[sane-devel] Patch to scanimage.c for 16-bit PNM files (was: Epson 2450: scanimage produces invalid PNM files)

[Roland Roberts]

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>>>>> "Oliver" == Oliver Rauch <oliver.rauch@rauch-domain.de> writes:

    Oliver> The pnm format has been extended in april 2000.
    Oliver> As far as I can see there are two interesting new things:
    Oliver> 1) 16 bit raw data
    Oliver> 2) more than one image in a pnm file

Here is a patch against the source in sane-backends 1.07.  To be
complete, it requires a patch to configure.in to test for
WORDS_BIGENDIAN since it only byte-flips values in the read buffer if
the native byte-order is little-endian.  When writing TIFF files, it
does nothing.

roland
-- 
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Roland B. Roberts, PhD                             RL Enterprises
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Content-Type: text/x-patch
Content-Disposition: attachment; filename=scanimage.diff
Content-Description: Write 16-bit/color PNM files MSB first

--- scanimage.c.~1~	Sat Apr 13 12:06:45 2002
+++ scanimage.c	Sun Apr 14 18:37:01 2002
@@ -1187,7 +1187,24 @@
 		}
 	    }
 	  else
+  	    {
+	      if ((output_format == OUTPUT_TIFF) || (image.Bpp == 1))
+		 fwrite (buffer, 1, len, stdout);
+	      else
+	        {
+#if !defined(WORDS_BIGENDIAN)
+		  int i;
+		  for (i = 0; i < len; i += 2)
+		    {
+		      unsigned char LSB;
+		      LSB = buffer[i];
+		      buffer[i] = buffer[i+1];
+		      buffer[i+1] = LSB;
+		    }
+#endif
 	    fwrite (buffer, 1, len, stdout);
+		}
+	    }
 
 	  if (verbose && parm.depth == 8)
 	    {
@@ -1210,7 +1227,22 @@
 				 parm.lines, parm.depth, resolution_value);
       else
 	write_pnm_header (parm.format, image.width, image.height, parm.depth);
+      if ((output_format == OUTPUT_TIFF) || (image.Bpp == 1))
       fwrite (image.data, image.Bpp, image.height * image.width, stdout);
+      else /* image.Bpp == 2 assumed */
+        {
+#if !defined(WORDS_BIGENDIAN)
+	  int i;
+	  for (i = 0; i < image.Bpp * image.height * image.width; i += 2)
+	    {
+	      unsigned char LSB;
+	      LSB = image.data[i];
+	      image.data[i] = image.data[i+1];
+	      image.data[i+1] = LSB;
+	    }
+#endif
+	  fwrite (image.data, image.Bpp, image.height * image.width, stdout);
+	}
     }
 
 cleanup:

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