# Displays

These functions are declared in the main Allegro header file:

~~~~c
 #include <allegro5/allegro.h>
~~~~

All drawing operations end up being visible on a display which is the same as
a window in windowed environments. Thus, before anything is displayed,
a display needs to be created.

Before creating a display with [al_create_display], flags and options can be set
with [al_set_new_display_flags] and [al_set_new_display_option]. For example, you
can enable the use of shaders or choose between the OpenGL and Direct3D backends
(on platforms that support both) with [al_set_new_display_flags]. Display options
are rather optional settings that do not affect Allegro itself, e.g. they allow
you to specify whether you want a depth buffer or enable multisampling.

The actual properties of a display that has been successfully created can be queried
via [al_get_display_option], [al_get_display_flags], [al_get_display_width] etc.
Note that you can query some additional read-only properties such as the maximum
allowed bitmap (i.e. texture) size via [al_get_display_option].

Each display has a backbuffer associated to it which is the default target for any
drawing operations. In order to make visible what has been drawn previously, you
have to to call [al_flip_display]. Note that it is generally advisable to redraw
the whole screen (or [clear][al_clear_to_color] it in advance) to avoid artefacts
of uninitialised memory becoming visible with some drivers.

You don't have to use Allegro's drawing routines, however: since creating a display
implies the creation of an OpenGL context or Direct3D device respectively, you can
use these APIs directly if you prefer to do so. Allegro provides integration for
both (see the OpenGL / Direct3D sections), so you can retrieve the underlying
textures of [ALLEGRO_BITMAP]s, for example.

In order to write a well-behaved application, it is necessary to remember that
displays will also inform you about important [events][ALLEGRO_EVENT_DISPLAY_EXPOSE]
via their [event sources][al_get_display_event_source].

## Display creation

### API: ALLEGRO_DISPLAY

An opaque type representing an open display or window.

### API: al_create_display

Create a display, or window, with the specified dimensions.
The parameters of the display are determined by the last calls to
al_set_new_display\_\*. Default parameters are used if none are set
explicitly.
Creating a new display will automatically make it the active one, with the
backbuffer selected for drawing.

Returns NULL on error.

Each display that uses OpenGL as a backend has a distinct OpenGL rendering context
associated with it. See [al_set_target_bitmap] for the discussion about rendering contexts.

See also: [al_set_new_display_flags], [al_set_new_display_option],
[al_set_new_display_refresh_rate], [al_set_new_display_adapter], [al_set_new_window_title]
[al_set_window_position]

### API: al_destroy_display

Destroy a display.

If the target bitmap of the calling thread is tied to the display, then it
implies a call to "al_set_target_bitmap(NULL);" before the display is
destroyed.

That special case notwithstanding, you should make sure no threads are
currently targeting a bitmap which is tied to the display before you destroy
it.

See also: [al_set_target_bitmap]

### API: al_get_new_display_flags

Get the display flags to be used when creating new displays on the calling
thread.

See also: [al_set_new_display_flags], [al_set_display_flag]

### API: al_set_new_display_flags

Sets various flags to be used when creating new displays on the calling thread.
flags is a bitfield containing any reasonable combination of the following:

ALLEGRO_WINDOWED
:   Prefer a windowed mode.

    Under multi-head X (not XRandR/TwinView), the use of more than one adapter is
    impossible due to bugs in X and GLX. [al_create_display] will fail if more than one
    adapter is attempted to be used.

ALLEGRO_FULLSCREEN_WINDOW
:   Make the window span the entire screen. Unlike ALLEGRO_FULLSCREEN this
    will never attempt to modify the screen resolution. Instead the pixel
    dimensions of the created display will be the same as the desktop.

    The passed width and height are only used if the window is switched
    out of fullscreen mode later but will be ignored initially.

