6242b2ee9c
With a complete reorganisation of the directory structure and most of the content converted to pandoc-flavoured markdown. Some TODO's left before this can go live: - Main page - Atom feeds - Bug tracker
86 lines
2.7 KiB
Markdown
86 lines
2.7 KiB
Markdown
% Colours in NCurses
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I decided to do some experimentation with how the colours defined in ncurses
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are actually displayed in terminals, what the effects are of combining these
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colours with other attributes, and how colour schemes of a terminal can affect
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the displayed colours. To this end I wrote a small c file and ran it in
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different terminals and different configurations. Note that only the 8 basic
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NCurses colours are tested, the more flexible init\_color() function is not
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used.
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**Source code:** [nccolour.c](/download/code/nccolour.c)
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([syntax highlighed version](http://p.blicky.net/xu35c))
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## Notes / observations
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- The most obvious conclusion: the displayed colours do not have the exact same
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colour value in every terminal. Some terminals also allow users to modify
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these colours.
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- You can not assume that the default foreground or background colour can be
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represented by one of the 8 basic colours defined by NCurses.
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- Specifying -1 as colour, to indicate the default foreground or background
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colour, seems to work fine in any terminal tested so far.
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- All tested terminals render the foreground colour in a lighter shade when the
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A\_BOLD attribute is set. This does not apply to the background colour. The
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result of this is that the text becomes visible when using A\_BOLD when the
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foreground and background colour are set to the same value.
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- Unfortunately, not all terminals are configured in such a way that all
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possible colours are readable. So as a developer you'll still have to support
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configurable colour schemes in your ncurses application. :-(
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- On most terminals, setting the foreground and background colour to the same
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value without applying the A\_BOLD attribute will make the text invisible.
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Don't rely on this, however, as this is not the case on OS X.
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## Full screenshot
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To avoid wasting unecessary space, the comparison screenshots below only
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display the colour table. Here's a screenshot of the full output of the
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program, which also explains what each column means.
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## Screenshots
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Arch Linux, Roxterm, Default color scheme
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Arch Linux, Roxterm, GTK color scheme
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Arch Linux, Roxterm, Tango color scheme
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Arch Linux, Roxterm, Modified Tango color scheme
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Arch Linux, xterm (default settings)
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Ubuntu 11.10, Gnome-terminal
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Debian Squeeze, VT (default settings)
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FreeBSD, VT (default settings)
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Mac OS X, Terminal
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Mac OS X, iTerm2
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CentOS 6.4
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