1489392 - Update wpt to accept the non-normalized svg path at computed time

Status: RESOLVED FIXED

(Core :: CSS Transitions and Animations, enhancement, P3)

Description

[Boris Chiou [:boris]]

In bug 1486094, we make path() animatable, and normalize the svg paths at animation time. However, according to the svg spec proposal [1], it has some benefits to normalize the svg paths at computed time, so if we call getComputedStyle, the output is the normalized svg path. For now, the normalization is to convert the absolute coordinates into relative coordinates. We could do more in a separate follow-up bug, I think.

[1] https://github.com/w3c/svgwg/issues/321

Comment 1

[Boris Chiou [:boris]]

Google guys agree to update this, so I will fix this bug soon.

Comment 2

[Boris Chiou [:boris]]

Attachment: Bug 1489392 - Part 1: Re-define CoordPair struct.

I would like to move the normalization into parser, and it seems
re-defining CoordPair makes us easier to reuse the macros.

Comment 3

[Boris Chiou [:boris]]

Attachment: Bug 1489392 - Part 2: Normalize path string in parser

This is about the spec issue: https://github.com/w3c/svgwg/issues/321.

There are some benefits for SVG path and its animations if we could
normalize it at computed time (or even earlier, at parser time). The
computed value of SVG path is the same the specified value, and we have
an agreement with Google chrome to do the normalization for both
specified and computed values, so we move the normalization into the
parser.

Depends on D5903

Comment 4

[Boris Chiou [:boris]]

Attachment: Bug 1489392 - Part 3: Simplify BuildPath

The svg path string is always "absolute" coordinates now, so we could drop the
absolute flag to save more memory.

Depends on D5904

Comment 5

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9009251 [details]
Bug 1489392 - Part 1: Re-define CoordPair struct.

Emilio Cobos Álvarez (:emilio) has approved the revision.

Comment 6

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9009253 [details]
Bug 1489392 - Part 2: Normalize path string in parser

Emilio Cobos Álvarez (:emilio) has approved the revision.

Comment 7

[Emilio Cobos Álvarez (:emilio)]

Comment on attachment 9009254 [details]
Bug 1489392 - Part 3: Simplify BuildPath

Emilio Cobos Álvarez (:emilio) has approved the revision.

Comment 8

[Boris Chiou [:boris]]

svgwg still discuss this topic. I will hold these patches for a while.

Comment 9

[Boris Chiou [:boris]]

Sorry, these patches should be updated. I thought Google chrome wants to make both specified and computed values normalized. Just checked their patchset 10 [1], and the wpt is updated as now only computed styles use absolute commands. In other words, the normalization should happens in `ToComputedValue` or `ToCss` for `computed::SVGPathData`.

[1] https://chromium-review.googlesource.com/c/chromium/src/+/1215150

Comment 10

[Boris Chiou [:boris]]

Attachment: Bug 1489392 - Part 2: Normalize svg path at computed time

According to https://github.com/w3c/svgwg/issues/321, we do normalization
at computed time. That means the specified value still uses original
coordinates, but the computed value always uses absolute coordinates.

Depends on D5903

Comment 11

[Brian Birtles (:birtles)]

Comment on attachment 9010117 [details]
Bug 1489392 - Part 2: Normalize svg path at computed time

Brian Birtles (:birtles) has approved the revision.

Comment 12

[Boris Chiou [:boris]]

It seems AmeliaBR has the strong preference that we should do normalization only for intermediate values [1]. (In other words, keep the current implementation which does normalization at animation time.)

[1] https://github.com/w3c/svgwg/issues/321#issuecomment-423257880

Comment 13

[Boris Chiou [:boris]]

Attachment: Bug 1489392 - Part 2: Update wpt to accept non-normalized path string at computed time.

There is still no conclusion in https://github.com/w3c/svgwg/issues/321,
so we follow the option 3 in [1] for now:
Don't absolutize anywhere except when needed for animations.

[1] https://github.com/w3c/svgwg/issues/321#issuecomment-423309441

Note:

1. Drop "offset-path-serialization.html" because we are doing the simliar
   thing in offset-path-computed.html and offset-path-parsing-valid.html.
2. 'z' is serialized as Z because Z and z commands take no parameters,
   they have an identical effect.
   (https://www.w3.org/TR/SVG2/paths.html#PathDataClosePathCommand)

Comment 14

[Boris Chiou [:boris]]

We could file a new bug for doing normalization once https://github.com/w3c/svgwg/issues/321 gets resolved.

Comment 15

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/13ce81b9b7a4
Part 1: Re-define CoordPair struct. r=emilio
https://hg.mozilla.org/integration/autoland/rev/4ee091c23aa2
Part 2: Update wpt to accept non-normalized path string at computed time. r=emilio

Comment 16

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/38942 for changes under testing/web-platform/tests

Comment 17

[Norisz Fay [:noriszfay]]

https://hg.mozilla.org/mozilla-central/rev/13ce81b9b7a4
https://hg.mozilla.org/mozilla-central/rev/4ee091c23aa2

Comment 18

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot