Add custom gradient start point

[tbaranes]

Close #378

Using StartPoint.custom(0,0.5,0,0), it will render:

That may be useful! After a quick first look to update the example app, I have to say that I'm a bit lost with the ParamType 😨 @lastMove How am I supposed to create ParamType using custom parameters?

Missing:

• Example app
• Changelog

[IBAnimatableBot]

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⚠️	Consider adding supporting documentation to this change. Documentation can be found in the docs directory.

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[lastMove]

Hello,
Nice feature !
How do you want to render it ?
Presently in the Playground part of the app in "predefined gradients" section;
there is a Picker with 2 components (one for the gradient, the other one for the startPoint).
So it will be difficult to had 4 more components to customise that.
Maybe we should create another section.
ParamType allows To generate and manage arrays of possible values for a pickerComponent.
And you can generate this array from enum; Sample :

let gradientValues = ParamType(fromEnum: GradientStartPoint.self)
print(gradientValues.value(at: 0))
// "top"
print(gradientValues.value(at: 4))
// "bottomRight"

It's like an array generated from enum values.

It works also to generate array of possible values from number interval :

private let numberParam = ParamType.number(min: -50, max: 50, interval: 5, ascending: true, unit: "")
// this will generate this array : [-50, -45, -40, -35, ... , 35, 40, 45, 50]

So numberParam.value(at: 0) will gives -50.

[tbaranes]

I was thinking to add directly a predefined startPoint, but you are right, it will be for the best to add a section to render it.
Thanks for the explanation! I will give it a try.

[tbaranes]

Working perfectly @lastMove! Thanks for the tips.

One more question, any suggestion how we should update the current example (it won't compile since .custom isn't compatible with the other startPoint). I see that for the animation you used PickerEntry, should I do the same or is there a better existing solution?

[JakeLin]

I think it is ready to go👍

[JakeLin]

Great method from @lastMove for safe extracting data from params

[tbaranes]

Not really, the gradient example is still broken 😬 Open to any suggestion

[JakeLin]

haha, I always forgot that.

[lastMove]

:) It's error-prone. I saw it when testing with the exemple app.

[lastMove]

Should be good know.
@tbaranes the problem was that since GradientStartPoint does not anymore have a String RawValue ParamType.enumeration(values: ["top", "topLeft", "topRight", "left", "right", "bottom", "bottomRight", "bottomLeft"])

[tbaranes]

@lastMove thanks for that!