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Re: [csswg-drafts] [css-color-4] Define gamut mapping (#5191)

From: Mike Bremford via GitHub <sysbot+gh@w3.org>
Date: Thu, 11 Jun 2020 09:54:59 +0000
To: public-css-archive@w3.org
Message-ID: <issue_comment.created-642542435-1591869298-sysbot+gh@w3.org>
That's an interesting proposal. On my to-do list was filing an issue on the `rendering-intent` property which can currently be specified as part of a `@color-profile` rule. 

The problem is that it sets the intent for the color-space as a whole, but that's not how I expect it will be used (if it's used at all, which quite frankly I'm doubtful of). For example, if I'm drawing a gradient in CMYK, I may want to use "perceptual" intent, but if I then want to do some block colors in the same colorspace, say for a barchart, I'd want to use "saturation".

So the `rendering-intent` really needs to be specified on the element, not on the color-profile.

It's of such limited applicability for browsers (only applying if the color they need to convert to their display colorspace is specified in an ICC profile with A2Bn tables, i.e. a CMYK profile) that I expect browser vendors can get away with ignoring it completely. For the CSS-to-PDF vendors, the rendering intent is applied to an individual drawing operation, not the color-space as a whole, so this is a more natural fit.

So hopefully promoting it from the @color-profile rule to a regular property will make next to no difference for anyone.

Anyway, the point I came here to make was that if you're going to do this, and also need to define some sort of gamut-mapping function, it might not be a bad idea to roll it into the same property. So, for example, your element could have `rendering-intent: saturation` to use the saturation tables in the ICC profiles if available, or `rendering-intent: whizzy-lch-function` to use whatever @svgeesus digs up.

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Received on Thursday, 11 June 2020 09:55:00 UTC

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