all done, I think

ChangeLog

@@ -19,6 +19,8 @@
   VIPS_LIBRARY_AGE
 - better support for bscale / bzero in fits images
 - deprecate vips_warn() / vips_info(); use g_warning() / g_info() instead
+- vipsthumbnail supports much fancier geometry strings
+- vips_thumbnail() has new @size option
 
 8/12/16 started 8.4.5
 - allow libgsf-1.14.26 to help centos, thanks tdiprima

TODO

@@ -1,3 +1,35 @@
+- </>
+
+	convert k2.jpg -resize "100x100<" x.jpg
+
+		downsize, ie. factor < 1
+		does not resize
+
+	convert x.jpg -resize "200x200<" y.jpg
+
+		upsize, ie. factor > 1
+		resizes
+
+	convert k2.jpg -resize "100x100>" x.jpg
+
+		downsize, ie. factor < 1
+		resizes
+
+	convert x.jpg -resize "200x200>" y.jpg
+
+		upsize, ie. factor > 1
+		does not resize
+
+  so: < means only resize if input size is less than, > means only resize if
+  input size is > than
+
+  awkward to fit inside vipsthumbnail.c, since we'd have to copy/paste all the
+  resize calcs
+
+  have to add another param to thumbnail ... up or down, only up, only down
+
+
+
 - vipsdisp-tiny makes stripes if the image is not tagged correctly
 
   is one of the colourspace functions not reading format?

libvips/include/vips/enumtypes.h

@@ -9,6 +9,8 @@ G_BEGIN_DECLS
 /* enumerations from "../../../libvips/include/vips/resample.h" */
 GType vips_kernel_get_type (void) G_GNUC_CONST;
 #define VIPS_TYPE_KERNEL (vips_kernel_get_type())
+GType vips_size_get_type (void) G_GNUC_CONST;
+#define VIPS_TYPE_SIZE (vips_size_get_type())
 /* enumerations from "../../../libvips/include/vips/foreign.h" */
 GType vips_foreign_flags_get_type (void) G_GNUC_CONST;
 #define VIPS_TYPE_FOREIGN_FLAGS (vips_foreign_flags_get_type())

libvips/include/vips/resample.h

@@ -47,6 +47,13 @@ typedef enum {
 	VIPS_KERNEL_LAST
 } VipsKernel;
 
+typedef enum {
+	VIPS_SIZE_BOTH,
+	VIPS_SIZE_UP,
+	VIPS_SIZE_DOWN,
+	VIPS_SIZE_LAST
+} VipsSize;
+
 int vips_shrink( VipsImage *in, VipsImage **out, 
 	double hshrink, double vshrink, ... )
 	__attribute__((sentinel));

libvips/iofuncs/enumtypes.c

@@ -26,6 +26,25 @@ vips_kernel_get_type( void )
 
 	return( etype );
 }
+GType
+vips_size_get_type( void )
+{
+	static GType etype = 0;
+
+	if( etype == 0 ) {
+		static const GEnumValue values[] = {
+			{VIPS_SIZE_BOTH, "VIPS_SIZE_BOTH", "both"},
+			{VIPS_SIZE_UP, "VIPS_SIZE_UP", "up"},
+			{VIPS_SIZE_DOWN, "VIPS_SIZE_DOWN", "down"},
+			{VIPS_SIZE_LAST, "VIPS_SIZE_LAST", "last"},
+			{0, NULL, NULL}
+		};
+		
+		etype = g_enum_register_static( "VipsSize", values );
+	}
+
+	return( etype );
+}
 /* enumerations from "../../libvips/include/vips/foreign.h" */
 GType
 vips_foreign_flags_get_type( void )

libvips/resample/resample.c

@@ -82,6 +82,18 @@
  * Finally, vips_mapim() can apply arbitrary 2D image transforms to an image.
  */
 
