It might help to try to kinda cut down the volume of code to the relevant parts. I suppose it's hard to know what's relevant though. Personally, I think it's this.

 $text_color = $image->colorAllocate($custom_colors->{text_color});
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According to the GD docs, colorAllocate takes three args, not one. Presumably $custom_colors->{text_color} is a scalar arrayref. If that's the case, you'll want to explode it over the callstack like so.

 $text_color = $image->colorAllocate(@{ $custom_colors->{text_color} }
+);
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If, on the other hand, your text color is a webified color (e.g., "#ffff00"), you'd do something like this instead

if( $custom_colors->{text_color} =~ m/#(..)(..)(..)/ ) {
    $text_color = $image->colorAllocate(map {hex($_)} ($1, $2, $3) )
}
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