In Inkscape - can you have multiple Viewboxes ?
If so how should it be interpreted ?

On 9/12/2014 12:58 AM, Tavmjong Bah wrote:
>                         Units in Inkscape
>                         =================
>
> Introduction
> -----------
>
> The recent debate about units in Inkscape highlights the fact that we do
> not have a clearly defined approach on how to handle units in Inkscape.
> Units are not as straight-forward as one should think they are. This
> essay attempts to resolve this problem.
>
> Historical View
> ---------------
>
> Part of the problem with units in SVG and CSS in general is why they are
> there in the first place. In the early days it was assumed that one
> would want to display drawings on a screen at full scale. In other
> words, a "one inch square" would be display on a screen as a physical
> one inch square. This required that displays be queryable as to what
> there true DPI was. Display manufactures rarely provided the means to
> query the DPI of the display, and when they did, they often returned
> incorrect results. Thus, the use of "real" units never became popular
> and in reality is usually not what one wanted. Eventually, after long
> arguments, the CSS working group dictated that one inch would be fixed
> to 96 pixels regardless of screen resolution (ironically, with so called
> "Retina" displays, there is once again interest in scaling drawings
> based on DPI).
>
>
> A Philosophy
> ------------
>
> Absolute units should not be used inside an SVG file with one exception:
>
> The 'root' width and height may have units, which with a proper
> 'viewBox' determines an appropriate scale for a drawing. (This sets the
> 'real' world value of the SVG 'user unit.) This reflect the opinion of
> the majority of the SVG working group.
>
> It should be noted that the relative units 'em', 'ex', and '%' can be
> useful in some cases.
>
>
> Inkscape & Units
> ----------------
>
> Inkscape should not write out absolute units other than in the root SVG
> element. Inkscape must, however, be able to interpret units from
> non-Inkscape produced files according to the CSS defined value of 96
> pixels (initial user-units) per inch.
>
> The use of units in the Inkscape GUI is for ease of authoring only. The
> actual values should be stored as 'user-units'.
>
> Changing the "Inkscape GUI unit" should not introduce any 'transforms'
> on elements (as seems to being done now) nor should changing the SVG
> root 'width'/'height units or the 'viewBox'.
>
> The GUI should reflect the chosen Inkscape GUI unit scaled to take into
> account the SVG root 'width'/'height' and 'viewBox'.
>
>
> For example:
>
> <svg width="100mm" height="100mm" viewBox="0 0 100 100">
>
> describes a drawing 100mm x 100mm where one 'user-unit' is equivalent to
> one mm.
>
> If the Inkscape property inkscape:document-units="mm" then the GUI would
> show a width of '25.4' for a rectangle 25.4 'user-units' wide. If
> inkscape:document-units="in", the GUI would show '1.0'.
>
>
> To implement this, one either needs to find the proper scaling from
> examining the SVG root 'width'/'height' and 'viewBox' properties or
> create a new Inkscape property that fixes this scale (in which case
> changing the 'width'/'height' would change the 'viewBox' and vice
> versa).
>
>
> Tav
>
>
>
>
>
>
>
>
>
>
>
> ------------------------------------------------------------------------------
> Want excitement?
> Manually upgrade your production database.
> When you want reliability, choose Perforce
> Perforce version control. Predictably reliable.
> http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk
> _______________________________________________
> Inkscape-devel mailing list
> Inkscape-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/inkscape-devel
>
>

> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2014.0.4765 / Virus Database: 4015/8192 - Release Date: 09/11/14

>
>


------------------------------------------------------------------------------
Want excitement?
Manually upgrade your production database.
When you want reliability, choose Perforce
Perforce version control. Predictably reliable.
http://pubads.g.doubleclick.net/gampad/clk?id=157508191&iu=/4140/ostg.clktrk
_______________________________________________
Inkscape-devel mailing list
Inkscape-devel@...1794...s.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/inkscape-devel