[PATCH sk1libs] import/dxf: Use style's primaty font name in TEXT

[Kirill Smelkov]

In my DXF I have lots of TEXT entries which reference ST style as
attribute 7. And ST style itself looks like this:

          0
        STYLE
          5
        FF
        330
        3
        100
        AcDbSymbolTableRecord
        100
        AcDbTextStyleTableRecord
          2
        ST
         70
             0
         40
        0.0
         41
        1.0
         50
        15.0
         71
             0
         42
        3.0
          3
        geniso.shx
          4

So when load_text() tries to extract font_name from style['1000'] there
is nothing, and oops, I get lot's of crashes on TEXT nodes, e.g. like
this:

    DXFLoader: error
    Traceback (most recent call last):
      File "/home/kirr/src/tools/gfx/sk1/sk1/sk1libs/src/sk1libs/filters/import/dxfloader.py", line 1416, in run
        return_code = method()
      File "/home/kirr/src/tools/gfx/sk1/sk1/sk1libs/src/sk1libs/filters/import/dxfloader.py", line 1119, in load_text
        style_text.font = GetFont(font_name)
      File "/home/kirr/src/tools/gfx/sk1/sk1/sk1libs/src/sk1libs/ft2engine/__init__.py", line 148, in GetFont
        if fontname.count(family):
    AttributeError: 'NoneType' object has no attribute 'count'

According to DXF specification (I've checked R14 and 2011) "Primary font
file name" for a STYLE is attribute 3, so I think we should always try
to get font_name from there.

I don't know where attribute 1000 comes from (can't find a reference to it in
dxf spec), but if it is needed, let's leave a check for style['1000'] first so
that old behaviour is preserved, and we only use style['3'] when style['1000']
fails.

Doing so, resolves crashes and also makes text appear in destination SVG!
(tested with unioconvertor)

Please apply and thanks,
Kirill

[max (maxim-s-barabash)]

This is not enough.
shx fonts are not supported anyway, the need to create an alias for ttf fonts.

For ttf font style['1000 '] contains information about the font family name.
In style['3'] contains the name of the font file.
To correct the error must be improved ft2engine.

Thanks.

[Kirill Smelkov (kirr)]

Max, thanks for your reply.

Am I right understanding you that we should put shx -> ttf font-name translation table into dxfloader.py? Or maybe even into ft2engine?

If such translation table is ok for dxfloader.py, I could try do it, but if it's deeper - sorry, I can't afford myself to dive in.

Thanks,
Kirill

P.S.

Just for the record: as already said, I have no style['1000'] entry in my DXF, and more, even when attribute 3 references geniso.shx, which is for sure absent on my system, in target SVG I get russian text more or less correctly rendered (as it turned out with fallback uniconvertor font BitstreamVeraSans-Roman).

That's why there is maybe a third option: just use shx font-name as-is, and issue an user-visible warning, that such-and-such dxf font was used without converting to TrueType.

Of course, it's a hack, but maybe if proper solution will be somehow delayed, it's better to have text with default font than not to have any text at all.