gx - operator overloading not working for Color

[Linklancien]

Describe the bug

gx - operator overloading not working for Color

Reproduction Steps

import gx
print(gx.rgba(128, 128, 128, 255) - gx.rgba(0, 0, 0, 155))

Expected Behavior

gx - operator have to return 128, 128, 128, 100

Current Behavior

return 128, 128, 128, 255

Possible Solution

mut na := int(a.a) - b.a
if na < 0 {
na = 0
}

Additional Information/Context

No response

V version

V 0.4.6 7a36b44

Environment details (OS name and version, etc.)

windows, Microsoft Windows 10 Famille v19045 64 bits

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[Linklancien]

After reading the code of gx, a thinks it isn't a bug but maybe it nead some comment or else about it in the doc

[spytheman]

We can special case the .a == 255 case, to not modify the alpha, so that the tests for the defined colors (that are fully visible) will continue to work, while the - can be closer to the reverse operation for the + operation.

I do not see the use case for the current behavior 🤔 .