412033 - non-stretchy-or-centred operators don't paint on scrolling with Cambria Math

Status: RESOLVED FIXED

(Core :: MathML, defect, P3)

Description

[Karl Tomlinson (:karlt)]

When STIX fonts are not installed but Cambria Math is, MathML operators that
do not use nsMathMLChar (those that are not stretchy or centred,
e.g. <mo>&leqq<mo>) don't paint when scrolling into the visible
region. Characters paint again when selected.

http://bonsai.mozilla.org/cvsblame.cgi?file=mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp&rev=1.99&mark=898-907#898

aDesiredStretchSize.height is based on the maximum of tight glyph bounds and
GetMetricsFor(GetStyleFont()->mFont)->GetMaxAscent/Descent, which is the
ascent and descent of the first CSS font on the system.  However the child
frame height is based on the maximum ascent of any font used to provide a
glyph, which can be much larger.  Therefore this code is truncating the size
of the frame, which is used as the overflow area, which is used to determine
whether painting is necessary.

Comment 1

[Karl Tomlinson (:karlt)]

Attachment: don't change the size of child frames of <mo>

Leaving child frames with their desired size.

I've left the code for when using nsMathMLChar instead of the descendent text frame, because I don't know what it was meant to do, and "#if 0"ed it out because it doesn't seem to be doing what it was meant to do.

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Just remove this code, don't #if 0 it. Maybe leave a comment behind to say what this code was trying to do and we're not doing anymore, up to you.

Comment 3

[Karl Tomlinson (:karlt)]

Attachment: don't change the size of child frames of <mo> v2

Removed the code and left a comment.

Comment 4

[Karl Tomlinson (:karlt)]

Checked-in:
1.100       mozilla/layout/mathml/base/src/nsMathMLmoFrame.cpp