No Decode Delegate when using stdin

[jocolloman]

I am having a problem when passing an image to ImageMagick via stdin.

The following command is the one in question.

$ display < frog.pgm
display: no decode delegate for this image format `/var/tmp/magick-2094Xb6fonFohOuc' @ error/constitute.c/ReadImage/550.

However,

display frog.pgm

works just fine.

Interestingly, this works fine on Ubuntu but is not working on the Mac distribution.

Any thoughts?

[fmw42]

try piping the output from your other tool something equivalent to

convert rose: PGM:- | display -

[jocolloman]

Unfortunately, the same error message comes up.

[fmw42]

Do you have X11 installed. IM display needs X11 (unix and mac)

[Petr]

We experience the same problem.

Code: Select all

cat any.jpg | display

doesn't work.

Code: Select all

cat any.jpg | display jpg:-

works. Same e. g. for png. So it seems that the type of image is not correctly recognized.

See
https://bugzilla.novell.com/show_bug.cgi?id=882456

Do you have X11 installed. IM display needs X11 (unix and mac)

Reporter said that display works for him, no?

[Petr]

Hmm,

Code: Select all

cat any.png | display -

works.

[Petr]

It seems that block 0000 - 0fff of the stdin is not copyied into temporary file in the wrong case.

[Petr]

In the correct case:

Code: Select all

read(0, "\211PNG\r\n\32\n\0\0\0\rIHDR\0\0\0\30\0\0\0\30\10\6\0\0\0\340w="..., 262142) = 4380
read(0, "", 257762)                     = 0
read(0, "", 262142)    

In the wrong case:

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read(0, "\211PNG\r\n\32\n\0\0\0\rIHDR\0\0\0\30\0\0\0\30\10\6\0\0\0\340w="..., 4096) = 4096
read(0, "=I\22\202c\307\216\21\4\1\3\3\3W\327\33\r=;[y\241\263\263\263\305\267\2161I\262\261"..., 262142) = 284
read(0, "", 261858)                     = 0
read(0, "", 262142)      

The first 'wrong' read is thanks to DisplayImageCommand() behaviour, which is checking with getc() if there is some input on stdin or not. So at the end, it looks like:

Code: Select all

  char c, buffer[N];
  c = getc(stdin);    /* DisplayImageCommand() */
  ungetc(c, stdin);   /* DisplayImageCommand() */
  read(0, buffer, N); /* ReadBlob() */

[magick]

We can reproduce the problem you posted and have a patch in ImageMagick 6.8.9-4 Beta available within a few days. Thanks.

[Petr]

Excelent, thanks! May I have the patch, please?