Layers were a feature of the legacy drawing path. If we re-add them at
some point, it probably makes more sense to make them a product of
display list inspection.
This change also remove a bunch of dead painting code.
dom: getElementsFromPoint does the hit testing on viewport coordinates.
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We got this wrong (I think it wasn't my fault actually), I was just writing a test for #12777 when I found this.
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stylo: Stop restyling display: none elements, remove the has_changed hack that made us use ReconstructFrame unconditionally.
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r? @bholley
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It's a pointless abstraction that propagates the obsolete chan terminology,
swaps the order in which the sender and receiver are returned, and hides a
source of panics.
Add new compositor message to get scroll_offset;
Add new layout query for computed value of overflow-x/y;
Implement layer_id method for ThreadSafeLayoutNode;
Add new layout query for layer_id;
Implement script interface for getting scrollTop and scrollLeft, as well as relavant helper functions.
This fixes a bug where partially loaded content is displayed to the user
before it should be, usually before stylesheets have loaded. This commit
supresses reflows until either FirstLoad or RefreshTick, whichever comes
first.
Unfortunately, hit_test and mouse_over did not do reflows if they were
necessary, and so by suppressing the initial spurious reflows, these
methods started to panic without a display list to query. This patch
also transforms these into queries similar to the other existing
queries.
Now we only query for the topmost node, and apply the hover state to all
of the parent elements.
This fixes things like #9705, where the hover state was applied only to
the children.
This also makes us more conformant with other browsers in the case of
taking in account margins and paddings.
For example, prior to this PR, when your mouse was over the inner
element, in the bottom part, `hover` styles didn't apply to the parent.
```html
<style>
div {
padding: 10px;
margin: 10px;
height: 15px;
background: blue;
}
div:hover {
background: red;
}
</style>
<div>
<div></div>
</div>
```
Fixes#9705
Instead of producing a tree of stacking contexts, display list
generation now produces a flat list of display items and a tree of
stacking contexts. This will eventually allow display list construction
to produce and modify WebRender vertex buffers directly, removing the
overhead of display list conversion. This change also moves
layerization of the display list to the paint thread, since it isn't
currently useful for WebRender.
To accomplish this, display list generation now takes three passes of
the flow tree:
1. Calculation of absolute positions.
2. Collection of a tree of stacking contexts.
3. Creation of a list of display items.
After collection of display items, they are sorted based upon the index
of their parent stacking contexts and their position in CSS 2.1
Appendeix E stacking order.
This is a big change, but it actually simplifies display list generation.