    Under Windows and X11 a fullscreen display created with this flag
    will behave differently from one created with the ALLEGRO_FULLSCREEN
    flag - even if the ALLEGRO_FULLSCREEN display is passed the desktop
    dimensions. The exact difference is platform dependent, but some
    things which may be different is how alt-tab works, how fast you can
    toggle between fullscreen/windowed mode or how additional monitors
    behave while your display is in fullscreen mode.

    Additionally under X, the use of more than one adapter in multi-head mode
    or with true Xinerama enabled is impossible due to bugs in X/GLX,
    creation will fail if more than one adapter is attempted to be used.

ALLEGRO_FULLSCREEN
:   Prefer a fullscreen mode.

    Under X the use of more than one FULLSCREEN display when using multi-head X,
    or true Xinerama is not possible due to bugs in X and GLX,
    display creation will fail if more than one adapter is attempted to be used.

    > *Note:* Prefer using ALLEGRO_FULLSCREEN_WINDOW as it typically provides a
    better user experience as the monitor doesn't change resolution and
    switching away from your game via Alt-Tab works smoothly.
    ALLEGRO_FULLSCREEN is typically less well supported compared to
    ALLEGRO_FULLSCREEN_WINDOW.

ALLEGRO_RESIZABLE
:   The display is resizable (only applicable if combined with
    ALLEGRO_WINDOWED).

ALLEGRO_MAXIMIZED
:   The display window will be maximized (only applicable if combined
    with ALLEGRO_RESIZABLE).
    Since: 5.1.12

ALLEGRO_OPENGL
:   Require the driver to provide an initialized OpenGL context after returning
    successfully.

ALLEGRO_OPENGL_3_0
:   Require the driver to provide an initialized OpenGL
    context compatible with OpenGL version 3.0.

ALLEGRO_OPENGL_FORWARD_COMPATIBLE
:   If this flag is set, the OpenGL
    context created with ALLEGRO_OPENGL_3_0 will be forward compatible *only*,
    meaning that all of the OpenGL API declared deprecated in OpenGL 3.0 will not
    be supported. Currently, a display created with this flag will *not* be
    compatible with Allegro drawing routines; the display option
    ALLEGRO_COMPATIBLE_DISPLAY will be set to false.

ALLEGRO_OPENGL_ES_PROFILE
:   Used together with ALLEGRO_OPENGL, requests that the OpenGL context
    uses the OpenGL ES profile. A specific version can be requested
    with [al_set_new_display_option].
    Note: Currently this is only supported by the X11/GLX driver.
    Since: 5.1.13

ALLEGRO_OPENGL_CORE_PROFILE
:   Used together with ALLEGRO_OPENGL, requests that the OpenGL context
    uses the OpenGL Core profile. A specific version can be requested
    with [al_set_new_display_option].
    Note: Currently this is only supported by the X11/GLX driver.
    Since: 5.2.7

ALLEGRO_DIRECT3D
:   Require the driver to do rendering with Direct3D and
    provide a Direct3D device.

ALLEGRO_PROGRAMMABLE_PIPELINE
:   Require a programmable graphics pipeline.
    This flag is required to use [ALLEGRO_SHADER] objects.
    Since: 5.1.6

ALLEGRO_FRAMELESS
:   Try to create a window without a frame (i.e. no border or titlebar).
    This usually does nothing for fullscreen modes, and even in windowed modes
    it depends on the underlying platform whether it is supported or not.
    Since: 5.0.7, 5.1.2

ALLEGRO_NOFRAME
:   Original name for ALLEGRO_FRAMELESS.
    This works with older versions of Allegro.

ALLEGRO_GENERATE_EXPOSE_EVENTS
:   Let the display generate expose events.

ALLEGRO_GTK_TOPLEVEL
:   Create a GTK toplevel window for the display, on X.
    This flag is conditionally defined by the native dialog addon.
    You must call [al_init_native_dialog_addon] for it to succeed.
    ALLEGRO_GTK_TOPLEVEL is incompatible with ALLEGRO_FULLSCREEN.
    Since: 5.1.5

0 can be used for default values.

