change @whole_slide to @autocrop

on seconds thoughts, make openslide crop-on-load an option, not the
default

also, clip image bounds against image size

ChangeLog

@@ -2,7 +2,7 @@
 - fix a race in im_maxpos_avg()
 - limit n_thr on tiny images
 - don't exit() on memleak detected, just warn
-- add "whole_slide" option to openslide load
+- add "autocrop" option to openslide load
 
 4/7/14 started 7.40.4
 - fix vips_rawsave_fd(), thanks aferrero2707 

libvips/foreign/foreign.c

@@ -2307,6 +2307,7 @@ vips_openexrload( const char *filename, VipsImage **out, ... )
  *
  * @level: load this level
  * @associated: load this associated image
+ * @autocrop: crop to image bounds
  *
  * Read a virtual slide supported by the OpenSlide library into a VIPS image.
  * OpenSlide supports images in Aperio, Hamamatsu, MIRAX, Sakura, Trestle,
@@ -2324,8 +2325,7 @@ vips_openexrload( const char *filename, VipsImage **out, ... )
  * A slide's associated images are listed in the
  * "slide-associated-images" metadata item.
  *
- * The output of this operator is in pre-multipled ARGB format. Use
- * im_argb2rgba() to decode to png-style RGBA. 
+ * The output of this operator is always RGBA.
  *
  * See also: vips_image_new_from_file().
  *

libvips/foreign/openslide2vips.c

@@ -42,7 +42,7 @@
  * 25/1/14
  * 	- use openslide_detect_vendor() on >= 3.4.0
  * 30/7/14
- * 	- add whole_slide toggle
+ * 	- add autocrop toggle
  */
 
 /*
@@ -94,10 +94,9 @@ typedef struct {
 
 	char *associated;
 
-	/* Normally we crop to image bounds, if set. @whole_slide means, get the
-	 * whole image.
+	/* Crop to image bounds if @autocrop is set. 
 	 */
-	gboolean whole_slide;
+	gboolean autocrop;
 	VipsRect bounds;
 
 	/* Only valid if associated == NULL.
@@ -218,7 +217,7 @@ get_bounds( openslide_t *osr, VipsRect *rect )
 
 static ReadSlide *
 readslide_new( const char *filename, VipsImage *out, 
-	int level, gboolean whole_slide, const char *associated )
+	int level, gboolean autocrop, const char *associated )
 {
 	ReadSlide *rslide;
 	int64_t w, h;
@@ -240,7 +239,7 @@ readslide_new( const char *filename, VipsImage *out,
 		rslide );
 
 	rslide->level = level;
-	rslide->whole_slide = whole_slide;
+	rslide->autocrop = autocrop;
 	rslide->associated = g_strdup( associated );
 
 	/* Non-crazy defaults, override below if we can.
@@ -305,18 +304,35 @@ readslide_new( const char *filename, VipsImage *out,
 		if( value )
 			VIPS_DEBUG_MSG( "readslide_new: found tile-size\n" );
 
-		/* Some images have a bounds in the header. Try to crop to 
-		 * that, unless whole_slide is set. 
+		/* Some images have a bounds in the header. Crop to 
+		 * that if autocrop is set. 
 		 */
-		if( !rslide->whole_slide ) 
+		if( rslide->autocrop ) 
 			if( !get_bounds( rslide->osr, &rslide->bounds ) )
-				rslide->whole_slide = TRUE; 
-		if( !rslide->whole_slide ) {
+				rslide->autocrop = FALSE; 
+		if( rslide->autocrop ) {
+			VipsRect image;
+
 			rslide->bounds.left /= rslide->downsample;
 			rslide->bounds.top /= rslide->downsample;
 			rslide->bounds.width /= rslide->downsample;
 			rslide->bounds.height /= rslide->downsample;
 
+			/* Clip against image size.
+			 */
+			image.left = 0;
+			image.top = 0;
+			image.width = w;
+			image.height = h;
+			vips_rect_intersectrect( &rslide->bounds, &image, 
+				&rslide->bounds );
+
+			/* If we've clipped to nothing, ignore bounds.
+			 */
+			if( vips_rect_isempty( &rslide->bounds ) )
+				rslide->autocrop = FALSE;
+		}
+		if( rslide->autocrop ) {
 			w = rslide->bounds.width;
 			h = rslide->bounds.height;
 		}
@@ -341,7 +357,7 @@ readslide_new( const char *filename, VipsImage *out,
 		return( NULL );
 	}
 
