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Window Management

The following functions provide routines for managing the window, including opening the graphics device and closing the graphics window.

closewindow

C void closewindow (window_id)
Fortran subroutine closewindow (window_id)

Description

Closes the specified graphics window or, optionally, all windows. If window_id is not included (Fortran only), this call will close all windows. The window_id parameter should be the window’s id as referred to by initwindow or one of the following constants:

Constant Description
ALL_WINDOWS All open graphics windows (default)
CURRENT_WINDOW The current window
NO_CURRENT_WINDOW All windows except the current window

Parameters

Parameter C Type Fortran Type Description
window_id int integer1 The id of the window to close or, optionally, a constant described above

disableresize

C void disableresize ()
Fortran subroutine disableresize ()

Description

Disables resizing for the current window. By default, new windows are not resizeable.

enableresize

C void enableresize ( callback )
Fortran subroutine enableresize ( callback )

Description

Enables resizing for the current window. By default, new windows are not resizeable. The argument can specify a function to call whenever the window’s size changes.

Parameters

Parameter C Type Fortran Type Description
callback void callback( void ) subroutine callback()1 The screen width of one pixel on the device

enablewindow

C void enablewindow ( window, enabled )
Fortran subroutine enablewindow ( window, enabled )

Description

Enables or disables an entire window. This routine can effectively be used to simulate a modal experience by disabling a background window. The background window will no longer be able to respond to clicks, messages, or mouse events once disabled.

Parameters

Parameter C Type Fortran Type Description
window int integer The window id to disable or enable
enabled int logical Either 1 in C or .TRUE. in Fortran to enable, or 0 or .FALSE. to disable

getactivepage

C int getactivepage ( )
Fortran function getactivepage ( )

Description

Returns the page number of the graphics device where drawing is currently taking place. If double buffering is enabled, this will not necessarily be the visible page.

Return Value

C int
Fortran integer

The page that is currently being drawn.

getaspectratio

C void getaspectratio (xaspect, yaspect)
Fortran subroutine getaspectratio (xaspect, yaspect)

Description

Retrieves the aspect ratio for the current window. The values are returned via the two parameters. The yaspect parameter will always be normalized to 10,000, with xaspect scaled accordingly.

Parameters

Parameter C Type Fortran Type Description
xaspect int * integer The screen width of one pixel on the device
yaspect int * integer The screen height of one pixel on the device

getcurrentwindow

C int getcurrentwindow ( )
Fortran function getcurrentwindow ( )

Description

Returns the current window used for all drawing operations.

Return Value

C int
Fortran integer

Returns the current window identifier

getmaxheight

C int getmaxheight ( )
Fortran function getmaxheight ( )

Description

Returns the largest possible height of a window such that it will fit on screen.

Return Value

C int
Fortran integer

The largest height of a window possible.

getmaxwidth

C int getmaxwidth ( )
Fortran function getmaxwidth ( )

Description

Returns the largest possible width of a window such that it will fit on screen.

Return Value

C int
Fortran integer

The largest width of a window possible.

getmaxx

C int getmaxx ( )
Fortran function getmaxx ( )

Description

Returns the largest possible x position within the current window.

Return Value

C int
Fortran integer

The largest horizontal position possible in the current window.

getmaxy

C int getmaxy ( )
Fortran function getmaxy ( )

Description

Returns the largest possible y position within the current window.

Return Value

C int
Fortran integer

The largest vertical position possible in the current window.

getrefreshing

C bool getrefreshing ( )
Fortran function getrefreshing ( )

Description

Retrieves the current state of automatic window refreshing. If True is returned, the window is automatically refreshed when needed. If False, the calling code must manually request refreshes.

Return Value

C bool
Fortran logical

The current state of automatic window refreshing

getsignallingwindow

C int getsignallingwindow ( )
Fortran function getsignallingwindow ( )

Description

From within a callback, this function will return the identifier of the window that triggered the callback. This function would conceptually allow developers to reuse the same callback handlers for multiple windows by allowing the retrieval of the window from which the callback originated. If called from outside a callback or subsequent child call, this function will return -1 as an error. For more about callbacks, see Windows Controls and Mouse Events and Queries where callbacks are normally used.

Return Value

C int
Fortran integer

The window that signalled the callback, or -1 if an error occurred.

getvisualpage

C int getvisualpage ( )
Fortran function getvisualpage ( )

Description

Returns the page number of the graphics device that is currently displayed on screen. If double buffering is enabled, this will not necessarily be the active page.

Return Value

C int
Fortran integer

The page that is currently being shown.

getwindowheight

C int getwindowheight ( )
Fortran function getwindowheight ( )

Description

Returns the current height in pixels of the current window.

Return Value

C int
Fortran integer

The height of the current window.

getwindowwidth

C int getwindowwidth ( )
Fortran function getwindowwidth ( )

Description

Returns the current width in pixels of the current window.

