SVG width/height in rem causes incorrect warning in the console
Categories
(Core :: SVG, defect)
Tracking
()
People
(Reporter: 326374, Unassigned)
References
(Blocks 1 open bug)
Details
Attachments
(3 files)
Warnings displayed in the console
Steps to reproduce:
Use the rem unit in the width/height attributes of <svg>.
Example SVG file:
<svg xmlns="http://www.w3.org/2000/svg" width="1rem" height="1rem"/>
Example HTML file:
<!DOCTYPE html>
<svg width="1rem" height="1rem"/>
Actual results:
Got warning in the console
Expected results:
No warning
Most other units seem to cause the same warnings: ch, cap, Q, ic, vb, vi, vw, vh, vmin, vmax and their small/large/dynamic counterparts. All of them seem to work, though.
I believe that support for these units was implemented in bug 1383650.
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Comment 3•2 years ago
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Thanks! I can reproduce.
I believe that support for these units was implemented in bug 1383650.
Thanks, that's helpful. --> Adding a dependency on that bug.
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Comment 4•2 years ago
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Looks like SVGAnimatedLength.cpp GetUnitTypeForString is failing to match when we look up the unit (while parsing the value).
It's failing because the unit isn't listed in unitMap:
https://searchfox.org/mozilla-central/rev/1ce190047b9556c3c10ab4de70a0e61d893e2954/dom/svg/SVGAnimatedLength.cpp#65
static const nsStaticAtom* const unitMap[] = {
nullptr, /* SVG_LENGTHTYPE_UNKNOWN */
nullptr, /* SVG_LENGTHTYPE_NUMBER */
nsGkAtoms::percentage,
nsGkAtoms::em,
nsGkAtoms::ex,
nsGkAtoms::px,
nsGkAtoms::cm,
nsGkAtoms::mm,
nsGkAtoms::in,
nsGkAtoms::pt,
nsGkAtoms::pc};
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Comment 5•2 years ago
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Maybe (?) it's as simple as just adding the new unit values to that unitMap?
I suspect our current implementation (a vestige from before bug 1383650) is based on this spec text from SVG1.1 (which has an allow-list of allowed units):
https://www.w3.org/TR/SVG11/types.html#DataTypeLength
When a <length> is used in an SVG presentation attribute, the syntax must match the following pattern:
length ::= number ("em" | "ex" | "px" | "in" | "cm" | "mm" | "pt" | "pc" | "%")?
But SVG2 section 7.8 defers to CSS for the definition of width (including syntax, etc):
https://www.w3.org/TR/SVG2/geometry.html#Sizing
...and there's additional text deferring to CSS for units here:
https://www.w3.org/TR/SVG2/coords.html#Units
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Comment 6•2 years ago
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longsonr, maybe you'd be interested to work on this? (Not sure if it's as trivial as I think in comment 5, but hopefully a quick and easy win.)
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| Comment hidden (off-topic) |
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Comment 9•1 year ago
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You can't just add a unit, you have to add code to process that unit. bug 1836995 adds support for q units although since they are absolute units (i.e. they don't depend on some external property such as font size or display width) they are somewhat easier.
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Updated•1 year ago
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Description
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