.TH "pngpack.c" 3 "Fri Jun 3 2022" "Version 1.6.4" "NCEPLIBS-g2c" \" -*- nroff -*-
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.SH NAME
pngpack.c
.SH SYNOPSIS
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.PP
\fC#include <stdlib\&.h>\fP
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\fC#include <math\&.h>\fP
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\fC#include 'grib2\&.h'\fP
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.SS "Functions"

.in +1c
.ti -1c
.RI "int \fBenc_png\fP (char *, \fBg2int\fP, \fBg2int\fP, \fBg2int\fP, char *)"
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.RI "Encode PNG\&. "
.ti -1c
.RI "void \fBpngpack\fP (\fBg2float\fP *fld, \fBg2int\fP width, \fBg2int\fP height, \fBg2int\fP *idrstmpl, unsigned char *cpack, \fBg2int\fP *lcpack)"
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.RI "This subroutine packs up a data field into PNG image format\&. "
.in -1c
.SH "Detailed Description"
.PP 

.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2003-08-27 
.RE
.PP

.PP
Definition in file \fBpngpack\&.c\fP\&.
.SH "Function Documentation"
.PP 
.SS "int enc_png (char * data, \fBg2int\fP width, \fBg2int\fP height, \fBg2int\fP nbits, char * pngbuf)"

.PP
Encode PNG\&. 
.PP
\fBParameters\fP
.RS 4
\fIdata\fP data\&. 
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\fIwidth\fP width\&. 
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\fIheight\fP height\&. 
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\fInbits\fP number of bits\&. 
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\fIpngbuf\fP PNG buffer\&.
.RE
.PP
\fBReturns\fP
.RS 4
PNG length, or negative number for error\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP

.PP
Definition at line 81 of file enc_png\&.c\&.
.PP
References user_flush_data(), and user_write_data()\&.
.PP
Referenced by pngpack()\&.
.SS "void pngpack (\fBg2float\fP * fld, \fBg2int\fP width, \fBg2int\fP height, \fBg2int\fP * idrstmpl, unsigned char * cpack, \fBg2int\fP * lcpack)"

.PP
This subroutine packs up a data field into PNG image format\&. After the data field is scaled, and the reference value is subtracted out, it is treated as a grayscale image and passed to a PNG encoder\&. It also fills in GRIB2 Data Representation Template 5\&.41 or 5\&.40010 with the appropriate values\&.
.PP
\fBParameters\fP
.RS 4
\fIfld\fP Contains the data values to pack\&. 
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\fIwidth\fP number of points in the x direction\&. 
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\fIheight\fP number of points in the y direction\&. 
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\fIidrstmpl\fP Contains the array of values for Data Representation Template 5\&.41 or 5\&.40010\&.
.IP "\(bu" 2
0 Reference value - ignored on input, set by pngpack routine\&.
.IP "\(bu" 2
1 Binary Scale Factor - used on input\&.
.IP "\(bu" 2
2 Decimal Scale Factor - used on input\&.
.IP "\(bu" 2
3 number of bits for each grayscale pixel value - ignored on input\&.
.IP "\(bu" 2
4 Original field type - currently ignored on input, set = 0 on output\&. Data values assumed to be reals\&. 
.PP
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\fIcpack\fP The packed data field\&. 
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\fIlcpack\fP length of packed field cpack\&.
.RE
.PP
\fBAuthor\fP
.RS 4
Stephen Gilbert 
.RE
.PP
\fBDate\fP
.RS 4
2003-08-27 
.RE
.PP

.PP
Definition at line 34 of file pngpack\&.c\&.
.PP
References enc_png(), int_power(), mkieee(), and sbits()\&.
.PP
Referenced by g2_addfield()\&.
.SH "Author"
.PP 
Generated automatically by Doxygen for NCEPLIBS-g2c from the source code\&.