Cross-platform font handling, and why you don't want to do it

[Mike Kerner]

Other tools that we use have implemented CSS to manage this, but that does
not make it easier.
fonts have been a menace since we first had x-platform dev tools and
meaningful WYSIWYG rendering (Win 95?). at the time, dpi differences made
the issue impossible to resolve for smaller fonts, especially.
the mechanisms for handling those issues have changed, but it has not
gotten better.

On Mon, Sep 5, 2022 at 12:07 PM Tom Glod via use-livecode <
use-livecode at lists.runrev.com> wrote:

> It seems like you have an approach that can work well, despite being more
> work.
> Mainly shipping the fonts, which cancels out most of the issues, but
> requires handling each case.
>
> I don't know if any multi-platform dev tool deals with fonts without any
> extra hoops.
> If I recall correctly, flutter did  OK, but not perfectly on the 2 mobile
> platforms, but I've not tested the desktops, which I am guessing will be
> worse.
>
> Hopefully your wrap up can help people to avoid trying to stick ..... the
> thing in the thing.
> Good luck to us all.
>
>
> On Mon, Sep 5, 2022 at 3:03 AM Quentin Long via use-livecode <
> use-livecode at lists.runrev.com> wrote:
>
> > Cross-platform font compatibility is a hellacious rat's nest of
> > mismatches. It may or may not be worse than handling time (Daylight
> Savings
> > Time? leap years? leap *seconds*? etc, ad nauseum), but it's plenty bad
> > enough on its own merits, or lack thereof.
> > * You can't be 100% confident that your user will have the same font(s)
> > you do installed on their system.
> > * If your user has a font *of the same name* as your font installed on
> > their system, you can't be 100% confident that *their* font came from the
> > same font foundry as *your* font. Yes, font names are legally protected,
> > but... Helvetica, anyone?
> > * If your user has a font *of the same name* as your font installed on
> > their system, you can't be 100% confident that it's the *same* font you
> > have. Again: Font names are legally protected. But what if you
> > have version 15.0 of RandomFontFoundry's WhateverFont on your system, but
> > your user only has version 1.0 of RandomFontFoundry's WhateverFont? Who
> > *knows* what tweaks RandomFontFoundry may have made to WhateverFont in
> > between those two version numbers?
> > * Can you be 100% confident that version 15.0
> > of RandomFontFoundry's WhateverFont *for Mac* is going to render *exactly
> > the same* as version 15.0 of RandomFontFoundry's WhateverFont *for
> Windows*
> > or *for Linux*? No. You cannot. Different type rendering engines on
> > different OSes *ensure* that rendering compatibility will be problematic
> at
> > best.
> > * Assuming your user has exactly the same version of exactly the same
> font
> > on exactly the same OS you do, you can't be 100% confident that your user
> > has installed the font metrics data (kerning, sidebearings, etc)—which
> > means you have no idea if the damn thing will look the same on your
> user's
> > system as on your system.
> > If you want to *ensure* that some piece of text looks *exactly the same*
> > cross-platform, the only way to get there is to format the text the way
> you
> > want it on one platform, take a screenshot, and use that graphic. But
> even
> > then, can you be 100% confident that your user *hasn't* tweaked some
> > setting on their system which messes with graphics..?
> >
> > The "take a screenshot" solution is not well-suited for any use-case
> > involving text which varies from time to time, and largely impractical
> for
> > any use-case involving text which is input by the user. In principle, it
> > should be possible to create a library of glyph-images of all glyphs in a
> > font, and import those glyph-images as necessary—no, mass quantities of
> > "set the imageSource of char X to $GlyphImage" commands ain't gonna fly,
> > cuz letterspacing will look crappy—but that "solution" is tantamount to
> > building your own, redundant, set of text-handling routines. Yuck!
> > If "take a screenshot" doesn't work for you, I suspect the next-best
> route
> > to achieving Absolute Cross-Platform Font Fidelity may be this:
> >  1) Open up your font in your font-editing utility of choice
> > (Fontographer, Glyphs, FontLab, whatever)
> > 2) Export your font N times, once for each of the *other* OSes you need
> > font compatibility with—WhateverFontMac, WhateverFontWindows,
> > WhateverFontLinux, etc
> > 3) Open up your stack within each of the OSes you're working with, always
> > using the appropriate OS-specific version of your font, and see how
> > different your stack looks on the other OSes
> > 4) Tweak the font metrics on the other-OS versions of your font until
> your
> > stack looks the same on all OSes
> > 5) When it's time to distribute your stack, be sure to bundle *all* the
> > hand-tuned OS-versions of your font with your stack
> > This procedure is, of course, a royal pain in the arse. Hellacious rat's
> > nest of mismatches, yada yada yada. But regardless of how painful it is?
> If
> > you need absolute visual fidelity cross-platform, *and* total flexibility
> > in the *content* of text, this procedure may be your least-bad option.
> > As a perhaps-preferable option:
> > 1) Open up your stack on each of the OSes you're striving for font
> > compatibility on
> > 2) Tweak the appearance-relevant text properties (textFont, textHeight,
> > textShift, etc) on each OS until you get an acceptable approximation of
> > identical appearance
> > 3) Make note of the values of all these text properties for each OS
> > 4) Assuming you have however-many fonts specified by fontName, be sure
> you
> > bundle all those fonts with your stack when you distribute it
> > 5) Include in your stack's preOpenStack handler a switch which
> > includes "case = WhateverOS" for each OS you want font compatibility for
> > 6) Within each OS's "case", set all the appearance-relevant text
> > properties for that OS
> > This procedure is not going to achieve anywhere near the degree of
> > cross-platform font fidelity as the "roll your own" solution above. On
> the
> > plus side, it's *significantly* less nitpicky/picayune/painful. You puts
> in
> > your money, and you takes your chances...
> >
> > "Bewitched" + "Charlie's Angels" - Charlie = "At Arm's Length" Read the
> > webcomic at [ http://www.atarmslength.net ]! If you like "At Arm's
> > Length", support it at [ http://www.patreon.com/DarkwingDude ].
> > _______________________________________________
> > use-livecode mailing list
> > use-livecode at lists.runrev.com
> > Please visit this url to subscribe, unsubscribe and manage your
> > subscription preferences:
> > http://lists.runrev.com/mailman/listinfo/use-livecode
> >
> _______________________________________________
> use-livecode mailing list
> use-livecode at lists.runrev.com
> Please visit this url to subscribe, unsubscribe and manage your
> subscription preferences:
> http://lists.runrev.com/mailman/listinfo/use-livecode
>


-- 
On the first day, God created the heavens and the Earth
On the second day, God created the oceans.
On the third day, God put the animals on hold for a few hours,
   and did a little diving.
And God said, "This is good."