diff mbox series

[RFC] dt-bindings: display: document display panel occlusions

Message ID 20231009-caleb-notch-example-v1-1-9e0a43ae233c@linaro.org
State New
Headers show
Series [RFC] dt-bindings: display: document display panel occlusions | expand

Commit Message

Caleb Connolly Oct. 9, 2023, 5:32 p.m. UTC
Some display panels found in modern phones and laptops feature
non-standard display shapes with features like rounded corners, notches
(sections of the display that are cut-out from the edge), and cutouts
(such as circular "hole punch" camera cutouts, or wider pill-shaped
"islands").

Some discussion has been underway previously on how best to describe
these features [1][2], including a reference userspace implementation
using SVG paths [3]. Using this previous discussion as a jumping off
point, this RFC allows for describing the following display features:

* Corner radius (on a per-corner basis)
* Circular or pill-shaped cutouts
* Notches with arbitrary shapes

It's easy to make a case for only using rectangles to describe these
missing parts of a display, however this severely limits their utility.
Describing display occlusions as accurately as possible allows for a lot of
useful UX features. For example, displaying a ring around a hole-punch
camera when it's in use, or wrapping UI elements around a notch. These
behaviours are only possible to implement when the dimensions are known
with near pixel-perfect accuracy.

Cutouts are described as rectangles with a width, height, and corner
radius.
A radius of half the width longest edge will definitionally be an ellipse.
This simple description is suitable for describing hole-punch cameras,
as well
as pill-shaped cutouts. I'm not aware of any devices that can't be
described like this.

Notches are a little more complicated, they usually feature convex and
concave corners as well as straight lines. Here they are described as a
sequence of optionally disjoint arcs, where the space between one arc ending
and another starting is inferred to be a straight line.

Each arc is described with an X and Y pixel coordinate, a radius, and a
start and end point in degrees. These arcs can precisely describe the
shape of a notch, and easily allow for a basic bounding box to be
derived using the min/max coordinates specified in the path.

Some displays feature partially occluded edges ("waterfall edges") where
the screen bends, it may be useful for user interfaces to avoid placing
certain UI elements like buttons too close to these edges. These edges
are described by a distance from the edge where it begins to be
occluded, and the number of degrees that the display curves (this
directly affects how usable this edge of the screen is).

[1]: https://lore.kernel.org/dri-devel/f8747f99-0695-5be0-841f-4f72ba5d5da3@connolly.tech/
[2]: https://gitlab.freedesktop.org/wayland/wayland-protocols/-/issues/87
[3]: https://gitlab.gnome.org/World/Phosh/gmobile

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
---
Some folks have previously suggested that this information belongs in
userspace and not in devicetree. I would like to be clear that
devicetree is for describing hardware, and parts of a display which can
never actually be seen are very much properties of the underlying
hardware.
---
base-commit: 268c4b354d66908697299063c44c0b553b01d935

// Caleb (they/them)
---
 .../bindings/display/panel/panel-common.yaml       |   7 +
 .../bindings/display/panel/panel-occlusions.yaml   | 182 +++++++++++++++++++++
 2 files changed, 189 insertions(+)

Comments

Piotr Masłowski Oct. 10, 2023, 8:01 p.m. UTC | #1
Hi Caleb,

Thanks for posting this. I've been meaning to chime in on the discussion
about notches and co. for months now, so this makes a perfect opportunity
to finally do so.

On Mon Oct 9, 2023 at 7:32 PM CEST, Caleb Connolly wrote:

> Some folks have previously suggested that this information belongs in
> userspace and not in devicetree. I would like to be clear that
> devicetree is for describing hardware, and parts of a display which can
> never actually be seen are very much properties of the underlying
> hardware.

Yes, thank you! Seeing the kernel log (or Tuxes) partially hidden behind
the notch (or the top-left rounded corner) is just so annoying, so DT is
definitely the way to go here.

> Some discussion has been underway previously on how best to describe
> these features [1][2], including a reference userspace implementation
> using SVG paths [3]. Using this previous discussion as a jumping off
> point, this RFC allows for describing the following display features:
>
> * Corner radius (on a per-corner basis)
> * Circular or pill-shaped cutouts
> * Notches with arbitrary shapes
>
> It's easy to make a case for only using rectangles to describe these
> missing parts of a display, however this severely limits their utility.
> Describing display occlusions as accurately as possible allows for a lot of
> useful UX features. For example, displaying a ring around a hole-punch
> camera when it's in use, or wrapping UI elements around a notch. These
> behaviours are only possible to implement when the dimensions are known
> with near pixel-perfect accuracy.


