gtk-0.12.2: Binding to the Gtk+ graphical user interface library.

Portability | portable (depends on GHC)
Stability | provisional
Maintainer | gtk2hs-users@lists.sourceforge.net

Graphics.UI.Gtk.Gdk.Screen

Contents

- Detail
- Class Hierarchy
- Types
- Methods
- Attributes
- Signals

Description

Object representing a physical screen

- Module available since Gdk version 2.2

Synopsis

- data Screen
- class GObjectClass o => ScreenClass o
- castToScreen :: GObjectClass obj => obj -> Screen
- gTypeScreen :: GType
- toScreen :: ScreenClass o => o -> Screen
- screenGetDefault :: IO (Maybe Screen)
- screenGetSystemColormap :: Screen -> IO Colormap
- screenGetRGBAColormap :: Screen -> IO (Maybe Colormap)
- screenGetDefaultColormap :: Screen -> IO Colormap
- screenSetDefaultColormap :: Screen -> Colormap -> IO ()
- screenIsComposited :: Screen -> IO Bool
- screenGetRootWindow :: Screen -> IO DrawWindow
- screenGetDisplay :: Screen -> IO Display
- screenGetNumber :: Screen -> IO Int
- screenGetWidth :: Screen -> IO Int
- screenGetHeight :: Screen -> IO Int
- screenGetWidthMm :: Screen -> IO Int
- screenGetHeightMm :: Screen -> IO Int
- screenGetWidthMM :: Screen -> IO Int
- screenGetHeightMM :: Screen -> IO Int
- screenListVisuals :: Screen -> IO [Visual]
- screenGetToplevelWindows :: Screen -> IO [DrawWindow]
- screenMakeDisplayName :: Screen -> IO String
- screenGetNMonitors :: Screen -> IO Int
- screenGetMonitorGeometry :: Screen -> Int -> IO Rectangle
- screenGetMonitorAtPoint :: Screen -> Int -> Int -> IO Int
- screenGetMonitorAtWindow :: Screen -> DrawWindow -> IO Int
- screenGetMonitorHeightMm :: Screen -> Int -> IO Int
- screenGetMonitorWidthMm :: Screen -> Int -> IO Int
- screenGetMonitorPlugName :: Screen -> Int -> IO (Maybe String)
- screenGetActiveWindow :: Screen -> IO (Maybe DrawWindow)
- screenGetWindowStack :: Screen -> IO (Maybe [DrawWindow])
- screenFontOptions :: Attr Screen (Maybe FontOptions)
- screenResolution :: Attr Screen Double
- screenDefaultColormap :: Attr Screen Colormap
- screenSizeChanged :: ScreenClass self => Signal self (IO ())
- screenCompositedChanged :: ScreenClass self => Signal self (IO ())
- screenMonitorsChanged :: ScreenClass self => Signal self (IO ())

# Detail

`Screen` objects are the GDK representation of a physical screen. It is used throughout GDK and Gtk+ to specify which screen the top level windows are to be displayed on. It is also used to query the screen specification and default settings such as the default colormap (`screenGetDefaultColormap`), the screen width (`screenGetWidth`), etc.

Note that a screen may consist of multiple monitors which are merged to form a large screen area.

# Class Hierarchy

     | GObject
     | +----Screen

# Types

data Screen

Instances

Eq Screen |
Ord Screen |
GObjectClass Screen |
ScreenClass Screen |

class GObjectClass o => ScreenClass o

Instances

ScreenClass Screen |

castToScreen :: GObjectClass obj => obj -> Screen

gTypeScreen :: GType

toScreen :: ScreenClass o => o -> Screen

# Methods

screenGetDefault

Arguments

:: IO (Maybe Screen) | returns a `Screen`, or `Nothing` if there is no default display.

Gets the default screen for the default display. (See `displayGetDefault`).

screenGetSystemColormap

Arguments

:: Screen |
-> IO Colormap | returns the default colormap for `screen`.

Gets the system default colormap for `screen`

screenGetRGBAColormap

Arguments

:: Screen |
-> IO (Maybe Colormap) | returns a colormap to use for windows with an alpha channel or `Nothing` if the capability is not available.

Gets a colormap to use for creating windows or pixmaps with an alpha channel. The windowing system on which Gtk+ is running may not support this capability, in which case `Nothing` will be returned. Even if a non-`Nothing` value is returned, its possible that the window's alpha channel won't be honored when displaying the window on the screen: in particular, for X an appropriate windowing manager and compositing manager must be running to provide appropriate display.

- Available since Gdk version 2.8

screenGetDefaultColormap

Arguments

:: Screen |
-> IO Colormap | returns the default `Colormap`.

screenSetDefaultColormap

Arguments

:: Screen |
-> Colormap | `colormap` - a `Colormap`
-> IO () |

screenIsComposited

Arguments

:: Screen |
-> IO Bool | returns Whether windows with RGBA visuals can reasonably be expected to have their alpha channels drawn correctly on the screen.

Returns whether windows with an RGBA visual can reasonably be expected to have their alpha channel drawn correctly on the screen.

On X11 this function returns whether a compositing manager is compositing `screen`.

- Available since Gdk version 2.10

screenGetRootWindow

Arguments

:: Screen |
-> IO DrawWindow | returns the root window

Gets the root window of `screen`.

screenGetDisplay

Arguments

:: Screen |
-> IO Display | returns the display to which `screen` belongs

Gets the display to which the `screen` belongs.

screenGetNumber

Arguments

:: Screen |
-> IO Int | returns the index

Gets the index of `screen` among the screens in the display to which it belongs. (See `screenGetDisplay`)

screenGetWidth

Arguments

:: Screen |
-> IO Int | returns the width of `screen` in pixels.

