[webkit-dev] canvas and sRGB

[Rik Cabanier]

On Mon, May 2, 2016 at 1:58 PM, Simon Fraser <simon.fraser at apple.com> wrote:

> On May 2, 2016, at 1:45 PM, Rik Cabanier <cabanier at gmail.com> wrote:
>
> All,
>
> with the release of DCI-P3 screen, WebKit began supporting the display of
> high gamut images.
> Specifically, if you have an image with a DCI-P3 profile, its pixels
> render untouched on the new displays.
>
> However, if you try do do any sort of canvas manipulation, you will see
> that the colors are being compressed to sRGB and you will lose the depth of
> the color.
>
> Was it an oversight to always create the canvas imagebuffer in sRGB? [1]
>
>
> No, this was a deliberate choice. We can't change author expectations for
> what getImageData() return.
>

Now we see different visual output which is also not what an author expects
:-(

Can you elaborate what is unexpected with getImageData? Is it that css
"red" no longer returns 100% red pixels?

> If this is as-designed, how can we work around this limitation?
>
>
> With possible future enhancements to the canvas spec that allow authors to
> request backing store with a different format and/or color profile.
>
>
> PS
> I asked the same question on WhatWG. [2]
>
>
> 1:
> https://github.com/WebKit/webkit/blob/112c663463807e8676765cb7a006d415c372f447/Source/WebCore/platform/graphics/ImageBuffer.h#L73
> 2:
> https://lists.w3.org/Archives/Public/public-whatwg-archive/2016Apr/0036.html
>
>
> Simon
>
>
>
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