There are two aspects at play here: simplicity and correctness. Fully
sacrificing one for the other would be a grave mistake. But that does
not mean those two are inherently opposed.

I'd argue that they actually go hand in hand. Keeping the format simple
will make gathering and submitting high-quality data easier. Conversly,
accurately describing the hardware requires *not including* redundant
or non-applicable information.


So why am I writing all of this? Well, the problem I see is that any
shape-based approach will likely suffer from both accuracy and
complexity issues. Describing curves is hard and processing them is
not something that should be included in e.g. whatever handles VTs.

[TLDR: you can skip ahead]

Morover, short of some Turing-complete arbitrary path function, it
sacrifices a bit of expressivity and thus correctness as there will
always be shapes you cannot describe accurately. This may be irrelevant
because in practice you don't need those details. But that highlights
a different problem: there will be many distinct ways to describe many
similar things.

It's also hard to tell if a given curve really has the right shape:

* similar shapes exist – How do you tell whether e.g. a rounded corner
  is circular or not? If a DT gets that wrong and the UI decides to for
  example draw constant-width padding around such feature it will likely
  look very off and ugly.
* measurement precision is a thing – Unless you measure everything on a
  scale significantly smaller than individual pixels, sections of your
  curves may end up on different pixels than in reality.
* different people have different standards – And so the quality will
  vary greatly between devices.
* corners will be cut – This is basically the previous point but I
  liked the pun way too much to just delete it, lol
* pixels vs millimeters – Converting between these two will also
  increase the overall wobbliness and worsen the user experience.
  But is it feasible to measure everything in pixels accurately?


Picking a very small set of basic curve shapes might be a good option if
that can cover all the shapes we expect to find in the wild. It does not
resolve the possible accuracy problems but it would at least be simple.

[TLDR – skip to here]:

However, there's a different approach that is both extremely simple and
yet trivially correct – pixel masks!

Basically, instead of trying to describe what shape a cutout, notch or
other feature has, we just say which pixels belong to it. In short, this:

- can be easily processed even by 'dumb' programs – for example, you can
  derive minimal margins to 'letterbox' the screen
- gathering the data is very straightforward – just light the relevant
  pixels one-by-one and check if you see them
- pixel-perfect accuracy is the default

Of course this is not a perfect solution. Here are the drawback that I
can see:

- low resolution screens mean low resolution data
- 'smart' programs may or may not need a bit more logic than otherwise
- sub-pixel accuracy is impossible or requires extending this scheme
  - non-binary (fractional) weights
  - partially-occluded pixels on a separate mask (so each feature would
    have two adjacent masks – for its interior and for the border)


As a futher improvement, besides looking at pixels we could think about
subpixels instead. Still, this can easily be added later and likely even
in a backwards-compatible manner.

An orthogonal issue is labeling all of those regions. I think we should
start with fully obscured areas and maybe less readable ones like the
waterfall edges. Still, different features should live on different
masks – even if we don't attach meaningfull labels (like 'notch' or
'camera cutout') to them right away.


What do you all think of that? I didn't see this approach considered in
any of the earlier discussions, yet it seems so elegant to me. Am I
missing something?

--
Cheers,
Piotr Masłowski
Caleb Connolly Oct. 10, 2023, 8:36 p.m. UTC | #2
On 10/10/2023 21:01, Piotr Masłowski wrote:
> Hi Caleb,
> 
> Thanks for posting this. I've been meaning to chime in on the discussion
> about notches and co. for months now, so this makes a perfect opportunity
> to finally do so.
> 
> On Mon Oct 9, 2023 at 7:32 PM CEST, Caleb Connolly wrote:
> 
>> Some folks have previously suggested that this information belongs in
>> userspace and not in devicetree. I would like to be clear that
>> devicetree is for describing hardware, and parts of a display which can
>> never actually be seen are very much properties of the underlying
>> hardware.
> 
> Yes, thank you! Seeing the kernel log (or Tuxes) partially hidden behind
> the notch (or the top-left rounded corner) is just so annoying, so DT is
> definitely the way to go here.


Exactly! Glad that others care about the _real_ issue here ;P

[...]
> 
> 
> So why am I writing all of this? Well, the problem I see is that any
> shape-based approach will likely suffer from both accuracy and
> complexity issues. Describing curves is hard and processing them is
> not something that should be included in e.g. whatever handles VTs.

