make_picture_current(3G)

NAME

make_picture_current − output buffered primitives to display and wait for display hardware to finish

SYNOPSIS

C Syntax:

void make_picture_current(fildes);
int fildes;

FORTRAN77 Syntax:

subroutine make_picture_current(fildes)
integer*4 fildes

Pascal Syntax:

procedure make_picture_current(fildes:integer);

DESCRIPTION

Input Parameters

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

Discussion

Make_picture_current outputs any previous primitives that may still be in the device or driver buffers to the display device fildes. Next, the command waits for the display hardware to finish its processing in order to guarantee that when the subroutine returns, all pixels will be displayed.

It is commonly used:

• in interactive graphics sessions at points where the operator must see the entire image in order to proceed,

• or in hard-copy graphics at the end of the picture generation process such as when transferring an image from the raster buffer to the printed page in a buffered raster printer.

Gclose also performs a make_picture_current operation before closing the device.

Note that make_picture_current will degrade performance, especially on accelerated devices, since the CPU will wait for the graphics device to finish all of its processing. Therefore this procedure should be used with caution. For better performance, use flush_buffer which causes all output buffers to be flushed, but does not wait for the device to finish before returning. This allows more parallel processing with accelerated devices, while still bringing the picture up to date just as fast as make_picture_current.

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