VIDEO

Name

VIDEO -- 

Function

nVMode              FT_GETMODE()
<aCurInfo>          FT_GETVCUR( [ <nPage> ] )
<nPage>             FT_GETVPG()
<nStackSize>        FT_PopVid()
<nStackSize>        FT_PushVid()
NIL                 FT_RGNSTACK( <cAction>, [ <nTop> ], [ <nLeft> ], [ <nBottom> ], [ <nRight> ] )
NIL                 FT_RSTRGN( <cScreen>, [ <nTop> ], [ <nLeft> ] )
cScreen             FT_SAVRGN( <nTop>, <nLeft>, <nBottom>, <nRight> )
NIL                 FT_SETMODE( <nMode> )
NIL                 FT_SETVCUR( [ <nPage> ], [ <nRow> ], [ <nCol> ] )
NIL                 FT_SETVPG( <nPage> )

Description

Function FT_GETMODE()

 FT_GETMODE() --> nVMode

Use this function to find out what mode your display adapter is in. Uses DOS interrupt 10h to get the mode. For a table of modes available on various graphics adapters, refer to a book such as Wilton's "Programmer's Guide to PC & PS/2 Video Systems" (Microsoft Press)

Function FT_GETVCUR()

 FT_GETVCUR( [ <nPage> ] ) --> <aCurInfo>

FT_GETVCUR() uses FT_INT86() to invoke interrupt 10h, function 3, to return the character cursor location for the specified video page.

The top line and bottom line of cursor are set depending on the current cursor mode, and are only meaningful in alphanumeric video modes.

For more information on graphics programming, cursors, and cursor modes, refer to Richard Wilton's _Programmer's Guide to PC and PS/2 Video Systems_ (Microsoft Press).

Function FT_GETVPG()

 FT_GETVPG() --> <nPage>

Get the currently selected video page

For more information on graphics programming and video pages, consult a reference such as _Programmer's Guide to PC and PS/2 Video Systems_ (Microsoft Press).

Function FT_POPVID()

 FT_PopVid() --> <nStackSize>

This is the complementary function to FT_PushVid(). At some time after saving the video states it will probably be necessary to restore them. This is done by restoring the settings from the last call to FT_PushVid(). The number of items on the internal stack is then reduced by one. Note that the use of stack logic means that items on the stack are retrieved in Last In First Out order.

Function FT_PUSHVID()

 FT_PushVid() --> <nStackSize>

Menus, picklists, browses, and other video-intensive items often require you to save certain video states -- screen image, cursor position, and so forth. Constantly saving and restoring these items can get very tedious. This function attempts to alleviate this problem. When called, it saves the cursor position, color setting, screen image, cursor style, blink setting, scoreboard setting, snow setting, and maximum row and column to a series of static arrays. All that is needed to restore the saved settings is a call to FT_PopVid().

Function FT_RGNSTACK()

 FT_RGNSTACK( <cAction>, [ <nTop> ], [ <nLeft> ], [ <nBottom> ],
 [ <nRight> ] ) --> NIL

FT_RGNSTACK() allows multiple screens to be saved and restored from a stack. The stack is implemented with Clipper static array that is visible only to FT_RGNSTACK().

The purpose of FT_RGNSTACK() is to allow multiple screen regions to be managed without the need to remember the original coordinates or to create variables for each one.

When called with "push", FT_RGNSTACK() places the saved screen area at the end of the static array. The array size is incremented by one to accommodate the new screen area.

When called with "pop", the function restores the screen image stored in the last element of the array, and the array size is decremented by one. If "pop all" is specified, all the saved screens are restored until the array is empty.

FT_RGNSTACK() calls FT_SAVRGN() and FT_RSTRGN(). Refer to the documentation for these two functions for more information.

Function FT_RSTRGN()

 FT_RSTRGN( <cScreen>, [ <nTop> ], [ <nLeft> ] ) --> NIL

FT_RSTRGN() restores a screen region previously saved with FT_SAVRGN(). Calling FT_RSTRGN() with <cScreen> as the only parameter will restore the saved region to its original location. <nTop> and <nLeft> may be used to define a new location for the upper left corner of the saved region.

<nTop> and <nLeft> are dependent upon each other. You may not specify one without the other.

FT_RSTRGN() calls Clipper's RESTSCREEN(). Refer to the Clipper documentation for more information regarding this function.

Function FT_SAVRGN()

 FT_SAVRGN( <nTop>, <nLeft>, <nBottom>, <nRight> ) --> cScreen

FT_SAVRGN() is similar to Clipper's SAVESCREEN(), but it saves the screen coordinates as well as the display information. The saved area can be restored by passing the returned string to FT_RSTRGN().

Note that the strings returned from FT_SAVRGN() and Clipper's SAVESCREEN() are not interchangeable. A screen region saved with with FT_SAVRGN() must be restored using FT_RSTRGN().

FT_SAVRGN() calls Clipper's SAVESCREEN(). Refer to the Clipper documentation for more information regarding this function.

Function FT_SETMODE()

 FT_SETMODE( <nMode> ) --> NIL

Use this function to put your display adapter into a video mode. Uses DOS interrupt 10h to set the mode. For a table of modes available on various graphics adapters, refer to a book such as Wilton's "Programmer's Guide to PC & PS/2 Video Systems" (Microsoft Press)

Function FT_SETVCUR()

 FT_SETVCUR( [ <nPage> ], [ <nRow> ], [ <nCol> ] ) --> NIL

FT_SETVCUR() sets the cursor position on a specific video page. It uses FT_INT86() to invoke interrupt 10h, function 2.

For more information on graphics programming, cursors, and video pages, refer to Richard Wilton's _Programmer's Guide to PC and PS/2 Video Systems_ (Microsoft Press).

Function FT_SETVPG()

 FT_SETVPG( <nPage> ) --> NIL

Selects the video page.

For more information on graphics programming and video pages, consult a reference such as "Programmer's Guide to PC and PS/2 Video Systems" (Microsoft Press).