How to check if hex color is “too black”?

Question

I\'m trying to evaluate the darkness of a color chosen by a color picker to see if it\'s \"too black\", and if so, set it to white. I thought I could use the first character

Answer 1

I realize this conversation is a few years old, but it is still relevant. I wanted to add that my team was having the same issue in Java (SWT) and found this to be a bit more accurate:

private Color getFontColor(RGB bgColor) {
    Color COLOR_BLACK = new Color(Display.getDefault(), 0, 0, 0);
    Color COLOR_WHITE = new Color(Display.getDefault(), 255, 255, 255);

    double luminance = Math.sqrt(0.241 
       * Math.pow(bgColor.red, 2) + 0.691 * Math.pow(bgColor.green, 2) +  0.068 
       * Math.pow(bgColor.blue, 2));
    if (luminance >= 130) {
        return COLOR_BLACK;
    } else {
        return COLOR_WHITE;
    }
}