Re: Problems with backart

[Fred Kiefer]

Hi Charles,

I am not able to help you very specifically with this problem. As could
anybody else I looked up the code of [FTFontInfo
initWithFontName:matrix:screenFont:] and there is nothing in there,
which gives away what may go wrong. One would suspect that either it is
an internal error of the freetype library, a version mismatch or the art
backend is passing in the wrong values. There isn't to much parameter
checking going on here, so it may be the later. You should be able to
check in gdb the parameter passed into FTC_CMapCache_Lookup(), most
likely one of them will be NULL. If we know which one, we could add a
check in the art backend and perhaps even track down, where this invalid
value comes from.

Where did you get the fonts from that you are using here? It may be just
that they are invalid or not properly installed.

Hope this helps
Fred


Charles Philip Chan wrote:
> 
> I am trying out the libart backend again after a long time. The
> problem is that now it just crashes with SIGSEGV. I am using
> libart-gpl 2.3.17 and my freetype2 version is 2.1.10. Here is the GDB
> backtrace:
> 
> ,----[ GDB Backtrace ]
> | Program received signal SIGSEGV, Segmentation fault.
> | [Switching to Thread 16384 (LWP 18974)]
> | 0xa7070a3f in FTC_CMapCache_Lookup () from //usr/lib/libfreetype.so.6
> | (gdb) backtrace
> | #0  0xa7070a3f in FTC_CMapCache_Lookup () from //usr/lib/libfreetype.so.6
> | #1  0xa719c880 in -[FTFontInfo initWithFontName:matrix:screenFont:] ()
> |    from 
> /usr/GNUstep/System/Library/Bundles/libgnustep-back-010.bundle/./libgnustep-back-010
> | #2  0xa7e03379 in +[GSFontInfo fontInfoForFontName:matrix:screenFont:] ()
> |    from /usr/GNUstep/System/Library/Libraries/libgnustep-gui.so.0.10
> | #3  0xa7ce86d0 in -[NSFont initWithName:matrix:fix:screenFont:role:] ()
> |    from /usr/GNUstep/System/Library/Libraries/libgnustep-gui.so.0.10
> | #4  0xa7ce7fcd in +[NSFont _fontWithName:size:role:] ()
> |    from /usr/GNUstep/System/Library/Libraries/libgnustep-gui.so.0.10
> | #5  0xa7edd2a8 in _OBJC_SELECTOR_TABLE ()
> |    from /usr/GNUstep/System/Library/Libraries/libgnustep-gui.so.0.10
> | #6  0xa71cf464 in _OBJC_INSTANCE_86.130 ()
> |    from 
> /usr/GNUstep/System/Library/Bundles/libgnustep-back-010.bundle/./libgnustep-back-010
> | #7  0xaff2ad60 in ?? ()
> | #8  0x00000000 in ?? ()
> | #9  0x00000000 in ?? ()
> | #10 0x0000000c in ?? ()
> | #11 0xa7924170 in -[GSDictionary objectEnumerator] ()
> |    from /usr/GNUstep/System/Library/Libraries/libgnustep-base.so.1.11
> | Previous frame inner to this frame (corrupt stack?)
> `----