NCEPLIBS-g2  3.4.8
pngpack.F90 File Reference

This subroutine packs up a data field into PNG image format. More...

Go to the source code of this file.

Functions/Subroutines

subroutine pngpack (fld, width, height, idrstmpl, cpack, lcpack)
 This subroutine packs up a data field into PNG image format. More...
 

Detailed Description

This subroutine packs up a data field into PNG image format.

Author
Stephen Gilbert
Date
2002-12-21

Definition in file pngpack.F90.

Function/Subroutine Documentation

◆ pngpack()

subroutine pngpack ( real, dimension(width * height), intent(in)  fld,
integer, intent(in)  width,
integer, intent(in)  height,
integer, dimension(*), intent(inout)  idrstmpl,
character(len = 1), dimension(*), intent(out)  cpack,
integer, intent(out)  lcpack 
)

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.

Parameters
[in]fldContains the data values to pack.
[in]widthnumber of points in the x direction.
[in]heightnumber of points in the y direction.
[in,out]idrstmplContains the array of values for Data Representation Template 5.2 or 5.3.
  • idrstmpl(1) Reference value - ignored on input.
  • idrstmpl(2) Binary Scale Factor.
  • idrstmpl(3) Decimal Scale Factor.
  • idrstmpl(4) Number of bits containing each grayscale pixel value.
  • idrstmpl(5) Original field type, currently set = 0 on output Data values assumed to be reals.
  • idrstmpl(6) = 0 use lossless compression; = 1 use lossy compression.
  • idrstmpl(7) Desired compression ratio, if idrstmpl(6)=1.
[out]cpackThe packed data field (character*1 array)
[out]lcpackThe length of packed field cpack.
Author
Stephen Gilbert
Date
2002-12-21

Definition at line 28 of file pngpack.F90.

References enc_png(), g2_sbytesc(), and mkieee().

Referenced by addfield().