invert on jpeg cmyk write

TODO

@@ -1,10 +1,12 @@
 - JPEG write should know about CMYK as well, maybe write all 4 band images as
-  CMYK?
+  CMYK? probably need to test Type so we don't get confused by RGBA
 
   test CMYK JPEG write, also PNG write with new saveable
 
   can we use convert_saveable for PPM and friends as well?
 
+  should we invert CMYK on JPEG save?
+
 - HAVE_HYPOT could define a hypot() macro?
 
 - write our own python extension to call a vips operation by name
@@ -48,10 +50,12 @@
 
 - test maxpos_avg, quite a few changes
 
-- im_exr2vips can now use c++ api
+WONTFIX
+=======
 
-Python binding
-==============
+- HAVE_HYPOT could define a hypot() macro?
+
+- im_exr2vips can now use c++ api
 
 - python startup fails with plugins in vipslib:
 
@@ -68,8 +72,17 @@ Python binding
   	http://www.swig.org/Doc1.3/SWIGDocumentation.html#Python_nn8
 	http://docs.python.org/dist/dist.html
 
-WONTFIX
-=======
+- write our own python extension to call a vips operation by name
+
+	result = vips_call ("name", args)
+
+  then call that from VImage_method
+
+- do we really need VImage_method? Can't we write
+
+	__getattr__ (self, name) = lambda (obj_to_call, arguments):
+
+  or something like that?
 
 - can we use GraphicsMagick instead of ImageMagick?
 

libsrc/conversion/im_jpeg2vips.c

@@ -460,10 +460,10 @@ read_jpeg_header( struct jpeg_decompress_struct *cinfo,
 
 	case JCS_CMYK:
 		type = IM_TYPE_CMYK;
-		/* Photoshop writes CMYK JPEG inverted :-( Hopefully this is a
-		 * reliable way to spot photoshop CMYK JPGs.
+		/* Photoshop writes CMYK JPEG inverted :-( Maybe this is a
+		 * way to spot photoshop CMYK JPGs.
 		 */
-		if( cinfo->saw_Adobe_marker )
+		if( cinfo->saw_Adobe_marker ) 
 			*invert_pels = TRUE;
 		break;
 

libsrc/conversion/im_vips2jpeg.c

@@ -196,6 +196,7 @@ typedef struct {
 	JSAMPROW *row_pointer;
 	char *profile_bytes;
 	unsigned int profile_length;
+	IMAGE *inverted;
 } Write;
 
 static void
@@ -207,6 +208,7 @@ write_destroy( Write *write )
 	IM_FREEF( fclose, write->eman.fp );
 	IM_FREE( write->row_pointer );
 	IM_FREE( write->profile_bytes );
+	IM_FREEF( im_close, write->inverted );
 	im_free( write );
 }
 
@@ -226,22 +228,16 @@ write_new( IMAGE *in )
 		return( NULL );
 	}
 
-	write->tg = im_threadgroup_create( write->in );
-
-	write->row_pointer = IM_ARRAY( NULL, write->tg->nlines, JSAMPROW );
-
+	write->tg = NULL;
+	write->row_pointer = NULL;
         write->cinfo.err = jpeg_std_error( &write->eman.pub );
 	write->eman.pub.error_exit = new_error_exit;
 	write->eman.pub.output_message = new_output_message;
 	write->eman.fp = NULL;
 	write->profile_bytes = NULL;
 	write->profile_length = 0;
+	write->inverted = NULL;
 
-	if( !write->tg || !write->row_pointer ) {
-		write_destroy( write );
-		return( NULL );
-	}
-	
         return( write );
 }
 
@@ -542,9 +538,13 @@ write_jpeg_block( REGION *region, Rect *area, void *a, void *b )
 static int
 write_vips( Write *write, int qfac, const char *profile )
 {
-	IMAGE *in = write->in;
+	IMAGE *in;
 	J_COLOR_SPACE space;
 
+	/* The image we'll be writing ... can change, see CMYK.
+	 */
+	in = write->in;
+
 	/* Should have been converted for save.
 	 */
         assert( in->BandFmt == IM_BANDFMT_UCHAR );
@@ -565,8 +565,15 @@ write_vips( Write *write, int qfac, const char *profile )
         write->cinfo.image_width = in->Xsize;
         write->cinfo.image_height = in->Ysize;
 	write->cinfo.input_components = in->Bands;
-	if( in->Bands == 4 && in->Type == IM_TYPE_CMYK )
+	if( in->Bands == 4 && in->Type == IM_TYPE_CMYK ) {
 		space = JCS_CMYK;
+		/* IJG always sets an Adobe marker, so we should invert CMYK.
+		 */
+		if( !(write->inverted = im_open( "vips2jpeg_invert", "p" )) ||
+			im_invert( in, write->inverted ) )
+			return( -1 );
+		in = write->inverted;
+	}
 	else if( in->Bands == 3 )
 		space = JCS_RGB;
 	else if( in->Bands == 1 )
@@ -577,6 +584,13 @@ write_vips( Write *write, int qfac, const char *profile )
 		space = JCS_UNKNOWN;
 	write->cinfo.in_color_space = space; 
 
+	/* Build VIPS output stuff now we know the image we'll be writing.
+	 */
+	write->tg = im_threadgroup_create( in );
+	write->row_pointer = IM_ARRAY( NULL, write->tg->nlines, JSAMPROW );
+	if( !write->tg || !write->row_pointer ) 
+		return( -1 );
+
 	/* Rest to default. 
 	 */
         jpeg_set_defaults( &write->cinfo );
@@ -607,7 +621,6 @@ write_vips( Write *write, int qfac, const char *profile )
 		return( -1 );
 
 	/* We have to reinstate the setjmp() before we jpeg_finish_compress().
-	 * No need to destroy the write: our parent does that.
 	 */
 	if( setjmp( write->eman.jmp ) ) 
 		return( -1 );