Inside Macintosh: QuickTime Components /

Chapter 5 - Sequence Grabber Components / Sequence Grabber Components Reference

Sequence Grabber Component Functions / Working With Video Channels

SGGetUseScreenBuffer

The SGGetUseScreenBuffer function allows you to determine whether a video channel is allowed to use an offscreen buffer.

pascal ComponentResult SGGetUseScreenBuffer (SGChannel c, 
                                       Boolean *useScreenBuffer);

c

Identifies the channel for this operation. You provide your
connection identifier. You connect to a channel component by calling the SGNewChannel or SGNewChannelFromComponent function, discussed on page 5-29 and page 5-30, respectively.

useScreenBuffer

Contains a pointer to a Boolean value. The sequence grabber sets this field to reflect whether you have allowed the channel to draw offscreen. If this field is set to true, the channel draws directly to the screen. If it is set to false, the channel may use an offscreen buffer. If the channel cannot work with offscreen buffers, it ignores this value.

DESCRIPTION

By default, video channels draw directly to the screen. You can direct a channel to draw to an offscreen buffer by calling the SGSetUseScreenBuffer function. Channels that can work offscreen then allocate and draw to an offscreen buffer.

SEE ALSO

You can allow a channel to draw offscreen by calling the SGSetUseScreenBuffer function, which is described in the previous section.

Main | Top of Section | What's New | Apple Computer, Inc. | Find It | Feedback | Help