The only accepted syntax for these seems to be
<color> <length percentage> <length percentage>, no other order.
But that's just gathered from looking at other browsers as though
these are supported by all major browsers, they don't appear in
the W3C spec.
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.
The -webkit version of linear-gradient does not include the `to`
before a <side or corner>. The angles of the <side or corner>
for the webkit version are also opposite that of the standard one.
So for the standard: linear-gradient(to left, red, blue)
The webkit version is: -webkit-linear-gradient(right, red, blue)
Adding the `to` in the -webkit version is invalid, omitting it in
the standard one is also invalid.
When a `calc()` is resolved, it can only return a Percentage value if
the requested type is Percentage. In all other cases, it returns a
concrete value.
eg, a `calc()` with Lengths and Percentages in will always resolve to a
Length, never a Percentage. This means we can just return Length
directly instead of LengthPercentage, which simplifies things in a few
places.
It's probably not in 1:1 as spec says, as it wants us to first upscale
the image to the nearest integer and then downscale it bilinearly.
But this mode still falls into the general description of the value:
> The image is scaled in a way that preserves the pixelated nature of
> the original as much as possible, but allows minor smoothing instead
> of awkward distortion when necessary.
Also, this way we don't have to allocate the memory just for the integer
scale. :^) :^)
Every StyleValue type now has its own `equals()` method, rather than
relying on the default "compare the to_string() output" method, which
has now been removed. This logic is still used by UnresolvedSV and
CalculatedSV, because it's probably the best option for them unless
performance becomes a real issue.
Also took this opportunity to move all the `equals()` implementations
into the .cpp file, which may or may not actually help with compile
times but StyleValue.h is huge and included everywhere, so it can't
hurt.
"Component value" is the term used in the spec, and it doesn't conflict
with any other types, so let's use the shorter name. :^)
Also, this doesn't need to be friends with the Parser any more.
CSS Values and Units Module Level 5 defines attr as:
`attr(<q-name> <attr-type>?, <declaration-value>?)`
This implementation does not contain support for the type argument,
effectively supporting `attr(<q-name>, <declaration-value>?)`
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. :^)
This patch adds support for "crisp-edges", "high-quality" and "smooth"
for the CSS image-rendering property.
"crisp-edges" maps to nearest-neighbor scaling for <canvas> and <img>
elements, while "high-quality" and "smooth" both use bilinear blending.
Instead of awkwardly visiting and mutating lengths inside StyleValues,
we now simply create a new StyleValue instead.
This fixes an issue where inherited relative lengths could get
absolutized using a parent as reference, and then not having the correct
values when used in a child context.
For now, we only understand `none`, `normal`, `<image>` and `<string>`.
The various other functions and identifiers can be added later.
We can *almost* use a StyleValueList for this, except it's divided into
two parts - the content, and the optional "alt text". So, I've added a
new StyleValue for it.
Depending on the type of the calc() expression, the percentage_basis has
to be the same dimension type. Several places were already passing `
{}` for this, so let's make that an empty Variant instead of an
undefined Length. :^)