See also: [al_set_new_display_option], [al_get_display_option], [al_set_display_option]

### API: al_get_new_display_option

Retrieve an extra display setting which was previously set with
[al_set_new_display_option].

### API: al_set_new_display_option

Set an extra display option, to be used when creating new displays on the
calling thread.  Display options differ from display flags, and specify some
details of the context to be created within the window itself.
These mainly have no effect on Allegro itself, but you may want to specify
them, for example if you want to use multisampling.

The 'importance' parameter can be either:

* ALLEGRO_REQUIRE - The display will not be created if the setting can
    not be met.
* ALLEGRO_SUGGEST - If the setting is not available, the display will
    be created anyway with a setting as close as possible to the
    requested one.
    You can query the actual value used in that case by calling
    [al_get_display_option] after the display has been created.
* ALLEGRO_DONTCARE - If you added a display option with one of the above
    two settings before, it will be removed again. Else this does
    nothing.

The supported options are:

ALLEGRO_COLOR_SIZE
:   This can be used to ask for a specific bit depth. For example to
    force a 16-bit framebuffer set this to 16.

ALLEGRO_RED_SIZE, ALLEGRO_GREEN_SIZE, ALLEGRO_BLUE_SIZE, ALLEGRO_ALPHA_SIZE
:   Individual color component size in bits.

ALLEGRO_RED_SHIFT, ALLEGRO_GREEN_SHIFT, ALLEGRO_BLUE_SHIFT, ALLEGRO_ALPHA_SHIFT
:   Together with the previous settings these can be used to specify the
    exact pixel layout the display should use. Normally there is no reason to use these.

ALLEGRO_ACC_RED_SIZE, ALLEGRO_ACC_GREEN_SIZE, ALLEGRO_ACC_BLUE_SIZE, ALLEGRO_ACC_ALPHA_SIZE
:   This can be used to define the required accumulation buffer size.

ALLEGRO_STEREO
:   Whether the display is a stereo display.

ALLEGRO_AUX_BUFFERS
:   Number of auxiliary buffers the display should
    have.

ALLEGRO_DEPTH_SIZE
:   How many depth buffer (z-buffer) bits to use.

ALLEGRO_STENCIL_SIZE
:   How many bits to use for the stencil buffer.

ALLEGRO_SAMPLE_BUFFERS
:   Whether to use multisampling (1) or not (0).

ALLEGRO_SAMPLES
:   If the above is 1, the number of samples to use
    per pixel. Else 0.

ALLEGRO_RENDER_METHOD:
:   0 if hardware acceleration is not used with this display.

ALLEGRO_FLOAT_COLOR
:   Whether to use floating point color components.

ALLEGRO_FLOAT_DEPTH
:   Whether to use a floating point depth buffer.

ALLEGRO_SINGLE_BUFFER
:   Whether the display uses a single buffer (1)
    or another update method (0).

ALLEGRO_SWAP_METHOD
:   If the above is 0, this is set to 1 to indicate
    the display is using a copying method to make the next buffer in
    the flip chain available, or to 2 to indicate a flipping or other
    method.

ALLEGRO_COMPATIBLE_DISPLAY
:   Indicates if Allegro's graphics
    functions can use this display. If you request a display not
    useable by Allegro, you can still use for example OpenGL to draw
    graphics.

ALLEGRO_UPDATE_DISPLAY_REGION
:   Set to 1 if the display is
    capable of updating just a region, and 0 if calling
    [al_update_display_region] is equivalent to [al_flip_display].

ALLEGRO_VSYNC
:   Set to 1 to tell the driver to wait for vsync
    in [al_flip_display], or to 2 to force vsync off. The default of
    0 means that Allegro does not try to modify the vsync behavior so
    it may be on or off.
    Note that even in the case of 1 or 2 it is possible to override
    the vsync behavior in the graphics driver so you should not rely
    on it.