Gets the width of `screen` in pixels

screenGetHeight

Arguments

:: Screen |
-> IO Int | returns the height of `screen` in pixels.

Gets the height of `screen` in pixels

screenGetWidthMm :: Screen -> IO Int

screenGetHeightMm :: Screen -> IO Int

screenGetWidthMM

Arguments

:: Screen |
-> IO Int | returns the width of `screen` in millimeters.

Gets the width of `screen` in millimeters. Note that on some X servers this value will not be correct.

screenGetHeightMM

Arguments

:: Screen |
-> IO Int | returns the heigth of `screen` in millimeters.

Returns the height of `screen` in millimeters. Note that on some X servers this value will not be correct.

screenListVisuals

Arguments

:: Screen |
-> IO [Visual] | returns a list of visuals

Lists the available visuals for the specified `screen`. A visual describes a hardware image data format. For example, a visual might support 24-bit color, or 8-bit color, and might expect pixels to be in a certain format.

screenGetToplevelWindows

Arguments

:: Screen |
-> IO [DrawWindow] | returns list of toplevel windows

Obtains a list of all toplevel windows known to GDK on the screen `screen`. A toplevel window is a child of the root window (see `getDefaultRootWindow`).

screenMakeDisplayName

Arguments

:: Screen |
-> IO String | returns a newly allocated string

Determines the name to pass to `displayOpen` to get a `Display` with this screen as the default screen.

screenGetNMonitors

Arguments

:: Screen |
-> IO Int | returns number of monitors which `screen` consists of.

Returns the number of monitors which `screen` consists of.

screenGetMonitorGeometry

Arguments

:: Screen |
-> Int | `monitorNum` - the monitor number.
-> IO Rectangle |

Retrieves the `Rectangle` representing the size and position of the individual monitor within the entire screen area.

Note that the size of the entire screen area can be retrieved via `screenGetWidth` and `screenGetHeight`.

screenGetMonitorAtPoint

Arguments

:: Screen |
-> Int | `x` - the x coordinate in the virtual screen.
-> Int | `y` - the y coordinate in the virtual screen.
-> IO Int | returns the monitor number in which the point (`x`,`y`) lies, or a monitor close to (`x`,`y`) if the point is not in any monitor.

Returns the monitor number in which the point (`x`,`y`) is located.

screenGetMonitorAtWindow

Arguments

:: Screen |
-> DrawWindow | `window` - a `DrawWindow`
-> IO Int | returns the monitor number in which most of `window` is located, or if `window` does not intersect any monitors, a monitor, close to `window`.

Returns the number of the monitor in which the largest area of the bounding rectangle of `window` resides.

screenGetMonitorHeightMm

Arguments

:: Screen |
-> Int | `monitorNum` - number of the monitor
-> IO Int | returns the height of the monitor, or -1 if not available

Gets the height in millimeters of the specified monitor.

- Available since Gdk version 2.14

screenGetMonitorWidthMm

Arguments

:: Screen |
-> Int | `monitorNum` - number of the monitor
-> IO Int | returns the width of the monitor, or -1 if not available

Gets the width in millimeters of the specified monitor, if available.

- Available since Gdk version 2.14

screenGetMonitorPlugName

Arguments

:: Screen |
-> Int | `monitorNum` - number of the monitor
-> IO (Maybe String) | returns a newly-allocated string containing the name of the monitor, or `Nothing` if the name cannot be determined

Returns the output name of the specified monitor. Usually something like VGA, DVI, or TV, not the actual product name of the display device.

- Available since Gdk version 2.14

screenGetActiveWindow

Arguments

:: Screen |
-> IO (Maybe DrawWindow) | returns the currently active window, or `Nothing`.

Returns the currently active window of this screen.

On X11, this is done by inspecting the _NET_ACTIVE_WINDOW property on the root window, as described in the Extended Window Manager Hints. If there is no currently currently active window, or the window manager does not support the _NET_ACTIVE_WINDOW hint, this function returns `Nothing`.

On other platforms, this function may return `Nothing`, depending on whether it is implementable on that platform.

- Available since Gdk version 2.10

screenGetWindowStack

Arguments

:: Screen |
-> IO (Maybe [DrawWindow]) | returns a list of `DrawWindow`s for the current window stack, or `Nothing`.

Returns a list of `DrawWindow`s representing the current window stack.

On X11, this is done by inspecting the _NET_CLIENT_LIST_STACKING property on the root window, as described in the Extended Window Manager Hints. If the window manager does not support the _NET_CLIENT_LIST_STACKING hint, this function returns `Nothing`.

On other platforms, this function may return `Nothing`, depending on whether it is implementable on that platform.

- Available since Gdk version 2.10

# Attributes

screenFontOptions :: Attr Screen (Maybe FontOptions)

The default font options for the screen.

screenResolution :: Attr Screen Double

The resolution for fonts on the screen.

Default value: -1

screenDefaultColormap :: Attr Screen Colormap

Sets the default `colormap` for `screen`.

Gets the default colormap for `screen`.

# Signals

screenSizeChanged :: ScreenClass self => Signal self (IO ())

The ::size_changed signal is emitted when the pixel width or height of a screen changes.

screenCompositedChanged :: ScreenClass self => Signal self (IO ())

The `screenCompositedChanged` signal is emitted when the composited status of the screen changes

- Available since Gdk version 2.10

screenMonitorsChanged :: ScreenClass self => Signal self (IO ())

The `screenMonitorsChanged` signal is emitted when the number, size or position of the monitors attached to the screen change.

Only for X for now. Future implementations for Win32 and OS X may be a possibility.

- Available since Gdk version 2.14