Length units are either relative to the font, or to the viewport, but
never both. So we can save some work by not gathering font metrics for
a viewport unit, and not retrieving the viewport for a font unit.
Currently this is only helpful when the `to_px(Layout::Node)` method is
called, but since that is 208 places according to CLion, (plus 33
indirect uses via `Length::resolved()`) it still seems worthwhile. :^)
`*vi` and `*vb` vary on which direction they check depending on whether
the writing mode is horizontal or vertical, so they will need some
modification once we support that.
Using the rough heuristic instead of the actual spec measurement. It's
allowed by the spec, but not ideal:
> In the cases where it is impossible or impractical to determine the
ideographic advance measure, it must be assumed to be 1em.
As noted, the ascent of the font is not the best heuristic for this, but
it is one that's listed as OK to use by the spec:
> In the cases where it is impossible or impractical to determine the
cap-height, the font’s ascent must be used.
Rather than passing an increasingly-unwieldy number of font parameters
individually to every function that resolves lengths, let's wrap them
up.
This is frustratingly close to being `Gfx::FontPixelMetrics`, but bitmap
fonts cause issues: We choose the closest font to what the CSS
requests, but that might have a wildly different size than what the
page expects, so we have to fudge the numbers.
No behaviour changes.
They previously weren't sorted at all. Alphabetical would be nice, but
then things like `em` and `rem` would be separated. So, let's copy the
spec's order. That way it's easier to keep track of which units we have
or haven't implemented. (Since there are so many...)
This bit is mostly ad-hoc for now. This simply turns fill: url(#grad1)
into document().get_element_by_id('grad1') then resolves the gradient.
This seems to do the trick for most use cases, but this is not
attempting to follow the spec yet to keep things simple.
This will be needed to access the color of a stop from a SVG gradient
<stop> element (which does not participate in layout, so does not have
a layout node).
When deciding on a box type transformation (blockify/inlinify) for a
pseudo element, we have to use the originating element as a reference
rather than the parent.
(The originating element *is* the parent for its pseudo elements.)
This appears to be consistent with other engines, and fixes many pages
where we were misinterpreting super large z-index values as something
else entirely.
Now that LengthStyleValue never contains `auto`, IdentifierStyleValue is
the only type that can hold an identifier. This lets us remove a couple
of virtual methods from StyleValue.
I've kept `has_auto()` and `to_identifier()` for convenience, but they
are now simple non-virtual methods.
Previously, whether trying to parse a `<length>` or `<dimension>`, we
would accept `auto` and produce a `LengthStyleValue` from it. This
would fool the `property_accepts_value()` into allowing `auto` where it
does not belong, if the property did accept lengths.
Of the few places in the parser that called `parse_dimension_value()` or
`parse_length()`, none of them were expecting it to accept `auto`, so
this fixes those too. :^)
Currently, `property_accepts_value()` always returns `true` if the
property is a shorthand. (This is a bug, and should actually be fixed
properly at some point...) This means that all identifiers are caught
here, including `auto`, which should be handled by the `flex-basis`
branch instead.
This works currently because `auto` is a LengthStyleValue, but that's
about to change!
This code assumed that `auto` was always stored as a LengthStyleValue,
which will not be true in the next commit. (And was not a safe
assumption to make anyway.)
This is a tiny bit messy because:
- The spec says we should expand this to `flex: <flex-grow> 1 0`
- All major engines expand it to `flex: <flex-grow> 1 0%`
Spec bug: https://github.com/w3c/csswg-drafts/issues/5742
This change adds rules for background-attachment, background-clip,
background-image, background-origin, and background-repeat.
As a result, Window.getComputedStyle() will no longer return empty
strings on these properties after a page is loaded, and the background
shorthand will show the resolved values instead of the default ones for
these values. :^)
VALUES-4 defines the internal representation of `calc()` as a tree of
calculation nodes. ( https://www.w3.org/TR/css-values-4/#calc-internal )
VALUES-3 lacked any definition here, so we had our own ad-hoc
implementation based around the spec grammar. This commit replaces that
with CalculationNodes representing each possible node in the tree.
There are no intended functional changes, though we do now support
nested calc() which previously did not work. For example:
`width: calc( 42 * calc(3 + 7) );`
I have added an example of this to our test page.
A couple of the layout tests that used `calc()` now return values that
are 0.5px different from before. There's no visual difference, so I
have updated the tests to use the new results.
This makes it possible to do arithmetic on them without having to
resolve to their canonical unit, which often requires context
information that is not available until the last minute. For example, a
Length cannot be resolved to px without knowing the font size, parent
element's size, etc.
Only Length currently requires such context, but treating all these
types the same means that code that manipulates them does not need to
know or care if a new unit gets added that does require contextual
information.
Level 4 drops the limitations of what types can be a denominator, which
means `<calc-number-sum>`, `<calc-number-product>` and
`<calc-number-value>` all go away.
This ports MouseEvent, UIEvent, WheelEvent, and Event to new String.
They all had a dependency to T::create() in
WebDriverConnection::fire_an_event() and therefore had to be ported in
the same commit.
This fixes multi-layer backgrounds with background positions. This
is a little awkard, so maybe it would be better to refactor the
parsing code to make these lists directly, but right now this is
the simplest fix.
This parses the new background-position-x/y longhands and properly
hooks up them up. This requires converting PositionStyleValue to
just contain two EdgeStyleValues so that it can be easily expanded
into the longhands.
This solves an awkward dependency cycle, where CalculatedStyleValue
needs the definition of Percentage, but including that would also pull
in PercentageOr, which in turn needs CalculatedStyleValue.
Many places that previously included StyleValue.h no longer need to. :^)
