403559 - "ASSERTION: something is probably wrong somewhere" with very stretchy <mfenced> parentheses

Status: RESOLVED FIXED

(Core :: MathML, defect)

Description

[Jesse Ruderman]

Attachment: testcase

Loading the testcase triggers:

###!!! ASSERTION: something is probably wrong somewhere: '1000 != count', file /Users/jruderman/trunk/mozilla/layout/mathml/base/src/nsMathMLChar.cpp, line 2410

Comment 1

[Karl Tomlinson (:karlt)]

Attachment: calculate maximum height when measuring

Decide on the maximum number of glue glyphs to draw during measuring and detect zero-sized glue, rather than leaving a big gap when painting.

Comment 2

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

Comment on attachment 295028 [details] [diff] [review]
calculate maximum height when measuring

+  nscoord sum = 0;
+  if (aGlyphs[first] != aGlyphs[glue]) sum = aSizes[first];
+  if (aGlyphs[middle] != aGlyphs[glue]) sum += aSizes[middle];
+  if (aGlyphs[last] != aGlyphs[glue]) sum += aSizes[last];

Slight simplification: define static SizeOfNonGlueGlyph(aGlyphs, aSizes, index) and set "sum = SizeOfNonGlueGlyph(aGlyphs, aSizes, first) + SizeOfNonGlueGlyph(aGlyphs, aSizes, middle) + SizeOfNonGlueGlyph(aGlyphs, aSizes, last);"

+  else if (bmdata[3].ascent + bmdata[3].descent > 0) {

Can we use a symbolic constant instead of 3? I guess existing code uses '3', so never mind :-(

r+sr with the first comment

Comment 3

[Karl Tomlinson (:karlt)]

(In reply to comment #2)
> (From update of attachment 295028 [details] [diff] [review])
> +  nscoord sum = 0;
> +  if (aGlyphs[first] != aGlyphs[glue]) sum = aSizes[first];
> +  if (aGlyphs[middle] != aGlyphs[glue]) sum += aSizes[middle];
> +  if (aGlyphs[last] != aGlyphs[glue]) sum += aSizes[last];
> 
> Slight simplification: define static SizeOfNonGlueGlyph(aGlyphs, aSizes,
> index) and set "sum = SizeOfNonGlueGlyph(aGlyphs, aSizes, first) +
> SizeOfNonGlueGlyph(aGlyphs, aSizes, middle) + SizeOfNonGlueGlyph(aGlyphs,
> aSizes, last);"

After discussion with roc, used a while^Wfor loop instead.

Checked in: layout/mathml/base/src/nsMathMLChar.cpp revision 1.137.