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diff --git a/Master/texmf-dist/tex/generic/pst-geo/data/README b/Master/texmf-dist/tex/generic/pst-geo/data/README new file mode 100644 index 00000000000..bd25910dd4e --- /dev/null +++ b/Master/texmf-dist/tex/generic/pst-geo/data/README @@ -0,0 +1,86 @@ +Project pst-geo-compress 2009-07-30 +======================== + +Author: Heiko Oberdiek <oberdiek@uni-freiburg.de> +License is LPPL 1.3c, + maintainance status: maintained + current maintainer: author + +Files: + README (this file) + pst-geo-compress.pl + pst-geo-decompress.pl + +Requirements: Ghostscript >= 8.56 (if prediction is used) + +`pst-geo' (CTAN:graphics/pstricks/contrib/pst-geo/) comes with +huge data files: + CTAN:graphics/pstricks/contrib/pst-geo/data/data.tgz + CTAN:graphics/pstricks/contrib/pst-geo/dataII/dataII.tgz +Unpacked the data files consume about 134 MB. + +The data files (files with extension `.dat') are PostScript files. +PostScript supports compression and decompression via filter. +The Perl script `pst-geo-compress.pl' compresses the data files +using the /FlateEncode filter and adds code to decompresses the file, +if read by a PostScript interpreter. Now the space requirements of +the data files is about 24 MB. + +Caveat: Filters /FlateEncode and /FlateDecode require +PostScript language level 3 (supported by ghostscript). +(LZW compression don't need language level 3, but +the compression is less effective.) + +Size reduction details: +* Much unnecessary white space is removed. +* Some comments are removed (especially number comments + in .dat files of data.tgz), the remaining comments are preserved + (especially city names). +* /FlateEncode filter. +* PNG prediction (method `up') is used for most of the files. + Spaces at line ends are added to fill the space up to + to the columns count. This improves the prediction, + because these files contains long lists of sorted coordinate pairs. + The prediction columns count is also the maximal line length, + because of a ghostscript bug: + +Ghostscript has a bug regarding prediction, it is fixed in +version 8.56 (2007-03-14): + +| 2006-12-11T17:30:53.980862Z L. Peter Deutsch +| +| Fixes bug: the PNG predictor filters produced incorrect data for the last +| pixel of each row. (The encoder and decoder had matching bugs, so +| encode+decode produced the correct result!) Fixes a diff in PS3 CET +| 23-12U-1. + +By having each line at the same length, the last byte of a row +has always the same value (end of line character). This does +not trigger this bug (tested with gs 7.07/8.64). + +After compression the files aren't human-readable any more. +The Perl script `pst-geo-decompress.pl' can be used to +decompress a data file. + +Both scripts know option -h that prints a short usage screen. +Option --gscmd allows to configure the ghostscript programm call, +if the automatic ghostscript isn't sufficient. + +`pst-geo-compress.pl' is called inside the directory where +the data files are present. Options `-1' and `-2' choose +between the files from `data.tgz' and `dataII.tgz'. + +`pst-geo-decompress.pl' expects the data file to decompress. +If an output file is given, the result is stored there. Otherwise +standard output is used. + +History: + 2009-07-30 v1.0 First release + 2009-07-30 v1.1: + * Workaround for ghostscript bug added: + * Files that are compressed with prediction have + equal line length. + * Removing comments (except for city data files) + * Obsolete option --prediction is therefore removed + * Adding standalone test mode (option `--test'). + |