Reverse Number and LengthOrPercentage in LengthOrPercentageOrNumber
"0" must be parsed as the number 0, not the unitless 0px length.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16646)
<!-- Reviewable:end -->
Implement radial gradients
<!-- Please describe your changes on the following line: -->
This PR passes the `radial-gradient` function down from CSS parsed properties to webrender. It currently lacks tests but the examples from MDN and some other tests work fine. Probably there are some wpt tests I can enable?
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#11779 (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16385)
<!-- Reviewable:end -->
Use FunctionKeyword for computed_value of timing function
<!-- Please describe your changes on the following line: -->
https://bugzilla.mozilla.org/show_bug.cgi?id=1358330
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#15086
<!-- Either: -->
- [X] These changes do not require tests because mozilla-central has test cases. There might be some test cases in servo tree.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16640)
<!-- Reviewable:end -->
Fix WebGL premultiplied alpha. Fix texImage2D calls with RGB images.
Fix WebGL premultiplied alpha testcases.
Fix broken textures in some WebGL demos (e.g. Three.js). This was caused by WebGL::texImage2D calls with RGB formats. Alpha must be removed from the rgba8 pixel vector before submitting the data to the GPU.
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16590)
<!-- Reviewable:end -->
stylo: Bug 1357357 - Make the parser of transition-property match the spec.
These are interdependent patches of Bug 1357357. We add one more arm, TransitionProperty::Unsupported, which stores the string of non-animatable, custom, or unrecognized property, so we can parse these kinds of properties and serialize them correctly. This is necessary because we need to start transitions even though some transition-properties are non-animatable, custom, or unrecognized.
---
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [Bug 1357357](https://bugzilla.mozilla.org/show_bug.cgi?id=1357357).
- [X] There are tests for these changes.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16614)
<!-- Reviewable:end -->
1. We add a new arm to TransitionProperty, TransitionProperty::Unsupported,
which contains an Atom, so it's better to remove the Copy trait from
TransitionProperty.
2. TransitionProperty::Unsupported(Atom) represents any non-animatable, custom,
or unrecognized property, and we use Atom to store the ident string for
serialization.
stylo: support all overflow values
overflow:clip doesn't exist, it's just called clip internally. Renamed, and added the other missing values.
I also removed the overflow newtype -- no need for extra code bloat, and it's not protecting us from much.
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16597)
<!-- Reviewable:end -->
Add calc method for CalcLengthOrPercentage
* Add calc method to calculate formula value with parent size
* Add unit test case
<!-- Please describe your changes on the following line: -->
Please see this issue: https://github.com/servo/servo/issues/15986
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix#15986 (github issue number if applicable).
<!-- Either: -->
- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/16541)
<!-- Reviewable:end -->
* Add to_computed method to calculate `calc()` value with parent size,
if parent container size is `None`, the result will be `None`.
* Add from_option method for `MaybeAuto`, to construct from
`Option<Au>`.
* Update some test case.
