Is there a downwards double arrow with stroke unicode character? - unicode

I want the character ⇓ with stroke, just like ⇏ but downwards, but I can't find it. Does it exist?
Edit:
If you don't see the arrows (e.g. you use IE),
I want the character [downwards double arrow] with stroke, just like [rightwards double arrow with stroke] but downwards, but I can't find it. Does it exist?

There is no such character as a precomposed character (i.e., as a single encoded character, a code point assigned to a character), but you can in principle represent it using an arrow character followed by a combining overlay character.
The character “⇏” U+21CF RIGHTWARDS DOUBLE ARROW WITH STROKE has been defined as having the canonical decomposition RIGHTWARDS DOUBLE ARROW (U+21D2) COMBINING LONG SOLIDUS OVERLAY (U+0338). In principle, a character should be expected to be rendered the same way as its canonical decomposition. In practice, things don’t always go that way.
Along the same lines, a downwards double arrow with stroke could be written as the two-character sequence DOWNWARDS DOUBLE ARROW (U+21D3) COMBINING LONG SOLIDUS OVERLAY (U+0338) or, in HTML, as ⇓̸. In practice, few fonts contain these characters, and browsers may fail to implement the combination properly. Moreover, in many fonts, the result is awkward. In Arial Unicode MS and in DejaVu Serif, the result might be acceptable, but only the latter is free (can be legally used as a downloadable font via #font-face). Here’s the combination as rendered by your browser with the SO stylesheets in effect: ⇓̸.

It doesn't seem to exist, according to this page (compared to this).

Related

Are all "non-grapheme" code points invisible?

In a unicode string, each grapheme consists of one or more code points. However, there are some code points, such as the Zero-width joiner (ZWJ), which are never a part of a grapheme. The ZWJ is, in itself, invisible. Are all of those "non-grapheme" code points always invisible?
The Unicode representation of the Ogham script is notable for containing a non-invisible whitespace character. (U+1680: OGHAM SPACE MARK)
Tom Scott made an excellent YouTube video on the subject: link
There are many joining characters which are intended to modify a base character. Whether they provide a grapheme on their own is partially an implementation detail, I expect.
Example: o followed by U+0308 COMBINING DIAERESIS produces ö (the glyph in isolation is rendered by your browser as ̈)
List of all code points in this category: https://codepoints.net/search?lb=CM
Recent Unicode versions also have invisible characters which modify how a previous emoji is being rendered, famously to add e.g. a skin color trait to emojis with human figures or faces. These by definition are not graphemes in their own right, though again, rendering engines are probably free to figure out a way to represent them if they are encountered in isolation.
Example: 👋 U+1F44B WAVING HAND SIGN followed by U+1F3FB EMOJI MODIFIER FITZPATRICK TYPE-1-2 (which in isolation renders as 🏻) produces 👋🏻
Full catalog: https://www.unicode.org/emoji/charts/full-emoji-modifiers.html

Unicode value for right arrow with two strokes

I want to use the → character with two // strokes through the arrow but cannot find the unicode value for it anywhere. Does this exist in unicode? If not, is there a way to recreate it?
There are six Unicode characters whose name matches a right arrow with a double stroke, making use of the regular expression: /right.*arrow.*double.*stroke/.
Only two characters appear to be relevant candidates:
⇻ U+21FB RIGHTWARDS ARROW WITH DOUBLE VERTICAL STROKE
⭼ U+2B7C RIGHTWARDS TRIANGLE-HEADED ARROW WITH DOUBLE HORIZONTAL STROKE
(* RIGHTWARDS TRIANGLE-HEADED ARROW WITH DOUBLE VERTICAL STROKE)
Notes:
The official Unicode name of U+2B7C was initially wrong, but a corrected name has been added later as an alias.
U+2B7C appears to be quite uncommon, no suitable font was available in the OS used for the screenshot. Still, it is possible to see what it should look like in the Miscellaneous Symbols and Arrows - Range: 2B00–2BFF PDF document:
I was not successful in finding what you were looking for (negative result). U+0219B is a "Rightwards Arrow with Stroke" and U+021FB "Rightwards Arrow with Double Vertical Stroke". If it exist, it would probably be called "Rightwards Arrow with Double Stroke". https://en.wikipedia.org/wiki/Arrow_(symbol)
The following Unicode sequences should describe your character, but unfortunately fonts are not helping.
→⃫ : \u2192\u20EB
⟶⃫ : \u27F6\u20EB
They are normal and long arrow, with the combining U+20EB: COMBINING LONG DOUBLE SOLIDUS OVERLAY (long double slash overlay). You may find a technical font which can display both in the expected way.
You may get something acceptable also with:
⎯⎯⎯⃫⟶ \u23AF\u23AF\u23AF\u20EB\u27F6 (using arrow extension line)
⎯⎯⃫⟶ \u23AF\u23AF\u20EB\u27F6
Depending on the environment, one of the two seem much better (on my computers).
So: you can express it (semantically) with Unicode, but standards fonts are not helping us. You should experiment with many symbols/mathematical fonts, to get an acceptable solution.
As alternative, you can build such image easily with SVG (and use a SVG as character image).

