Custom Font -- Where to Map Glyphs, How to Display Characters?

GrannyGrump · 03-03-2014, 02:44 AM

Mods-- I wasn't sure whether to post this in Epub or in Workshop, please move me if needed.

I am assembling a custom font with fleurons and dividers, using freeware TypeLight (I would like to do a mini-tutorial later if I can get this question figured out.)

I remember Jellby remarking on another thread about fonts, that under epub specs, special symbols/glyphs must NOT be mapped to normal characters, and should be assigned to the "Private Use" unicode block. (Remember the thread about the Apple symbol? https://www.mobileread.com/forums/sho...d.php?t=222825
and the one about Old English Blackletter font?
https://www.mobileread.com/forums/sho...d.php?t=224276

BUT --- Apparently there is no way to call up Private Use characters in epub using the usual number entity or named entity code.

In my test epub, to be sure it wasn't a problem with my custom font, I embedded Wingdings font and also Quivira (a redistributable font with wide unicode coverage).

I checked to be sure that each one had a character existing at code point F021 in the Private Use block. I try to call the character using either/both &_#_xf021; or &_#_61473; [assume the underscores are not used, they are here to keep the forum from converting to actual characters].

Sigil, ADE, and Calibre Reader all show a missing character glyph.

Sigil and Calibre DO show the trigram character from code point 2630 in the "Dingbats" Area, but ADE does not, even though I have fonts correctly embedded. I am thinking this is something to do with insufficient Unicode support on the part of ADE.

So it would seem that there is no way to call up these characters programatically. The unicode.org site http://www.unicode.org/charts/#symbols says re: Private Use Area: "The Private Use Area does not contain any character assignments, consequently no character code charts or names lists are provided for this area."

HOWEVER --- if I map the glyphs in the Latin 1 or Latin Extended areas (for example, to tilde, bullet, underscore, etc ), all three softwares show the characters correctly.
So my wish is to map the glyphs to seldom-used Latin characters (or maybe Greek, Cyrillic, whatever would work) in order to get them to display correctly.

Will the Epub Spec Police come knocking at my door? Is there any other alternative that will work?

Jellby · 03-03-2014, 03:35 AM

As far as I know, that should work. So, if it doesn't it's probably an error in the code or a bug in the renderer.

Apparently, ADE does not like some fonts for some reason. I don't know if it has been found out which fonts or why. Moreover, in a hardware reader very large fonts can be ignored (my reader just refuses to show Arial Unicode or Code2000).

Could you try a test font with only two characters defined: "A" and U+F021, both with fleurons, to see if it's really been used?

GrannyGrump · 03-03-2014, 04:19 AM

Well, now. Here I sit with egg on my face again. I quickly threw together a 2-glyph font, made a new test epub per your suggestion, and tried it out. Quivira and my Test Font worked fine, Wingdings did not.

I had done a computer reboot meanwhile, and maybe that's why, or more likely, that the new epub didn't have whatever code error was in the first one.

But it seems like the Wingdings font still won't display, and maybe I found out why ...

TypeLight's Help manual gives an instruction that compounds the problem. It tells you to make the code page for "Symbol Character Set" active, and only characters in that set will be saved. But if I do that to my test font, the characters no longer appear when I use the number/name entities. If I leave the Latin Set active, it seems fine. Maybe that is why Wingdings font is invisible, too.

EDIT TO ADD--Yep, I took the "active" setting off the Wingdings "Symbol Character Set", and now it also is working as it should. I might have a word with the TypeLight folks to add a little warning to their help file...

Font adventures: not for the faint-of-heart!

Thanks for your reply, it got me going in a better direction!

mrmikel · 03-03-2014, 06:17 AM

No particular reason that these special characters all have to be in one set, is there, unless they must be used in the same line. Thanks again for the pointer. This is an area I have feared to tread in, having enough trouble banging my OCRed $%^&^(*&*& into submission!