ALLEGRO_MAX_BITMAP_SIZE
:   When queried this returns the maximum
    size (width as well as height) a bitmap can have for this
    display. Calls to [al_create_bitmap] or [al_load_bitmap] for
    bitmaps larger than this size will fail. It does not apply to memory
    bitmaps which always can have arbitrary size (but are slow for
    drawing).

ALLEGRO_SUPPORT_NPOT_BITMAP
:   Set to 1 if textures used for bitmaps
    on this display can have a size which is not a power of two. This
    is mostly useful if you use Allegro to load textures as otherwise
    only power-of-two textures will be used internally as bitmap
    storage.

ALLEGRO_CAN_DRAW_INTO_BITMAP
:   Set to 1 if you can use
    [al_set_target_bitmap] on bitmaps of this display to draw into them.
    If this is not the case software emulation will be used when drawing
    into display bitmaps (which can be very slow).

ALLEGRO_SUPPORT_SEPARATE_ALPHA
:   This is set to 1 if the
    [al_set_separate_blender] function is supported. Otherwise the
    alpha parameters will be ignored.

ALLEGRO_AUTO_CONVERT_BITMAPS
:   This is on by default. It causes any
    existing memory bitmaps with the ALLEGRO_CONVERT_BITMAP flag to be
    converted to a display bitmap of the newly created display with
    the option set.

    Since: 5.1.0

ALLEGRO_SUPPORTED_ORIENTATIONS
:   This is a bit-combination of the
    orientations supported by the application. The orientations are
    the same as for [al_get_display_orientation] with the additional
    possibilities:

    * ALLEGRO_DISPLAY_ORIENTATION_PORTRAIT
    * ALLEGRO_DISPLAY_ORIENTATION_LANDSCAPE
    * ALLEGRO_DISPLAY_ORIENTATION_ALL

    PORTRAIT means only the two portrait orientations are supported,
    LANDSCAPE means only the two landscape orientations and ALL allows
    all four orientations. When the orientation changes between a
    portrait and a landscape orientation the display needs to be
    resized. This is done by sending an [ALLEGRO_EVENT_DISPLAY_RESIZE]
    message which should be handled by calling [al_acknowledge_resize].

    Since: 5.1.0

ALLEGRO_OPENGL_MAJOR_VERSION
:   Request a specific OpenGL major version.

    Since: 5.1.13

ALLEGRO_OPENGL_MINOR_VERSION
:   Request a specific OpenGL minor version.

    Since: 5.1.13

ALLEGRO_DEFAULT_SHADER_PLATFORM
:   Specify the shader platform to use for the default shader. See
    [ALLEGRO_SHADER_PLATFORM]. The default is ALLEGRO_SHADER_AUTO.

    Since: 5.2.8


See also: [al_set_new_display_flags], [al_get_display_option]

### API: al_reset_new_display_options

This undoes any previous call to [al_set_new_display_option]
on the calling thread.

### API: al_get_new_window_position

Get the position where new non-fullscreen displays created by the calling
thread will be placed.

See also: [al_set_new_window_position]

### API: al_set_new_window_position

Sets where the top left pixel of the client area of newly
created windows (non-fullscreen) will be on screen,
for displays created by the calling thread.
Negative values are allowed on some multihead systems.

To reset to the default behaviour, pass (INT_MAX, INT_MAX).

See also: [al_get_new_window_position]

### API: al_get_new_display_refresh_rate

Get the requested refresh rate to be used when creating new displays on the
calling thread.

See also: [al_set_new_display_refresh_rate]

### API: al_set_new_display_refresh_rate

Sets the refresh rate to use when creating new displays on the calling thread.
If the refresh rate is not available, [al_create_display] will fail.
A list of modes with refresh rates can be found with [al_get_num_display_modes]
and [al_get_display_mode].

The default setting is zero (don't care).

See also: [al_get_new_display_refresh_rate]



## Display operations

### API: al_get_display_event_source

Retrieve the associated event source. See the
[documentation on events][ALLEGRO_EVENT_DISPLAY_EXPOSE]
for a list of the events displays will generate.

