[MPEG-OTSPEC] Requesting progress update on COLRv1 in fontTools, FreeType, etc.

[Peter Constable]

FYI:

While the draft provided before the recent SC29 meeting already included linear and radial gradients, we have had in mind to also propose adding support at some point for some other gradient types: sweep (or “conic” / “angular”) gradients, and mesh gradients.

Mesh gradients are _very_ different from other gradient types both in nature and in how they are defined, and there are two types (Coons patch, which use bilinear interpolation, and tensor patch, which use bicubic interpolation. Those definitely will need some time for investigation and design discussion.

But sweep gradients are, comparatively, similar to linear and radial gradients: they are defined by a color line that gets applied to a surface in some geometric way. Linear, radial and sweep gradients are the three basic gradient types that are commonly supported in 2D graphics apps or libraries.

With that in mind, we’ve decided to extend our proposal for COLR version 1 to include sweep gradients. See our proposal doc at https://github.com/googlefonts/colr-gradients-spec/blob/master/OFF_AMD2_WD.md; a description of sweep gradients is added in new sub-clause 5.7.11.1.2.4.


Peter


From: mpeg-otspec <mpeg-otspec-bounces at lists.aau.at> On Behalf Of Chris Lilley
Sent: Saturday, January 16, 2021 5:05 AM
To: mpeg-otspec at lists.aau.at
Subject: Re: [MPEG-OTSPEC] Requesting progress update on COLRv1 in fontTools, FreeType, etc.


Combining the graphical expressiveness of SVG with the typographic expressiveness of font variations (and of course using vectors not rasters) will make COLRv1 the clear leader among the assorted chromatic font options.
On 2021-01-14 23:04, Peter Constable wrote:
But it also goes beyond the SVG table in that everything (for which it would be meaningful) in the formats is variable. So, for instance, in a variable font, things that could be varied include the placement of colour stops in a gradient, alpha values, rotation angles, and more.


--

Chris Lilley

@svgeesus

Technical Director @ W3C

W3C Strategy Team, Core Web Design

W3C Architecture & Technology Team, Core Web & Media
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