plucky (3) scroll_screen.3alleg4.gz

NAME

       scroll_screen - Requests a hardware scroll request. Allegro game programming library.

SYNOPSIS

       #include <allegro.h>

       int scroll_screen(int x, int y);

DESCRIPTION

       Attempts  to  scroll  the hardware screen to display a different part of the virtual screen (initially it
       will be positioned at 0, 0, which is the top left corner). You can use this to move  the  screen  display
       around  in a large virtual screen space, or to page flip back and forth between two non-overlapping areas
       of the virtual screen. Note that to draw outside the original position in the screen bitmap you will have
       to alter the clipping rectangle with set_clip_rect().

       Mode-X  scrolling is reliable and will work on any card, other drivers may not work or not work reliably.
       See the platform-specific section of the docs for more information.

       Allegro will handle any necessary vertical retrace synchronisation when  scrolling  the  screen,  so  you
       don't  need to call vsync() before it. This means that scroll_screen() has the same time delay effects as
       vsync().

RETURN VALUE

       Returns zero on success. Returns non-zero if the graphics driver can't handle hardware scrolling  or  the
       virtual screen is not large enough.

SEE ALSO

       set_gfx_mode(3alleg4),                show_video_bitmap(3alleg4),                request_scroll(3alleg4),
       request_video_bitmap(3alleg4), exscroll(3alleg4)