preserve jpeg ipct data

now copies over ipct data from app13, thanks Gary

ChangeLog

@@ -21,6 +21,7 @@
 - better --help output for vips driver prog
 - vipsthumbnail -o allows absolute file names
 - much better exif handling for jpg images (thanks Gary)
+- preserve jpeg app13 (photoshop ipct)
 
 14/11/12 started 7.30.6
 - capture tiff warnings earlier

TODO

@@ -1,5 +1,3 @@
-- look into preserving IPTC data
-
 - check libtool version number, should be binary-compat with 7.30 
 
 - quadratic doesn't work for order 3

libvips/foreign/jpeg2vips.c

@@ -50,6 +50,9 @@
  * 16/11/12
  * 	- tag exif fields with their ifd
  * 	- attach rationals as a/b, don't convert to double
+ * 21/11/12
+ * 	- don't insist exif must have data
+ * 	- attach IPCT data (app13), thanks Gary
  */
 
 /*
@@ -79,9 +82,9 @@
  */
 
 /*
- */
 #define DEBUG_VERBOSE
 #define DEBUG
+ */
 
 #ifdef HAVE_CONFIG_H
 #include <config.h>
@@ -666,6 +669,34 @@ read_xmp( VipsImage *im, void *data, size_t data_length )
 	return( 0 );
 }
 
+static int
+read_ipct( VipsImage *im, void *data, size_t data_length )
+{
+	char *data_copy;
+
+	/* Only use the first one.
+	 */
+	if( vips_image_get_typeof( im, VIPS_META_IPCT_NAME ) ) {
+#ifdef DEBUG
+		printf( "read_ipct: second IPCT block, ignoring\n" );
+#endif /*DEBUG*/
+
+		return( 0 );
+	}
+
+#ifdef DEBUG
+	printf( "read_ipct: attaching %zd bytes of IPCT\n", data_length );
+#endif /*DEBUG*/
+
+	if( !(data_copy = vips_malloc( NULL, data_length )) )
+		return( -1 );
+	memcpy( data_copy, data, data_length );
+	vips_image_set_blob( im, VIPS_META_IPCT_NAME, 
+		(VipsCallbackFn) vips_free, data_copy, data_length );
+
+	return( 0 );
+}
+
 /* Number of app2 sections we can capture. Each one can be 64k, so 6400k should
  * be enough for anyone (haha).
  */
@@ -780,8 +811,6 @@ read_jpeg_header( ReadJpeg *jpeg, VipsImage *out )
 	for( p = cinfo->marker_list; p; p = p->next ) {
 #ifdef DEBUG
 {
-		int i;
-
 		printf( "read_jpeg_header: seen %d bytes of APP%d\n",
 			p->data_length,
 			p->marker - JPEG_APP0 );
@@ -828,6 +857,15 @@ read_jpeg_header( ReadJpeg *jpeg, VipsImage *out )
 			}
 			break;
 
+		case JPEG_APP0 + 13:
+			/* Possible IPCT data block.
+			 */
+			if( p->data_length > 5 &&
+				vips_isprefix( "Photo", (char *) p->data ) &&
+				read_ipct( out, p->data, p->data_length ) )
+				return( -1 );
+			break;
+
 		default:
 			break;
 		}
@@ -987,10 +1025,12 @@ vips__jpeg_read_file( const char *filename, VipsImage *out,
 		return( -1 );
 	}
 
-	/* Need to read in APP1 (EXIF metadata) and APP2 (ICC profile).
+	/* Need to read in APP1 (EXIF metadata), APP2 (ICC profile), APP13
+	 * (photoshop IPCT).
 	 */
 	jpeg_save_markers( &jpeg->cinfo, JPEG_APP0 + 1, 0xffff );
 	jpeg_save_markers( &jpeg->cinfo, JPEG_APP0 + 2, 0xffff );
+	jpeg_save_markers( &jpeg->cinfo, JPEG_APP0 + 13, 0xffff );
 
 	/* Convert!
 	 */

libvips/foreign/vips2jpeg.c

@@ -54,6 +54,8 @@
  * 	- read ifds from exif fields 
  * 	- optionally parse rationals as a/b
  * 	- update exif image dimensions
+ * 21/11/12
+ * 	- attach IPCT data (app13), thanks Gary
  */
 
 /*
@@ -705,8 +707,6 @@ write_xmp( Write *write )
 	unsigned char *data;
 	size_t data_length;
 
-	/* No libexif ... just copy the embedded EXIF over.
-	 */
 	if( vips_image_get_typeof( write->in, VIPS_META_XMP_NAME ) ) {
 		if( vips_image_get_blob( write->in, VIPS_META_XMP_NAME, 
 			(void *) &data, &data_length ) )
@@ -724,6 +724,29 @@ write_xmp( Write *write )
 	return( 0 );
 }
 
+static int
+write_ipct( Write *write )
+{
+	unsigned char *data;
+	size_t data_length;
+
+	if( vips_image_get_typeof( write->in, VIPS_META_IPCT_NAME ) ) {
+		if( vips_image_get_blob( write->in, VIPS_META_IPCT_NAME, 
+			(void *) &data, &data_length ) )
+			return( -1 );
+
+#ifdef DEBUG
+		printf( "write_ipct: attaching %zd bytes of IPCT\n", 
+			data_length  );
+#endif /*DEBUG*/
+
+		jpeg_write_marker( &write->cinfo, JPEG_APP0 + 13, 
+			data, data_length );
+	}
+
+	return( 0 );
+}
+
 /* ICC writer from lcms, slight tweaks.
  */
 
@@ -919,10 +942,9 @@ write_vips( Write *write, int qfac, const char *profile )
 
 	/* Write any APP markers we need.
 	 */
-	if( write_exif( write ) )
-		return( -1 );
-
-	if( write_xmp( write ) )
+	if( write_exif( write ) ||
+		write_xmp( write ) ||
+		write_ipct( write ) )
 		return( -1 );
 
 	/* A profile supplied as an argument overrides an embedded profile.

libvips/include/vips/header.h

@@ -51,6 +51,13 @@ extern "C" {
  */
 #define VIPS_META_XMP_NAME "xmp-data"
 
+/**
+ * VIPS_META_IPCT_NAME:
+ *
+ * The name that JPEG read and write operations use for the image's IPCT data.
+ */
+#define VIPS_META_IPCT_NAME "ipct-data"
+
 /**
  * VIPS_META_ICC_NAME:
  *