Display

ALLEGRO_DISPLAY_MODE

typedef struct ALLEGRO_DISPLAY_MODE

Used for display mode queries. Contains information about a supported fullscreen display mode.

typedef struct ALLEGRO_DISPLAY_MODE {
   int width;          // Screen width
   int height;         // Screen height
   int format;         // The pixel format of the mode
   int refresh_rate;   // The refresh rate of the mode
} ALLEGRO_DISPLAY_MODE;

ALLEGRO_MONITOR_INFO

typedef struct ALLEGRO_MONITOR_INFO

Describes a monitors size and position relative to other monitors. x1, y1 will be 0, 0 on the primary display. Other monitors can have negative values if they are to the left or above the primary display.

typedef struct ALLEGRO_MONITOR_INFO
{
   int x1;
   int y1;
   int x2;
   int y2;
} ALLEGRO_MONITOR_INFO;

al_acknowledge_resize

bool al_acknowledge_resize(ALLEGRO_DISPLAY *display)

When the user receives a resize event 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.

al_clear

void al_clear(ALLEGRO_COLOR color)

Clear a complete display, but confined by the clipping rectangle.

al_create_display

ALLEGRO_DISPLAY *al_create_display(int w, int h)

Create a display, or window, with the specified dimensions. The parameters of the display are determined by the last calls to al_set_newdisplay*. 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.

al_destroy_display

void al_destroy_display(ALLEGRO_DISPLAY *display)

Destroy a display.

al_flip_display

void al_flip_display(void)

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 and front buffer bitmaps remain valid and retain their semantics as back and front buffers respectively, although their contents may have changed.

al_get_backbuffer

ALLEGRO_BITMAP *al_get_backbuffer(void)

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

al_get_current_display

ALLEGRO_DISPLAY *al_get_current_display(void)

Query for the current display in the calling thread.

al_get_current_video_adapter

int al_get_current_video_adapter(void)

Gets the video adapter index where new displays will be created.

al_get_display_flags

int al_get_display_flags(void)

Gets the flags of the current display.

al_get_display_format

int al_get_display_format(void)

Gets the pixel format of the current display.

al_get_display_height

int al_get_display_height(void)

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

al_get_display_mode

ALLEGRO_DISPLAY_MODE *al_get_display_mode(int index, ALLEGRO_DISPLAY_MODE *mode)

Retrieves a display mode. Display parameters should not be changed between a call of al_get_num_display_modes and al_get_display_mode. index must be between 0 and the number returned from al_get_num_display_modes-1. mode must be an allocated ALLEGRO_DISPLAY_MODE structure. This function will return NULL on failure, and the mode parameter that was passed in on success.

al_get_display_refresh_rate

int al_get_display_refresh_rate(void)

Gets the refresh rate of the current display.

al_get_display_width

int al_get_display_width(void)

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

al_get_frontbuffer

ALLEGRO_BITMAP *al_get_frontbuffer(void)

Return a special bitmap representing the front-buffer of the current display. This may not be supported by the driver; returns NULL in that case.

al_get_monitor_info

void al_get_monitor_info(int adapter, ALLEGRO_MONITOR_INFO *info)

Get information about a monitor's position on the desktop. adapter is a number from 0 to al_get_num_video_adapters()-1.

al_get_new_display_flags

int al_get_new_display_flags(void)

Gets the current flags used for newly created displays.

al_get_new_display_format

int al_get_new_display_format(void)

Gets the current pixel format used for newly created displays.

al_get_new_display_refresh_rate

int al_get_new_display_refresh_rate(void)

Gets the current refresh rate used for newly created displays.

al_get_new_window_position

void al_get_new_window_position(int *x, int *y)

Gets the position where newly created non-fullscreen displays will be placed.

al_get_num_display_modes

int al_get_num_display_modes(void)

Get the number of available fullscreen display modes for the current set of display parameters. This will use the values set with al_set_new_display_format, al_set_new_display_refresh_rate, and al_set_new_display_flags to find the number of modes that match. Settings the new display parameters to zero will give a list of all modes for the default driver.

al_get_num_video_adapters

int al_get_num_video_adapters(void)

Get the number of video "adapters" attached to the computer. Each video card attached to the computer counts as one or more adapters. An adapter is thus really a video port that can have a monitor connected to it.

al_get_window_position

void al_get_window_position(ALLEGRO_DISPLAY *display, int *x, int *y)

Gets the position of a non-fullscreen display.

al_inhibit_screensaver

bool al_inhibit_screensaver(bool inhibit)

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.

al_resize_display

bool al_resize_display(int width, int height)

Resize the current 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.

al_set_current_display

bool al_set_current_display(ALLEGRO_DISPLAY *display)

Change the current display for the calling thread. Also sets the target bitmap to the display's backbuffer. Returns true on success.

al_set_current_video_adapter

void al_set_current_video_adapter(int adapter)

Sets the adapter to use for newly created displays. The adapter has a monitor attached to it. Information about the monitor can be gotten using al_get_num_video_adapters and al_get_monitor_info.

al_set_display_icon

void al_set_display_icon(ALLEGRO_BITMAP *icon)

Changes the icon associated with the current display (window).

Note: If the underlying OS can not use an icon with the size of the provided bitmap, it will be scaled.

TODO: Describe best practice for the size? TODO: Allow providing multiple icons in differet sizes?

al_set_new_display_flags

void al_set_new_display_flags(int flags)

Sets various flags for display creation. flags is a bitfield containing any reasonable combination of the following:

ALLEGRO_WINDOWED - prefer a windowed mode
ALLEGRO_FULLSCREEN - prefer a fullscreen mode
ALLEGRO_RESIZABLE - the display is resizable (only applicable if combined with ALLEGRO_WINDOWED)
ALLEGRO_OPENGL - require the driver to provide an initialized opengl context after returning successfully
ALLEGRO_DIRECT3D - require the driver to do rendering with Direct3D and provide a Direct3D device
ALLEGRO_DOUBLEBUFFER - use double buffering
ALLEGRO_PAGEFLIP - use page flipping
ALLEGRO_SINGLEBUFFER - use only one buffer (front and back buffer are the same)
ALLEGRO_NOFRAME - Try to create a window without a frame (i.e. no border or titlebar). This usualy does nothing for fullscreen modes, and even in windowed moded it depends on the underlying platform whether it is supported or not.

0 can be used for default values.

al_set_new_display_format

void al_set_new_display_format(int format)

Set the pixel format for al displays created after this call.

al_set_new_display_refresh_rate

void al_set_new_display_refresh_rate(int refresh_rate)

Sets the refresh rate to use for newly created displays. 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, documented above.

al_set_new_window_position

void al_set_new_window_position(int x, int y)

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

al_set_window_position

void al_set_window_position(ALLEGRO_DISPLAY *display, int x, int y)

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

al_set_window_title

void al_set_window_title(AL_CONST char *title)

al_toggle_window_frame

void al_toggle_window_frame(ALLEGRO_DISPLAY *display, bool onoff)

al_update_display_region

bool al_update_display_region(int x, int y, int width, int height)

Update the the front buffer from the backbuffer in the specified region. This does not flip the whole buffer and preserves the contents of the front buffer outside of the given rectangle. This may not be supported by all drivers, in which case it returns false.