1scroll_screen(3)                Allegro manual                scroll_screen(3)
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NAME

6       scroll_screen  -  Requests a hardware scroll request. Allegro game pro‐
7       gramming library.
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SYNOPSIS

10       #include <allegro.h>
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13       int scroll_screen(int x, int y);
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DESCRIPTION

16       Attempts to scroll the hardware screen to display a different  part  of
17       the  virtual  screen (initially it will be positioned at 0, 0, which is
18       the top left corner). You can use  this  to  move  the  screen  display
19       around  in a large virtual screen space, or to page flip back and forth
20       between two non-overlapping areas of the virtual screen. Note  that  to
21       draw  outside  the original position in the screen bitmap you will have
22       to alter the clipping rectangle with set_clip_rect().
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24       Mode-X scrolling is reliable and will work on any card,  other  drivers
25       may not work or not work reliably. See the platform-specific section of
26       the docs for more information.
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28       Allegro will handle any necessary vertical retrace synchronisation when
29       scrolling the screen, so you don't need to call vsync() before it. This
30       means that scroll_screen() has the same time delay effects as vsync().
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RETURN VALUE

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

38       set_gfx_mode(3),        show_video_bitmap(3),        request_scroll(3),
39       request_video_bitmap(3), exscroll(3)
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43Allegro                          version 4.2.3                scroll_screen(3)
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