+/** 
+ * VipsSize:
+ * @VIPS_SIZE_BOTH: size both up and down
+ * @VIPS_SIZE_UP: only upsize
+ * @VIPS_SIZE_DOWN: only downsize
+ *
+ * Controls whether an operation should upsize, downsize, or both up and
+ * downsize. 
+ *
+ * See also: vips_thumbnail().
+ */
+
 G_DEFINE_ABSTRACT_TYPE( VipsResample, vips_resample, VIPS_TYPE_OPERATION );
 
 static int

libvips/resample/thumbnail.c

@@ -3,6 +3,8 @@
  *
  * 2/11/16
  * 	- from vipsthumbnail.c
+ * 6/1/17
+ * 	- add @size parameter
  */
 
 /*
@@ -68,6 +70,7 @@ typedef struct _VipsThumbnail {
 	VipsImage *out;
 	int width;
 	int height;
+	VipsSize size;
 
 	gboolean auto_rotate;
 	gboolean crop;
@@ -122,6 +125,7 @@ vips_thumbnail_calculate_shrink( VipsThumbnail *thumbnail,
 		input_width : input_height;
 
 	VipsDirection direction;
+	double shrink;
 
 	/* Calculate the horizontal and vertical shrink we'd need to fit the
 	 * image to the bounding box, and pick the biggest. 
@@ -145,8 +149,17 @@ vips_thumbnail_calculate_shrink( VipsThumbnail *thumbnail,
 			direction = VIPS_DIRECTION_HORIZONTAL;
 	}
 
-	return( direction == VIPS_DIRECTION_HORIZONTAL ?
+	shrink = direction == VIPS_DIRECTION_HORIZONTAL ?
-		horizontal : vertical );  
+		horizontal : vertical;  
+
+	/* Restrict to only upsize, only downsize, or both.
+	 */
+	if( thumbnail->size == VIPS_SIZE_UP )
+		shrink = VIPS_MIN( 1, shrink );
+	if( thumbnail->size == VIPS_SIZE_DOWN )
+		shrink = VIPS_MAX( 1, shrink );
+
+	return( shrink ); 
 }
 
 /* Find the best jpeg preload shrink.
@@ -497,35 +510,42 @@ vips_thumbnail_class_init( VipsThumbnailClass *class )
 		G_STRUCT_OFFSET( VipsThumbnail, height ),
 		1, VIPS_MAX_COORD, 1 );
 
-	VIPS_ARG_BOOL( class, "auto_rotate", 114, 
+	VIPS_ARG_ENUM( class, "size", 114, 
+		_( "size" ), 
+		_( "Only upsize, only downsize, or both" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsThumbnail, size ),
+		VIPS_TYPE_SIZE, VIPS_SIZE_BOTH ); 
+
+	VIPS_ARG_BOOL( class, "auto_rotate", 115, 
 		_( "Auto rotate" ), 
 		_( "Use orientation tags to rotate image upright" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsThumbnail, auto_rotate ),
 		TRUE ); 
 
-	VIPS_ARG_BOOL( class, "crop", 115, 
+	VIPS_ARG_BOOL( class, "crop", 116, 
 		_( "Crop" ), 
 		_( "Reduce to fill target rectangle, then crop" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsThumbnail, crop ),
 		FALSE ); 
 
-	VIPS_ARG_BOOL( class, "linear", 116, 
+	VIPS_ARG_BOOL( class, "linear", 117, 
 		_( "Linear" ), 
 		_( "Reduce in linear light" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsThumbnail, linear ),
 		FALSE ); 
 
-	VIPS_ARG_STRING( class, "import_profile", 117, 
+	VIPS_ARG_STRING( class, "import_profile", 118, 
 		_( "Import profile" ), 
 		_( "Fallback import profile" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
 		G_STRUCT_OFFSET( VipsThumbnail, import_profile ),
 		NULL ); 
 
