Colors. Part 2.

Enumerate all Known Colors and put them in the dictionary

Dictionary<KnownColor, int> colorsRGB;

can be done this way:

int

    numAliceBlue = (int)KnownColor.AliceBlue,

    numYellowGreen = (int)KnownColor.YellowGreen,

    numColors = numYellowGreen - numAliceBlue + 1;

colorsRGB = new Dictionary<KnownColor, int>(numColors);

for (int i = numAliceBlue; i <= numYellowGreen; i++)

{

    KnownColor kc = (KnownColor)i;

    colorsRGB.Add(kc, Color.FromKnownColor(kc).ToArgb());

}

Then I can sort the collection using LINQ:

Sort by name:

var sortedColors = (from clr in colorsRGB

                    orderby clr.Key

                    select clr).ToArray();
by RGB value:

var sortedColors = (from clr in colorsRGB

                   orderby clr.Value descending

                   select clr).ToArray();

I created a function ColorWeight to “weight” a color (just sum of R, G, and B components),

And even can sort by the “weight”:

var sortedColors = (from clr in colorsRGB

                    orderby ColorWeight(clr.Key) descending

                    select clr).ToArray();

I do like LINQ!

For the test I draw buttons with KnownColor as background. I wanted to have foreground color to be recognizable on the background.

This turn out to be not easy task. I did not want to mess with non-RGB presentations (like HSV or HSL) which would simplify the task.

At first I tried “inverted” color:

return Color.FromArgb((int)backColor.ToArgb() ^ 0xF0F0F0);

It did not work well.

So I created “color weight”

private int ColorWeight(Color color)

{

    int bColor = (int)color.ToArgb(),

        r = (bColor & 0x00FF0000) >> 16,

        g = (bColor & 0x0000FF00) >> 8,

        b = bColor & 0x000000FF;

    return r + g + b;

}

It is not perfect, but kind of fit the purpose: after all I put Black text if “weight” > 0x60+0x60+0x60 and White text otherwise.

This is the result:

Download source code