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I provide the user with a list of key sequences that lets the user type only with ASCII characters and generate various Unicode characters. This is what they see in the sequence list window:

character list

My problem is that some sequences use Space, and using a space character in the “Sequence” column makes things confusing.

So I tried using {spc} but it’s not very aesthetically pleasing, because it takes too much place. Then I tried (U+2423) but I think it’s too easy to confuse with _ (underscore). In short, none of the following solutions were really satisfying:

 spc ␣

Can someone maybe suggest a single non-ASCII character that I could use, which would make it clear to the user that they are supposed to press Space as part of the sequence, while not taking too much screen space? Due to the limitations of the framework I am using (AutoHotKey) I would strongly prefer not having to rely on rare fonts/symbols or to use colour.

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Why not {space-bar} or even {space}? – JonW Apr 4 '14 at 13:08
The major problem is that it makes the “Sequence” column very wide, because it adapts to the width of the longest sequence. But you’re right — there is no reason why I couldn’t use it, and I think it’s worth making that suggestion an answer. – sam hocevar Apr 4 '14 at 13:22
This particular ASCII chart uses (sp). Emacs documentation (and the editor itself) use SPC. SP may not be immediately clear but would be shorter. Also there is . – Jason C Apr 5 '14 at 2:19
The one with ␣ looks good. I have seen ␣ used many times to represent space – kinokijuf Apr 5 '14 at 10:37
@Armstrongest it’s Unicode symbol U+2422 BLANK SYMBOL ␢ (as mentioned in one of the answers below). – sam hocevar Jun 16 at 8:46
up vote 8 down vote accepted

I had similar task — the dialog that showed specific keyboard shortcuts for map editing software. To solve such a case I've used visual keyboard button representations with labels on it — it took some space (and increased a visual noise a bit), but was ultimately obvious to most users:

Keyboard shortcuts

RC — Create new rectangle with it's centre in mouse position

RTL — Create new rectangle with it's top-left corner in mouse position

RSpace — Display list of possible options for new rectangle

Ctrl — Move to nearest left object


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Thanks. I eventually went for this solution. It required changing the GUI toolkit but the end result is a lot more satisfying. See – sam hocevar Nov 23 '15 at 16:18

If you don't have any technical reason not to, then I'd suggest actually using terms that users understand rather than just trying to get your fields to have nice alignment / visuals.

{SPACE-BAR} or even {SPACE} are pretty unambiguous and you want to ensure people actually understand what you're offering them, rather than just aiming for aesthetics.

Put it this way; you work in UX yet you - a professional - can't think of a term to use for the spacebar. How are 'normal' people supposed to feel if even you don't know of an alternative?

So go with {SPACE-BAR} as that's the name of the key, it's what people think of. For example, there is probably no confusion in the sentence {Press the Space-bar to continue} because it's an understood name for that button. Hell, that's more useful than giving them the Unicode code!

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In addition to OPEN BOX U+2423 ␣, which you have tried, there’s U+2420 SYMBOL FOR SPACE ␠ and U+2422 BLANK SYMBOL ␢. That’s pretty much all that Unicode has in this department.

BLANK SYMBOL does not look blank at all. SYMBOL FOR SPACE exists in a few fonts only, with great variation in shape. In some fonts, it contains “S” and “P” in very small size—almost illegible in normal copy text sizes. But in the Symbola font it looks nice (SP in a box with dotted border). But I’m afraid you would need a monospace font (and might even be fixed to a specific font).

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On my first computer job decades ago, long before unicode, when we wrote our code out by hand we used a crossed out "b", very similar to the unicode "blank symbol" 2422. When using coding forms we just left it blank. – Peter Wooster Apr 5 '14 at 12:06

For the first computer I ever had, the manual used a downward triangle where necessary to emphasise the presence of a space. U+25BD (▽) fits the bill, but you might consider that a "rare symbol".

I'm not claiming this is a universally-recognised symbol for a space character or anything. But provided that you're willing to define it in the introduction it would do the job. For that matter, so would anything that is obviously not an ASCII character.

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+1 for "define it in the introduction" – Erick Robertson Apr 5 '14 at 16:39

A space character with a grey background might work. If the menu you are writing cannot include that, you could try the various shades of checkerboard grey provided by unicode 2591 (the best one, ░ ) or 2592,2593,2588.

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Spaces in Unicode

Unicode defines several space characters with specific semantics and rendering characteristics, as shown in the table below. Depending on the browser and fonts used to view this table, not all spaces may display properly..."

ie: U+0020 32 Yes No Space Basic Latin ] [

U+200B 8203 Yes No Zero Width Space General Punctuation ]​[

Unicode also provides some visible characters to stand in for space when necessary:

Space illustrating characters (visible) in Unicode

U+00B7 183 Middle dot ·

U+237D 9085 Shouldered open box

U+2420 9248 Symbol for space

U+2422 9250 Blank symbol

U+2423 9251 Open box

The best character to use is the last character (Open Box) as used in Set Theory / Theory of Computation. When space codes require explicit indication:

enter image description here

for example when describing a turing machine overwriting a '1' with blank.

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Open Box would get my vote. I've never seen anything else used when it's necessary to unambiguously represent a space. – Peter Flynn Feb 10 at 22:03

Unicode uses U+25CC, the dotted circle ◌, for indicating empty space with combining characters. See combining diacritical marks (PDF). Seems like a reasonably “official” mark of “empty space” and it’s far less ambiguous than the actual space mark.

I do definitely agree with Steve Jessop that it would need defining in the introduction

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I encountered a similar problem when making preliminary analysis on some IMing typing data. Since I needed to be able to display the character many times in a visually distinct fashion, I ended up going the unicode route, and dug up a couple of characters that I liked on this wonderful site.

  • ◯ large circle
  • ○ white circle
  • ○ halfwidth white circle
  • ⚪ medium white circle
  • ⚬ medium small white circle
  • ◌ dotted circle

I ended up choosing ◌, but something else may be better for you depending on what font you're using and personal preference. ▽, ␣, and ░ are all good options that were already suggested.

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