Our "frame" concept very closely matches what the web specs call a
"browsing context", so let's rename it to that. :^)
The "main frame" becomes the "top-level browsing context",
and "sub-frames" are now "nested browsing contexts".
The Acid1 test has a bit of an unusual background - the html and body
tags have different background colors. Our painting order of the DOM was
such that the body background was painted first, then all other elements
were painted in-phase according to Appendix E of CSS 2.1. So the html
element's background color was painted over the body background.
This removes the special handling of the body background from
InitialContainingBlockBox and now all boxes are painted in-phase. Doing
this also exposed that we weren't handling Section 2.11.2 of the spec;
when the html background is unset, the body's background should be
propagated to the html element.
SPDX License Identifiers are a more compact / standardized
way of representing file license information.
See: https://spdx.dev/resources/use/#identifiers
This was done with the `ambr` search and replace tool.
ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
This is because it includes the initial node that the function was
called on, which makes it "inclusive" as according to the spec.
This is important as there are non-inclusive variants, particularly
used in the node mutation algorithms.
The background-repeat value may be specified as either one- or two-value
identifiers (to be interpreted as horizontal and vertical repeat). This
adds two pseudo-properties, background-repeat-x and background-repeat-y,
to handle this. One-value identifiers are mapped to two-value in
accordance with the spec.
For now, painting of background color is kept separate. The ICB needs to
perform a "translate" call between painting the color and background,
whereas other divs must not make that call.
Update the painting of background images for both <body> nodes and other
non-initial nodes. Currently, only the following values are supported:
repeat, repeat-x, repeat-y, no-repeat
This also doesn't support the two-value syntax which allows for setting
horizontal and vertical repetition separately.
Previously the page background was always draw relative to the viewport
instead of following with the content. This should eventually become
an opt-in mode (via CSS "background-attachment") but for now let's have
the default behavior be that backgrounds scroll with content.
Also take this opportunity to move the background painting code from
the two web views to a shared location in InitialContainingBlockBox.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
The approach of attaching sub-widgets to the web view widget was only
ever going to work in single-process mode, and that's not what we're
about anymore, so let's just get rid of WidgetBox so we don't have the
dead-end architecture hanging over us.
The next step here is to re-implement <input type=text> using LibWeb
primitives.
Image boxes want to know whether they are inside the visible viewport.
This is used to pause/resume animations, and to update the purgeable
memory volatility state.
Previously we would traverse the entire layout tree on every resize,
calling a helper on each ImageBox. Make those boxes register with the
frame they are interested in instead, saving us all that traversal.
This also makes it easier for other parts of the code to learn about
viewport changes in the future. :^)
