[inx] min/max float values ignored with locale using comma as decimal separator

[su_v]

Follow-up to Bug #442642 “Inkscape crashes on Effects: render: grid without default”

Reported on #inkscape irc channel:
Miraceti wrote:
> I have noticed a bug in 0.47 and 0.48. When running
> Extension->Render->Grid, it is possible to enter horizontal
> and/or vertical spaces = 0 which causes 100% CPU usage in
> apparently neverending loop.

> Well, experiencing problems with small values could be unpleasant
> but zero should not definitely be tried to render at all.

> Division by zero is much worse than just consuming a lot of memory.

> I guess, zero should be filtered out already on UI level.

The lower limit to '0.1' doesn't seem to be in effect with certain locale setting (LC_NUMERIC): a comma as decimal separator apparently allows to enter '0,0' into the dialog:

Reported on irc by Miraceti with
Linux jiri1 2.6.35-gentoo-r4 #1 Sat Sep 4 13:26:57 EEST 2010 i686 AMD Athlon(tm) XP 1800+ AuthenticAMD GNU/Linux
LC_NUMERIC=cs_CZ.UTF-8
gentoo package media-gfx/inkscape-0.48.0 (marked unstable in Gentoo now)

Also confirmed by sanguivor (on irc) for the bzr version:
Locale is a mixture of en_DK.UTF-8 and fi_FI.UTF-8.

Reproduced with Inkscape 0.48+devel r9785 on OS X 10.5.8: If I change the language ($LANG) for the Inkscape process so that comma is used as decimal separator, the lower limit for x/y spacing (0.1) no longer applies.

[su_v (suv-lp)]

The min/max values are defined in the extension definition file:
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/annotate/head%3A/src/extension/internal/grid.cpp#L194>

            "<param name=\"xspacing\" gui-text=\"" N_("Horizontal Spacing:") "\" type=\"float\" min=\"0.1\" max=\"1000\">10.0</param>\n"
            "<param name=\"yspacing\" gui-text=\"" N_("Vertical Spacing:") "\" type=\"float\" min=\"0.1\" max=\"1000\">10.0</param>\n"

Ignoring the min/max float values depending on decimal separator is possibly a similar issue as reported in bug #571196.

[Alvin Penner (apenner)]

confirmed in Windows XP using Render->Grid
If I use Control Panel->Regional Options->Customize and set the decimal symbol to be 'comma', then the Render Grid spinbox allows me to choose a spacing of 0,0. If I type manually the value 0, then this gets converted to 0,0 on loss of focus, instead of the expected value of 0,1

[jazzynico (jazzynico)]

Since I can lead to crashes, setting Importance to High.

[jazzynico (jazzynico)]

Patch attached, please test.

[Craig Marshall (craig9-deactivatedaccount)]

This patch works for me using win7 and rev9788

[su_v (suv-lp)]

Fix confirmed with Inkscape 0.48+devel r9788 + InxFloatMinMax.diff on OS X 10.5.8
(tested with 'export LANG="de_DE.UTF-8"' in the shell script launching inkscape-bin)

[jazzynico (jazzynico)]

Fix committed in the trunk (revision 9791) and 0.48.x branch (revision 9674).