done! but needs some tests

ChangeLog

@@ -4,6 +4,7 @@
   constant image
 - add new_from_image() to Python as well
 - slight change to cpp new_from_image() to match py/C behaviour
+- add FORCE resize mode to break aspect ratio
 
 23/4/17 started 8.5.5
 - doc polishing

TODO

@@ -1,4 +1,6 @@
-- cpp bandjoin should use bandjoin_const() where possibel ... currently 
+- need tests for new thumbnail mode
+
+- cpp bandjoin should use bandjoin_const() where possible ... currently 
   uses new_from_image
 
 - not sure about utf8 error messages on win

doc/How-it-opens-files.md

@@ -102,7 +102,7 @@ example:
 $ vips shrink fred.png jim.png 10 10
 ```
 
-meaning shrink `fred.png` by a factor of 10 in both axies and write as
+meaning shrink `fred.png` by a factor of 10 in both axes and write as
 `jim.png`.
 
 You can imagine this operation running without needing `fred.png` to be

libvips/iofuncs/enumtypes.c

@@ -831,6 +831,7 @@ vips_size_get_type( void )
 			{VIPS_SIZE_BOTH, "VIPS_SIZE_BOTH", "both"},
 			{VIPS_SIZE_UP, "VIPS_SIZE_UP", "up"},
 			{VIPS_SIZE_DOWN, "VIPS_SIZE_DOWN", "down"},
+			{VIPS_SIZE_FORCE, "VIPS_SIZE_FORCE", "force"},
 			{VIPS_SIZE_LAST, "VIPS_SIZE_LAST", "last"},
 			{0, NULL, NULL}
 		};

libvips/resample/thumbnail.c

@@ -5,6 +5,8 @@
  * 	- from vipsthumbnail.c
  * 6/1/17
  * 	- add @size parameter
+ * 4/5/17
+ * 	- add FORCE
  */
 
 /*
@@ -156,17 +158,17 @@ vips_thumbnail_calculate_shrink( VipsThumbnail *thumbnail,
 	 * In crop mode, we aim to fill the bounding box, so we must use the
 	 * smaller axis.
 	 */
-	double horizontal = (double) width / thumbnail->width;
+	*hshrink = (double) width / thumbnail->width;
-	double vertical = (double) height / thumbnail->height;
+	*vshrink = (double) height / thumbnail->height;
 
 	if( thumbnail->crop != VIPS_INTERESTING_NONE ) {
-		if( horizontal < vertical )
+		if( *hshrink < *vshrink )
 			direction = VIPS_DIRECTION_HORIZONTAL;
 		else
 			direction = VIPS_DIRECTION_VERTICAL;
 	}
 	else {
-		if( horizontal < vertical )
+		if( *hshrink < *vshrink )
 			direction = VIPS_DIRECTION_VERTICAL;
 		else
 			direction = VIPS_DIRECTION_HORIZONTAL;
@@ -174,24 +176,27 @@ vips_thumbnail_calculate_shrink( VipsThumbnail *thumbnail,
 
 	if( thumbnail->size != VIPS_SIZE_FORCE ) {
 		if( direction == VIPS_DIRECTION_HORIZONTAL )
-			vertical = horizontal;
+			*vshrink = *hshrink;
 		else
-			horizontal = vertical;
+			*hshrink = *vshrink;
 	}
-	else if( thumbnail->size == VIPS_SIZE_UP )
-		shrink = VIPS_MIN( 1, shrink );
-	else if( thumbnail->size == VIPS_SIZE_DOWN )
-		shrink = VIPS_MAX( 1, shrink );
-
 
+	if( thumbnail->size == VIPS_SIZE_UP ) {
+		*hshrink = VIPS_MIN( 1, *hshrink );
+		*vshrink = VIPS_MIN( 1, *vshrink );
+	}
+	else if( thumbnail->size == VIPS_SIZE_DOWN ) {
+		*hshrink = VIPS_MAX( 1, *hshrink );
+		*vshrink = VIPS_MAX( 1, *vshrink );
+	}
 }
 
-/* Just the common part of the shrink: the bit by which both axies must be
+/* Just the common part of the shrink: the bit by which both axes must be
  * shrunk.
  */
 static double
 vips_thumbnail_calculate_common_shrink( VipsThumbnail *thumbnail, 
-	int input_width, int input_height )
+	int width, int height )
 {
 	double hshrink;
 	double vshrink;
@@ -244,7 +249,7 @@ vips_thumbnail_open( VipsThumbnail *thumbnail )
 	VipsThumbnailClass *class = VIPS_THUMBNAIL_GET_CLASS( thumbnail );
 
 	VipsImage *im;
-	int shrink;
+	double shrink;
 	double scale;
 
 	if( class->get_info( thumbnail ) )
@@ -253,25 +258,26 @@ vips_thumbnail_open( VipsThumbnail *thumbnail )
 	g_info( "input size is %d x %d", 
 		thumbnail->input_width, thumbnail->input_height ); 
 
-	shrink = 1;
+	shrink = 1.0;
 	scale = 1.0;
 
 	if( vips_isprefix( "VipsForeignLoadJpeg", thumbnail->loader ) ) {
 		shrink = vips_thumbnail_find_jpegshrink( thumbnail, 