### API: al_get_backbuffer

Return a special bitmap representing the back-buffer of the
display.

Care should be taken when using the backbuffer bitmap (and its
sub-bitmaps) as the source bitmap (e.g as the bitmap argument to
[al_draw_bitmap]). Only untransformed operations are hardware
accelerated. These consist of [al_draw_bitmap] and
[al_draw_bitmap_region] when the current transformation is the identity.
If the transformation is not the identity, or some other drawing
operation is used, the call will be routed through the memory bitmap
routines, which are slow. If you need those operations to be accelerated,
then first copy a region of the backbuffer into a temporary bitmap (via
the [al_draw_bitmap] and [al_draw_bitmap_region]), and then use that
temporary bitmap as the source bitmap.

### API: al_flip_display

Copies or updates the front and back buffers so that what has
been drawn previously on the currently selected display becomes
visible on screen. Pointers to the special back buffer
bitmap remain valid and retain their semantics as the back buffer,
although the contents may have changed.

> *Note:* If not using the ALLEGRO_SINGLE_BUFFER option, you typically want to
redraw every pixel of the backbuffer bitmap to avoid uninitialized memory
artifacts.

Several display options change how this function behaves:

- With ALLEGRO_SINGLE_BUFFER, no flipping is done. You still have to
call this function to display graphics, depending on how the used
graphics system works.

- The ALLEGRO_SWAP_METHOD option may have additional information about what
kind of operation is used internally to flip the front and back buffers.

- If ALLEGRO_VSYNC is 1, this function will force waiting for vsync. If
ALLEGRO_VSYNC is 2, this function will not wait for vsync. With many
drivers the vsync behavior is controlled by the user and not the
application, and ALLEGRO_VSYNC will not be set; in this case
[al_flip_display] will wait for vsync depending on the settings set
in the system's graphics preferences.

See also: [al_set_new_display_flags], [al_set_new_display_option]

### API: al_update_display_region

Does the same as [al_flip_display], but tries to update only the
specified region. With many drivers this is not possible, but for
some it can improve performance. If this is not supported, this function falls
back to the behavior of [al_flip_display]. You can query the support for this
function using `al_get_display_option(display, ALLEGRO_UPDATE_DISPLAY_REGION)`.

See also: [al_flip_display], [al_get_display_option]

### API: al_wait_for_vsync

Wait for the beginning of a vertical retrace. Some
driver/card/monitor combinations may not be capable
of this.

Note how [al_flip_display] usually already waits for the vertical
retrace, so unless you are doing something special, there is no reason
to call this function.

Returns false if not possible, true if successful.

See also: [al_flip_display]



## Display size and position

### API: al_get_display_width

Gets the width of the display. This is like SCREEN_W in Allegro 4.x.

See also: [al_get_display_height]

### API: al_get_display_height

Gets the height of the display. This is like SCREEN_H in Allegro 4.x.

See also: [al_get_display_width]

### API: al_resize_display

Resize the display. Returns true on success, or false on error.
This works on both fullscreen and windowed displays, regardless of the
ALLEGRO_RESIZABLE flag.

Adjusts the clipping rectangle to the full size of the backbuffer.

See also: [al_acknowledge_resize]

### API: al_acknowledge_resize

When the user receives a [resize event][ALLEGRO_EVENT_DISPLAY_RESIZE]
from a resizable display, if they wish the display to be resized they
must call this function to let the graphics driver know that it can now
resize the display. Returns true on success.

Adjusts the clipping rectangle to the full size of the backbuffer. This also
resets the backbuffers projection transform to default orthographic transform
(see [al_use_projection_transform]).

Note that a resize event may be outdated by the time you acknowledge it;
there could be further resize events generated in the meantime.

See also: [al_resize_display], [ALLEGRO_EVENT]

### API: al_get_window_position

Gets the position of a non-fullscreen display.

See also: [al_set_window_position]

### API: al_set_window_position

Sets the position on screen of a non-fullscreen display.

