man/man1/rcrop.1

.\" RCSid "$Id: rcrop.1,v 1.5 2022/03/17 17:08:27 greg Exp $"
.TH RCROP 1 3/14/2022 RADIANCE
.SH NAME
rcrop - crop RADIANCE matrix or picture
.SH SYNOPSIS
.B "rcrop row0 col0 nrows ncols"
[
.B input
[
.B output
]
]
.SH DESCRIPTION
.I Rcrop
copies the indicated section of a matrix or RADIANCE picture.
The four required arguments are the initial row (scanline) to copy,
the initial column, the number of rows to copy, and the number of columns
to include per row.
Note that rows are numbered from 0 at the top of a matrix or picture,
and columns are changing fastest in the input, which can have any number
of components per matrix element.
.PP
The input must have a valid header, including dimensions and format,
and a header will always be produced.
This is similar behavior to
.I rmtxop(1).
If the input header is missing, one can usually be added with an
appropriate call to
.I rcollate(1).
If an output header is not desired, it can be removed using
.I getinfo(1).
.PP
One cannot specify crop boundaries outside the matrix dimension limits.
If a 0 value is specified for the number of rows to copy, then all rows
will be copied, starting from row0.
Similarly, a 0 value for the number of columns to copy implies all
columns >= col0 will be copied.
.PP
Using
.I rcrop
on a RADIANCE picture rather than
.I pcompos(1)
corrects the view parameters if present,
and preserves the exposure in a way that is compatible with
.I evalglare(1).
However, one must remember that rows correspond to Y
coordinates, and the orientation is reversed from a standard
picture, where Y=0 is the bottom scanline.
Spectral pictures, as might be produced by
.I rtrace(1)
or
.I rfluxmtx(1),
are also supported.
.PP
All matrix formats are supported, including text (ASCII), binary float
and double.
The
.I rcrop
tool also works on encoded normal vector files produced by
.I rcode_norm(1)
and encoded depth files produced by
.I rcode_depth(1).
Data is copied verbatim, i.e., there is no internal conversion to
another representation, although white space may change in text files.
.PP
If no input file is given, data will be taken from the standard input.
If no output file is specified, data will be copied to the standard output.
.SH EXAMPLES
To crop a matrix down to 15 rows by 19 columns,
starting at row 10 and column 12:
.IP "" .2i
rcrop 10 12 15 19 input.mtx > output.mtx
.PP
To extract column 35 from a matrix:
.IP "" .2i
rcrop 0 35 0 1 orig.mtx > col35.mtx
.PP
To crop a picture to (X by Y) = (1500 by 1000),
starting from upper-left corner:
.IP "" .2i
rcrop 0 0 1000 1500 orig.hdr cropped.hdr
.PP
Two ways of computing the inner product of row 15 in matrix 1 by
column 27 in matrix 2 and extracting the result without a header,
the second command being more efficient:
.IP "" .2i
rmtxop -fa mat1.mtx mat2.mtx | rcrop 15 27 1 1 | getinfo -
.IP "" .2i
rmtxop -fa '!rcrop 15 0 1 0 mat1.mtx' '!rcrop 0 27 0 1 mat2.mtx' | getinfo -
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
evalglare(1), pcompos(1), rcalc(1), rcode_depth(1), rcode_norm(1),
rcollate(1), rfluxmtx(1), rmtxop(1), rsplit(1), rtrace(1)
Revision:	1.6
Committed:	Tue Nov 21 02:16:59 2023 UTC (17 months, 3 weeks ago) by greg
Branch:	MAIN
Changes since 1.5:	+8 -3 lines
Log Message:	docs: Added mention of Radiance spectral picture support
#	User	Rev	Content
1	greg	1.6	.\" RCSid "$Id: rcrop.1,v 1.5 2022/03/17 17:08:27 greg Exp $"
2	greg	1.1	.TH RCROP 1 3/14/2022 RADIANCE
3			.SH NAME
4			rcrop - crop RADIANCE matrix or picture
5			.SH SYNOPSIS
6			.B "rcrop row0 col0 nrows ncols"
7			[
8			.B input
9			[
10			.B output
11			]
12			]
13			.SH DESCRIPTION
14			.I Rcrop
15			copies the indicated section of a matrix or RADIANCE picture.
