[csswg-drafts] [css-zoom] CSS Zoom and SVG (#10490)

progers has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-zoom] CSS Zoom and SVG ==
Should CSS zoom be supported in SVG? Below are some examples:
```
<svg width="100" height="100" style="background: #006AA7;">
  <!-- zoom affecting css properties -->
  <rect style="x: 5px; y: 5px; width: 40px; height: 5px; fill: #fecc0284; zoom: 2;" />

  <!-- zoom affecting geometry properties -->
  <rect x="5" y="15" width="40" height="5" fill="#fecc0284" style="zoom: 2;" />

  <!-- nested zoom and geometry properties -->
  <g style="zoom: 2">
    <rect x="5" y="25" width="40" height="5" fill="#fecc0284" />
  </g>

  <!-- zoom affecting geometry attributes -->
  <line x1="5" y1="37.5" x2="45" y2="37.5" stroke-width="5" stroke="#fecc0284" style="zoom: 2;"/>
</svg>
```

For historical reasons, Blink and Webkit currently implement zoom as an additional transform at the SVG root, and ignore zoom inside SVG.

CSS spec questions:

- Should used `<length>` properties (e.g., `x` and other [geometry properties](https://svgwg.org/svg2-draft/single-page.html#chapter-geometry)) be affected by zoom?
Yes, based on the existing text for [used values](https://drafts.csswg.org/css-cascade-3/#used) and the [zoom property](https://drafts.csswg.org/css-viewport/#zoom-property)?

SVG spec questions:

- Should `<length>` attributes (e.g., [`x1`](https://svgwg.org/svg2-draft/single-page.html#shapes-LineElementX1Attribute)) be affected by zoom?
Yes, for consistency with styles (requires spec update)?
- Should [getBBox](https://svgwg.org/svg2-draft/single-page.html#types-__svg__SVGGraphicsElement__getBBox) be affected by zoom?
No, as the spec intends it to be a local value which is not affected by transform (requires spec update)?
- Should [getCTM](https://svgwg.org/svg2-draft/single-page.html#types-__svg__SVGGraphicsElement__getCTM) be affected by zoom?
Yes, as it should be used with getBBox to get a rect in the root coordinate space (requires spec update)?

cc: https://github.com/w3c/csswg-drafts/issues/5623 @chrishtr @emilio @szager-chromium

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/10490 using your GitHub account


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Received on Monday, 24 June 2024 21:52:13 UTC