/// <summary>
/// Converts a string in Mapbox GL format to a Mapsui Color
///
/// This function assumes, that alpha is a float in range from 0.0 to 1.0.
/// It converts this float in Maspui Color alpha without rounding.
/// The following colors could be converted:
/// - Named colors with known Html names
/// - Colors as Html color values with leading '#' and 6 or 3 numbers
/// - Function rgb(r,g,b) with values for red, green and blue
/// - Function rgba(r,g,b,a) with values for red, green, blue and alpha. Here alpha is between 0.0 and 1.0 like opacity.
/// - Function hsl(h,s,l) with values hue (0.0 to 360.0), saturation (0.0% - 100.0%) and lightness (0.0% - 100.0%)
/// - Function hsla(h,s,l,a) with values hue (0.0 to 360.0), saturation (0.0% - 100.0%), lightness (0.0% - 100.0%) and alpha. Here alpha is between 0.0 and 1.0 like opacity.
/// </summary>
/// <param name="from">String with HTML color representation or function like rgb() or hsl()</param>
/// <returns>Converted Mapsui Color</returns>
public static Color FromString(string from)
{
Color result = null;
from = from.Trim().ToLower();
// Check, if it is a known color
if (KnownColors.ContainsKey(from))
{
from = KnownColors[from];
}
if (from.StartsWith("#"))
{
if (from.Length == 7)
{
var color = int.Parse(from.Substring(1), NumberStyles.AllowHexSpecifier,
CultureInfo.InvariantCulture);
result = new Color(color >> 16 & 0xFF, color >> 8 & 0xFF, color & 0xFF);
}
else if (from.Length == 4)
{
var color = int.Parse(from.Substring(1), NumberStyles.AllowHexSpecifier,
CultureInfo.InvariantCulture);
var r = (color >> 8 & 0xF) * 16 + (color >> 8 & 0xF);
var g = (color >> 4 & 0xF) * 16 + (color >> 4 & 0xF);
var b = (color & 0xF) * 16 + (color & 0xF);
result = new Color(r, g, b);
}
}
else if (from.StartsWith("rgba"))
{
var split = from.Substring(from.IndexOf('(') + 1).TrimEnd(')').Split(',');
if (split.Length != 4)
{
throw new ArgumentException($"color {from} isn't a valid color");
}
var r = int.Parse(split[0].Trim(), CultureInfo.InvariantCulture);
var g = int.Parse(split[1].Trim(), CultureInfo.InvariantCulture);
var b = int.Parse(split[2].Trim(), CultureInfo.InvariantCulture);
var a = float.Parse(split[3].Trim(), NumberStyles.Float, CultureInfo.InvariantCulture);
result = new Color(r, g, b, (int)(a * 255));
}
else if (from.StartsWith("rgb"))
{
var split = from.Substring(from.IndexOf('(') + 1).TrimEnd(')').Split(',');
if (split.Length != 3)
{
throw new ArgumentException($"color {from} isn't a valid color");
}
var r = int.Parse(split[0].Trim(), CultureInfo.InvariantCulture);
var g = int.Parse(split[1].Trim(), CultureInfo.InvariantCulture);
var b = int.Parse(split[2].Trim(), CultureInfo.InvariantCulture);
result = new Color(r, g, b);
}
else if (from.StartsWith("hsla"))
{
var split = from.Substring(from.IndexOf('(') + 1).TrimEnd(')').Split(',');
if (split.Length != 4)
{
throw new ArgumentException($"color {from} isn't a valid color");
}
var h = float.Parse(split[0].Trim(), CultureInfo.InvariantCulture);
var s = float.Parse(split[1].Trim().Replace("%", ""), CultureInfo.InvariantCulture);
var l = float.Parse(split[2].Trim().Replace("%", ""), CultureInfo.InvariantCulture);
var a = float.Parse(split[3].Trim(), NumberStyles.Float, CultureInfo.InvariantCulture);
result = FromHsl(h / 360.0f, s / 100.0f, l / 100.0f, (int)(a * 255));
}
else if (from.StartsWith("hsl"))
{
var split = from.Substring(from.IndexOf('(') + 1).TrimEnd(')').Split(',');
if (split.Length != 3)
{
throw new ArgumentException($"color {from} isn't a valid color");
}
var h = float.Parse(split[0].Trim(), CultureInfo.InvariantCulture);
var s = float.Parse(split[1].Trim().Replace("%", ""), CultureInfo.InvariantCulture);
var l = float.Parse(split[2].Trim().Replace("%", ""), CultureInfo.InvariantCulture);
result = FromHsl(h / 360.0f, s / 100.0f, l / 100.0f);
}
return(result);
}