That's what I'm trying to say. The actual pixels in the doc should not change. 1px should always equal 1px, regardless of what nonsense the CSS workgroup is doing to the dpi conversion. The user should expect to have to set the dpi themselves if they want a mm conversion from pixels. The css default could therefore change to 300 dpi, and nothing would change. This is the workflow I use: if I'm exporting to PNG I always use the dialog, and I set the pixel values to whatever. No changing of the document is necessary to export pixels. It would be great if Inkscape did this automatically when determining pixel width for xport of SVG for web. That's part of what I'll be looking into this weekend.

Thanks for the comments and support.
-C

On 26 Sep 2017 12:59, "Eduard Braun" <eduard.braun2@...26...> wrote:
Am 26.09.2017 um 11:49 schrieb C R:
The user should not have to understand native units. The
implementation is what I'll be trying to figure out.

If the user selects mm as the default units, regardless of what the
user units are, Inkscape should serve up a document for a mm workflow.
If the user selects px as the default value it should serve up a
document that does not care what physical mm dimensions are used.

Most importantly, when the CSS workgroup changes the value of "px"
again (corresponding to user units), it should not break backward
compatibility with mm formatted documents, nor should it change the
pixel dimensions of previous templates.
I mostly agree with you but I'm not sure I understood the last part of this sentence:
In the special case that a document that has px as user unit and a document size given in px it probably *should* adjust the pixel dimensions to whatever CSS dictates. Otherwise a full HD wallpaper (1920x1080 px²) would suddenly not have the proper document size in px any more.
A second case (I don't think we have a template for  that, though, so I hope there's not much content around that would be affected) that could prove difficult in that respect: If a document has px as user unit and a document size given in px but really is for example an A4 document, we have no way of knowing it's supposed to be A4.

Regards,
Eduard
Whatever is necessary to guarantee that, I'm all for.

I have to understand all possible solutions before suggesting one that
works, and a ui implementation that supports it best. I'll do that
this weekend.

Thanks for the thoughts/direction/preferences everyone. :)
-C




On Tue, Sep 26, 2017 at 9:05 AM, brynn <brynn@...3089...> wrote:
I'm totally happy with the first section, where you describe how users see
this issue.  But I disagree with your possible solutions.

I don't think "user units" should be used at all.  I don't think even the
concept of user units should be used.  Even after your generous explanation
for me, all I got from it (so far, without re-reading and studying) is that
I think "user units" means px, but it means a lot more than that too, which
is still fuzzy.  (Maybe it needs a better name as well?)

Of the 2 options:

1 -- go back to the old tried and true, px for native units
2 -- keep the new system but make it easier to use

I would prefer going back to the tried and true.  Because even making the
new system easier to use, there will still be times when the user needs to
really understand it, to be able to set up Inkscape for some unique project.
(And those who provide support need to really understand it, to be able to
provide support for it.)

Is it really so necessary for Inkscape to use mm for native units?  Is it
really fair to make it so complicated for those who don't use mm?  Going
back to the old way doesn't make it harder for the mm users.  They don't
lose anything by going back.  The old way makes it just the same for all use
cases and user groups.

You know what all this sounds like to me?  It sounds like finding a way to
bend over backwards to touch your feet, even though bending over the front
way already works very well (and has worked well from the beginning).  Oh,
don't worry, it won't hurt as much if you do it this way.  If you can't do
it that way, you'll have to do it this other way.  But either way, now we
all have to be gymnasts.

How I see it, is no one wins with this.  It's a new feature which doesn't
provide anything new or better.  It just makes it harder for users who don't
use mm, or who change their units often (including who provide support for
them).

Anyway, thanks for taking the time to explain it.  I will try to study all
the messages and try to understand better.  I don't have much hope of
success, but I promise I will keep trying.

I thought I already posted that I made the feature request to revert, but I
don't see the message.  So here's the report I made:

https://bugs.launchpad.net/inkscape/+bug/1719162

And now I'll sign off for this topic, and let the developers do their thing
:-)

Thanks again!

All best,
brynn


-----Original Message----- From: Eduard Braun
Sent: Sunday, September 24, 2017 5:40 AM
To: brynn ; inkscape-devel@...1841...ge.net
Cc: Inkscape User Community
Subject: Re: [Inkscape-user] [Inkscape-devel] the Scale setting and Display
units


Am 24.09.2017 um 11:33 schrieb brynn:
Before 0.92, it was very, very simple, and easy to understand and easy to
use. Now, it is not.

I think one of the main sources of confusion is the wording and design of
the document properties dialog, not the choice of units themselves:


We have a setting called "Display units". As a user I'd expect this to only
influence display (as the name suggests) but nothing else (i.e. I should be
able to switch this at will without causing any change for my document)
However, as soon as the user changes "display units" the "Scale" will change
too! As a user I'm now frightened: Did I just change the size of my
document? Should I revert to "Scale" = 1? (if they choose to do so it's very
bad as then they'll mess up their drawing)

The help of the "Scale" input is not helpful: "User units per {display
unit}"
As a user I ask myself: What is a "user unit"? If I (the user) just set
"display units" to what I (the user) want to be displayed - is that a "user
unit"?
It obviously is not... A user unit is (even if it has a name that might
suggest differently) something the user should not be bothered with (we
don't have that term explained or used anywhere else in Inkscape I think).

While I'm no UI expert (who is ever? ;-) ) I think a possible solution to
that would be:


Rephrase "user units" to "{document,internal,SVG} units" or similar -
something that makes clear that this is the unit stored in the resulting SVG
document.
(Problem: We used to call "Display units" "Document units" before 0.92,
which was probably a bad choice and might cause ambiguity now)

Potentially collapse the whole "Scale" section by default (not just the
"Viewbox" part) - users should probably never change it anyway (unless they
know what they're doing) and usually they also should not have to.
Add a big warning sign: "Changing scaling will change the layout of your
document - is this really what you want?"

Rethink if "Scale" is a suitable term for what we are doing here. If I
double the scale my document does not change it's size (but instead my
content is scaled down). Maybe this is a language problem but my general
impression is that in software "Scale" usually refers to "scaling (up) the
whole image" (which we do not do) and not "changing the scale as on a map"
(which is what we do).

*Optionally* expose "user units" (with a proper alias) as a dropdown - if
the user sets "display units" and "user units" to mm the scale will become
"1".
(Problem: How do we now what to put for "user units" when opening a file?
For new files we could store it. For old files we could do the math and try
to guess, but it might be hard to impossible in many cases).

Regards,
Eduard



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