Address review feedback on VRegion (#2684) (#2696)

* Add VRegion8.h to Makefile.am, meson.build, Doxyfile.in.

* Fix inaccurate function documentation.

* Add stride method to VRegion.

cplusplus/Doxyfile.in

@@ -835,6 +835,7 @@ INPUT                  = \
 	@DOXY_INPUT_DIRECTORY@/include/vips/VError8.h \
 	@DOXY_INPUT_DIRECTORY@/include/vips/VImage8.h \
 	@DOXY_INPUT_DIRECTORY@/include/vips/VInterpolate8.h \
+	@DOXY_INPUT_DIRECTORY@/include/vips/VRegion8.h \
 	@DOXY_INPUT_DIRECTORY@/include/vips/vips8
 
 # This tag can be used to specify the character encoding of the source files

cplusplus/include/vips/Makefile.am

@@ -2,6 +2,7 @@ pkginclude_HEADERS = \
 	VError8.h \
 	VImage8.h \
 	VInterpolate8.h \
+	VRegion8.h \
 	VConnection8.h \
 	vips8 
 

cplusplus/include/vips/VImage8.h

@@ -1057,7 +1057,7 @@ public:
 	}
 
 	/**
-	 * Acquire VRegion covering the whole image.
+	 * Acquire an unprepared VRegion.
 	 */
 	VRegion
 	region() const;

cplusplus/include/vips/VRegion8.h

@@ -122,6 +122,15 @@ public:
 		return VIPS_REGION_ADDR( get_region(), x, y );
 	}
 
+	/**
+	 * Get the stride (bytes per row, including padding) of the region.
+	 */
+	size_t
+	stride() const
+	{
+		return VIPS_REGION_LSKIP( get_region() );
+	}
+
 	/**
 	 * Get VipsPel at the given index of the region.
 	 */

cplusplus/include/vips/meson.build

@@ -2,6 +2,7 @@ public_cpp_headers = files(
     'VError8.h',
     'VImage8.h',
     'VInterpolate8.h',
+    'VRegion8.h',
     'VConnection8.h',
     'vips8',
 )