Perspective fails with non-Inkscape SVG

[Tim Tröndle]

When opening an SVG file that hasn't been created by Inkscape, there may no "width" and "height" attributes exist in the svg tag. The "Modify Path -> Perspective" script expects these attributes to exist and fails with the error message below if they don't. Adding these attributes manually solves the issue.

```
Traceback (most recent call last):
  File "perspective.py", line 153, in <module>
    e.affect()
  File "/Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/inkex.py", line 265, in affect
    self.getposinlayer()
  File "/Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/inkex.py", line 207, in getposinlayer
    x = self.unittouu( xattr[0] + 'px' )
  File "/Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/inkex.py", line 351, in unittouu
    return retval * (self.__uuconv[u.string[u.start():u.end()]] / self.__uuconv[self.getDocumentUnit()])
  File "/Applications/Inkscape.app/Contents/Resources/share/inkscape/extensions/inkex.py", line 304, in getDocumentUnit
    p = param.match(svgwidth)
TypeError: expected string or buffer
```

[Alvin Penner (apenner)]

thank you for taking the time to issue a report.
could you indicate which OS, and which version of Inkscape? (see Help->About)

using Windows 10, Inkscape 0.92.1 r15371, I am not able to reproduce the problem, using the attached file.

[su_v (suv-lp)]

AFAICT a duplicate of
* Bug #1463623 “Error trying to save Optimized SVG (no 'width' attribute for SVGRoot)”
  https://bugs.launchpad.net/inkscape/+bug/1463623

Failure with missing 'height' attribute is tracked in
* Bug #1461346 “getposinlayer fails if height attribute is missing”
  https://bugs.launchpad.net/inkscape/+bug/1461346

(The OS of the reporter is OS X, based on the paths in the backtrace - there have been no new Inkscape packages for OS X available yet which would include the fix for the two mentioned issues (Inkscape >= 0.92)).

[Tim Tröndle (timtroendle)]

I'm using Inkscape 0.91 r13725 as downloaded from the website 2 days ago and I am on macOS 10.12.3.

Using your attached file I am seeing not the width error as stated above, but the height error as stated in bug #1461346.

[su_v (suv-lp)]

Tim Tröndle wrote:
> Using your attached file I am seeing not the width error as stated
> above, but the height error as stated in bug #1461346.

That's because the file from comment #1 also lacks the 'viewBox' attribute - if at least the 'viewBox' attribute is present, the first error encountered will be about the missing 'width' attribute.

Since launchpad does not allow to link a report as duplicate to multiple other reports, linking this one based on the backtrace in the original bug description as duplicate to bug #1463623.