[webkit-reviews] review denied: [Bug 217529] Define image intrinsic aspect ratio by mapping to the `aspect-ratio` property. : [Attachment 429180] Patch

Thu May 20 09:55:57 PDT 2021

Antti Koivisto <koivisto at iki.fi> has denied cathiechen
<cathiechen at igalia.com>'s request for review:
Bug 217529: Define image intrinsic aspect ratio by mapping to the
`aspect-ratio` property.
https://bugs.webkit.org/show_bug.cgi?id=217529

Attachment 429180: Patch

https://bugs.webkit.org/attachment.cgi?id=429180&action=review

--- Comment #14 from Antti Koivisto <koivisto at iki.fi> ---
Comment on attachment 429180
  --> https://bugs.webkit.org/attachment.cgi?id=429180
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=429180&action=review

> Source/WebCore/style/StyleAdjuster.cpp:508
> +    if (m_element &&
m_document.settings().aspectRatioOfImgFromWidthAndHeightEnabled() &&
style.aspectRatioType() == AspectRatioType::Auto) {
> +	   double attributeWidth = -1;
> +	   double attributeHeight = -1;
> +	   if (m_element->useWidthHeightAsAspectRatioHint(attributeWidth,
attributeHeight)) {
> +	       style.setAspectRatioType(AspectRatioType::AutoAndRatio);
> +	       style.setAspectRatio(attributeWidth, attributeHeight);
> +	   }
> +    }

"When the text below says that a pair of attributes w and h on an element
element map to the aspect-ratio property (using dimension rules), it means that
if element has both attributes w and h, and parsing those attributes' values
using the rules for parsing dimension values doesn't generate an error or
return a percentage for either, then the user agent is expected to use the
parsed dimensions as a presentational hint for the 'aspect-ratio' property of
the form auto w / h."

So the concept used in the spec here is "presentational hint",
https://html.spec.whatwg.org/#the-css-user-agent-style-sheet-and-presentational
-hints

It is the same concept as used for stuff like <body bgcolor="blue">

In WebKit this is implemented as Element::presentationAttributeStyle(). To
generate it correctly see for example
HTMLBodyElement::collectStyleForPresentationAttribute.

You shouldn't need anything in style adjuster for this feature.