BANK_SWITCH(3G)

NAME

bank_switch − set graphics bank for multiple-byte-per-pixel frame buffers

SYNOPSIS

C Syntax:

void bank_switch(fildes,wbank,dbank);
int fildes,wbank,dbank;

FORTRAN77 Syntax:

subroutine bank_switch(fildes,wbank,dbank)
integer*4 fildes,wbank,dbank

Pascal Syntax:

procedure bank_switch(fildes,wbank,dbank:integer);

DESCRIPTION

Input Parameters

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

wbank Set graphics bank to be used for output primitives and raster operations.

dbank Set graphics bank to be displayed.

Discussion

The bank_switch parameter wbank defines:

• The bank used for byte-per-pixel output from block_write, define_raster_echo, and all output primitives,

• Data source bank for block_read,

• The bank where block_move is performed.

The dbank parameter defines which bank is to be displayed. Allowable value ranges for wbank and dbank are device-dependent, and may or may not be identical for both parameters. The lowest bank is numbered 0.

On a 24-plane graphics device, if in CMAP_FULL mode as set by shade_mode, if an output primitive color is specified with red, green and blue parameters, the output from the primitives is sent to all three banks.

Due to interactions between the two procedures, avoid using bank_switch when double buffering has been enabled by double_buffer.

On devices that support video blending the dbank parameter usage may be altered by blending control routines. See the Starbase Device Drivers Library Manual for details.

DEFAULTS

wbank = 0: enable lowest buffer for writing.
dbank = 0: enable lowest buffer for display.

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