tiff loader always offers thinstrip

the tiff loader now always offers thinstrip ... later stages can then
pick any demand style they like (thanks Diuming)

ChangeLog

@@ -3,6 +3,7 @@
 - use TIFF_CFLAGS output from pkg-config (thanks Jay)
 - much faster vips_argument_map()
 - make jpeg pyramids work with tiff4
+- tiff loader always offers THINSTRIP (thanks Diuming)
 
 19/4/12 started 7.28.5
 - ifthenelse blend mode was broken

libvips/foreign/foreign.c

@@ -2151,19 +2151,10 @@ vips_fitssave( VipsImage *in, const char *filename, ... )
  *
  * Optional arguments:
  *
- * @sequential: sequential read only 
- *
  * Read a PNG file into a VIPS image. It can read all png images, including 8-
  * and 16-bit images, 1 and 3 channel, with and without an alpha channel.
  *
- * Setting @sequential to %TRUE means you promise to only demand tiles from
- * this image top-top-bottom, ie. to read sequentially. This means the png
- * loader can read directly from the image without having to generate a
- * random-access intermediate. This can save a lot of time and memory for
- * large images, but limits the sorts of operation you can perform. It's
- * useful for things like generating thumbnails. 
- *
- * There is no support for embedded ICC profiles.
+ * Any ICC profile is read and attached to the VIPS image.
  *
  * See also: vips_image_new_from_file().
  *
@@ -2202,7 +2193,9 @@ vips_pngload( const char *filename, VipsImage **out, ... )
  * than an interlaced PNG can be up to 7 times slower to write than a
  * non-interlaced image.
  *
- * There is no support for attaching ICC profiles to PNG images.
+ * If the VIPS header 
+ * contains an ICC profile named VIPS_META_ICC_NAME ("icc-profile-data"), the
+ * profile from the VIPS header will be attached.
  *
  * The image is automatically converted to RGB, RGBA, Monochrome or Mono +
  * alpha before saving. Images with more than one byte per band element are

libvips/foreign/tiff2vips.c

@@ -128,6 +128,9 @@
  * 18/2/12
  * 	- switch to sequential read
  * 	- remove the lock ... tilecache does this for us
+ * 3/6/12
+ * 	- always offer THINSTRIP ... later stages can ask for something more
+ * 	  relaxed if they wish
  */
 
 /*
@@ -1090,6 +1093,12 @@ parse_header( ReadTiff *rtiff, VipsImage *out )
 			(VipsCallbackFn) vips_free, data_copy, data_length );
 	}
 
+	/* Offer the most restrictive style. This can be changed downstream if
+	 * necessary.
+	 */
+        vips_demand_hint( out, 
+		VIPS_DEMAND_STYLE_THINSTRIP, NULL );
+
 	return( 0 );
 }
 
@@ -1257,16 +1266,19 @@ read_tilewise( ReadTiff *rtiff, VipsImage *out )
 	if( parse_header( rtiff, raw ) )
 		return( -1 );
 
-	/* Process and save as VIPS.
+	/* Process and save as VIPS. 
+	 *
+	 * Even though this is a tiled reader, we hint thinstrip since with
+	 * the cache we are quite happy serving that if anything downstream 
+	 * would like it.
 	 */
         vips_demand_hint( raw, 
-		VIPS_DEMAND_STYLE_SMALLTILE, NULL );
+		VIPS_DEMAND_STYLE_THINSTRIP, NULL );
 	if( vips_image_generate( raw, 
 		tiff_seq_start, tiff_fill_region, tiff_seq_stop, 
 		rtiff, NULL ) )
 		return( -1 );
 
-
 	/* Copy to out, adding a cache. Enough tiles for two complete rows.
 	 */
 	if( vips_tilecache( raw, &t,

libvips/resample/im_shrink.c

@@ -58,6 +58,10 @@
 
  */
 
+/*
+#define DEBUG
+ */
+
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif /*HAVE_CONFIG_H*/
@@ -244,6 +248,11 @@ shrink_gen( REGION *or, void *vseq, void *a, void *b )
 
 	int x, y;
 
+#ifdef DEBUG
+	printf( "shrink_gen: generating %d x %d at %d x %d\n",
+		r->width, r->height, r->left, r->top ); 
+#endif /*DEBUG*/
+
 	for( y = 0; y < r->height; y += ystep )  
 		for( x = 0; x < r->width; x += xstep ) { 
 			/* Clip the this rect against the demand size.
@@ -257,6 +266,10 @@ shrink_gen( REGION *or, void *vseq, void *a, void *b )
 			s.top = (r->top + y) * st->yshrink;
 			s.width = 1 + ceil( width * st->xshrink );
 			s.height = 1 + ceil( height * st->yshrink );
+#ifdef DEBUG
+			printf( "shrink_gen: requesting %d x %d at %d x %d\n",
+				s.width, s.height, s.left, s.top ); 
+#endif /*DEBUG*/
 			if( im_prepare( ir, &s ) )
 				return( -1 );