Meaning of identifier "id" and "color" in ColorMask or ImageMask

[BestVanRome]

Hi Guys,

In image_mask.h:

struct  ColorMask {
	QColor id;
	QColor color;
};

struct ImageMask {
    QImage id;      //carries the label-id information (boudries information ?)
    QImage color;   //carries the color information of the labeled image ?

I don't get the difference between the identifiers.
What is their purpose ?
What is the difference ?

They are both QImages or both QColor, so why is there also so the need to have a function like "Id2Color" ???

Appreciate the upcoming answers!

EDIT:
I think I got the idea:
Qimage id = You store an Image where the pixelsvalues carry the label-id, so actually the number of the label
and
QImage color = You store here the color of the label, so that it can be visualized!

Is my understanding right?

[BestVanRome]

It is!
As my code-tryings have proven me.
Also thanks to Zartris @ Issue #70 !