start fixing up the auto-decode stuff

README.md

@@ -1,5 +1,7 @@
 # libvips : an image processing library
 
+[![Build Status](https://secure.travis-ci.org/jcupitt/libvips.png)](http://travis-ci.org/jcupitt/libvips)
+
 libvips is a 2D image processing library. Compared to similar libraries, 
 [libvips runs quickly and uses little
 memory](http://www.vips.ecs.soton.ac.uk/index.php?title=Speed_and_Memory_Use).

TODO

@@ -1,3 +1,16 @@
+- should we decode to LAB, rather than LABS, by default?
+
+  causing all sorts of problems 
+
+- have a decode-to-float flag?
+
+- when do we want LABS? for speed in conv ... have a special unpacker there?
+
+  any time we won't be breaking bands apart or using a constant, I guess?
+
+- change measure to use the regular decoder
+
+
 - quickly wrap the useful bits of mosaicing/
 
   nip2 uses:

libvips/arithmetic/linear.c

@@ -125,18 +125,7 @@ vips_linear_build( VipsObject *object )
 	int bands;
 	int i;
 
-	/* How many bands will our input image have after decoding?
-	 */
-	switch( unary->in->Coding ) {
-	case VIPS_CODING_RAD:
-	case VIPS_CODING_LABQ:
-		bands = 3;
-		break;
-
-	default:
-		bands = unary->in->Bands;
-		break;
-	}
+	vips_image_decode_predict( unary->in, &bands, NULL ); 
 
 	/* If we have a three-element vector we need to bandup the image to
 	 * match.

libvips/arithmetic/measure.c

@@ -21,6 +21,8 @@
  * 	- changes for im_extract() broke averaging
  * 9/11/11
  * 	- redo as a class
+ * 19/5/14
+ * 	- add auto-unpack
  */
 
 /*
@@ -91,6 +93,7 @@ vips_measure_build( VipsObject *object )
 	VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
 	VipsMeasure *measure = (VipsMeasure *) object;
 
+	VipsImage *ready;
 	int bands;
 	double pw;
 	double ph;
@@ -101,7 +104,23 @@ vips_measure_build( VipsObject *object )
 	if( VIPS_OBJECT_CLASS( vips_measure_parent_class )->build( object ) )
 		return( -1 );
 
-	bands = vips_image_get_bands( measure->in );
+	/* We can't use vips_image_decode(), we want Lab, not LabS.
+	 */
+	if( measure->in->Coding == VIPS_CODING_LABQ ) {
+		if( vips_LabQ2Lab( measure->in, &ready, NULL ) )
+			return( -1 );
+	} 
+	else if( measure->in->Coding == VIPS_CODING_RAD ) {
+		if( vips_rad2float( measure->in, &ready, NULL ) )
+			return( -1 );
+	}
+	else {
+		if( vips_copy( measure->in, &ready, NULL ) )
+			return( -1 );
+	}
+	vips_object_local( measure, ready ); 
+
+	bands = vips_image_get_bands( ready );
 
 	g_object_set( object, 
 		"out", vips_image_new_matrix( bands, measure->h * measure->v ),
@@ -111,11 +130,11 @@ vips_measure_build( VipsObject *object )
 	 */
 	if( !vips_object_argument_isset( object, "width" ) )
 		g_object_set( object, 
-			"width", vips_image_get_width( measure->in ),
+			"width", vips_image_get_width( ready ),
 			NULL );
 	if( !vips_object_argument_isset( object, "height" ) )
 		g_object_set( object, 
-			"height", vips_image_get_height( measure->in ),
+			"height", vips_image_get_height( ready ),
 			NULL );
 
 	/* How large are the patches we are to measure?
@@ -141,7 +160,7 @@ vips_measure_build( VipsObject *object )
 
 				/* Extract and measure.
 				 */
-				if( vips_extract_area( measure->in, &t[0], 
+				if( vips_extract_area( ready, &t[0], 
 						x, y, w, h, NULL ) ||
 					vips_extract_band( t[0], &t[1], 
 						b, NULL ) ||

libvips/conversion/extract.c

@@ -371,18 +371,22 @@ vips_extract_band_build( VipsObject *object )
 	VipsExtractBand *extract = (VipsExtractBand *) object;
 
 	if( extract->in ) {
+		int bands; 
+
+		vips_image_decode_predict( extract->in, &bands, NULL );
+
 		bandary->n = 1;
 		bandary->in = &extract->in;
 		bandary->out_bands = extract->n;
 