03-03-2014, 02:44 AM	#1
GrannyGrump Obsessively Dedicated... Posts: 3,200 Karma: 34977896 Join Date: May 2011 Location: JAPAN (US expatriate) Device: Sony PRS-T2, ADE on PC	Custom Font -- Where to Map Glyphs, How to Display Characters? Mods-- I wasn't sure whether to post this in Epub or in Workshop, please move me if needed. I am assembling a custom font with fleurons and dividers, using freeware TypeLight (I would like to do a mini-tutorial later if I can get this question figured out.) I remember Jellby remarking on another thread about fonts, that under epub specs, special symbols/glyphs must NOT be mapped to normal characters, and should be assigned to the "Private Use" unicode block. (Remember the thread about the Apple symbol? https://www.mobileread.com/forums/sho...d.php?t=222825 and the one about Old English Blackletter font? https://www.mobileread.com/forums/sho...d.php?t=224276 BUT --- Apparently there is no way to call up Private Use characters in epub using the usual number entity or named entity code. In my test epub, to be sure it wasn't a problem with my custom font, I embedded Wingdings font and also Quivira (a redistributable font with wide unicode coverage). I checked to be sure that each one had a character existing at code point F021 in the Private Use block. I try to call the character using either/both &_#_xf021; or &_#_61473; [assume the underscores are not used, they are here to keep the forum from converting to actual characters]. Sigil, ADE, and Calibre Reader all show a missing character glyph. Sigil and Calibre DO show the trigram character from code point 2630 in the "Dingbats" Area, but ADE does not, even though I have fonts correctly embedded. I am thinking this is something to do with insufficient Unicode support on the part of ADE. So it would seem that there is no way to call up these characters programatically. The unicode.org site http://www.unicode.org/charts/#symbols says re: Private Use Area: "The Private Use Area does not contain any character assignments, consequently no character code charts or names lists are provided for this area." HOWEVER --- if I map the glyphs in the Latin 1 or Latin Extended areas (for example, to tilde, bullet, underscore, etc ), all three softwares show the characters correctly. So my wish is to map the glyphs to seldom-used Latin characters (or maybe Greek, Cyrillic, whatever would work) in order to get them to display correctly. Will the Epub Spec Police come knocking at my door? Is there any other alternative that will work? Last edited by GrannyGrump; 03-03-2014 at 02:56 AM.

03-03-2014, 04:19 AM	#3
GrannyGrump Obsessively Dedicated... Posts: 3,200 Karma: 34977896 Join Date: May 2011 Location: JAPAN (US expatriate) Device: Sony PRS-T2, ADE on PC	Well, now. Here I sit with egg on my face again. I quickly threw together a 2-glyph font, made a new test epub per your suggestion, and tried it out. Quivira and my Test Font worked fine, Wingdings did not. I had done a computer reboot meanwhile, and maybe that's why, or more likely, that the new epub didn't have whatever code error was in the first one. But it seems like the Wingdings font still won't display, and maybe I found out why ... TypeLight's Help manual gives an instruction that compounds the problem. It tells you to make the code page for "Symbol Character Set" active, and only characters in that set will be saved. But if I do that to my test font, the characters no longer appear when I use the number/name entities. If I leave the Latin Set active, it seems fine. Maybe that is why Wingdings font is invisible, too. EDIT TO ADD--Yep, I took the "active" setting off the Wingdings "Symbol Character Set", and now it also is working as it should. I might have a word with the TypeLight folks to add a little warning to their help file... Font adventures: not for the faint-of-heart! Thanks for your reply, it got me going in a better direction! Last edited by GrannyGrump; 03-03-2014 at 04:35 AM.

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03-03-2014, 03:35 AM	#2
Jellby frumious Bandersnatch Posts: 7,515 Karma: 18512745 Join Date: Jan 2008 Location: Spaniard in Sweden Device: Cybook Orizon, Kobo Aura	As far as I know, that should work. So, if it doesn't it's probably an error in the code or a bug in the renderer. Apparently, ADE does not like some fonts for some reason. I don't know if it has been found out which fonts or why. Moreover, in a hardware reader very large fonts can be ignored (my reader just refuses to show Arial Unicode or Code2000). Could you try a test font with only two characters defined: "A" and U+F021, both with fleurons, to see if it's really been used?

03-03-2014, 06:17 AM	#4
mrmikel Color me gone Posts: 2,089 Karma: 1445295 Join Date: Apr 2008 Location: Central Oregon Coast Device: PRS-300	No particular reason that these special characters all have to be in one set, is there, unless they must be used in the same line. Thanks again for the pointer. This is an area I have feared to tread in, having enough trouble banging my OCRed $%^&^(&& into submission!

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