-	VIPS_ARG_STRING( class, "export_profile", 118, 
+	VIPS_ARG_STRING( class, "export_profile", 119, 
 		_( "Export profile" ), 
 		_( "Fallback export profile" ),
 		VIPS_ARGUMENT_OPTIONAL_INPUT,
@@ -643,6 +663,7 @@ vips_thumbnail_file_init( VipsThumbnailFile *file )
  * Optional arguments:
  *
  * * @height: %gint, target height in pixels
+ * * @size: #VipsSize, upsize, downsize or both
  * * @auto_rotate: %gboolean, rotate upright using orientation tag
  * * @crop: %gboolean, shrink and crop to fill target
  * * @linear: %gboolean, perform shrink in linear light
@@ -658,11 +679,18 @@ vips_thumbnail_file_init( VipsThumbnailFile *file )
  * See vips_thumbnail_buffer() to thumbnail from a memory source. 
  *
  * The output image will fit within a square of size @width x @width. You can
- * specify a height with the @height option. 
+ * specify a separate height with the @height option. 
  *
  * If you set @crop, then the output image will fill the whole of the @width x
  * @height rectangle, with any excess cropped away.
  *
+ * Normally the operation will upsize or downsize as required. If @size is set
+ * to #VIPS_SIZE_UP, the operation will only upsize and will just
+ * copy if asked to downsize. 
+ * If @size is set
+ * to #VIPS_SIZE_DOWN, the operation will only downsize and will just
+ * copy if asked to upsize. 
+ *
  * Normally any orientation tags on the input image (such as EXIF tags) are
  * interpreted to rotate the image upright. If you set @auto_rotate to %FALSE,
  * these tags will not be interpreted.
@@ -803,6 +831,7 @@ vips_thumbnail_buffer_init( VipsThumbnailBuffer *buffer )
  * Optional arguments:
  *
  * * @height: %gint, target height in pixels
+ * * @size: #VipsSize, upsize, downsize or both
  * * @auto_rotate: %gboolean, rotate upright using orientation tag
  * * @crop: %gboolean, shrink and crop to fill target
  * * @linear: %gboolean, perform shrink in linear light

man/vipsthumbnail.1

@@ -26,7 +26,7 @@ and write thumbnails to the files
 and
 .B tn_jim.jpg.
 
- $ vipsthumbnail --size=64 -f thumbnails/%s.png fred.jpg
+ $ vipsthumbnail --size=64 -o thumbnails/%s.png fred.jpg
 
 will read image file
 .B fred.jpg
@@ -42,10 +42,12 @@ x
 .B N 
 pixels. You can use MxN to specify a rectangular bounding box.
 The image is shrunk so that it just fits within this area, images
-which are smaller than this are expanded.
+which are smaller than this are expanded. Use "xN" or "Mx" to just resize on
+one axis. Append "<" to only resize if the input image is smaller than the
+target, append ">" to only resize if the input image is larger than the target.
 
 .TP
-.B -f FORMAT, --format=FORMAT     
+.B -o FORMAT, --output=FORMAT     
 Set the output format string. The input filename has any file type suffix
 removed, then that value is substitued into 
 .B FORMAT
@@ -65,27 +67,6 @@ prepended. You can add format options too, for example
 .B tn_%s.jpg[Q=20]
 will write JPEG images with Q set to 20.
 
-.TP
-.B -p I, --interpolator=I               
-Resample with interpolator 
-.B I.
-Use 
-.B vips --list classes
-to see a list of valid interpolators. The default is 
-.B bilinear.
-
-.TP
-.B -r, --sharpen=none|mild|MASKFILE
-Images can look a little soft after shrinking.  This option lets you specify
-a sharpening mask. Use "none" to disable sharpening, or "mild" to sharpen
-lightly, or give the filename of a custom mask file to use. The default is
-"mild".  The built-in mild sharpen mask is:
-
- 3 3 24 0
- -1 -1 -1
- -1 32 -1
- -1 -1 -1
-
 .TP
 .B -e PROFILE, --eprofile=PROFILE        
 Export thumbnails with this ICC profile. Images are only colour-transformed if
@@ -114,10 +95,12 @@ Delete the output profile from the image. This can save a small amount of
 space. 
 
