This is a big and messy change, and here's the gist:
- AvaliableSpace is now 2x AvailableSize (width and height)
- Layout algorithms are redesigned around the idea of available space
- When doing layout across nested formatting contexts, the parent
context tells the child context how much space is available for the
child's root box in both axes.
- "Available space" replaces "containing block width" in most places.
- The width and height in a box's UsedValues are considered to be
definite after they're assigned to. Marking something as having
definite size is no longer a separate step,
This probably introduces various regressions, but the big win here is
that our layout system now works with available space, just like the
specs are written. Fixing issues will be much easier going forward,
since you don't need to do nearly as much conversion from "spec logic"
to "LibWeb logic" as you previously did.
Instead of formatting contexts flailing around to figure out from the
"inside" how much space is available on the "outside", we should
provide the amount of available space in both axes as an input to run().
This basically means that when something creates a nested formatting
context, the parent context is responsible for telling the nested context
how much space is available for layout. This information is provided
immediately when invoking run().
Note that this commit doesn't pass accurate values in all cases yet.
This first step just makes it build, and passes available values in some
cases where getting them was trivial.
This function should return the automatic height of the formatting
context's root box.
Until now, we've been relying on some magical handshakes between parent
and child context, when negotiating the height of child context root
boxes. This is a step towards something more reasonable.
Now that the positions of each grid item have been calculated, and the
sizes of the individual rows and columns ascertained, can actually
layout the different items.
According to the spec it's necessary to:
1. Layout the cells in the grid
2. Find the sizes of the rows and columns
Since I had started to do this backwards, and as I expand in future
commits, I take here the opportunity to start with a clean state.
The occupation_grid keeps track of which cells in the grid have been
filled out.
This is a really starter attempt at formatting the grid. It doesn't yet
take into account the computed_values of grid-template-rows, nor the
values in grid-column-start and like CSS properties.
But these changes are a start and make it so the examples in
display-grid.html work.
To be fleshed out further..