 			thumbnail->input_width, thumbnail->input_height );
+
 		g_info( "loading jpeg with factor %g pre-shrink", shrink ); 
 	}
 	else if( vips_isprefix( "VipsForeignLoadPdf", thumbnail->loader ) ||
 		vips_isprefix( "VipsForeignLoadSvg", thumbnail->loader ) ) {
-		scale = 1.0 / 
+		shrink = vips_thumbnail_calculate_common_shrink( thumbnail, 
-			vips_thumbnail_calculate_common_shrink( thumbnail, 
+			thumbnail->input_width, thumbnail->input_height );
-				width, height );
+		scale = 1.0 / shrink; 
 
 		g_info( "loading PDF/SVG with factor %g pre-scale", scale ); 
 	}
 	else if( vips_isprefix( "VipsForeignLoadWebp", thumbnail->loader ) ) {
 		shrink = vips_thumbnail_calculate_common_shrink( thumbnail, 
-			width, height );
+			thumbnail->input_width, thumbnail->input_height );
 
 		g_info( "loading webp with factor %g pre-shrink", shrink ); 
 	}
@@ -393,12 +399,13 @@ vips_thumbnail_build( VipsObject *object )
 		in = t[3];
 	}
 
-	shrink = vips_thumbnail_calculate_shrink( thumbnail, 
+	vips_thumbnail_calculate_shrink( thumbnail, 
-		in->Xsize, in->Ysize );
+		in->Xsize, in->Ysize, &hshrink, &vshrink );
 
 	/* Use centre convention to better match imagemagick.
 	 */
-	if( vips_resize( in, &t[4], 1.0 / shrink, 
+	if( vips_resize( in, &t[4], 1.0 / hshrink, 
+		"vscale", 1.0 / vshrink, 
 		"centre", TRUE, 
 		NULL ) ) 
 		return( -1 );
@@ -659,8 +666,6 @@ vips_thumbnail_file_open( VipsThumbnail *thumbnail, int shrink, double scale )
 {
 	VipsThumbnailFile *file = (VipsThumbnailFile *) thumbnail;
 
-	/* We can't use UNBUFERRED safely on very-many-core systems.
-	 */
 	if( shrink != 1 ) 
 		return( vips_image_new_from_file( file->filename, 
 			"access", VIPS_ACCESS_SEQUENTIAL,

man/vipsthumbnail.1

@@ -94,7 +94,7 @@ option.
 .TP
 .B -c, --crop
 Crop the output image down. The image is shrunk so as to completely fill the
-bounding box in both axies, then any excess is cropped off. 
+bounding box in both axes, then any excess is cropped off. 
 
 .TP
 .B -d, --delete

tools/vipsthumbnail.c

@@ -90,6 +90,8 @@
  * 6/1/17
  * 	- fancy geometry strings
  * 	- support VipSize restrictions
+ * 4/5/17
+ * 	- add ! geo modifier
  */
 
 #ifdef HAVE_CONFIG_H
@@ -333,7 +335,7 @@ thumbnail_parse_geometry( const char *geometry )
 			p++;
 	}
 
-	/* Get the final < or >.
+	/* Get the final <>!
 	 */
 	while( isspace( *p ) )
 		p++;
@@ -341,6 +343,8 @@ thumbnail_parse_geometry( const char *geometry )
 		size_restriction = VIPS_SIZE_UP;
 	else if( *p == '>' ) 
 		size_restriction = VIPS_SIZE_DOWN;
+	else if( *p == '!' ) 
+		size_restriction = VIPS_SIZE_FORCE;
 	else if( *p != '\0' ||
 		(thumbnail_width == VIPS_MAX_COORD && 
 			thumbnail_height == VIPS_MAX_COORD) ) {
@@ -348,12 +352,24 @@ thumbnail_parse_geometry( const char *geometry )
 		return( -1 );
 	}
 
-	/* If --crop is set, both width and height must be specified,
+	/* If force is set and one of width or height isn't set, copy from the
-	 * since we'll need a complete bounding box to fill.
+	 * one that is.
 	 */
-	if( (crop_image || smartcrop_image) &&
+	if( size_restriction == VIPS_SIZE_FORCE ) {
-		(thumbnail_width == VIPS_MAX_COORD ||
+		if( thumbnail_width == VIPS_MAX_COORD )
-			thumbnail_height == VIPS_MAX_COORD) ) {
+			thumbnail_width = thumbnail_height;
+		if( thumbnail_height == VIPS_MAX_COORD )
+			thumbnail_height = thumbnail_width;
+	}
+
+	/* If --crop is set or force is set, both width and height must be 
+	 * specified, since we'll need a complete bounding box to fill.
+	 */
+	if( crop_image || 
+		smartcrop_image || 
+		size_restriction == VIPS_SIZE_FORCE ) 
+		if( thumbnail_width == VIPS_MAX_COORD ||
+			thumbnail_height == VIPS_MAX_COORD ) {
 			vips_error( "thumbnail",
 				"both width and height must be given if "
 				"crop is enabled" );