My proposal here doesn't require processing curves or doing any
complicated calculations. If you know that the display has a 30px radius
on all corners, you can adjust the VT to not use the top 30px of the
screen and it will start exactly where the radius stops.

If you know that there is a (potentially very curvy) notch at the top of
the screen, you can just iterate over the arcs, add their radius to
their Y coordinate and take the maximum. This will always give you at
least the height of the notch (you'd probably want to check that their
angle is vaguely downward, but again this is trivial fast integer math).

[...]
> 
> However, there's a different approach that is both extremely simple and
> yet trivially correct – pixel masks!
> 
> Basically, instead of trying to describe what shape a cutout, notch or
> other feature has, we just say which pixels belong to it. In short, this:
> 
> - can be easily processed even by 'dumb' programs – for example, you can
>   derive minimal margins to 'letterbox' the screen

As above (and as mentioned in the patch) this is also trivial to derive
from the curves.
> - gathering the data is very straightforward – just light the relevant
>   pixels one-by-one and check if you see them
> - pixel-perfect accuracy is the default

I think it would be fairly straightforward to do this for curve data
too. You just bump the radius up/down until it looks right, or "good enough"
> 
> Of course this is not a perfect solution. Here are the drawback that I
> can see:
> 
> - low resolution screens mean low resolution data
> - 'smart' programs may or may not need a bit more logic than otherwise
> - sub-pixel accuracy is impossible or requires extending this scheme
>   - non-binary (fractional) weights
>   - partially-occluded pixels on a separate mask (so each feature would
>     have two adjacent masks – for its interior and for the border)
> 
> 
> As a futher improvement, besides looking at pixels we could think about
> subpixels instead. Still, this can easily be added later and likely even
> in a backwards-compatible manner.
> 
> An orthogonal issue is labeling all of those regions. I think we should
> start with fully obscured areas and maybe less readable ones like the
> waterfall edges. Still, different features should live on different
> masks – even if we don't attach meaningfull labels (like 'notch' or
> 'camera cutout') to them right away.
> 
> 
> What do you all think of that? I didn't see this approach considered in
> any of the earlier discussions, yet it seems so elegant to me. Am I
> missing something?

I think the unfortunate truth is that approximating notches and rounded
corners exclusively with regular arcs at the cost of pixel accuracy is
just such a no-brainer. Pixel masks would be pixel accurate, but there
is no benefit compared to a slightly underfit curve.

Any program which wanted to make use of the curve information would have
to run a whole curve fitting algorithm, whereas there simply aren't any
programs which need to know about display occlusions to a pixel-accurate
level. For padding a status bar you do a single trig equation, for
avoiding the notch in fullscreen you would query the DRM subsystem which
presumably would export the dimensions of a letterboxed "usable size".

To be clear though, I wouldn't mind being proven wrong on this, but I'm
yet to find some information which doesn't line up with this conclusion.
> 
> --
> Cheers,
> Piotr Masłowski
Caleb Connolly Oct. 10, 2023, 11:35 p.m. UTC | #3
On 10/10/2023 23:53, Piotr Masłowski wrote:
> On Tue Oct 10, 2023 at 10:36 PM CEST, Caleb Connolly wrote:
> 
>>> So why am I writing all of this? Well, the problem I see is that any
>>> shape-based approach will likely suffer from both accuracy and
>>> complexity issues. Describing curves is hard and processing them is
>>> not something that should be included in e.g. whatever handles VTs.
>>
>> My proposal here doesn't require processing curves or doing any
>> complicated calculations. If you know that the display has a 30px radius
>> on all corners, you can adjust the VT to not use the top 30px of the
>> screen and it will start exactly where the radius stops.
> 
> Just a nitpick, but on a round smartwatch this approach will give you
> a $width × 0px famebuffer ;D

right right, it's a little more complicated, but not more or less with
either approach.

[...]
>>> - gathering the data is very straightforward – just light the relevant
>>>   pixels one-by-one and check if you see them
>>> - pixel-perfect accuracy is the default
>>
>> I think it would be fairly straightforward to do this for curve data
>> too. You just bump the radius up/down until it looks right, or "good enough"
> 
> Well, different people will have different standards and what might be
> good enough for some will annoy others. I'm not saying that we need to
> be perfect at all cost, but if there's a relatively easy way to cut down
> on inconsistency, it might be worth taking.
> 
> Additionally, having a very clear-cut quality indicator could remove a
> whole class of bikeshedding options. (speaking of the devil xD)
> 
> 
> The problem I have with curves is, the more 'correct' you make them, the
> more convoluted they become. Like take for example the corners. Rounded
> corners are circular right? But what if someone makes them 'squircular'?
> Well, they are usually quite small anyway so maybe it will work out.
> 
> But then what about a smartwatch with big, squircle-shaped display? Bam,
> now you need to complicate how corners are handled.