-	if( rslide->whole_slide ) {
+	if( !rslide->autocrop ) {
 		rslide->bounds.left = 0;
 		rslide->bounds.top = 0;
 		rslide->bounds.width = w;
@@ -366,9 +382,9 @@ readslide_new( const char *filename, VipsImage *out,
 
 int
 vips__openslide_read_header( const char *filename, VipsImage *out, 
-	int level, gboolean whole_slide, char *associated )
+	int level, gboolean autocrop, char *associated )
 {
-	if( !readslide_new( filename, out, level, whole_slide, associated ) )
+	if( !readslide_new( filename, out, level, autocrop, associated ) )
 		return( -1 );
 
 	return( 0 );
@@ -457,7 +473,7 @@ vips__openslide_generate( VipsRegion *out,
 
 int
 vips__openslide_read( const char *filename, VipsImage *out, 
-	int level, gboolean whole_slide )
+	int level, gboolean autocrop )
 {
 	ReadSlide *rslide;
 	VipsImage *raw;
@@ -470,7 +486,7 @@ vips__openslide_read( const char *filename, VipsImage *out,
 	vips_object_local( out, raw );
 
 	if( !(rslide = readslide_new( filename, raw, 
-		level, whole_slide, NULL )) )
+		level, autocrop, NULL )) )
 		return( -1 );
 
 	if( vips_image_generate( raw, 

libvips/foreign/openslide2vips.h

@@ -37,9 +37,9 @@ extern "C" {
 
 int vips__openslide_isslide( const char *filename );
 int vips__openslide_read_header( const char *filename, VipsImage *out, 
-	int level, gboolean whole_slide, char *associated );
+	int level, gboolean autocrop, char *associated );
 int vips__openslide_read( const char *filename, VipsImage *out, 
-	int level, gboolean whole_slide );
+	int level, gboolean autocrop );
 int vips__openslide_read_associated( const char *filename, VipsImage *out, 
 	const char *associated );
 

libvips/foreign/openslideload.c

@@ -70,9 +70,9 @@ typedef struct _VipsForeignLoadOpenslide {
 	 */
 	int level;
 
-	/* Don't crop to image bounds.
+	/* Crop to image bounds.
 	 */
-	gboolean whole_slide;
+	gboolean autocrop;
 
 	/* Load this associated image. 
 	 */
@@ -113,7 +113,7 @@ vips_foreign_load_openslide_header( VipsForeignLoad *load )
 	VipsForeignLoadOpenslide *openslide = (VipsForeignLoadOpenslide *) load;
 
 	if( vips__openslide_read_header( openslide->filename, load->out, 
-		openslide->level, openslide->whole_slide, 
+		openslide->level, openslide->autocrop, 
 		openslide->associated ) )
 		return( -1 );
 
@@ -129,7 +129,7 @@ vips_foreign_load_openslide_load( VipsForeignLoad *load )
 
 	if( !openslide->associated ) {
 		if( vips__openslide_read( openslide->filename, load->real, 
-			openslide->level, openslide->whole_slide ) )
+			openslide->level, openslide->autocrop ) )
 			return( -1 );
 	}
 	else {
@@ -195,11 +195,11 @@ vips_foreign_load_openslide_class_init( VipsForeignLoadOpenslideClass *class )
 		G_STRUCT_OFFSET( VipsForeignLoadOpenslide, level ),
 		0, 100000, 0 );
 
-	VIPS_ARG_BOOL( class, "whole_slide", 11,
-		_( "Whole slide" ),
-		_( "Output entire side area" ),
+	VIPS_ARG_BOOL( class, "autocrop", 11,
+		_( "Autocrop" ),
+		_( "Crop to image bounds" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
-		G_STRUCT_OFFSET( VipsForeignLoadOpenslide, whole_slide ),
+		G_STRUCT_OFFSET( VipsForeignLoadOpenslide, autocrop ),
 		FALSE ); 
 
 	VIPS_ARG_STRING( class, "associated", 12,