public static LinearGradient Parse(ReadOnlySpan <char> text)
{
if (text.StartsWith("linear-gradient(".AsSpan()))
{
text = text.Slice(16, text.Length - 17);
}
if (text.Length == 0)
{
throw new ArgumentException("May not be empty", nameof(text));
}
double?angle = null;
LinearGradientDirection direction = default;
if (char.IsDigit(text[0]) || text[0] == '-')
{
angle = ReadAngle(text, out int read);
text = text.Slice(read);
}
else if (LinearGradientDirectionHelper.TryParse(text, out direction, out int read))
{
text = text.Slice(read);
}
var colorStops = new List <ColorStop>();
while (text.Length > 0)
{
if (text[0] == ',')
{
text = text.Slice(1);
}
if (text.TryReadWhitespace(out int read))
{
text = text.Slice(read);
}
if (text[0] == ',')
{
text = text.Slice(1);
}
var colorStop = ColorStop.Read(text, out read);
text = text.Slice(read);
colorStops.Add(colorStop);
}
// TODO: Set the default stops
// // [ <angle> | to [top | bottom] || [left | right] ],]? <color-stop>[, <color-stop>]+);
return(new LinearGradient(direction, angle, colorStops.ToArray()));
}
public static bool TryParse(ReadOnlySpan <char> text, out LinearGradientDirection result, out int read)
{
read = 0;
// NOTE: The legacy prefix did not include too
if (text.StartsWith("to ".AsSpan()))
{
read += 3;
text = text.Slice(3);
}
if (text.StartsWith("top".AsSpan()))
{
read += 3;
text = text.Slice(3);
if (text.StartsWith(" left".AsSpan()))
{
read += 5;
result = TopLeft;
}
else if (text.StartsWith(" right".AsSpan()))
{
read += 6;
result = TopRight;
}
else
{
result = Top;
}
}
else if (text.StartsWith("bottom".AsSpan()))
{
read += 6;
text = text.Slice(6);
if (text.StartsWith(" left".AsSpan()))
{
read += 5;
result = Left;
}
else if (text.StartsWith(" right".AsSpan()))
{
read += 6;
result = BottomRight;
}
else
{
result = Bottom;
}
}
else if (text.StartsWith("left".AsSpan()))
{
read += 4;
result = Left;
}
else if (text.StartsWith("right".AsSpan()))
{
read += 5;
result = Right;
}
else
{
result = default;
return(false);
}
return(true);
}
public static string Canonicalize(LinearGradientDirection value) => value switch
{
public LinearGradient(LinearGradientDirection direction, double?angle, ColorStop[] colorStops)
{
Direction = direction;
Angle = angle;
Stops = colorStops;
}
