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fli_bmp_dirty_from(3)           Allegro manual           fli_bmp_dirty_from(3)

NAME
       fli_bmp_dirty_from, fli_bmp_dirty_to - Indicate which parts of the
       image have changed. Allegro game programming library.

SYNOPSIS
       #include <allegro.h>

       extern int fli_bmp_dirty_from;

       extern int fli_bmp_dirty_to;

DESCRIPTION
       These variables are set by next_fli_frame() to indicate which part of
       the fli_bitmap has changed since the last call to
       reset_fli_variables(). If fli_bmp_dirty_from is greater than
       fli_bmp_dirty_to, the bitmap has not changed, otherwise lines
       fli_bmp_dirty_from to fli_bmp_dirty_to (inclusive) have altered. You
       can use these when copying the fli_bitmap onto the screen, to avoid
       moving data unnecessarily. Example:

          if (fli_bmp_dirty_from <= fli_bmp_dirty_to)
             blit(fli_bitmap, screen, 0, fli_bmp_dirty_from,
                  0, fli_bmp_dirty_from, fli_bitmap->w,
                  fli_bmp_dirty_to - fli_bmp_dirty_from + 1);

SEE ALSO
       fli_bitmap(3), reset_fli_variables(3)

Allegro                          version 4.4.2           fli_bmp_dirty_from(3)