 .TP
-.B -v, --verbose
+.B -t, --rotate
-.B vipsthumbnail(1)
+Auto-rotate images using EXIF orientation tags. 
-normally runs silently, except for warning and error messages. This option
+
-makes it print a list of the operations it performs on each image.
+.TP
+.B -a, --linear
+Shrink images in linear light colour space. This can be much slower. 
 
 .SH RETURN VALUE
 returns 0 on success and non-zero on error. Error can mean one or more

tools/vipsthumbnail.c

@@ -85,6 +85,11 @@
  * 	- use scRGB as the working space in linear mode
  * 15/8/16
  * 	- can now remove 0.1 rounding adjustment
+ * 2/11/16
+ * 	- use vips_thumbnail(), most code moved there
+ * 6/1/17
+ * 	- fancy geometry strings
+ * 	- support VipSize restrictions
  */
 
 #ifdef HAVE_CONFIG_H
@@ -108,6 +113,7 @@
 static char *thumbnail_size = "128";
 static int thumbnail_width = 128;
 static int thumbnail_height = 128;
+static VipsSize size_restriction = VIPS_SIZE_BOTH;
 static char *output_format = "tn_%s.jpg";
 static char *export_profile = NULL;
 static char *import_profile = NULL;
@@ -229,10 +235,11 @@ thumbnail_write( VipsObject *process, VipsImage *im, const char *filename )
 static int
 thumbnail_process( VipsObject *process, const char *filename )
 {
-	VipsImage *in;
+	VipsImage *image;
 
-	if( vips_thumbnail( filename, &in, thumbnail_width, 
+	if( vips_thumbnail( filename, &image, thumbnail_width, 
 		"height", thumbnail_height, 
+		"size", size_restriction, 
 		"auto_rotate", rotate_image, 
 		"crop", crop_image, 
 		"linear", linear_processing, 
@@ -241,52 +248,103 @@ thumbnail_process( VipsObject *process, const char *filename )
 		NULL ) )
 		return( -1 );
 
-	if( thumbnail_write( process, in, filename ) ) {
+	if( thumbnail_write( process, image, filename ) ) {
-		g_object_unref( in ); 
+		g_object_unref( image ); 
 		return( -1 );
 	}
 
-	g_object_unref( in ); 
+	g_object_unref( image ); 
 
 	return( 0 );
 }
 
+/* Fetch a match_info string, NULL for "".
+ */
+static const char *
+fetch_match( GMatchInfo *match_info, int n )
+{
+	const char *str = g_match_info_fetch( match_info, n );
+
+	return( strcmp( str, "" ) == 0 ? NULL : str );
+}
+
 /* Parse a geometry string and set thumbnail_width and thumbnail_height.
  */
 static int
 thumbnail_parse_geometry( const char *geometry )
 {
-	GRegEx *regex;
+	GRegex *regex;
-
+	GMatchInfo *match_info;
-	regex = g_regex_new( "^(\d+)? (x)? (\d+)? ([<>])?$", 
-		G_REGEX_CASELESS | G_REGEX_EXTENDED, 0, NULL );
-	g_regex_match( regex, geometry, 0, &match_info );
-	if( 
-
-	char *p;
-
-	/* Up to 'x'
-
-
-
-	int w, h;
 	gboolean handled;
 
 	handled = FALSE;
 
