1fli_bmp_dirty_from(3)           Allegro manual           fli_bmp_dirty_from(3)
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NAME

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

10       #include <allegro.h>
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13       extern int fli_bmp_dirty_from;
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15       extern int fli_bmp_dirty_to;
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DESCRIPTION

18       These variables are set by next_fli_frame() to indicate which  part  of
19       the  fli_bitmap  has  changed  since  the  last call to reset_fli_vari‐
20       ables(). If fli_bmp_dirty_from is greater  than  fli_bmp_dirty_to,  the
21       bitmap   has   not   changed,  otherwise  lines  fli_bmp_dirty_from  to
22       fli_bmp_dirty_to (inclusive) have altered. You can use these when copy‐
23       ing the fli_bitmap onto the screen, to avoid moving data unnecessarily.
24       Example:
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26          if (fli_bmp_dirty_from <= fli_bmp_dirty_to)
27             blit(fli_bitmap, screen, 0, fli_bmp_dirty_from,
28                  0, fli_bmp_dirty_from, fli_bitmap->w,
29                  fli_bmp_dirty_to - fli_bmp_dirty_from + 1);
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SEE ALSO

33       fli_bitmap(3), reset_fli_variables(3)
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37Allegro                          version 4.2.2           fli_bmp_dirty_from(3)
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