.\" Generated by the Allegro makedoc utility
.TH fli_bmp_dirty_from 3alleg4 "version 4.4.3" "Allegro" "Allegro manual"
.SH NAME
fli_bmp_dirty_from, fli_bmp_dirty_to \- Indicate which parts of the image have changed. Allegro game programming library.\&
.SH SYNOPSIS
.B #include <allegro.h>

.sp
.B extern int fli_bmp_dirty_from;

.B extern int fli_bmp_dirty_to;
.SH 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:

.nf
   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);
.fi

.SH SEE ALSO
.BR fli_bitmap (3alleg4),
.BR reset_fli_variables (3alleg4)