Hello trid users,
some weeks ago i had to handle some ImageMagick bitmaps. Then i also look
for other Magick formats like Magick Vector Graphics ( *.mvg) described by
mvg.trid.xml. When running trid on such files some like file_move.mvg
and more test examples these are not recognized (See appended
output/trid-old.txt).
The recognition happens by global pattern via XML construct
<Bytes>7075736820677261706869632D636F6E746578740A20</Bytes>
<ASCII> p u s h g r a p h i c - c o n t e x t</ASCII>
<Pos>0</Pos>
This matches many examples like piechart.mvg where second line is intended
like:
push graphic-context
viewbox 0 0 624 369
The first sample i found that does not obey this description was
file_move.mvg. There second line was not intended and lines look like:
push graphic-context
viewbox 0 0 640 480
Then i read information mentioned by reference URL. There it is written that
MVG ignores all white-space between commands. So i modified piechart.mvg
after "push" phrase. Instead space character a tabulator character or a
carriage return character or more white spaces are used. Yes indeed all
these variants like piechart-tabSpace.mvg are valid MVG and are shown by
ImageMagick display command.
Now i run tridscan to update definition file. Now pattern becomes
<Bytes>70757368</Bytes>
<ASCII> p u s h</ASCII>
<Pos>0</Pos>
And the other relevant keywords now occur in global string section by lines:
<String>PUSH GRAPHIC-CONTEXT</String>
<String>VIEWBOX</String>
With the new trid definition all MVG examples are now described ( see
appended output/trid-new-v.txt). TrID definition, some examples and output
are stored in archive mvg.zip. I hope that my updated XML file can be used
in future version of triddefs.
With best wishes
Jörg Jenderek
# LocalWords: ImageMagick mif RefURL tridscan Pos trid TrID triddefs Jörg
# LocalWords: Jenderek sourceforge IANA Magick mvg piechart viewbox