16			The four required arguments are the initial row (scanline) to copy,
17			the initial column, the number of rows to copy, and the number of columns
18			to include per row.
19			Note that rows are numbered from 0 at the top of a matrix or picture,
20			and columns are changing fastest in the input, which can have any number
21			of components per matrix element.
22			.PP
23	greg	1.3	The input must have a valid header, including dimensions and format,
24			and a header will always be produced.
25			This is similar behavior to
26			.I rmtxop(1).
27			If the input header is missing, one can usually be added with an
28			appropriate call to
29			.I rcollate(1).
30			If an output header is not desired, it can be removed using
31			.I getinfo(1).
32			.PP
33	greg	1.1	One cannot specify crop boundaries outside the matrix dimension limits.
34			If a 0 value is specified for the number of rows to copy, then all rows
35			will be copied, starting from row0.
36			Similarly, a 0 value for the number of columns to copy implies all
37			columns >= col0 will be copied.
38			.PP
39			Using
40			.I rcrop
41			on a RADIANCE picture rather than
42			.I pcompos(1)
43			corrects the view parameters if present,
44			and preserves the exposure in a way that is compatible with
45			.I evalglare(1).
46			However, one must remember that rows correspond to Y
47			coordinates, and the orientation is reversed from a standard
48			picture, where Y=0 is the bottom scanline.
49	greg	1.6	Spectral pictures, as might be produced by
50			.I rtrace(1)
51			or
52			.I rfluxmtx(1),
53			are also supported.
54	greg	1.1	.PP
55	greg	1.5	All matrix formats are supported, including text (ASCII), binary float
56			and double.
57	greg	1.2	The
58			.I rcrop
59			tool also works on encoded normal vector files produced by
60			.I rcode_norm(1)
61			and encoded depth files produced by
62			.I rcode_depth(1).
63	greg	1.5	Data is copied verbatim, i.e., there is no internal conversion to
64			another representation, although white space may change in text files.
65	greg	1.2	.PP
66	greg	1.1	If no input file is given, data will be taken from the standard input.
67			If no output file is specified, data will be copied to the standard output.
68			.SH EXAMPLES
69			To crop a matrix down to 15 rows by 19 columns,
70			starting at row 10 and column 12:
71			.IP "" .2i
72			rcrop 10 12 15 19 input.mtx > output.mtx
73			.PP
74			To extract column 35 from a matrix:
75			.IP "" .2i
76			rcrop 0 35 0 1 orig.mtx > col35.mtx
77			.PP
78			To crop a picture to (X by Y) = (1500 by 1000),
79			starting from upper-left corner:
80			.IP "" .2i
81			rcrop 0 0 1000 1500 orig.hdr cropped.hdr
82	greg	1.3	.PP
83			Two ways of computing the inner product of row 15 in matrix 1 by
84			column 27 in matrix 2 and extracting the result without a header,
85			the second command being more efficient:
86			.IP "" .2i
87			rmtxop -fa mat1.mtx mat2.mtx \| rcrop 15 27 1 1 \| getinfo -
88			.IP "" .2i
89			rmtxop -fa '!rcrop 15 0 1 0 mat1.mtx' '!rcrop 0 27 0 1 mat2.mtx' \| getinfo -
90	greg	1.1	.SH AUTHOR
91			Greg Ward
92			.SH "SEE ALSO"
93	greg	1.6	evalglare(1), pcompos(1), rcalc(1), rcode_depth(1), rcode_norm(1),
94			rcollate(1), rfluxmtx(1), rmtxop(1), rsplit(1), rtrace(1)