Coloured Punctuation and Annotation
Peter Constable via Unicode
unicode at unicode.org
Mon Apr 10 16:56:02 CDT 2017
The color palette entries (CPAL) used for COLR or SVG can potentially be customized by an application — whether for user customization or to fit some context (such as selection).
From: Asmus Freytag (c) [mailto:asmusf at ix.netcom.com]
Sent: Monday, April 10, 2017 1:39 PM
To: Peter Constable <petercon at microsoft.com>; unicode at unicode.org
Subject: Re: Coloured Punctuation and Annotation
On 4/10/2017 9:30 AM, Peter Constable wrote:
> From: Unicode [mailto:unicode-bounces at unicode.org] On Behalf Of Asmus
> Sent: Wednesday, April 5, 2017 5:30 PM
>>> There are certainly MSS (in many languages) where some punctuation made of dots have some of the dots red and some black.
>> Agreed, those would be a challenge to reproduce with standard font technology and in plain text.
> Not at all. This capability has existed in all major OS platforms for some years now.
It may be in the platforms, but of the few clients I've tried this with, only one is reliably supporting this.
> It is what has enabled the growth of interest in Unicode emoji, but it is by no means limited to Unicode emoji: it can be used for multi-color rendering of any text in ways defined within a font. The OpenType spec supports this through a few techniques:
> - Decomposing a glyph into several glyphs that are layered (z-ordered) with colour assignments.
> - Glyphs expressed as embedded colour bitmaps.
> - Glyphs expressed as embedded SVG.
Khaled gave a very nice demonstration of that on this list (which allowed me to test this).
>> But for the same reason, they are out of scope for plain text (and therefore a bit irrelevant to the current discussion).
> I agree, the rendering aspect is completely orthogonal to Unicode plain-text encoding.
The problem with multicolored fonts would be the integration into font color selection via styling.
If you select a section of this text, the black ink will invert as you select it, but the other colors remain the same, which is different from selecting a multicolored image or different from selecting multiple runs of fonts in different colors.
I wonder whether high-end tools like Indesign would be able to allow styling of individual color levels. For rendering emoji colors via fonts that wouldn't matter, but for the kind of annotated text example, it could be interesting to be able to tweak these layer colors.
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