What's the character code for exclamation mark in circle?

What's the Unicode or Segoe UI Symbols (or other font) code for exclamation mark in circle?
There is no single Unicode codepoint for that particular symbol.
Unicode does define a U+20DD COMBINING ENCLOSING CIRCLE codepoint, but most fonts (including Segoe) do not treat it as a combining symbol, but rather as its own character. In Word, for instance, you would have to adjust the character spacing between it and a preceding character (in this case U+0021 EXCLAMATION MARK) to a negative offset to make them overlap (see Using the “Combining Enclosing Circle” character in Word).
Some fonts do support U+20DD in general (see COMBINING ENCLOSING CIRCLE (U+20DD) Font Support), and some of them do treat it as a combining mark (Code2000, GNU FreeFont fonts, STIX fonts, Symbola, XITS, etc), but the resulting overlap may not visually be exactly what you are looking for, depending on the size and alignment of the character it is being combined with.

How can I detect any unicode characters which have descenders, using .NET

I am trying to minimize the vertical distance between controls on a programmatically constructed Windows Form (using C#). This involves setting the Height property appropriately.
I have found that if the text of the control does not contain any letters with descenders in them (i.e. does not have any of the characters j, g, p, q or y) then the control Height can be smaller than when it does contain such letters (if it does contain letters with descenders then the descenders are chopped off if the Height isn't enough).
It will work fine to test for any of the above 5 characters as long as the language is English, or English - like, but I need to be able to cater for (just about) any language.
Is there a way, given some arbitrary Unicode character (and perhaps a font) to determine if that Unicode character has a descender or not?
There is no property defined for Unicode characters to indicate the presence of a descender, and it’s really a feature of glyph design rather than characters. For example, “Q” has a descenders in many fonts, and “J” has one in some. Besides, given the context, you should also consider diacritic marks placed below a letter, not just descenders of base letters. And probably diacritics above letters, too.
So you would need to read the font information (when available) about character dimensions, or tentatively draw characters in your software and measure their dimensions.
As a rule of thumb, any line height below 1.1 times the font size will cause problems with some characters and fonts. Using 1 (“setting solid”) is not enough, because characters may in fact extend outside the font size.
In Windows, you call GetPath() to get an array containing the X/Y coordinates of every point making up the perimeter or outline of the string of glyphs. Search the array for min/max, which will get you the rectangle exactly enclosing the string. Right to the edge of the letters.

Unicode character that lines up with ⎮ but is as long as ⎢

Sorry if this isn't the right overflow for this question. I need a unicode character that is as long as ⎢ (23A2, LEFT SQUARE BRACKET EXTENSION) but lines up horizontally with ⎮ (23AE, INTEGRAL EXTENSION). Is there such a character?
Take a look at shapecatcher. If you draw a straight line, it shows plenty of different codepoints resembling |.
As already pointed out, exact placement and size may depend on the font, but if you know that the font is going to be a specific one (because you supply it), you could still find the character you're looking for.
It turns out this does depend on the font. If I use DejaVu Sans Mono, INTEGRAL EXTENSION is as long as I want it to be. This font appears to be almost exactly the same as the font I was using, Menlo, except for some small differences with some characters (including this one).