lenses | Composable kmett style lenses | Functional Programming library

BACKWARD_COMPATIBLE devices are ones that support YUV and JPEG output and a bunch of basic camera behavior.

In general, only very few camera types won't list BACKWARD_COMPATIBLE; one such example is a pure depth camera, which won't produce JPEGs. For such devices, you have to manually check what output formats are actually supported via 'getOutputFormats', since it's likely something like JPEG won't be listed, or it may only support monochrome output and not color, which may make it impossible to use it with a video recorder.

If you're seeing a lot of devices get filtered out by excluding BACKWARD_COMPATIBLE, it'd be interesting to know, since in my experience they're very rare.

Once you calibrate your system, if extrinsic (relative position) and intrinsic (camera lenses, focal length, image resolution) parameters remain the same, then you don't need to recalculate the fundamental matrix F. You do it only once, and may store it for future use.

This is exactly what I do in my library, where you can find also an example where the fundamental matrix is calculated and used to draw epipolar lines.

I hope this answers your question.

Cheers

I think you are on the right track.

You can create the left half from the right half by applying transformations to it using let leftHalf = rightHalf.transformed(by: transformation). The transformation should mirror it and translate it to the correct position, i.e., next to the right half.

You can them combine the two into one image using let result = leftHalf.composited(over: rightHalf) and render that result using a CIContext.

Updated: As per comments, I've fixed some errors and added a few asides in [[double square brackets]].

Here's how/why your first mMistake works...

A prism is an optic that focus on a "part" that may or may not be present in the "whole". [[Technically, it focuses on the sort of part that can be used to reconstruct an entire whole, so it really pertains to a whole that can come in several alternative forms (as in the case of a sum type), with the "part" being one of those alternative forms. However, if you're only using a prism for viewing and not setting, this added functionality isn't too important.]]

In your example, both _StateRun and _Just are prisms. The _Just prism focuses on the a part of a Maybe a whole. Such an a may or may not be present. If the Maybe a value is Just x for some x :: a, the part a is present and has value x, and that's what _Just focuses on. If the Maybe a value is Nothing, then the part a is not present, and _Just doesn't focus on anything.

It's somewhat similar for your prism _StateRun. If the whole StateStep is a StateRun x y value, then _StateRun focuses on that "part", represented as a tuple of the fields of the StateRun constructor, namely (x, y) :: (Int, Maybe Text). On the other hand, if the whole StateStep is a StatePause, that part isn't present, and the prism doesn't focus on anything.

When you compose prisms, like _StateRun and _Just, and lenses, like stStep and _2, you create a new optic that combines the composed series of focusing operations.

[[As was pointed out in the comments, this new optic isn't a prism; it's "only" traversal. In fact, it's a specific kind of traversal, called an "affine traversal". A run-of-the-mill traversal can focus on zero or more parts, while an affine traversal focuses on exactly zero (part not present) or one (unique part present). The lens library doesn't make the distinction between affine traversals and other sorts of traversals, though. The reason the new optic is "only" an affine traversal instead of a prism relates to that earlier technical point. Once you add lenses, you remove your ability to reconstruct the entire "whole" from a single "part". Again, if you're only using the optics for viewing, not setting, it won't really matter.]]

Anyway, consider the optic (affine traversal):

ix 0 doesn't produce a lens, but a traversal.¹

Informally, a lens is a "path" that will definitively reach a single value (if you follow it within a hypothetical larger value). A traversal is a path to zero or more values. You can set or view the single target of a lens. And you can set the zero or more targets of a traversal (this simply updates all of them that are present, which is a no-op if there are zero present). But viewing the targets of a traversal is less straightforward.

If view simply took a traversal, and an outer structure, and gave you the target value, then it would have a problem. If there are multiple targets, how should it decide which to return? And if there are zero targets, it can't return anything; it would have to be partial. What it needs is a way of condensing zero-or-more values into a single value, so it can return that. And the Monoid class provides exactly the facilities to do that; mempty for if there aren't any targets at all, and <> to condense multiple values to a single one. So view with a traversal² actually requires a Monoid constraint on the returned type, and that's why you're getting the complaint about No instance for (Monoid Int) arising from a use of `ix'.

And in case it isn't clear, you can often compose (with .) different types of optics (the general term for "lens-ish things", including lenses, traversals, and several others). But the result has the capabilities of the least capable of the two inputs. So even though your inner and w are full lenses, composing them with a traversal produced by ix results in a traversal, not a lens.

But in this case you know that you're using ix. The specific kind of traversals ix makes end up having zero or one target, rather than the zero or more targets that traversals have in general. So you could use preview instead of view; for a traversal it will produce a Maybe containing Just the first target of the traversal, or Nothing if there weren't any. A Maybe is exactly what the type system deems appropriate here, since ix can't guarantee there will be a target value, but there won't be more than one.

In my experience, when I try to view something and get this Monoid instance error, it almost always means I have an optic that can't guarantee a result and I should actually be using preview to get a Maybe.

Simple example:

Completely removing the other options is currently not available. However, you can lock them as shown in the picture.

1. Remove databricks-sql-access entitlement from default users group.
2. Create a new group called 'sql-users-only' and give them only this entitlement. (so they won't see workspace and they can't spin up endpoints)

Resources: Databricks provide a lot of control using ACLs. Access control overview You can restrict the dashboard viewing options as well. Dashboard permissions

Add the type Todo to the lensProp call. You can also move it out of the component, because you don't need to generate the function whenever the component re-renders:

The parent column needs to be the column that forms the relationship between the two. That is it should be the fk_lensId column.

So :-

It seems like because the JSON object is not an array of objects, the deserializer cannot convert it to an IEnumerable

Yes, it is not an array of objects, it is an object with others objects in it, I believe that using default serializers/deserializers you will not be able to work this JSON out.

Unless you end up using dynamic objects (can be a JObject) and then cast it to another structure, the only way is to write a custom serializer for this specific case and build an workaround this JSON.

You can try this: