Fix linear gradient's specified form #13892
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WIP for #13892
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Implement background-position-x/y
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This is a WIP PR. Just HorizontalPosition / VerticalPosition implementations are complete. I would like to get early feedbacks about this architecture. Here's some architectural topics to consider:
- I created `HorizontalPosition` and `VerticalPosition` structs for this and used them in `Position` as well. We have decided to split `Keyword` enum, but we need them as unified for `PositionComponent` enum. So I didn't split but I can split it if we prefer to change PositionComponent as well.
- If we prefer Keyword enum like this, we can create a SubPosition(or something like this) instead of HorizontalPosition/VerticalPosition enums since only difference is 2 lines in `parse` functions. We can create a `parse_horizontal` and `parse_vertical` instead and a lot of code duplication can be cleared.
- I couldn't find a good way to use HorizontalPosition/VerticalPosition's parse functions in `Position`'s parse function. It is a bit more complicated. I'm open to suggestions :)
- I don't know much about logical keywords so do I need to do something different? I placed some comments where logical keywords are processing.
Any advice about these?
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Only allow border-image-outset to use non-negative numbers.
Restricts border-image-outline to only allow positive values.
Fixes#14295
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Added parsing/serialization for text-emphasis-position
Implemented parsing/serialization for text-emphasis-position
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- [ ] These changes fix#13850
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Implement border-image shorthand
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Implementation of border-image shorthand.
r? Manishearth
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Adds parsing test for linear-gradient
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Tests if `linear-gradient` is correctly parsed without `<side-or-corner>` as well as with `to left` and `to right`.
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13894 Use graphenes in text-emphasis-style
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Use `unicode_segmentation` crate to truncate strings on grapheme boundaries.
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Font feature settings
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Implement parsing/serialization for font-feature-settings
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Fix radial gradient's <size>/<ending-shape> parsing
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Parsing now handles sizes and shapes in various order.
I had to delete `EndingShape`'s parse implementation and mix it with `Position` in `parse_radial`. It became a bit complicated to read but I couldn't make it simpler.
r? @Manishearth
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