c# rgb colour scale

Question

I have a requirement to display a particular colour representation dependant upon data. At one end of the scale is green and the other red. The scale should cover the colours in between.

I am comfortable with the actual programming, but unsure of how to scale the rgb colours. Does anybody know any scales for this sort of thing?

Thanks.

Answer 1

The following method should work for you :

    Color GetColor(Int32 rangeStart /*Complete Red*/, Int32 rangeEnd /*Complete Green*/, Int32 actualValue)
    {
        if (rangeStart >= rangeEnd) return Colors.Black;

        Int32 max = rangeEnd - rangeStart; // make the scale start from 0
        Int32 value = actualValue - rangeStart; // adjust the value accordingly

        Int32 green = (255 * value) / max; // calculate green (the closer the value is to max, the greener it gets)
        Int32 red = 255 - green; // set red as inverse of green

        return Color.FromRgb((Byte)red, (Byte)green, (Byte)0);
    }

Answer 2

Is this what you mean?

Color GetColor(int scale)
{
    // scale is between 1 and 255
    return Color.FromArgb(255, scale, 255 - scale, 0);
}