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 specifies:

• the destination bank for block_write();

• the source bank for block_read();

• the source/destination bank for block_move();

• the definition bank for define_raster_echo(); and

• a logical bank that is dependent on the state of double-buffering.

The dbank parameter of bank_switch() is ignored.

A bank_switch() call will not set the graphics bank to be used for output primitives.

Depth-8 graphics devices must implement double buffering with double_buffer() and dbuffer_switch().

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.

See the chapter titled "Using Starbase in the X Window System" in Starbase Graphics Techniques for more information about using this routine with a window system.

DEFAULTS

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

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