1367977 - Add serialization tests for SVG unitless length values

Status: RESOLVED FIXED

(Core :: CSS Parsing and Computation, enhancement)

Description

[Jeremy Chen ([e-mail])]

There're 3 SVG properties that accept SVG unitless length, stroke-width, stroke-dasharray, and stroke-dashoffset [1]. We should compute and store them as a factor number instead of rounding them to pixels. Although we compute and store them correctly, I just found that We don't have that kind of tests yet. So I'd like to add some tests for them.

I'll start with adding some small factor numbers to these three properties, and see how it goes.


[1] http://searchfox.org/mozilla-central/search?q=symbol:M_8b66591b5a234643ab62b847a70746707a32d04b&redirect=false

Comment 1

[Jeremy Chen ([e-mail])]

Let's see how it goes on try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=d2ef53b3f1fdd7f538ace8d08612541b6bff3800

Comment 2

[Jeremy Chen ([e-mail])]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=7ec0c52c3b396de7db9fadcf68add6b162a69307

Comment 3

[Jeremy Chen ([e-mail])]

I also notice that get the computed value of a SVG unitless length value is a bit different between Firefox, Chrome, and Safari.

Try

getComputedStyle(document.getElementById('svg1')).strokeWidth

with the following examle:

<svg xmlns="http://www.w3.org/2000/svg"> <rect width="100%" height="100%" fill="lime"/> <circle id="svg1" cx="0" cy="0" r=".0008" fill="none" stroke="blue" stroke-width=".0002" transform="translate(180, 300) scale(100000, 100000)"/> </svg>

For an unitless length, such like the stroke-width in the following svg example:

<svg xmlns="http://www.w3.org/2000/svg">
  <rect width="100%" height="100%" fill="lime"/>
  <circle id="svg1" cx="0" cy="0" r=".0008" fill="none" stroke="blue" stroke-width=".0002" transform="translate(180, 300) scale(100000, 100000)"/>
</svg>

The getComputedStyle() API would return

0.0002 on Firefox
0.0002px on Chrome
0.00019999999494757503px on Safari.

Although there's a slice precision diff between Chrome and Safari, the main difference is that Firefox does not return the "px" unit for unitless length, whereas the others do. From the spec [1], it's not clear to me which one is the right behavior.

Filed https://github.com/w3c/svgwg/issues/319 for this.


[1] https://svgwg.org/svg2-draft/types.html#__svg__SVGLength__SVG_LENGTHTYPE_NUMBER

Comment 4

[Jeremy Chen ([e-mail])]

Try in comment 2 looks fine. Upload patch and ask for review then.

Comment 5

[Jeremy Chen ([e-mail])]

Attachment: Bug 1367977 - add serialization tests for SVG unitless length values.

Add small factor numbers as valid values for SVG unitless length values,
so we could ensure that an unitless length can not be rounded accidentally
during computation and serialization.

Review commit: https://reviewboard.mozilla.org/r/143168/diff/#index_header
See other reviews: https://reviewboard.mozilla.org/r/143168/

Comment 6

[Cameron McCormack (:heycam)]

Comment on attachment 8871651 [details]
Bug 1367977 - add serialization tests for SVG unitless length values.

https://reviewboard.mozilla.org/r/143168/#review146856

::: commit-message-5d6fe:4
(Diff revision 1)
> +Bug 1367977 - add serialization tests for SVG unitless length values.
> +
> +Add small factor numbers as valid values for SVG unitless length values,
> +so we could ensure that an unitless length can not be rounded accidentally

s/an unitless/a unitless/
s/can not/will not/

Comment 7

[Jeremy Chen ([e-mail])]

Comment on attachment 8871651 [details]
Bug 1367977 - add serialization tests for SVG unitless length values.

Review request updated; see interdiff: https://reviewboard.mozilla.org/r/143168/diff/1-2/

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ab6539ba5d37
add serialization tests for SVG unitless length values. r=heycam

Comment 9

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/ab6539ba5d37