvertedPolarity
Signature hs.screen.getInvertedPolarity() -> boolean
Type Method
Description Gets the screen's InvertedPolarity setting
Parameters
  • None
Returns
  • A boolean, true if the InvertedPolarity mode is set, otherwise false
Source extensions/screen/internal.m
getUUID
Signature hs.screen:getUUID() -> string
Type Method
Description Gets the UUID of an `hs.screen` object
Parameters
  • None
Returns
  • A string containing the UUID, or nil if an error occurred.
Source extensions/screen/internal.m
id
Signature hs.screen:id() -> number
Type Method
Description Returns a screen's unique ID
Parameters
  • None
Returns
  • A number containing the ID of the screen
Source extensions/screen/internal.m
localToAbsolute
Signature hs.screen:localToAbsolute(geom) -> hs.geometry object
Type Method
Description Transforms from the screen's local coordinate space, where `0,0` is at the screen's top left corner, to the absolute coordinate space used by OSX/Hammerspoon
Parameters
  • geom - an hs.geometry point or rect, or arguments to construct one
Returns
  • an hs.geometry point or rect, transformed to the absolute coordinate space
Source extensions/screen/init.lua
mirrorOf
Signature hs.screen:mirrorOf(aScreen[, permanent]) -> bool
Type Method
Description Make this screen mirror another
Parameters
  • aScreen - an hs.screen object you wish to mirror
  • permament - an optional bool, true if this should be configured permanently, false if it should apply just for this login session. Defaults to false.
Returns
  • true if the operation succeeded, otherwise false
Source extensions/screen/internal.m
mirrorStop
Signature hs.screen:mirrorStop([permanent]) -> bool
Type Method
Description Stops this screen mirroring another
Parameters
  • permanent - an optional bool, true if this should be configured permanently, false if it should apply just for this login session. Defaults to false.
Returns
  • true if the operation succeeded, otherwise false
Source extensions/screen/internal.m
name
Signature hs.screen:name() -> string or nil
Type Method
Description Returns the preferred name for the screen set by the manufacturer
Parameters
  • None
Returns
  • A string containing the name of the screen, or nil if an error occurred
Source extensions/screen/internal.m
next
Signature hs.screen:next() -> screen
Type Method
Description Gets the screen 'after' this one (in arbitrary order); this method wraps around to the first screen.
Parameters
  • None
Returns
  • An hs.screen object
Source extensions/screen/init.lua
position
Signature hs.screen:position() -> x, y
Type Method
Description Return a given screen's position relative to the primary screen - see 'hs.screen.screenPositions()'
Parameters
  • None
Returns
  • two integers indicating the screen position in the current screen arrangement, in the x and y axis respectively.
Source extensions/screen/init.lua
previous
Signature hs.screen:previous() -> screen
Type Method
Description Gets the screen 'before' this one (in arbitrary order); this method wraps around to the last screen.
Parameters
  • None
Returns
  • An hs.screen object
Source extensions/screen/init.lua
rotate
Signature hs.screen:rotate([degrees]) -> bool or rotation angle
Type Method
Description Gets/Sets the rotation of a screen
Parameters
  • degrees - An optional number indicating how many degrees clockwise, to rotate. If no number is provided, the current rotation will be returned. This number must be one of:
    • 0
    • 90
    • 180
    • 270
Returns
  • If the rotation is being set, a boolean, true if the operation succeeded, otherwise false. If the rotation is being queried, a number will be returned
Source extensions/screen/internal.m
setBrightness
Signature hs.screen:setBrightness(brightness) -> hs.screen object
Type Method
Description Sets the screen's brightness
Parameters
  • brightness - A floating point number between 0 and 1
Returns
  • The hs.screen object
Source extensions/screen/internal.m
setForceToGray
Signature hs.screen.setForceToGray(ForceToGray) -> None
Type Method
Description Sets the screen's ForceToGray mode
Parameters
  • ForceToGray - A boolean if ForceToGray mode should be enabled
Returns
  • None
Source extensions/screen/internal.m
setGamma
Signature hs.screen:setGamma(whitepoint, blackpoint) -> boolean
Type Method
Description Sets the current white point and black point of the screen
Parameters
  • whitepoint - A table containing color component values between 0.0 and 1.0 for each of the keys:
    • red
    • green
    • blue
  • blackpoint - A table containing color component values between 0.0 and 1.0 for each of the keys:
    • red
    • green
    • blue
Returns
  • A boolean, true if the gamma settings were applied, false if an error occurred
Notes
  • If the whitepoint and blackpoint specified, are very similar, it will be impossible to read the screen. You should exercise caution, and may wish to bind a hotkey to hs.screen.restoreGamma() when experimenting
Source extensions/screen/internal.m
setInvertedPolarity
Signature hs.screen.setInvertedPolarity(InvertedPolarity) -> None
Type Method
Description Sets the screen's InvertedPolarity mode
Parameters
  • InvertedPolarity - A boolean if InvertedPolarity mode should be enabled
Returns
  • None
Source extensions/screen/internal.m
setMode
Signature hs.screen:setMode(width, height, scale, frequency, depth) -> boolean
Type Method
Description Sets the screen to a new mode
Parameters
  • width - A number containing the width in points of the new mode
  • height - A number containing the height in points of the new mode
  • scale - A number containing the scaling factor of the new mode (typically 1 for native pixel resolutions, 2 for HiDPI/Retina resolutions)
  • frequency - A number containing the vertical refresh rate, in Hertz of the new mode
  • depth - A number containing the bit depth of the new mode
Returns
  • A boolean, true if the requested mode was set, otherwise false
Notes
  • The available widths/heights/scales can be seen in the output of hs.screen:availableModes(), however, it should be noted that the CoreGraphics subsystem seems to list more modes for a given screen than it is actually prepared to set, so you may find that seemingly valid modes still return false. It is not currently understood why this is so!
