Discussion:
[Inkscape-user] Problem with Image Sizing in Inkscape 0.92
Mick Ralph
2017-05-12 20:46:11 UTC
Permalink
As the background to my problem, I use Inkscape to prepare drawings
of sides and ends, etc, to be made into model railway carriages. The
designs are then opened in the Designer Edition (DE) of Silhouette
Studio for cutting out of styrene sheet on the Silhouette Portrait
cutting machine. DE can open SVG files, as created with Inkscape.

For Inkscape 0.48 and 0.91, this works fine and the parts are cut to
the same size as the Inkscape drawing, although it is necessary to
ensure that the document properties are set to "default units" of mm
and "custom size" "units" of px; if custom size units are left as mm,
then the actual size of a part decreases from (say) 110mm to about
88mm. I created a new default template with these properties to
ensure that the Inkscape drawings would always cut at the right sizes.

When Inkscape 0.92 was released I downloaded it and I have just used
it to draw out another carriage. I then opened the svg file in DE
and without examining it, sent it to the cutter. The parts seemed
too small. I then realised that the default template was no longer
in mm/px, but was now in mm/mm. When I altered the document
properties back to mm/px, I opened the file in DE and examined the
size of the parts. I now find that the part which should have been
110mm is now about 117mm.

This is clearly useless for making scale models. I opened in v 0.92
a file which was originally created in Inkscape 0.91 and received the
message that the original file was drawn at 1 inch = 90 px, but the
new version uses 1 inch = 96 px. As a user rather than a developer,
I do not understand the reason for this (nor do I need to understand
it) - I just need to know that if I draw a line 100mm long it will
cut at that length, as in the earlier versions.

As I can see no option in v 0.92 to allow compatibility with earlier
versions, it seems that I will have to reload v 0.91 and use that to
create my drawings.

Is there a compatibility option to allow drawings to be made at 90px
per inch in v 0.92?

Mick Ralph
Maren Hachmann
2017-05-12 21:56:58 UTC
Permalink
Hi Mick,

the change was necessary to be compatible with CSS standards.

When you open the file with Inkscape, it will offer to scale it in that
dialog where it tells you about the changed size, which intends to make
the file compatible again.

In your specific case, the option "Scale elements" will hopefully do
what you need. Can you try that?

Kind Regards,
Maren
Post by Mick Ralph
As the background to my problem, I use Inkscape to prepare drawings
of sides and ends, etc, to be made into model railway carriages. The
designs are then opened in the Designer Edition (DE) of Silhouette
Studio for cutting out of styrene sheet on the Silhouette Portrait
cutting machine. DE can open SVG files, as created with Inkscape.
For Inkscape 0.48 and 0.91, this works fine and the parts are cut to
the same size as the Inkscape drawing, although it is necessary to
ensure that the document properties are set to "default units" of mm
and "custom size" "units" of px; if custom size units are left as mm,
then the actual size of a part decreases from (say) 110mm to about
88mm. I created a new default template with these properties to
ensure that the Inkscape drawings would always cut at the right sizes.
When Inkscape 0.92 was released I downloaded it and I have just used
it to draw out another carriage. I then opened the svg file in DE
and without examining it, sent it to the cutter. The parts seemed
too small. I then realised that the default template was no longer
in mm/px, but was now in mm/mm. When I altered the document
properties back to mm/px, I opened the file in DE and examined the
size of the parts. I now find that the part which should have been
110mm is now about 117mm.
This is clearly useless for making scale models. I opened in v 0.92
a file which was originally created in Inkscape 0.91 and received the
message that the original file was drawn at 1 inch = 90 px, but the
new version uses 1 inch = 96 px. As a user rather than a developer,
I do not understand the reason for this (nor do I need to understand
it) - I just need to know that if I draw a line 100mm long it will
cut at that length, as in the earlier versions.
As I can see no option in v 0.92 to allow compatibility with earlier
versions, it seems that I will have to reload v 0.91 and use that to
create my drawings.
Is there a compatibility option to allow drawings to be made at 90px
per inch in v 0.92?
Mick Ralph
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C R
2017-05-12 21:58:10 UTC
Permalink
It's because svg was designed as a web format and according to the wiki:
"Eventually, after long arguments, the CSS working group dictated that
one inch would be fixed to 96 pixels regardless of screen resolution"

Yea, that's the insanity we are stuck with. Pixels being units of
physical measurement.

The cure is to never, ever under ANY circumstances uses pixels as a
unit of measurement. It was always a bad idea, but since svg was meant
to contain css it's kinds what we are stuck with if we want to be/stay
compatible with web standards... even the ones that make no goram
sense. :)

Note: Inkscape still correctly will output your vectors at any dpi you
wish, but pixels should always be calculated based on a physical
measurement (metric or imperial), and pixels calculated as a dpi.

This is not a problem that will go away. The CSS working group will no
doubt decide to haphazardly change it again because "retina" displays
are so popular, in which case it will probably be 300px / inch.

It doesn't matter though. If you're using pixels to calculate witdth,
you will have to expect that the width will change based on the pixel
size of your output, so best thing is to not do that again in the
future.

Here's the scoop on units in Inkscape:
http://wiki.inkscape.org/wiki/index.php/Units_In_Inkscape

-C
Post by Mick Ralph
As the background to my problem, I use Inkscape to prepare drawings
of sides and ends, etc, to be made into model railway carriages. The
designs are then opened in the Designer Edition (DE) of Silhouette
Studio for cutting out of styrene sheet on the Silhouette Portrait
cutting machine. DE can open SVG files, as created with Inkscape.
For Inkscape 0.48 and 0.91, this works fine and the parts are cut to
the same size as the Inkscape drawing, although it is necessary to
ensure that the document properties are set to "default units" of mm
and "custom size" "units" of px; if custom size units are left as mm,
then the actual size of a part decreases from (say) 110mm to about
88mm. I created a new default template with these properties to
ensure that the Inkscape drawings would always cut at the right sizes.
When Inkscape 0.92 was released I downloaded it and I have just used
it to draw out another carriage. I then opened the svg file in DE
and without examining it, sent it to the cutter. The parts seemed
too small. I then realised that the default template was no longer
in mm/px, but was now in mm/mm. When I altered the document
properties back to mm/px, I opened the file in DE and examined the
size of the parts. I now find that the part which should have been
110mm is now about 117mm.
This is clearly useless for making scale models. I opened in v 0.92
a file which was originally created in Inkscape 0.91 and received the
message that the original file was drawn at 1 inch = 90 px, but the
new version uses 1 inch = 96 px. As a user rather than a developer,
I do not understand the reason for this (nor do I need to understand
it) - I just need to know that if I draw a line 100mm long it will
cut at that length, as in the earlier versions.
As I can see no option in v 0.92 to allow compatibility with earlier
versions, it seems that I will have to reload v 0.91 and use that to
create my drawings.
Is there a compatibility option to allow drawings to be made at 90px
per inch in v 0.92?
Mick Ralph
------------------------------------------------------------------------------
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engaging tech sites, Slashdot.org! http://sdm.link/slashdot
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