printout is not precise

[canesinang]

printout somehow smaller.
it also happened when i try to open the .svg file in the corel draw. even a simple line i created with inkscape, would come smaller than measured state in the inkscape.
is there any chance to fix this? because i can use the printout to make architectural scaled model.
thank you very much....

[Pablo Trabajos (pajarico)]

Please add inkscape version and Operating System. I advice you to attach the problematic file, also.

[canesinang (canesinang)]

hallo, thank you for the respond..i use inkscape ver 0.46, i just downloaded it like 2 months ago...the os is windows xp sp2...and the attachmet: drawing.svg is the original file i created with inkscape 0.46. and the other one, drawing.cdr is file the i created by opent direcly the .svg file in the corel draw ver 12 than saved in corel draw format..as you will see that the line weight and the thickness is shrinked like 0.5% or something...
thank you very much, for inkscape is a wonderful thing...
sinang aribowoindonesia

--- On Wed, 5/8/09, Pablo Trabajos <email address hidden> wrote:

From: Pablo Trabajos <email address hidden>
Subject: [Bug 409122] Re: printout is not precise
To: <email address hidden>
Date: Wednesday, 5 August, 2009, 7:36 AM

Please add inkscape version and Operating System. I advice you to attach
the problematic file, also.

--
printout is not precise
https://bugs.launchpad.net/bugs/409122
You received this bug notification because you are a direct subscriber
of the bug.

Status in Inkscape: A Vector Drawing Tool: New

Bug description:
printout somehow smaller.
it also happened when i try to open the .svg file in the corel draw. even a simple line i created with inkscape, would come smaller than measured state in the inkscape.
is there any chance to fix this? because i can use the printout to make architectural scaled model.
thank you very much....

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[su_v (suv-lp)]

The CDR input extension is based on UniConverter. In bug #387946 "UniConvertor called with wrong filename" comments 3-7 describe a scale bug in UniConverter for *.plt and *.hpgl, which is fixed upstream in UniConverter 1.1.5. Could this bug here also be due to the same issue in UniConverter?

Can someone who has UniConverter trunk installed confirm this is fixed upstream?

[su_v (suv-lp)]

Another reason for the scale difference might be a different implementation of 'SVG pixels' or 'SVG user units' in Inkscape and Corel Draw. I have read about it before, but can't find it at the moment - just an older posting to inkscape-devel by bulia where he writes:

"
> The bad news is that I can't figure out the "right way" to get inkscape
> units into inches. I found some constants in src/unit-constant.h which
> tell me that 90 units / inch is set at compile-time, but it seems like
> the svg file should contain something which makes that explicit.

There are no "inkscape units". They are SVG user units, aka px, aka
unnamed unit.

In Inkscape, 1px = 0.8pt. This is fixed and cannot be changed from
SVG. Viewbox does not affect that.

The only problem is that other SVG renderers can and do use other
fixed values for this (e.g. in Batik it's 0.75 I think). It's a badly
defined part of SVG standard. However, it's not a good SVG practice to
mix abs units ans px, so this discrepancy rarely bites you. Most real
world files just use only px; Inkscape files can only contain abs
units in width/height attrs on <svg>. So I think you can use our value
of 0.8 at least for now without too many problems."

<http://article.gmane.org/gmane.comp.graphics.inkscape.devel/14026/>

[su_v (suv-lp)]

See also these bug reports related to svg units:

Bug #348611 “Measure Path off by a small amount”
Bug #168753 “SVG defaults to pixels (90dpi) despite default units”

[canesinang (canesinang)]

hmmm.....
actually my problem is the printout, i don't really care about the .cdr file since i've decided to start use inkscape...:)
right now i use inkscape intensively. and the only problem just in the printout. the printout would not printed the exact measure.
later i found that the same problem would happened when the .svg file directly open in coreldraw.
i don't know if there's any connection between that.
but what i need is if the printout is perfectly in exact measure as i designed in inkscape so i can cut along the path to make a perfectly scaled model.
and i think if the problem with printout can be solved it will make inkscape way more superior than coreldraw.

[su_v (suv-lp)]

Keep in mind that Inkscape is a SVG editor, not a CAD program. In SVG world, there are no 'real units' AFAIU. The comments in bug #168753 mention a workaround using the 'viewBox' attribute.

There's a Blueprint: “Implement real world units using Viewbox and Transform” <https://blueprints.launchpad.net/inkscape/+spec/real-units>, which leads to the spec <http://wiki.inkscape.org/wiki/index.php/BlueprintRealUnit>, and a 'inkscape-devel' mailing list thread <http://thread.gmane.org/gmane.comp.graphics.inkscape.devel/24275/>.

I think the scale difference between Inkscape, Corel Draw and printout could related (if UniConverter is not involved as intermediary tool) - the content of the svg document is 'unit-less' and each output is generated based on a 'device specific' (monitor, screen) dpi or ppi value. Inkscape converts pixel to units based on internal 90 dpi (hardwired), Corel Draw otoh might assume 72 or 96 dpi, I don't know.

In my limited experience printing from within Inkscape (0.46+devel) keeps the scaling to the mm. You might try if you get better results with a recent prerelease build from <http://sourceforge.net/projects/inkscape/files/>.

[su_v (suv-lp)]

Another workaround you might try: export to PDF and print the PDF - any difference in printout matching the drawing scale?

JFTR - the numbers from the attached documents (CDR converted to SVG on the command line with UniConverter from SVN) opened with Inkscape r21973 on OS X 10.5.8, measured with Extension 'measure.py':

  drawing.svg: 176.46 px length, path with 2 nodes, stroke width 0.709 px
  drawing.cdr: 132.36 px length, path with 4 nodes, stroke width 0.664 px

the CDR path is 0.75 of the length of the Inkscape SVG path, the vertical scale difference is far less: 0.94.

[Nathan Lee (nathan.lee)]

Closing as part of the bug migration to Gitlab, remaining issue for 1.1 and later is now tracked in https://gitlab.com/inkscape/inkscape/-/issues/2983

Please feel free to file new bugs about the issues you're seeing at
http://inkscape.org/report.