Add Color::parse

[vladh]

This function has certain advantages over creating hex colours with color!:

• It allows parsing of hex color strings
• It allows opacity to be specified in hex, such as #ffffff00
• It allows the shorthand #fff notation
• It has better error handling; you can, for example, do color!(0xfafafa9) and there won't be an error, despite the hex string being invalid

If this PR gets merged, I'll send another patch to have color! use from_hex.

[VAWVAW]

You missed the format #abcf in your documentation.

[VAWVAW]

Is there a reason you don't use the more self-explaining #rgba, #rrggbb, ... for documentation?

[vladh]

@VAWVAW Good points, thank you! Fixed.

[n1ght-hunter]

@vladh what the advantage of this over just using the color macro

iced/core/src/color.rs

Line 199 in 950bfc0

($hex:expr) => {{

[vladh]

@n1ght-hunter Oops, I didn't know about color!, thank you. Maybe I should send a patch to better document color!.

That being said, I still think my PR has certain advantages:

• It allows parsing of hex color strings
• It allows opacity to be specified in hex, such as #ffffff00
• It allows the shorthand #fff notation
• It has better error handling; you can, for example, do color!(0xfafafa9) and there won't be an error, despite the hex string being invalid

If this PR gets merged, I'll send another patch to have color! use from_hex.

[nednoodlehead]

i would love this. Sort of annoying when I open a hex color editor, pick a color and I can't easily use it to color buttons and whatnot.

[vladh]

@hecrj Let me know if you want any changes on this (or just don’t want it which is fine).

[hecrj]

Thanks!

I renamed the method to parse, which I believe conveys clearly that there is a runtime cost involved with this helper.

The color! macro should be preferred since it leverages hexadecimal literal notation and arithmetic directly. The compiler is able to optimize most of these operations away in most cases, so no parsing and runtime cost necessary.

I have also extended the macro to support short hand notation and added some debug assertions for good measure.