-		if( extract->band + extract->n > extract->in->Bands ) {
+		if( extract->band + extract->n > bands ) {
 			vips_error( class->nickname, 
 				"%s", _( "bad extract band" ) );
 			return( -1 );
 		}
 
-		if( extract->band == 0 &&
-			extract->n == extract->in->Bands ) 
+		if( extract->band == 0 && 
+			extract->n == bands ) 
 			return( vips_bandary_copy( bandary ) );
 	}
 

libvips/conversion/insert.c

@@ -232,24 +232,7 @@ vips__vector_to_ink( const char *domain,
 	printf( "vips__vector_to_ink: starting\n" );
 #endif /*VIPS_DEBUG*/
 
-	/* We need to know the bands and format we are matching to. But im may
-	 * be coded, so simulate decoding. We can't call vips_image_decode()
-	 * on im, since vips__vector_to_ink() needs to be able to work during
-	 * im's construction and im may not be ready yet.
-	 */
-	if( im->Coding == VIPS_CODING_LABQ ) {
-		bands = 3;
-		format = VIPS_FORMAT_SHORT;
-	}
-	else if( im->Coding == VIPS_CODING_RAD ) {
-		bands = 3;
-		format = VIPS_FORMAT_FLOAT;
-	}
-	else {
-		bands = im->Bands;
-		format = im->BandFmt;
-	}
-
+	vips_image_decode_predict( im, &bands, &format );
 	ones = VIPS_ARRAY( im, n, double );
 	for( i = 0; i < n; i++ )
 		ones[i] = 1.0;

libvips/foreign/vipspng.c

@@ -440,8 +440,8 @@ png2vips_generate( VipsRegion *or,
 	int y;
 
 #ifdef DEBUG
-	printf( "png2vips_generate: line %d, %d rows\n", 
-		r->top, r->height );
+	printf( "png2vips_generate: line %d, %d rows\n", r->top, r->height );
+	printf( "png2vips_generate: y_top = %d\n", read->y_pos );
 #endif /*DEBUG*/
 
 	/* We're inside a tilecache where tiles are the full image width, so

libvips/include/vips/image.h

@@ -430,6 +430,8 @@ VipsImage *vips_image_new_temp_file( const char *format );
 int vips_image_write( VipsImage *image, VipsImage *out );
 int vips_image_write_to_file( VipsImage *image, const char *filename );
 
+int vips_image_decode_predict( VipsImage *im, 
+	int *bands, VipsBandFormat *format );
 int vips_image_decode( VipsImage *in, VipsImage **out );
 int vips_image_encode( VipsImage *in, VipsImage **out, VipsCoding coding );
 

libvips/iofuncs/image.c

@@ -2030,6 +2030,45 @@ vips_image_decode( VipsImage *in, VipsImage **out )
 	return( 0 );
 }
 
+/**
+ * vips_image_decode_predict:
+ * @in: image to decode
+ * @bands: predict bands here
+ * @format: predict format here
+ *
+ * We often need to know what an image will decode to without actuaklly
+ * decoding it, for example, in arg checking.
+ *
+ * See also: vips_image_decode().
+ */
+int
+vips_image_decode_predict( VipsImage *im, 
+	int *out_bands, VipsBandFormat *out_format )
+{
+	VipsBandFormat format;
+	int bands; 
+
+	if( im->Coding == VIPS_CODING_LABQ ) {
+		bands = 3;
+		format = VIPS_FORMAT_SHORT;
+	}
+	else if( im->Coding == VIPS_CODING_RAD ) {
+		bands = 3;
+		format = VIPS_FORMAT_FLOAT;
+	}
+	else {
+		bands = im->Bands;
+		format = im->BandFmt;
+	}
+
+	if( out_bands )
+		*out_bands = bands;
+	if( out_format )
+		*out_format = format;
+
+	return( 0 );
+}
+
 /**
  * vips_image_encode:
  * @in: image to encode