Add functionality to begin parsing grid-template-columns and
grid-template-rows. There are still things to be added, like parsing
functions, but I would say a couple of the major points are already
adressed like length, percentage, and flexible-length.
This commit moves both the ImageStyleValue and LinearGradientStyleValue
to a common base class of AbstractImageStyleValue. This abstracts
getting the natural_width/height, loading/resolving, and painting
the image.
Now for 'free' you get:
- Linear gradients working with the various background sizing/repeat
properties.
- Linear gradients working as list-markers :^) -- best feature ever!
P.s. This commit is a little large as it's tricky to make this change
incrementally without breaking things.
Previously, we considered all LengthPercentage values for used flex
basis to be definite. This is not accurate, as percentages should only
be considered definite if the reference value they resolve against is
a definite size.
Fix this by checking the flex container's main definite size flag.
Also, made the `reference_length` parameter optional for the lambda that
extracts transform-function parameters, since it is only needed to
resolve `LengthPercentage` parameters.
Instead of using Optional<LengthPercentage>, we now use LengthPercentage
for these values. The initial values are all `auto`.
This avoids having to check `has_value()` in a ton of places.
Anonymous wrappers get their non-inherited properties from the initial
state of a new CSS::ComputedValues object. Before this patch, all the
values in their margin and padding LengthBox would be "auto".
The spec grammar for `text-decoration-line` is:
`none | [ underline || overline || line-through || blink ]`
Which means that it's either `none`, or any combination of the other
values. This patch makes that parse for `text-decoration-line` and
`text-decoration`, stores the results as a Vector, and adjusts
`paint_text_decoration()` to run as a loop over all the values that are
provided.
As noted, storing a Vector of values is a bit wasteful, as they could be
stored as flags in a single `u8`. But I was getting too confused trying
to do that in a nice way.
Previously the default was always 1px, which didn't look great on higher
font sizes.
This changes the default thickness to one-tenth to the font height. The
one-tenth part was chosen arbitrarily, but I think it does the job
pretty well. :^)
The `text-shadow` property is almost identical to `box-shadow`:
> Values are interpreted as for box-shadow [CSS-BACKGROUNDS-3].
> (But note that the inset keyword are not allowed.)
So, let's use the same data structures and parsing code for both. :^)
Previosly, we used only the text color as a line decoration color.
The FIXME comment has been directly copy-pasted from the border color
note a few lines below.
"5em" means 5*font-size, but by forcing "em" to mean the presentation
size of the bitmap font actually used, we broke a bunch of layouts that
depended on a correct interpretation of "em".
This means that "em" units will no longer be relative to the exact
size of the bitmap font in use, but I think that's a compromise we'll
have to make, since accurate layouts are more important.
This yields a visual progression on both ACID2 and ACID3. :^)
We also pass whether the shadow goes inside or outside the element. Only
outer shadows are rendered currently, and inner ones may want to be
handled separately from them, as they will never interfere with each
other.
A lot of this is quite ugly, but it should only be so until I remove
Length::Type::Percentage entirely. (Which should happen later in this
PR, otherwise, yell at me!) For now, a lot of things have to be
resolved twice, first from a LengthPercentage to a Length, and then
from a Length to a pixel one.
The flexbox logic confuses me so regressions are possible, though our
test page looks the same as before so it should be fine.
Renamed FlexBasis::Length -> LengthPercentage too, for clarity.
These aren't needed now that we render using background_layers instead.
The one casualty is the resolved style for background-repeat, but that
was incorrect anyway.
Instead of storing these as individual `background-foo` properties, we
combine them together into layers, since that is how they will be
painted. It also makes it more convenient to pass them around.
While right now this doesn't save much complexity, it will do once we
care about multiple background layers per node. Then, having a single
repeat value per layer will simplify things.
It also means we can remove the pseudo-property concept entirely! :^)
