add changelog notes

and linewrap for 80 column limit

ChangeLog

@@ -19,6 +19,10 @@
 - deprecate "properties" option to dzsave (now always on)
 - always set the min stack size for pthreads, if we can
 - add fail-on to thumbnail
+- add "gap" option to vips_reduce[hv]() and vips_resize() [kleisauke]
+- add "ceil" option to vips_shrink() [kleisauke]
+- quality improvements for image resizing [kleisauke]
+
 
 26/11/21 started 8.12.3
 - better arg checking for hist_find_ndim [travisbell]

libvips/resample/reduce.c

@@ -138,7 +138,7 @@
 typedef struct _VipsReduce {
 	VipsResample parent_instance;
 
-	double hshrink;		/* Shrink factors */
+	double hshrink;			/* Shrink factors */
 	double vshrink;
 	double gap;			/* Reduce gap */
 

libvips/resample/reduceh.cpp

@@ -65,7 +65,7 @@
 typedef struct _VipsReduceh {
 	VipsResample parent_instance;
 
-	double hshrink;		/* Reduce factor */
+	double hshrink;			/* Reduce factor */
 	double gap;			/* Reduce gap */
 
 	/* The thing we use to make the kernel.
@@ -477,8 +477,8 @@ vips_reduceh_build( VipsObject *object )
 
 		/* The int part of our reduce.
 		 */
-		int_hshrink = VIPS_MAX( 1,
+		int_hshrink = VIPS_MAX( 1, VIPS_FLOOR( 
-			VIPS_FLOOR( (double) in->Xsize / width / reduceh->gap ) );
+			(double) in->Xsize / width / reduceh->gap ) );
 
 		if( int_hshrink > 1 ) {
 			g_info( "shrinkh by %d", int_hshrink );

libvips/resample/reducev.cpp

@@ -105,7 +105,7 @@ typedef struct _VipsReducev {
 	VipsResample parent_instance;
 
 	double vshrink;		/* Reduce factor */
-	double gap;			/* Reduce gap */
+	double gap;		/* Reduce gap */
 
 	/* The thing we use to make the kernel.
 	 */
@@ -846,8 +846,8 @@ vips_reducev_build( VipsObject *object )
 
 		/* The int part of our reduce.
 		 */
-		int_vshrink = VIPS_MAX( 1,
+		int_vshrink = VIPS_MAX( 1, VIPS_FLOOR( 
-			VIPS_FLOOR( (double) in->Ysize / height / reducev->gap ) );
+			(double) in->Ysize / height / reducev->gap ) );
 
 		if( int_vshrink > 1 ) {
 			g_info( "shrinkv by %d", int_vshrink );

libvips/resample/resize.c

@@ -178,10 +178,12 @@ vips_resize_build( VipsObject *object )
 			target_width = VIPS_ROUND_UINT( in->Xsize * hscale );
 			target_height = VIPS_ROUND_UINT( in->Ysize * vscale );
 
-			int_hshrink = 
+			int_hshrink = VIPS_FLOOR( 
-				VIPS_FLOOR( (double) in->Xsize / target_width / resize->gap );
+				(double) in->Xsize / target_width / 
-			int_vshrink = 
+					resize->gap );
-				VIPS_FLOOR( (double) in->Ysize / target_height / resize->gap );
+			int_vshrink = VIPS_FLOOR( 
+				(double) in->Ysize / target_height / 
+					resize->gap );
 		}
 
 		int_hshrink = VIPS_MAX( 1, int_hshrink );

libvips/resample/shrink.c

@@ -65,7 +65,7 @@ typedef struct _VipsShrink {
 
 	double hshrink;		/* Shrink factors */
 	double vshrink;
-	gboolean ceil;			/* Round operation */
+	gboolean ceil;		/* Round operation */
 
 } VipsShrink;
 
@@ -95,21 +95,21 @@ vips_shrink_build( VipsObject *object )
 		/* Shrink by int factors, reduce to final size.
 		 */
 		if( vips_reducev( resample->in, &t[0], shrink->vshrink,
-			"gap", 1.0,
+				"gap", 1.0,
-			NULL ) ||
+				NULL ) ||
 			vips_reduceh( t[0], &t[1], shrink->hshrink,
-			"gap", 1.0,
+				"gap", 1.0,
-			NULL ) ||
+				NULL ) ||
 			vips_image_write( t[1], resample->out ) )
 			return( -1 );
 	}
 	else {
 		if( vips_shrinkv( resample->in, &t[0], shrink->vshrink,
-			"ceil", shrink->ceil, 
+				"ceil", shrink->ceil, 
-			NULL ) ||
+				NULL ) ||
 			vips_shrinkh( t[0], &t[1], shrink->hshrink,
-			"ceil", shrink->ceil, 
+				"ceil", shrink->ceil, 
-			NULL ) ||
+				NULL ) ||
 			vips_image_write( t[1], resample->out ) )
 			return( -1 );
 	}

libvips/resample/shrinkh.c

@@ -278,7 +278,8 @@ vips_shrinkh_build( VipsObject *object )
 	 */
 	resample->out->Xsize = shrink->ceil ?
 		VIPS_CEIL( (double) resample->in->Xsize / shrink->hshrink ) :
-		VIPS_ROUND_UINT( (double) resample->in->Xsize / shrink->hshrink );
+		VIPS_ROUND_UINT( 
+			(double) resample->in->Xsize / shrink->hshrink );
 	if( resample->out->Xsize <= 0 ) { 
 		vips_error( class->nickname, 
 			"%s", _( "image has shrunk to nothing" ) );

libvips/resample/shrinkv.c

@@ -383,7 +383,8 @@ vips_shrinkv_build( VipsObject *object )
 	 */
 	t[2]->Ysize = shrink->ceil ?
 		VIPS_CEIL( (double) resample->in->Ysize / shrink->vshrink ) :
-		VIPS_ROUND_UINT( (double) resample->in->Ysize / shrink->vshrink );
+		VIPS_ROUND_UINT( 
+			(double) resample->in->Ysize / shrink->vshrink );
 	if( t[2]->Ysize <= 0 ) {
 		vips_error( class->nickname, 
 			"%s", _( "image has shrunk to nothing" ) );