Autotrace -centerline option gives segmentation fault

[ThSGM]

With the help of @jnweiger and his autotrace fork I have been able to build autotrace for OSX 10.11 and 10.13.

It works with the following command:

autotrace -output-file test.svg -output-format svg -report-progress test_image.bmp

However, if I use the `-centerline' option:

autotrace -centerline -output-file test.svg -output-format svg -report-progress test_image.bmp

It gives me the following errors:

test_image.bmp|Magick: abort due to signal 11 (SIGSEGV) "Segmentation Fault"...
[1]    11733 abort      autotrace -centerline -output-file test.svg -output-format svg

[lemenkov]

Could you please attach test_image.bmp?

[ThSGM]

@lemenkov

Thanks. It does seem to be image dependent. I've tested it on the two images below in the zip file. One is half the size of the other. It works on the smaller of the two. So

autotrace -centerline -output-file test.svg -output-format svg -report-progress trace02.bmp

works but trace01.bmp does not.

Archive.zip

[jnweiger]

I can reproduce the crash on Ubuntu18.04

Core was generated by `autotrace -centerline -output-file test.svg -output-format svg trace01.bmp'.
Program terminated with signal SIGSEGV, Segmentation fault.
0x00007ffff7bbd39a in at_bitmap_get_color (bitmap=0x555555787de0, row=285, col=4294967295, color=0x7fffffffda65) at src/autotrace.c:210
210	    at_color_set(color, p[0], p[1], p[2]);
(gdb) where
#0  0x00007ffff7bbd39a in at_bitmap_get_color (bitmap=0x555555787de0, row=285, col=4294967295, color=0x7fffffffda65)
    at src/autotrace.c:210
#1  0x00007ffff7bbf38e in is_valid_dir (row=284, col=0, dir=SOUTHWEST, bitmap=0x555555787de0, marked=0x555555787d40)
    at src/pxl-outline.c:208
#2  0x00007ffff7bc017e in find_centerline_pixels (bitmap=0x555555787de0, bg_color=..., notify_progress=0x0, progress_data=0x7fffffffdcdc, test_cancel=0x0, testcancel_data=0x0, exp=0x7fffffffdc50) at src/pxl-outline.c:256
#3  0x00007ffff7bbd7f4 in at_splines_new_full (bitmap=0x555555787de0, opts=0x555555787ce0, msg_func=0x555555557b28 <exception_handler>, msg_data=0x0, notify_progress=0x0, progress_data=0x7fffffffdcdc, test_cancel=0x0, testcancel_data=0x0) at src/autotrace.c:289
#4  0x0000555555556564 in main (argc=7, argv=0x7fffffffde38) at src/main.c:147
(gdb) 

[jnweiger]

Manually using imagemagick convert trace01.bmp trace01.pbm produces a pbm image that works fine. Converting to png does not work for me, it prints a chunk error like
y[B8][AD][D9]: invalid chunk type -- but that is probably a different issue.

[martweb1]

Should now work fine with the patches provided here:
#15