NAME

clear_control − select type of clearing for subsequent clear_view_surface procedures

SYNOPSIS

C Syntax:

void clear_control(fildes,mode);
int fildes,mode;

FORTRAN77 Syntax:

subroutine clear_control(fildes,mode)
integer*4 fildes,mode

Pascal Syntax:

procedure clear_control(fildes,mode:integer);

DESCRIPTION

Input Parameters

fildes integer file descriptor returned by gopen when an I/O path to a graphic device is opened. 

mode One of the following values:

CLEAR_VDC_EXTENT Clear Virtual Device Coordinate extent area. 

CLEAR_CLIP_RECTANGLE Clear clip rectangle area. 

CLEAR_DISPLAY_SURFACE Clear entire display surface. 

CLEAR_VIEWPORT Clear current viewport area. 

Discussion

For continuous-feed hardcopy devices, CLEAR_DISPLAY_SURFACE ejects a new page.

For multibank graphics devices, only the current bank as set by bank_switch is cleared.  If CLEAR_ALL_BANKS is ORed with mode, all graphics banks are cleared to zero simultaneously, independent of write_enable, bank_switch, and background_color.

DEFAULTS

Clear entire display surface. 

SEE ALSO

background_color(3G), bank_switch(3G), clear_view_surface(3G), clip_rectangle(3G),
set_p1_p2(3G), vdc_extent(3G), view_port(3G).

Hewlett-Packard Company  —  May 11, 2021