Substitute missing characters with "?" character - xna

Is there an easy way to make default XNA method SpriteBatch.DrawString substitute characters that are not in spritefont with ? sign? I could go with an extension method, but I'm not sure how to implement it, as there is no way to know if a character is not in the spritefont beforehand.

This functionality is built-in. Open the .spritefont file for your font and scroll down to here:
<!--
If you uncomment this line, the default character will be substituted if you draw
or measure text that contains characters which were not included in the font.
-->
<!-- <DefaultCharacter>*</DefaultCharacter> -->
Uncomment that line and replace the character with the one you want, like so:
<DefaultCharacter>?</DefaultCharacter>
You can also achieve the same effect by modifying the SpriteFont.DefaultCharacter property at runtime.
If you need it, you can get a list of the available characters in a font through the SpriteFont.Characters property.

Related

Porting Arabic font to iOS System

I am just looking to get a better look for my iPad using custom font.
The default Arabic font for iOS8 devices is GeezaPro. and it's in .ttc format.
I am trying to replace it with my custom font.
I use DOSBOX to break system font ttc file into ttf files to make them editable.
Then i use FontLab Studio to replace system font glyphs with my custom font glyphs.
I just copy the glyph from custom font and paste them in the system font (using special paste option FontLab provide).
Then i use DOSBOX again to join these ttf files into ttc file.
That's worked for custom English fonts i used. but using it with arabic fonts show some issues.
The text letters appear separated in iOS apps and everywhere.(as you already know that Arabic language use joined letters and sometimes separated letters depending on the context. if the letter is the first letter it will use specific glyph, the same goes if the letter is in the middle or in the end using different glyph. while in English all letters are always remain separated no matter what. except for handwritten scripts.)
any idea how to fix?
some links:
tutorial I followed to port my fonts
the arabic font I am trying to accomplish (it's free and legit)
P.S: some may say use Bytafont library of fonts but i want to use this specific font. and arabic fonts also limited in the library (20 font only available).
Fonts are complex programs that run on embedded hardware interpreters and font engines (the same way game ROMs run on game hardware or in emulators), and don't just contain the pictures for each letter, but also all the instructions on how to position, combine, and substitute those letters based on what sequence of input it's being told to process.
For almost every font, just copying the glyph outlines is not enough, you also need to make sure that:
the original font's glyph ordering is preserved,
the GPOS table gets copied over (which determines mark positioning, kerning, etc), and
the GSUB table gets copied over (which handles glyph substitution, without which you can't even write Arabic. As an example, you need ـب, ـبـ, بـ or ب depending on context for the same "letter" bā’)
So you generally want to unpack the TTC (which as of OpenType 1.7 can be either truetype or postscript/type2, so that's a thing to remember for the future), then perform the replacements of glyphs (with order-preservation), as well as replacing the GPOS and GSUB tables (using FontForge or TTX) and then pack it back up into the TTC.

MathJax overarrow too short

I am trying to place an overarrow over a piece of text in MathJax.
I am using a custom font that I declare in the code-
\(\overrightarrow{\style{font-family: mysans, TeX, Arial, sans-serif;}{\text{" + tString + "}}}\)"
It works ok for most letters- for capital W or M , using a couple in a row like "WWW" the overbar is too short.
For lowercase i , using a couple in a row, ie "iii" it is too long. My hunch is that MathJax is using a standard character width size to figure out the length of the overarrow and when the character is much longer or shorter than that size, it calculates the overarrow incorrectly. Is there any way around this?
Thanks!
First off, you generally cannot use custom fonts with MathJax. As the documentation says
Since browsers do not provide APIs to access font metrics, MathJax has to ship with the necessary font data; this font data is generated during development and cannot be generated on the fly. In addition, most fonts do not cover the relevant characters for mathematical layout. Finally, some fonts (e.g. Cambria Math) store important glyphs outside the Unicode range, making them inaccessible to JavaScript.
However, if you are only looking to use custom fonts in text elements, then there is a way to work around this: style the surrounding context and set mtextFontInherit:true for the output jax, cf. e.g. here for HTML-CSS.
Unfortunately, this won't actually help you right now. There's a minor regression in MathJax 2.5 (see this discussion leading to the result you describe). This will be fixed in 2.5.1 and in the mean time you could set noReflows:false for the HTML-CSS output.

In a UILabel, is it possible to force a line NOT to break in a certain place

I have a UILabel that is supposed to be two lines long. The text is localized into French and English.
I'm setting the attributedText property of the label. The text is constructed from three appended strings, say textFragment1, textFragment2 and textFragment3. The middle string is actually an image created with an NSTextAttachment.
I want to make sure that textFragment2 and textFragment3 are on the same line. The first string may or may not wrap depending on how long it is. The problem is that my French text is currently fairly short, so the line is wrapping after textFragment2.
I have fixed this temporarily by adding a line break symbol in the localized French text for textFragment1. I don't really love this solution though. I was wondering if there is a way to treat textFragment2 and textFragment3 so that they will always be together on the same line.
You could use a non-breaking space (\u00a0) to join textFragment2 and textFragment3. This character looks just like a normal space—i.e. it results in the same amount of whitespace—but line breaking will not take place on either side of it.
You could also use a zero-width space (\u2060). Using this character will not result in any whitespace, but it will still prevent line breaking on either side. This is what you want if you don’t want any space between textFragment2 and textFragment3 but you still want to prevent line breaking there. (It’s also useful if you have a word with a hyphen in the middle of it but you want to prevent the line from being broken after the hyphen.)
You can read more about these kinds of characters on Wikipedia.

How to stop DrawText from underlining alt characters?

I'm using DrawText to draw text onto a DBGrid canvas. The text comes from the database. But when the string contains an ampersand (&) it treats it as an alt shortcut and underlines it.
For example, what should be
Wool & Silk
winds up being
Wool _Silk
How do I stop this behavior?
Suppress prefix handling with the DT_NOPREFIX flag. This is the way forward if you know you do not want any prefixes drawn.
If you want to draw text with both prefixes and ampersand, you can escape the ampersand by doubling it up. So pass && when you want a single ampersand.
You can find all this information, and more, in the documentation.

How to stop UILabel from replacing "..." with an ellipsis character

I have an iOS app which uses fixed width font label extensively.
After changing to the iOS 7 sdk and build target 6.1, all the label automagically replace occurences of three punctuation marks with an ellipsis character. This breaks a lot of stuff and looks weird, since the ellipsis character is not present in the font I use, and iOS sees fit to use one from a different font.
How do I stop this behaviour?
This is a ligature, and iOS seems to replace them automatically (like fl becomes fl). Seems like there are some options to disable them, see this question: Adjoining "f" and "l" characters
Alternative number three: insert a zero-width space (U+200B) between the dots.
(Posted as an answer per request of the OP)
One way around this is to replace the ASCII periods with a unicode 2024 character ("ONE DOT LEADER"). It looks exactly like a period but should not get converted automatically.
What you could do if this is widespread is to change all your UILabels to a subclass, MyLabel, and intercept messages to set the text, look for three dots, and if found change them to the unicode character above.
Yeah, this is a big PITA but I know of no other workaround.
EDIT
Another idea - find an open source UILabel (there must be at least one) and use it.
Another alternative : the ellipsis is a true character of its own. Why don't you try to add it yourself in your font (with Fontlab, FontForge or Glyphs) at the same width than the other characters?

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