See also: [al_get_window_position]

### API: al_get_window_constraints

Gets the constraints for a non-fullscreen resizable display.

Since: 5.1.0

See also: [al_set_window_constraints]

### API: al_set_window_constraints

Constrains a non-fullscreen resizable display.
The constraints are a hint only, and are not necessarily respected
by the window environment.
A value of 0 for any of the parameters indicates no constraint
for that parameter.

The constraints will be applied to a display only after the
[al_apply_window_constraints] function call.

Since: 5.1.0

See also: [al_apply_window_constraints], [al_get_window_constraints]

### API: al_apply_window_constraints

Enable or disable previously set constraints by
[al_set_window_constraints] function.

If enabled, the specified display will be automatically resized
to new sizes to conform constraints in next cases:

* The specified display is resizable, not maximized and is not
    in fullscreen mode.
* If the appropriate current display size (width or height) is less 
    than the value of constraint. Applied to minimum constraints.
* If the appropriate current display size (width or height) is greater
    than the value of constraint. Applied to maximum constraints.

Constrains are not applied when a display is toggle from
windowed to maximized or fullscreen modes.
When a display is toggle from maximized/fullscreen to windowed
mode, then the display may be resized as described above.
The later case is also possible when a user drags the maximized
display via mouse.

If disabled, the specified display will stop using constraints.

See also: [al_get_window_constraints], [al_set_window_constraints]



## Display settings

### API: al_get_display_flags

Gets the flags of the display.

In addition to the flags set for the display at creation time with
[al_set_new_display_flags] it can also have the ALLEGRO_MINIMIZED flag
set, indicating that the window is currently minimized. This flag
is very platform-dependent as even a minimized application may still
render a preview version so normally you should not care whether it
is minimized or not.

See also: [al_set_new_display_flags], [al_set_display_flag]

### API: al_set_display_flag

Enable or disable one of the display flags. The flags are the same
as for [al_set_new_display_flags]. The only flags that can be changed
after creation are:

- ALLEGRO_FULLSCREEN_WINDOW
- ALLEGRO_FRAMELESS
- ALLEGRO_MAXIMIZED

Returns true if the driver supports toggling the specified flag else
false. You can use [al_get_display_flags] to query whether the given
display property actually changed.

Since: 5.0.7, 5.1.2

See also: [al_set_new_display_flags], [al_get_display_flags]

### API: al_get_display_option

Return an extra display setting of the display.

See also: [al_set_new_display_option]

### API: al_set_display_option

Change an option that was previously set for a display. After displays are
created, they take on the options set with [al_set_new_display_option]. Calling
[al_set_new_display_option] subsequently only changes options for newly created
displays, and doesn't touch the options of already created displays.
[al_set_display_option] allows changing some of these values. Not all
display options can be changed or changing them will have no effect. Changing
options other than those listed below is undefined.

* ALLEGRO_SUPPORTED_ORIENTATIONS - This can be changed to allow new or restrict
    previously enabled orientations of the screen/device. See
    [al_set_new_display_option] for more information on this option.

Since: 5.1.5

See also: [al_set_new_display_option]

### API: al_get_display_format

Gets the pixel format of the display.

See also: [ALLEGRO_PIXEL_FORMAT]

### API: al_get_display_orientation

Return the display orientation, which can be one of the following:

-  ALLEGRO_DISPLAY_ORIENTATION_UNKNOWN
-  ALLEGRO_DISPLAY_ORIENTATION_0_DEGREES
-  ALLEGRO_DISPLAY_ORIENTATION_90_DEGREES
-  ALLEGRO_DISPLAY_ORIENTATION_180_DEGREES
-  ALLEGRO_DISPLAY_ORIENTATION_270_DEGREES
-  ALLEGRO_DISPLAY_ORIENTATION_FACE_UP
-  ALLEGRO_DISPLAY_ORIENTATION_FACE_DOWN

Since: 5.1.0

### API: al_get_display_refresh_rate

Gets the refresh rate of the display.