They don't need to be correct, you don't need to complicate it, you just
need a value that plays nice. When it comes down to it you're much more
likely to be constrained by UI layout limitations by not being able to
model the precise corner curves of your device. The difference between a
circular and elliptical arc is negligible in all real world use cases.
> 
> But also: are rounded coners typically circular? Just now I've thrown a
> OnePlus 6 (thank you so much for the great mainline support btw!) onto a
> flatbed scanner. While a circle fits decently well there it's not really
> a perfect fit, so maybe they went with a different curve after all.
> 
> That being said, imperfection isn't my main issue with curves. It's all
> the non-discreteness they bring to the table. As in, you now need to care
> about approximations, rounding, imprecise measurements and so on.

My point is that actually you don't. Other than for animated visual
effects (where an undersized curve would absolutely be acceptable) I
can't conceive of a situation where plain triangles wouldn't be
suitable, again slightly undersized of course.
> 
> 
>> I think the unfortunate truth is that approximating notches and rounded
>> corners exclusively with regular arcs at the cost of pixel accuracy is
>> just such a no-brainer. Pixel masks would be pixel accurate, but there
>> is no benefit compared to a slightly underfit curve.
> 
> Frankly, I don't see any significant cost here. It's very easy to gather
> and rather easy to process.

Unless I'm mistaken, it would mean that for "odd" shapes like rounded
corners, the number of values you need to record would be directly
proportional to the number of rows. You can do some optimisations, but
that worst case is really not great. Especially when the arc
approximation requires a single value and covers all the same usecases
as well or better.
> 
> Let me think about it… The most common operations I see people actually
> doing with this data would be:
> 
> * letterboxing – easy with both curves and masks
> * ensuring padding | margins for icons on the screen – with curves you
>   can use a formula, but won't it be easier to just count pixels anyway?

You'd probably want your status bar icons to be equi-distant from the
top and side, at least that's what my Android phone does. But hey, maybe
you don't, we can't bikeshed UX design all day but I'd think a simple
radius is gonna be easier to deal with than a pixel mask in most cases
(especially considering that most UI frameworks don't work in the pixel
space anyway because of scaling).

> * routing a spline along the border – like if you want to have some
>   periodic pattern drawn there, it's probably a bit easier to do with
>   curves
> * drawing something at a constant distance from the border – with curves
>   you can again use exact formulas. But isn't that an overkill really?
>   I'd think most people will go for something like a morphological
>   dilation instead

Right right
> 
>>
>> Any program which wanted to make use of the curve information would have
>> to run a whole curve fitting algorithm, whereas there simply aren't any
>> programs which need to know about display occlusions to a pixel-accurate
>> level. For padding a status bar you do a single trig equation, for
>> avoiding the notch in fullscreen you would query the DRM subsystem which
>> presumably would export the dimensions of a letterboxed "usable size".
> 
> What could the curve information be needed for though?
> The more I think about it, the less value I see in it really. Like, if
> you're adjusting the screen contents, pixels _are_ the smallest unit you
> need to concern yourself with. The only thing that comes up to my mind
> is if you were to animate the cutout shape somewhere else, zoomed in.
> And thats already a quite contrived scenario.

GNOME doesn't even use real pixels, macOS doesn't use real pixels. When
scaling comes into play the advantage is lost either way.
> 
> Is there actually any use case that instead of ending up with pixels
> either way, would be better served by a (possibly inaccurate) curve?
> (future me here: that spline-along-the-border from earlier I guess)

I feel like the burden of proof still lies with you here. I feel much
more comfortable with a handful of easy to reason about and explain
values (that can be easily reviewed by maintainers) over a blob of data
that grows with the resolution of your display.

Thanks,
> 
> --
> Cheers,
> Piotr Masłowski
Piotr Masłowski Oct. 11, 2023, 1:34 a.m. UTC | #4
On Wed Oct 11, 2023 at 1:35 AM CEST, Caleb Connolly wrote:
> On 10/10/2023 23:53, Piotr Masłowski wrote:

> They don't need to be correct, you don't need to complicate it, you just
> need a value that plays nice. When it comes down to it you're much more
> likely to be constrained by UI layout limitations by not being able to
> model the precise corner curves of your device. The difference between a
> circular and elliptical arc is negligible in all real world use cases.