Return Value

C int
Fortran integer

The width of the current window.

graphdefaults

C void graphdefaults ( )
Fortran subroutine graphdefaults ( )

Description

Return the graphics window to its default settings, including:

  • sets the viewport to the entire window
  • moves the current position to (0,0)
  • sets the default palette colors, background color, and drawing color
  • sets the default fill style and pattern
  • sets the default text font and justification

graphresult

C int graphresult ( )
Fortran function graphresult ( )

Description

Returns the status of the last graphics operation.

Return Value

C int
Fortran integer

Ths return code will always be one of the following values:

Constant Description
grOk No error
grNoInitGraph (BGI) graphics not installed (use initgraph)
grNotDetected Graphics hardware not detected
grFileNotFound Device driver file not found
grInvalidDriver Invalid device driver file
grNoLoadMem Not enough memory to load driver
grNoScanMem Out of memory in scan fill
grNoFloodMem Out of memory in flood fill
grFontNotFound Font file not found
grNoFontMem Not enough memory to load font
grInvalidMode Invalid graphics mode for selected driver
grError Graphics error
grIOerror Graphics I/O error
grInvalidFont Invalid font file
grInvalidFontNum Invalid font number
grInvalidDeviceNum Invalid device number
grInvalidVersion Invalid version number

initwindow

C int initwindow (width, height, title, left, top, dbflag, closeflag)
Fortran function initwindow (width, height, title, left, top, dbflag, closeflag)

Description

Initializes and opens a window for graphics output. This routine is the recommended method for opening a graphics output device.

Parameters

Parameter C Type Fortran Type Description
width int integer Width of the window
height int integer Height of the window
title char * character(*)1 Title to display in the titlebar
left int integer1 Horizontal screen position of the window. Omitting the value or specifying DEFAULT_POSITION allows the operating system to determine position
top int integer1 Vertical screen position of the window. Omitting the value or specifying DEFAULT_POSITION allows the operating system to determine position
dbflag bool logical1 Enable double-buffering
closeflag bool logical1 Kill program on window close

Return Value

C int
Fortran integer

Unique identifier of the opened window

refreshall

C void refreshall ( )
Fortran subroutine refreshall ( )

Description

Refreshes the entire current window.

setcurrentwindow

C void setcurrentwindow (window_id)
Fortran subroutine setcurrentwindow (window_id)

Description

Selects the window of the specified id to be the current window and brings the window to the foreground (if the application is currently in the foreground). All subsequent graphics operations will be applied to the specified window until it is either closed or another window becomes the current window.

Parameters

Parameter C Type Fortran Type Description
window_id int integer The window id

setactivepage

C void setactivepage (page)
Fortran subroutine setactivepage (page)

Description

Sets the specified page, normally a number returned by either getactivepage or getvisualpage, to the active page for drawing.

Parameters

Parameter C Type Fortran Type Description
page int integer The page to act as the active page for drawing

setaspectratio

C void setaspectratio (xaspect, yaspect)
Fortran subroutine setaspectratio (xaspect, yaspect)

Description

Sets the aspect ratio for the current window. The aspect ratio is used for ensuring shapes are displayed properly. For example, it is used to ensure circles appear as such rather than elipses.

Parameters

Parameter C Type Fortran Type Description
xaspect int integer The screen width of one pixel on the device
yaspect int integer The screen height of one pixel on the device

setdialoghotkeys

C void setdialoghotkeys (enable)
Fortran subroutine setdialoghotkeys (enable)

Description

Enables or disables the use of Windows dialog-like hotkeys for navigation between possible Windows controls in the current window. For example, when enabled, the Tab and arrow keys will move the current keyboard focus between edit boxes, buttons, etc. present within the current window. When disabled, the application can continue to process all keystrokes itself.

Parameters

Parameter C Type Fortran Type Description
enable bool logical True to enable dialog hotkeys, false (the default) to allow the application to handle all keystrokes

setrefreshing

C void setrefreshing (value)
Fortran subroutine setrefreshing (value)

Description

Enables or disables screen refreshing for a period. Most drawing operations will refresh only the portion of the screen that has been modified. If disabled, multiple drawing operations can be completed faster.

Parameters

Parameter C Type Fortran Type Description
value bool logical If True, automatic screen refreshing is enabled (the default)

setvisualpage

C void setvisualpage (page)
Fortran subroutine setvisualpage (page)

Description

Sets the specified page, normally a number returned by either getactivepage or getvisualpage, to the page displayed on screen.

Parameters

Parameter C Type Fortran Type Description
page int integer The page to act as the visual page for display

setwindowtitle

C void setwindowtitle (title)
Fortran subroutine setwindowtitle (title)

Description

Sets the title of the current window to the specified string

Parameters

Parameter C Type Fortran Type Description
title char * character(len=*) The new title of the window

swapbuffers

C void swapbuffers ( )
Fortran subroutine swapbuffers ( )

Description

For double-buffered graphics, this routine will swap the currently visible graphics with the current in-memory buffer. It effectively swaps the visual and active pages.

1 Optional named argument