See also: [al_set_new_display_refresh_rate]

### API: al_set_window_title

Set the title on a display.

See also: [al_set_display_icon], [al_set_display_icons]


### API: al_set_new_window_title

Set the title that will be used when a new display is created.
Allegro uses a static buffer of [ALLEGRO_NEW_WINDOW_TITLE_MAX_SIZE] to
store this, so the length of the titme you set must be less than this.

See also: [al_set_window_title], [al_get_new_window_title], [al_create_display],
          [ALLEGRO_NEW_WINDOW_TITLE_MAX_SIZE]

Since: 5.1.12

### API: ALLEGRO_NEW_WINDOW_TITLE_MAX_SIZE

This is the maximum size of the title that can be set with
[al_set_new_window_title].

See also: [al_set_new_window_title]

Since: 5.1.12

### API: al_get_new_window_title

Returns the title that will be used when a new display is created. This
returns the value that [al_set_window_title] was called with. If that function
wasn't called yet, the value of [al_get_app_name] is returned as a default.
The current implementation returns a pointer to a static buffer of which you
should make a copy if you want to modify it.

See also: [al_set_window_title], [al_set_new_window_title], [al_create_display]

Since: 5.1.12


### API: al_set_display_icon

Changes the icon associated with the display (window).
Same as [al_set_display_icons] with one icon.

See also: [al_set_display_icons], [al_set_window_title]

### API: al_set_display_icons

Changes the icons associated with the display (window).
Multiple icons can be provided for use in different contexts, e.g. window
frame, taskbar, alt-tab popup.  The number of icons must be at least one.

> *Note:* If the underlying OS requires an icon of a size not provided
then one of the bitmaps will be scaled up or down to the required size.
The choice of bitmap is implementation dependent.

Since: 5.0.9, 5.1.5

See also: [al_set_display_icon], [al_set_window_title]



## Drawing halts

### API: al_acknowledge_drawing_halt

Call this in response to the [ALLEGRO_EVENT_DISPLAY_HALT_DRAWING] event.
This is currently necessary for Android and iOS as you are not allowed to draw
to your display while it is not being shown. If you do not call this
function to let the operating system know that you have stopped
drawing or if you call it to late the application likely will be
considered misbehaving and get terminated.

Since: 5.1.0

See also: [ALLEGRO_EVENT_DISPLAY_HALT_DRAWING]

### API: al_acknowledge_drawing_resume

Call this in response to the [ALLEGRO_EVENT_DISPLAY_RESUME_DRAWING] event.

Since: 5.1.1

See also: [ALLEGRO_EVENT_DISPLAY_RESUME_DRAWING]

## Screensaver

### API: al_inhibit_screensaver

This function allows the user to stop the system
screensaver from starting up if true is passed,
or resets the system back to the default state
(the state at program start) if false is passed.
It returns true if the state was set successfully,
otherwise false.



## Clipboard

With the clipboard API of Allegro, text can be copied from and to the clipboard.
Currentlly, only UTF8 encoded text is supported. It currently works on Linux,
Windows, OSX, Android and IOS.


### API: al_get_clipboard_text

This function returns a pointer to a string, allocated with [al_malloc] with
the text contents of the clipboard if available. If no text is available on the
clipboard then this function returns NULL. You must call [al_free] on the
returned pointer when you don't need it anymore.

Beware that text on the clipboard on Windows may be in Windows format, that is,
it may have carriage return newline combinations for the line endings instead
of regular newlines for the line endings on Linux or OSX.

Since: 5.1.12

See also: [al_set_clipboard_text], [al_clipboard_has_text]

### API: al_set_clipboard_text

This function pastes the text given as an argument to the clipboard.

Since: 5.1.12

See also: [al_get_clipboard_text], [al_clipboard_has_text]


### API: al_clipboard_has_text

This function returns true if and only if the clipboard has text available.

Since: 5.1.12

See also: [al_set_clipboard_text], [al_get_clipboard_text]