Well, with a large, weirdly-shaped display the curve will have to pass
through more-or-less the right pixels for things like a-couple-px-thick
frame to look right. I would expect e.g. a smartwatch UI to sometimes
want to draw a constant-width frame along the screen border. Using a
significantly different curve there will break that, so you would need
to let them be similarly arbitrary to notches.


>> That being said, imperfection isn't my main issue with curves. It's all
>> the non-discreteness they bring to the table. As in, you now need to care
>> about approximations, rounding, imprecise measurements and so on.
>
> My point is that actually you don't. Other than for animated visual
> effects (where an undersized curve would absolutely be acceptable) I
> can't conceive of a situation where plain triangles wouldn't be
> suitable, again slightly undersized of course.

Well, what I meant is not that you "have to care or it won't look good",
but rather "that's an unnecessary degree of freedom" and I'm sure pepole
will spend non-insignificant amounts of time caring about it. Both while
gathering the data and while processing it.

But you're right that it won't matter for typical corners – they are
simply too small to make any difference here.


>> Frankly, I don't see any significant cost here. It's very easy to gather
>> and rather easy to process.
>
> Unless I'm mistaken, it would mean that for "odd" shapes like rounded
> corners, the number of values you need to record would be directly
> proportional to the number of rows. You can do some optimisations, but
> that worst case is really not great. Especially when the arc
> approximation requires a single value and covers all the same usecases
> as well or better.

You mean the devicetrees getting bloated? The blobs are already dozens
of KiB in size. As for the sources, I don't have any real experience
with them so I'm not sure what would be the best way of representing
masks. Worst-case, they can be treated as raw bitmaps. But since the
features will consist of typically one (or just a few) contiguous blobs
they can be efficiently represented using for example chain codes.


> You'd probably want your status bar icons to be equi-distant from the
> top and side, at least that's what my Android phone does. But hey, maybe
> you don't, we can't bikeshed UX design all day but I'd think a simple
> radius is gonna be easier to deal with than a pixel mask in most cases
> (especially considering that most UI frameworks don't work in the pixel
> space anyway because of scaling).

Good point!
(Though don't they need to still align stuff to the pixel grid to avoid
needless antialiasing?)

Hmm, but known radius only helps you with the corners. For the notch,
you would need a complex (and shape-shifting) equation, so you might as
well figure out the constant-distance based on a mask I guess.


> GNOME doesn't even use real pixels, macOS doesn't use real pixels. When
> scaling comes into play the advantage is lost either way.

Fractional scaling is a worthwile cause, but I don't think my argument
really changes much when you're working with scaled pixels instead of
real ones.

>>
>> Is there actually any use case that instead of ending up with pixels
>> either way, would be better served by a (possibly inaccurate) curve?
>> (future me here: that spline-along-the-border from earlier I guess)
>
> I feel like the burden of proof still lies with you here. I feel much
> more comfortable with a handful of easy to reason about and explain
> values (that can be easily reviewed by maintainers) over a blob of data
> that grows with the resolution of your display.

How are these reviewable without testing them on a device though? True
that with corners a maintainer can make sure the values make some sense.
But for notches they can only try visualizing the data to see if it more
or less looks right. And that's equally true for pixel masks. Drawing
the shape by hand would be less tedious for a curve I guess.


Thanks for going over these things with me. It has definitely clarified
many points and gave me a better understanding overall. I guess we won't
convince each other that easily, so maybe let's see what others think.
(but if you want to discuss it further, I'm all ears)


And now that I think about it, maybe it's chain codes that could be the
best of both worlds? They operate on pixels and so remain exact, but
also are basically curves – just very simple ones. I'll have to think
this through.

--
Cheers,
Piotr Masłowski
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/display/panel/panel-common.yaml b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
index 0a57a31f4f3d..6ea52a031872 100644
--- a/Documentation/devicetree/bindings/display/panel/panel-common.yaml
+++ b/Documentation/devicetree/bindings/display/panel/panel-common.yaml
@@ -150,6 +150,13 @@  properties:
       controller, this property contains a phandle that references the
       controller.
 
