91 lines
2.8 KiB
Groff
91 lines
2.8 KiB
Groff
.TH CONVERSIONS 3 "15 April 1991"
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.SH NAME
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im_c2amph, im_c2imag, im_c2ps, im_c2real, im_clip2fmt,
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im_ri2c \- conversion between image types
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.SH SYNOPSIS
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#include <vips/vips.h>
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int im_c2amph(in, out)
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.br
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IMAGE *in, *out;
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int im_c2rect(in, out)
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.br
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IMAGE *in, *out;
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int im_c2imag(in, out)
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.br
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IMAGE *in, *out;
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int im_c2ps(in, out)
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.br
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IMAGE *in, *out;
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int im_c2real(in, out)
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.br
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IMAGE *in, *out;
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int im_clip2fmt(in, out, ofmt)
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.br
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IMAGE *in, *out;
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.br
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int ofmt;
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int im_ri2c(in1, in2, out)
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.br
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IMAGE *in1, *in2, *out;
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.SH DESCRIPTION
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Each of the above functions converts the image held by the image descriptor in
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to another type image and writes the result on the image descriptor out.
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Sizes and the number of channels are identical to those of input. Whenever
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required by the conversion, the element values are rounded by calling floor().
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.B im_c2amph()
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converts a complex (float or double) input to (amplitude, phase), with phase
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in degrees. Output has the same format as input.
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.B im_c2rect()
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converts a complex (float or double) input in (amplitude, phase) form back to
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rectangular coordinates. Again, phase should be expressed in degrees.
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.B im_c2ps()
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convert a (float or double) complex image to amplitude (float or
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double) image. Complex input (a,b) is mapped to sqrt( a*a+b*b ).
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.B im_clip2fmt()
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converts the input image to 'ofmt', where ofmt is the new value for
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BandFmt. For example, im_clip2fmt(in, out, FMTUSHORT) converts any image to
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unsigned short.
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The number of
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clipped values (if any), are printed in the standard error output. Before
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clipping rounding is carried out if necessary. When converting between real
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and complex types with these functions, the imaginary part of the output is
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set to zero. When converting from complex to real types, the imaginary part is
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ignored. Use im_c2ps(), im_c2real() etc. to get other behaviour.
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Legacy functions are available, called im_clip(), im_clip2c(), im_clip2d(),
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im_clip2f(), im_clip2i(), im_clip2s(), im_clip2ui(), im_clip2us(),
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im_clip2cm() and im_clip2dcm() which convert the input image to unsigned char,
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signed char, double, float, int, short, unsigned int, unsigned short,
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complex and double complex respectively.
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.B im_ri2c()
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takes as inputs two non-complex images of equal sizes and number of
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channels. The output is a complex image with the real part coming from in1
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and the imaginary part coming from in2. Output is float complex (FMTCOMPLEX)
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only if none of the inputs is double. If one or both inputs are double the
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result is double complex (FMTDPCOMPLEX).
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.B im_c2real()
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and
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.B im_c2imag()
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extract the real or the imaginary part of a
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complex image respectively. If input is be float complex or double complex,
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then output is float or double respectively.
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.SH RETURN VALUE
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The functions returns 0 on success and -1 on error.
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.SH SEE ALSO
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im_scale(3).
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