Re: Glyph Generator & hiding glyphs -> _NSBlockNumberForIndex() errors
Re: Glyph Generator & hiding glyphs -> _NSBlockNumberForIndex() errors
- Subject: Re: Glyph Generator & hiding glyphs -> _NSBlockNumberForIndex() errors
- From: Keith Blount <email@hidden>
- Date: Sat, 15 Mar 2008 05:27:12 -0700 (PDT)
Hi,
Sorry to bother you with this again, but it appears that I spoke to soon when I said that this fixes the issue - it doesn't; it still crashes and throws exceptions. And unfortunately I'm now getting no reply from my DTS guy. I put *newGlyphs = NSControlGlyph at line 34 as suggested - you can see the results here:
http://www.literatureandlatte.com/misc/HiddenTextBasicUpdated.zip
If you start typing newlines into the range of text in the right-hand text view that is hidden in the left-hand view, you are right that it no longer crashes at this point. However, when you type newlines into the hidden text, they appear in the left-hand text view too - when they should be hidden, as they are part of the hidden text! Then, if you go back into the left-hand text view and start typing before the hidden text, the whole thing crashes and the following exception gets thrown:
*** layout manager 0x15d6f0 failed to progress beyond index 124 while drawing glyphs.
I don't quite know how I missed this when I first tested with the fix - I guess I was just over-eager for it to work.
I'm not sure if there is anything that can be done, but thank you for your help anyway.
Many thanks and all the best,
Keith
----- Original Message ----
From: Aki Inoue <email@hidden>
To: Keith Blount <email@hidden>
Cc: email@hidden
Sent: Monday, March 10, 2008 11:32:23 PM
Subject: Re: Glyph Generator & hiding glyphs -> _NSBlockNumberForIndex() errors
OK, it appears I made a mistake with the original DTS sample 8-).
NSLayoutManager requires each glyph segment to start with non-null glyphs whereas the sample was replacing all incoming glyphs in the hidden range to NSNullGlyph.
Beginning the range with NSControlGlyph fixes the issue.
Add the following line at HTGlyphGenerator.m:34.
*newGlyphs = NSControlGlyph;
Aki
On 2008/03/10, at 13:25, Keith Blount wrote:
Hi Aki,
Many thanks for your reply, much appreciated. I completely stripped all my custom drawing code and everything to double-check it wasn't just some bad expectation of glyph-to-character mapping in my own code, but the problem persists. I've uploaded the sample, stripped down project here:
http://www.literatureandlatte.com/misc/HiddenTextTestBasic.zip
All it contains is two text views that share the same text storage, one of which (the left one) uses the custom glyph generator to hide text (given that my real app allows the user to view the same text storage in different panes, it may be that the user has text hidden in one pane but not in the other).
To see the bug in action, all you need to do is build the project, then, in the right-hand text view (where the text isn't hidden), click somewhere between the square brackets (i.e. inside the text that has been hidden in the left-hand text view) and hit return to create a new line twice. The second time you hit return, you will get the following exceptions thrown on the console:
2008-03-10 20:15:21.121 HiddenTextTest[2956:813] Exception raised during background layout: *** NSRunStorage, _NSBlockNumberForIndex(): index (170) beyond array bounds (163)
2008-03-10 20:15:21.122 HiddenTextTest[2956:813] *** NSRunStorage, _NSBlockNumberForIndex(): index (170) beyond array bounds (163)
2008-03-10 20:15:23.320 HiddenTextTest[2956:813] *** NSRunStorage, _NSBlockNumberForIndex(): index (170) beyond array bounds (163)
2008-03-10 20:15:23.321 HiddenTextTest[2956:813] *** NSRunStorage, _NSBlockNumberForIndex(): index (170) beyond array bounds (163)
After that, you can't type any more - the text view is frozen. You just get more errors along the lines of:
2008-03-10 20:20:16.799 HiddenTextTest[2956:813] Exception raised during background layout: -[NSLayoutManager _fillLayoutHoleForCharacterRange:desiredNumberOfLines:isSoft:] *** attempted layout while textStorage is editing. It is not valid to cause the layoutManager to do layout while the textStorage is editing (ie the textStorage has been sent a beginEditing message without a matching endEditing.)
I did find that if I set -setBackgroundLayoutEnabled: to NO, these errors go away, but I suspect that this is really just masking the underlying problem rather than fixing it - and besides, I'd really prefer to have background layout enabled.
Many thanks for taking an interest in this.
All the best,
Keith
----- Original Message ----
From: Aki Inoue <email@hidden>
To: Keith Blount <email@hidden>
Cc: email@hidden
Sent: Monday, March 10, 2008 6:14:05 PM
Subject: Re: Glyph Generator & hiding glyphs -> _NSBlockNumberForIndex() errors
Keith,
I was consulted about the sample from DTS and didn't find any obvious
problem with it.
It would be great if you could provide further detail (for example, bt
of the exception raise).
Thanks,
Aki
On 2008/03/08, at 10:41, Keith Blount wrote:
Just to add a little info to my previous message, which was a little
misleading:a
My custom glyph generator replaces each glyph that is supposed to be
hidden with NSNullGlyph (it doesn't just insert one NSNullGlyph for
the lot of them), so I would expect the one-to-one mapping on this
first pass of glyph generation to be maintained. I'm therefore
really not sure why I'm getting all of these errors - it seems that
the presence of a group of null glyphs completely breaks things at
the typesetting stage (I'm guessing)? Hmm, given that there is so
little documentation about this sort of thing and most glyph
generation threads seem to have been unanswered, I don't hold out
much hope...
In case there is a better way of doing things: I am basically trying
to implement hidden text, so that text with a given custom attribute
does not get displayed in the text view. One way I could have done
this was via a custom text storage subclass that maintained two
representations of its text - one with the hidden text displayed,
one with it, um, hidden - but this is no good for what I want, as
the same text storage can be displayed in two different text views,
and there is more than one attribute type that can be hidden
separately.
Hence the custom glyph generator, which isn't working...
Thanks in advance for any help or pointers.
All the best,
Keith
--- ORIGINAL MESSAGE ---
Hi,
I have a custom glyph generator (NSGlyphGenerator subclass) that is
used to hide glyphs for text with certain attributes. It does this
by inserting a single NSNullGlyph for a range of glyphs representing
text with these hidden attributes. (This is basically a hidden text
toggle.) This all works brilliantly - I can completely hide whole
ranges of text - but only so long as the text is viewed in a single
text view.
If I have the same text storage shared between two text views, and
one view has the text hidden whilst the other doesn't, I get array
out of bounds errors under the following circumstances: If, in the
view where no text is hidden, I click in the range of text that IS
hidden in the other view, and then I hit return a couple of times, I
get these errors:
Exception raised during background layout: *** NSRunStorage,
_NSBlockNumberForIndex(): index (345) beyond array bounds (335)
2008-03-08 10:28:00.042 HiddenTextTest[42350:813] *** NSRunStorage,
_NSBlockNumberForIndex(): index (345)
Clearly, these errors are caused because my hidden-text view has
less glyphs in it than the non-hidden-text view, but they both share
the same text storage. So my question is, how do I fix this?
Somewhere it seems that I need to tell something else - other than
my glyph generator - that some text is hidden. The errors seem to
indicate that I might need to tell my text storage about this... But
where and how? But then, I can't tell the text storage, because it
has hidden text in one view but not the other...
The method of hiding text by inserting a null glyph was recommended
to me by DTS, but there is very little documentation on actually
achieving something like this, so I'm hoping some text expert here
will be able to give me some clues. :)
Many thanks in advance and all the best,
Keith
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