[FEATURE] set alpha to 'ff' by default in SKColor(UInt32) constructor

[beto-rodriguez]

Is your feature request related to a problem? Please describe.

Based on Live-Charts/LiveCharts2#602

When a SKColor is created using the uint constructor the alpha channel is 0 by default.

var a = new SKColor(0xD65282);
var b = new SKColor(0xFFD65282);

var alphaEquals = a.Alpha == b.Alpha ;
// should be true by default?

Describe the solution you'd like

It would be more intuitive that the alpha channel is 255 instead of zero when it is not specified.

Describe alternatives you've considered

Set the alpha channel manually.

Additional context

none.

[mattleibow]

This is an interesting one.

One of the issues with this is how would you represent a color that has no alpha? (not sure if that is something that people do)

This is also a breaking change, so not sure how possible if people are doing things with 0 alpha...

Maybe the unexpectedness of this warrants a change.

[beto-rodriguez]

I am not sure if there is a standard, but on HTML colors this is really common. The alpha channel is by default to 'ff' unless you specify it, there are multiple color tables on hexadecimal format, like material colors or fluent colors.

If this is implemented it would more intuitive to get a color from any color table on the web:

Not sure if the breaking change is worth.

[themcoo]

SKColor.Parse(string) does exactly that. It actually provides the same rules as you would expect from setting a hex color in CSS:

        foreach (var str in new [] { "123", "123456", "aabbccdd", "#112233" })
	{
		Console.WriteLine(SKColor.Parse(str).ToString());
	}

outputs:

#ff112233
#ff123456
#aabbccdd
#ff112233

I would be sad if the current behaviour for uint based constructor was changed.