% character in caption not appearing

[BigNoub]

I'm using ImageMagick 6.7.7-10 2016-11-29 Q16 on Ubuntu 14.04

I am using this command to add a caption to an image:

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convert -background black -bordercolor black -fill white -size 300x20 -pointsize $myFontsize caption:$title -trim -border 5 -channel A -fx '(lightness/2)+.8' -geometry +$myX+$myY $input +swap -composite $output

but when $title contains a % character, it is not visible in the caption, nor is the space character following the %.

For instance, if $title = "India contributes to 75% of the global spice production", the caption will read "India contributes to 75of the global spice production"

How can I avoid that?

[Bonzo]

I wonder if the % acting as an escape? First thing I would try is:

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caption:"$title" 

[BigNoub]

no, double quoting does not solve the problem

[magick]

Try 75%%. Escape a percent with another percent. If that fails, try 75\%.

[BigNoub]

Escaping the percent with another percent works! Although it is not very practical because my caption is read from a file, and I have lots of captions to write, potentially with lots of percent in them, I can't go throughout the file and change them all.

Is my only option to analyse each $title variable and transform all % characters into %%?

Could there be other characters affected?

[fmw42]

I can't go throughout the file and change them all.

Many text editors will do a global search and replace allowing you to change all % to %%.

[snibgo]

Or just filter each input with sed.

[BigNoub]

yes you're right, what I meant is that the files I use as inputs are generated in real time by users, I can't ask them to write %% as it's really not human-readable, and I can't myself do tens of global searches per day to change that manually, I need everything to be automated.

Is that a bug anyway? If yes it should be fixed in the future? Or is it limited to my version of IM?

[snibgo]

Not a bug, but a feature.

In "caption:", "%" is a special character, so we can do things like this:

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convert -size 300x300 caption:"Width is %w" x.png

In my view, IM should have a setting to "treat special characters as literals". But it doesn't, so sed or similar can be used on the fly.

EDIT: for example, suppose the file pc.txt contains:

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75% interest

Then use this bash command:

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convert -size 300x300 caption:"`sed -e s/%/%%/g pc.txt`" x.png

... and we get the expected image.

[BigNoub]

Perfect thanks!