+  occlusions:
+    $ref: panel-occlusions.yaml#
+    description:
+      Some panels have non-standard shapes due to features like rounded corners,
+      notches, cutouts, and "waterfall" edges. The panel-occlusions bindings
+      can be used to describe these features.
+
 dependencies:
   width-mm: [ height-mm ]
   height-mm: [ width-mm ]
diff --git a/Documentation/devicetree/bindings/display/panel/panel-occlusions.yaml b/Documentation/devicetree/bindings/display/panel/panel-occlusions.yaml
new file mode 100644
index 000000000000..0932026bbd8c
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/panel-occlusions.yaml
@@ -0,0 +1,182 @@ 
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/panel-occlusions.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Common Properties for describing display notches, cutouts, and other occlusions
+
+maintainers:
+  - Caleb Connolly <caleb.connolly@linaro.org>
+
+description: |
+  This document defines devicetree nodes that can be used to describe
+  different kind of display occlusions such as notches, camera cutouts, rounded
+  corners, and other features that may require special treatment by the display
+  subsystem. All pixel values should be given in the displays native resolution.
+
+properties:
+  $nodename:
+    const: occlusions
+
+  corners:
+    type: object
+    description: |
+      An area of the display which is fully obscured by a notch.
+    properties:
+      radius-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: Describes the radius when it's identical for all corners
+
+      radius-top-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: Describes the radius when it's identical for both top corners
+
+      radius-bottom-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: Describes the radius when it's identical for both top corners
+
+      radius-top-left-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The radius of the top left corner in pixels
+
+      radius-top-right-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The radius of the top right corner in pixels
+
+      radius-bottom-left-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The radius of the bottom left corner in pixels
+
+      radius-bottom-right-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The radius of the bottom right corner in pixels
+
+    dependencies:
+      radius-top-left-px: [ radius-top-right-px ]
+      radius-top-right-px: [ radius-top-left-px ]
+      radius-bottom-left-px: [ radius-bottom-right-px ]
+      radius-bottom-right-px: [ radius-bottom-left-px ]
+
+    anyOf:
+      - required:
+          - radius-px
+      - required:
+          - radius-top-px
+          - radius-bottom-px
+      - required:
+          - radius-top-px
+          - radius-bottom-left-px
+          - radius-bottom-right-px
+      - required:
+          - radius-bottom-px
+          - radius-top-left-px
+          - radius-top-right-px
+      - required:
+          - radius-top-left-px
+          - radius-top-right-px
+          - radius-bottom-left-px
+          - radius-bottom-right-px
+
+    additionalProperties: false
+
+patternProperties:
+  "^cutout(-[0-9])?$":
+    type: object
+    description: |
+      An area of the display which is not directly adjacent to an
+      edge and is fully occluded (for example, a camera cutout).
+    properties:
+      x-position-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The horizontal coordinate of the center of the cutout.
+
+      y-position-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The horizontal coordinate of the center of the cutout.
+
+      width-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The width of the cutout in pixels.
+
+      height-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The width of the cutout in pixels.
+
+      corner-radius-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: |
+          The radius of the corners in pixels. For a circle this should be half of
+          the width/height.
+
+    required:
+      - x-position-px
+      - y-position-px
+      - width-px
+      - height-px
+      - corner-radius-px
+
+    additionalProperties: false
+
+  "^notch(-[0-9])?$":
+    type: object
+    description: |
+      An area of the display which is fully occluded by a notch.
+    properties:
+      path:
+        $ref: /schemas/types.yaml#/definitions/uint32-matrix
+        description: |
+          Sequence of values defining the arcs which describe this path. Lines
+          are inserted between arcs that don't directly meet.
+        maxItems: 8 # Ought to cover most scenarios
+        items:
+          items:
+            - description: X coordinate of center point in pixels
+            - description: Y coordinate of center point in pixels
+            - description: Circle radius
+            - description: Starting angle in degrees
+            - description: Ending angle in degrees
+
+    required:
+      - path
+
+    additionalProperties: false
+
+  "^(left|right|top|bottom)-edge$":
+    type: object
+    description: |
+      An edge of the screen with reduced visibility due to a waterfall design
+      or similar.
+    properties:
+      size-px:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The distance from the edge where it begins to obscure visbility
+
+      curve-degrees:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description: The number of degrees that the display curves.
+        maximum: 100
+
+    required:
+      - size-px
+      - curve-degrees
+
+additionalProperties: false
+
+examples:
+  - | # A panel with a large-ish notch on the top edge, and different corner radii
+    panel {
+        occlusions {
+            notch {
+                path = <360 8  10 0    90>,
+                       <435 10 20 270 180>,
+                       <645 10 20 180  90>,
+                       <645 8  10  90   0>;
+            };
+
+            corners {
+                radius-top-px = <30>;
+                radius-bottom-px = <40>;
+            };
+        };
+    };