-colorspace CMYK -blur fails silently

[HugoRune]

i did some experiments manipulating images in the CMYK space, and came upon the following:

convert logo: -colorspace CMYK -channel CMY -blur 0x10 test.png
this works as expected, producing an image where the colors are blured but black is not

convert logo: -colorspace CMYK -channel K -blur 0x10 test.png
This does not work (produces no output and no error)

Althought strangely it does work with some images, but with incorrect output
convert lena.jpg -colorspace CMYK -channel K -blur 0x20 test.png
-->

[fmw42]

Seems to give me something, but don't know what to expect!



convert logo2.jpg -colorspace CMYK -channel K -blur 0x10 logo2_k_blur0x10a.png



IM 6.5.4-10 Q16 (sorry still HDRI)

[HugoRune]

interesting, mine does not produce a file (Version: ImageMagick 6.5.4-10 2009-08-08 Q16)

Nevertheless, your output is wrong too: the Black channel is not blurred, but somehow distorted, mostly zero with a few horizontal lines.

I tried to reproduce how it is supposed to look, but could not do it with imagemagick: I was stopped by the following possibly related odd behavior:

convert logo: -colorspace CMYK -channel CMYK -separate -combine test.png

[magick]

We can reproduce the problem and will have a patch available within the next day or two. Thanks.

[HugoRune]

We can reproduce the problem and will have a patch available within the next day or two. Thanks.

That's great, thanks!