/// <summary>
// Try to parse a color given in different flavours (hex, rgb, name)
/// </summary>
public static bool TryParseColor(string strVal, double alpha, out Color color)
{
// 1: color is specified in rgb values
if (strVal.StartsWith("rgb(", StringComparison.OrdinalIgnoreCase))
{
var str = strVal.Substring(4, strVal.Length - 5);
string[] parts = str.Split(',');
if (parts.Length != 3)
{
color = Colors.Black;
return(false);
}
try
{
string redStr = parts[0].Trim();
string greenStr = parts[1].Trim();
string blueStr = parts[2].Trim();
byte red;
byte green;
byte blue;
if (string.IsNullOrWhiteSpace(redStr) ||
string.IsNullOrWhiteSpace(greenStr) ||
string.IsNullOrWhiteSpace(blueStr))
{
red = 0;
green = 0;
blue = 0;
}
else
{
red = (byte)ParseColorValue(redStr);
green = (byte)ParseColorValue(greenStr);
blue = (byte)ParseColorValue(blueStr);
}
color = Color.FromArgb((byte)(alpha * 255), red, green, blue);
return(true);
}
catch
{
}
color = Colors.Black;
return(false);
}
// 2: color is specified in rgba values
if (strVal.StartsWith("rgba(", StringComparison.OrdinalIgnoreCase))
{
var str = strVal.Substring(5, strVal.Length - 6);
string[] parts = str.Split(',');
if (parts.Length != 4)
{
color = Colors.Black;
return(false);
}
try
{
string redStr = parts[0].Trim();
string greenStr = parts[1].Trim();
string blueStr = parts[2].Trim();
string alphaStr = parts[3].Trim();
byte red;
byte green;
byte blue;
double alphaD;
if (string.IsNullOrWhiteSpace(alphaStr) ||
string.IsNullOrWhiteSpace(redStr) ||
string.IsNullOrWhiteSpace(greenStr) ||
string.IsNullOrWhiteSpace(blueStr))
{
alphaD = 1;
red = 0;
green = 0;
blue = 0;
}
else
{
red = (byte)ParseColorValue(redStr);
green = (byte)ParseColorValue(greenStr);
blue = (byte)ParseColorValue(blueStr);
(_, alphaD) = DoubleParser.GetNumberPercent(alphaStr);
}
color = Color.FromArgb((byte)(alpha * alphaD * 255), red, green, blue);
return(true);
}
catch
{
}
color = Colors.Black;
return(false);
}
// 3: color is specified in hsl values
if (strVal.StartsWith("hsl(", StringComparison.OrdinalIgnoreCase))
{
var str = strVal.Substring(4, strVal.Length - 5);
string[] parts = str.Split(',');
if (parts.Length != 3)
{
color = Colors.Black;
return(false);
}
try
{
string hueStr = parts[0].Trim();
string saturationStr = parts[1].Trim();
string luminosityStr = parts[2].Trim();
if (string.IsNullOrWhiteSpace(hueStr) ||
string.IsNullOrWhiteSpace(saturationStr) ||
string.IsNullOrWhiteSpace(luminosityStr))
{
color = Colors.Black;
return(true);
}
else
{
var hue = DoubleParser.GetNumber(hueStr);
var(_, saturation) = DoubleParser.GetNumberPercent(saturationStr);
var(_, luminosity) = DoubleParser.GetNumberPercent(luminosityStr);
color = ColorSpaceConverter.ConvertHlsToRgb(alpha, hue, saturation, luminosity);
return(true);
}
}
catch
{
}
color = Colors.Black;
return(false);
}
// 4: color is either given as name or hex values
try
{
if (strVal == "grey")
{
strVal = "gray";
}
var color2 = (Color)ColorConverter.ConvertFromString(strVal);
color = Color.FromArgb((byte)(alpha * 255), color2.R, color2.G, color2.B);
return(true);
}
catch
{
}
color = Colors.Black;
return(false);
}
