1299575 - printing with some italic fonts from google documents results in leftward-marching margins

Status: NEW

(Core :: Layout, defect, P3)

Description

[Nathan Froyd [:froydnj]]

STR:

1. Go to the document (requires Mozilla google account; I can change this if need be):

https://docs.google.com/a/mozilla.com/document/d/1TIqN1qxOisA3MIUMACCNrAOqZk8tBESTELRRqXH0W9k/edit?usp=sharing

2. Select "File -> Print Preview".

Expected results:

Document displays more or less as is.

Actual result:

Each successive line gets positioned slightly to the left of the line above it; depending on the font, the text eventually slides off the left side of the page.

AFAICT, this is specifically because of the italic-ness of the font; if you make the text non-italic, the leftward marching does not happen.  It also doesn't happen with all fonts: I see the effect with "Impact" and "Cookie", but not with "Droid Serif", for instance.  I have seen this happen on both Linux nightly and Mac release, so I don't think it's a new problem.

Jonathan, do you have an idea of where the bug might lie?

Comment 1

[Jonathan Kew [:jfkthame]]

Sounds like this is related to the use of a skew transform to produce "synthetic" italics (obliqued glyphs) for font families that don't have a true italic face. Look for uses of OBLIQUE_SKEW_FACTOR to see where this initially gets set up.

I don't know why this would be affecting the positions of the lines (and only when printing? weird...), but my guess is that somehow it's leaking out from transforming the actual glyphs and having an unwanted impact on....something else, not sure what exactly.

I notice that if I go to the browser's standard File/Print command, and then choose Open PDF in Preview in the system Print dialog, I _don't_ see the problem; it only occurs when using the Print function within Google Docs, which appears to work by generating a PDF on the server which is then downloaded to the browser to open in Preview.