Update GObject instrospection annotations for libvips/freqfilt directory

configure.ac

@@ -101,6 +101,7 @@ headers="\
 	image.h \
 	error.h \
 	foreign.h \
+	freqfilt.h \
 	interpolate.h \
 	header.h \
 	operation.h \

libvips/freqfilt/freqmult.c

@@ -141,10 +141,10 @@ vips_freqmult_init( VipsFreqmult *freqmult )
 }
 
 /**
- * vips_freqmult:
+ * vips_freqmult: (method)
  * @in: input image 
  * @mask: mask image
- * @out: output image
+ * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
  *
  * Multiply @in by @mask in Fourier space.

libvips/freqfilt/fwfft.c

@@ -345,9 +345,9 @@ vips_fwfft_init( VipsFwfft *fwfft )
 #endif /*HAVE_FFTW*/
 
 /**
- * vips_fwfft:
+ * vips_fwfft: (method)
  * @in: input image 
- * @out: output image
+ * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
  *
  * Transform an image to Fourier space.

libvips/freqfilt/invfft.c

@@ -269,9 +269,9 @@ vips_invfft_init( VipsInvfft *invfft )
 #endif /*HAVE_FFTW*/
 
 /**
- * vips_invfft:
+ * vips_invfft: (method)
  * @in: input image 
- * @out: output image
+ * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
  *
  * Optional arguments:

libvips/freqfilt/phasecor.c

@@ -125,7 +125,7 @@ vips_phasecor_init( VipsPhasecor *phasecor )
  * vips_phasecor:
  * @in1: first input image
  * @in2: second input image
- * @out: output image
+ * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
  *
  * Convert the two input images to Fourier space, calculate phase-correlation,

libvips/freqfilt/spectrum.c

@@ -109,9 +109,9 @@ vips_spectrum_init( VipsSpectrum *spectrum )
 }
 
 /**
- * vips_spectrum:
+ * vips_spectrum: (method)
  * @in: input image 
- * @out: output image
+ * @out: (out): output image
  * @...: %NULL-terminated list of optional named arguments
  *
  * Make a displayable (ie. 8-bit unsigned int) power spectrum.