Source extensions/screen/internal.m
setOrigin
Signature hs.screen:setOrigin(x, y) -> bool
Type Method
Description Sets the origin of a screen in the global display coordinate space. The origin of the main or primary display is (0,0). The new origin is placed as close as possible to the requested location, without overlapping or leaving a gap between displays. If you use this function to change the origin of a mirrored display, the display may be removed from the mirroring set.
Parameters
  • x - The desired x-coordinate for the upper-left corner of the display.
  • y - The desired y-coordinate for the upper-left corner of the display.
Returns
  • true if the operation succeeded, otherwise false
Source extensions/screen/internal.m
setPrimary
Signature hs.screen:setPrimary() -> boolean
Type Method
Description Sets the screen to be the primary display (i.e. contain the menubar and dock)
Parameters
  • None
Returns
  • A boolean, true if the operation succeeded, otherwise false
Source extensions/screen/internal.m
shotAsJPG
Signature hs.screen:shotAsJPG(filePath[, screenRect])
Type Method
Description Saves an image of the screen to a JPG file
Parameters
  • filePath - A string containing a file path to save the screenshot as
  • screenRect - An optional hs.geometry rect (or arguments for its constructor) containing a portion of the screen to capture. Defaults to the whole screen
Returns
  • None
Source extensions/screen/init.lua
shotAsPNG
Signature hs.screen:shotAsPNG(filePath[, screenRect])
Type Method
Description Saves an image of the screen to a PNG file
Parameters
  • filePath - A string containing a file path to save the screenshot as
  • screenRect - An optional hs.geometry rect (or arguments for its constructor) containing a portion of the screen to capture. Defaults to the whole screen
Returns
  • None
Source extensions/screen/init.lua
snapshot
Signature hs.screen:snapshot([rect]) -> object
Type Method
Description Captures an image of the screen
Parameters
  • rect - An optional rect-table containing a portion of the screen to capture. Defaults to the whole screen
Returns
  • An hs.image object, or nil if an error occurred
Source extensions/screen/internal.m
toEast
Signature hs.screen:toEast(from, strict) -> hs.screen object
Type Method
Description Gets the first screen to the east of this one, ordered by proximity to its center or a specified point.
Parameters
  • from - An hs.geometry.rect or hs.geometry.point object; if omitted, the geometric center of this screen will be used
  • strict - If true, disregard screens that lie completely above or below this one (alternatively, set hs.screen.strictScreenInDirection)
Returns
  • An hs.screen object, or nil if not found
Source extensions/screen/init.lua
toNorth
Signature hs.screen:toNorth(from, strict) -> hs.screen object
Type Method
Description Gets the first screen to the north of this one, ordered by proximity to its center or a specified point.
Parameters
  • from - An hs.geometry.rect or hs.geometry.point object; if omitted, the geometric center of this screen will be used
  • strict - If true, disregard screens that lie completely to the left or to the right of this one (alternatively, set hs.screen.strictScreenInDirection)
Returns
  • An hs.screen object, or nil if not found
Source extensions/screen/init.lua
toSouth
Signature hs.screen:toSouth(from, strict) -> hs.screen object
Type Method
Description Gets the first screen to the south of this one, ordered by proximity to its center or a specified point.
Parameters
  • from - An hs.geometry.rect or hs.geometry.point object; if omitted, the geometric center of this screen will be used
  • strict - If true, disregard screens that lie completely to the left or to the right of this one (alternatively, set hs.screen.strictScreenInDirection)
Returns
  • An hs.screen object, or nil if not found
Source extensions/screen/init.lua
toUnitRect
Signature hs.screen:toUnitRect(rect) -> hs.geometry unitrect
Type Method
Description Returns the unit rect of a given rect, relative to this screen
Parameters
  • rect - an hs.geometry rect, or arguments to construct one
Returns
  • an hs.geometry unit rect describing the given rect relative to this screen's frame
Notes
  • this method is just a convenience wrapper for hs.geometry.toUnitRect(rect,this_screen:frame())
Source extensions/screen/init.lua
toWest
Signature hs.screen:toWest(from, strict) -> hs.screen object
Type Method
Description Gets the first screen to the west of this one, ordered by proximity to its center or a specified point.
Parameters
  • from - An hs.geometry.rect or hs.geometry.point object; if omitted, the geometric center of this screen will be used
  • strict - If true, disregard screens that lie completely above or below this one (alternatively, set hs.screen.strictScreenInDirection)
Returns
  • An hs.screen object, or nil if not found
Source extensions/screen/init.lua