-	if( sscanf( geometry, "%d x %d <", &w, &h ) == 2 ) {
+	regex = g_regex_new( "^(\\d+)? (x)? (\\d+)? ([<>])?$", 
-		thumbnail_width = w;
+		G_REGEX_CASELESS | G_REGEX_EXTENDED, 0, NULL );
-		thumbnail_height = h;
+	g_regex_match( regex, geometry, 0, &match_info );
-		crop_image = FALSE;
+	if( g_match_info_matches( match_info ) ) {
+		const char *w = fetch_match( match_info, 1 );
+		const char *x = fetch_match( match_info, 2 );
+		const char *h = fetch_match( match_info, 3 );
+		const char *s = fetch_match( match_info, 4 );
+
+		/* If --crop is set, both width and height must be specified,
+		 * since we'll need a complete bounding box to fill.
+		 */
+		if( crop_image && x && (!w || !h) ) {
+			vips_error( "thumbnail",
+				"both width and height must be given if "
+				"--crop is enabled" );
+			return( -1 );
+		}
+
+		if( !x ) { 
+			/* No "x" means we only allow a single number and it 
+			 * sets both width and height.
+			 */
+			if( w && !h ) {
+				thumbnail_width = thumbnail_height = atoi( w );
+				handled = TRUE;
+			}
+			if( !w && h ) {
+				thumbnail_width = thumbnail_height = atoi( h );
+				handled = TRUE;
+			}
+		}
+		else { 
+			/* w or h missing means replace with a huuuge value 
+			 * to prevent reduction or enlargement in that axis.
+			 */
+			thumbnail_width = VIPS_MAX_COORD;
+			thumbnail_height = VIPS_MAX_COORD;
+			if( w ) {
+				thumbnail_width = atoi( w );
+				handled = TRUE;
+			}
+			if( h ) {
+				thumbnail_height = atoi( h );
+				handled = TRUE;
+			}
+		}
+
+		if( s && strcmp( s, ">" ) == 0 )
+			size_restriction = VIPS_SIZE_DOWN;
+		if( s && strcmp( s, "<" ) == 0 )
+			size_restriction = VIPS_SIZE_UP;
 	}
 
-	if( sscanf( geometry, "%d x %d >", &w, &h ) == 2 ) {
+	g_match_info_free( match_info );
-		thumbnail_width = w;
+	g_regex_unref( regex );
-		thumbnail_height = h;
+
-		crop_image = TRUE;
+	if( !handled ) {
+		vips_error( "thumbnail",
+			"unable to parse size \"%s\" -- "
+			"use eg. 128 or 200x300>", geometry );
+
+		return( -1 );
 	}
 
-
+	return( 0 );
 }
 
 int
@@ -334,40 +392,15 @@ main( int argc, char **argv )
 
 	g_option_context_free( context );
 
-	/*
+	if( thumbnail_parse_geometry( thumbnail_size ) )
-	if( sscanf( thumbnail_size, "%d x %d", 
+		vips_error_exit( NULL ); 
-		&thumbnail_width, &thumbnail_height ) == 2 ) {
-		if( sscanf( thumbnail_size, "%d", &thumbnail_width ) != 1 ) 
-			vips_error_exit( "unable to parse size \"%s\" -- "
-				"use eg. 128 or 200x300", thumbnail_size );
 
-		thumbnail_height = thumbnail_width;
-	}
-	 */
-
-	if( sscanf( thumbnail_size, "%d x %d", 
-		&thumbnail_width, &thumbnail_height ) == 2 ) {
-		if( sscanf( thumbnail_size, "%d", &thumbnail_width ) != 1 ) 
-			vips_error_exit( "unable to parse size \"%s\" -- "
-				"use eg. 128 or 200x300", thumbnail_size );
-
-		thumbnail_height = thumbnail_width;
-	}
-
-	if( sscanf( thumbnail_size, "%d", &thumbnail_width ) != 1 ) 
-
-		thumbnail_height = thumbnail_width;
-	}
-		vips_error_exit( "unable to parse size \"%s\" -- "
-			"use eg. 128 or 200x300", thumbnail_size );
-
-	if( rotate_image ) {
 #ifndef HAVE_EXIF
+	if( rotate_image ) 
 		g_warning( "%s",
 			_( "auto-rotate disabled: "
 			      "libvips built without exif support" ) );
 #endif /*!HAVE_EXIF*/
-	}
 
 	result = 0;