[cairo-commit] cairo-demo/png write_png.c,1.1,1.2

[Carl Worth]

Committed by: cworth

Update of /cvs/cairo/cairo-demo/png
In directory pdx:/tmp/cvs-serv6891

Modified Files:
	write_png.c 
Log Message:

        * write_png.c (unpremultiply_data): Fix to keep libpng happy on
        big-endian machines.


Index: write_png.c
===================================================================
RCS file: /cvs/cairo/cairo-demo/png/write_png.c,v
retrieving revision 1.1
retrieving revision 1.2
diff -C2 -d -r1.1 -r1.2
*** write_png.c	18 Aug 2003 18:11:38 -0000	1.1
--- write_png.c	10 Dec 2003 21:32:10 -0000	1.2
***************
*** 39,54 ****
      for (i = 0; i < row_info->rowbytes; i += 4) {
          unsigned char *b = &data[i];
!         unsigned char alpha = b[3];
!         unsigned long pixel;
!         unsigned long *p;
!         if (alpha == 0)
!             pixel = 0;
!         else
!             pixel = ((((b[0] * 255) / alpha) << 0) |
!                      (((b[1] * 255) / alpha) << 8) |
!                      (((b[2] * 255) / alpha) << 16) |
!                      (alpha << 24));
!         p = (unsigned long *) b;
!         *p = pixel;
      }
  }
--- 39,53 ----
      for (i = 0; i < row_info->rowbytes; i += 4) {
          unsigned char *b = &data[i];
!         unsigned long *p = (unsigned long *) &data[i];
!         unsigned long pixel = *p;
!         unsigned char alpha = (pixel & 0xff000000) >> 24;
!         if (alpha == 0) {
!             *p = 0;
! 	} else {
!             b[0] = (((pixel & 0x0000ff) >>  0) * 255) / alpha;
!             b[1] = (((pixel & 0x00ff00) >>  8) * 255) / alpha;
!             b[2] = (((pixel & 0xff0000) >> 16) * 255) / alpha;
! 	    b[3] = alpha;
! 	}
      }
  }