/// <summary>
/// Parses the specified string into a collection of path segments.
/// </summary>
/// <param name="path">A <see cref="string"/> containing path data.</param>
public static SvgPathSegmentList Parse(ReadOnlySpan <char> path)
{
var segments = new SvgPathSegmentList();
try
{
var pathTrimmed = path.TrimEnd();
var commandStart = 0;
var pathLength = pathTrimmed.Length;
for (var i = 0; i < pathLength; ++i)
{
var currentChar = pathTrimmed[i];
if (char.IsLetter(currentChar) && currentChar != 'e' && currentChar != 'E') // e is used in scientific notiation. but not svg path
{
var start = commandStart;
var length = i - commandStart;
var command = pathTrimmed.Slice(start, length).Trim();
commandStart = i;
if (command.Length > 0)
{
var commandSetTrimmed = pathTrimmed.Slice(start, length).Trim();
var state = new CoordinateParserState(ref commandSetTrimmed);
CreatePathSegment(commandSetTrimmed[0], segments, ref state, ref commandSetTrimmed);
}
if (pathLength == i + 1)
{
var commandSetTrimmed = pathTrimmed.Slice(i, 1).Trim();
var state = new CoordinateParserState(ref commandSetTrimmed);
CreatePathSegment(commandSetTrimmed[0], segments, ref state, ref commandSetTrimmed);
}
}
else if (pathLength == i + 1)
{
var start = commandStart;
var length = i - commandStart + 1;
var command = pathTrimmed.Slice(start, length).Trim();
if (command.Length > 0)
{
var commandSetTrimmed = pathTrimmed.Slice(start, length).Trim();
var state = new CoordinateParserState(ref commandSetTrimmed);
CreatePathSegment(commandSetTrimmed[0], segments, ref state, ref commandSetTrimmed);
}
}
}
}
catch (Exception exc)
{
Trace.TraceError("Error parsing path \"{0}\": {1}", path.ToString(), exc.Message);
}
return(segments);
}
/// <summary>
/// Converts the given object to the type of this converter, using the specified context and culture information.
/// </summary>
/// <param name="context">An <see cref="T:System.ComponentModel.ITypeDescriptorContext"/> that provides a format context.</param>
/// <param name="culture">The <see cref="T:System.Globalization.CultureInfo"/> to use as the current culture.</param>
/// <param name="value">The <see cref="T:System.Object"/> to convert.</param>
/// <returns>
/// An <see cref="T:System.Object"/> that represents the converted value.
/// </returns>
/// <exception cref="T:System.NotSupportedException">The conversion cannot be performed. </exception>
public override object ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, object value)
{
if (value is string s)
{
var coords = s.AsSpan().Trim();
var state = new CoordinateParserState(ref coords);
var result = new SvgPointCollection();
while (CoordinateParser.TryGetFloat(out var pointValue, ref coords, ref state))
{
result.Add(new SvgUnit(SvgUnitType.User, pointValue));
}
return(result);
}
return(base.ConvertFrom(context, culture, value));
}
public static bool TryGetFloat(out float result, ref ReadOnlySpan <char> chars, ref CoordinateParserState state)
{
var charsLength = chars.Length;
while (state.CharsPosition < charsLength && state.HasMore)
{
var currentChar = chars[state.CharsPosition];
switch (state.CurrNumState)
{
case NumState.Separator:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.Integer;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else
{
switch (currentChar)
{
case '.':
state.NewNumState = NumState.DecPlace;
break;
case '+':
case '-':
state.NewNumState = NumState.Prefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
case NumState.Prefix:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.Integer;
}
else if (currentChar == '.')
{
state.NewNumState = NumState.DecPlace;
}
else
{
state.NewNumState = NumState.Invalid;
}
break;
case NumState.Integer:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.Integer;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else
{
switch (currentChar)
{
case '.':
state.NewNumState = NumState.DecPlace;
break;
case 'E':
case 'e':
state.NewNumState = NumState.Exponent;
break;
case '+':
case '-':
state.NewNumState = NumState.Prefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
case NumState.DecPlace:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.Fraction;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else
{
switch (currentChar)
{
case 'E':
case 'e':
state.NewNumState = NumState.Exponent;
break;
case '+':
case '-':
state.NewNumState = NumState.Prefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
case NumState.Fraction:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.Fraction;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else
{
switch (currentChar)
{
case '.':
state.NewNumState = NumState.DecPlace;
break;
case 'E':
case 'e':
state.NewNumState = NumState.Exponent;
break;
case '+':
case '-':
state.NewNumState = NumState.Prefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
case NumState.Exponent:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.ExpValue;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Invalid;
}
else
{
switch (currentChar)
{
case '+':
case '-':
state.NewNumState = NumState.ExpPrefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
case NumState.ExpPrefix:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.ExpValue;
}
else
{
state.NewNumState = NumState.Invalid;
}
break;
case NumState.ExpValue:
if (char.IsNumber(currentChar))
{
state.NewNumState = NumState.ExpValue;
}
else if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else
{
switch (currentChar)
{
case '.':
state.NewNumState = NumState.DecPlace;
break;
case '+':
case '-':
state.NewNumState = NumState.Prefix;
break;
default:
state.NewNumState = NumState.Invalid;
break;
}
}
break;
}
if (state.CurrNumState != NumState.Separator && state.NewNumState < state.CurrNumState)
{
#if NETSTANDARD2_1 || NETCORE || NETCOREAPP2_1 || NETCOREAPP3_1 || NET5_0
result = float.Parse(chars.Slice(state.Position, state.CharsPosition - state.Position), NumberStyles.Float, CultureInfo.InvariantCulture);
#else
result = float.Parse(chars.Slice(state.Position, state.CharsPosition - state.Position).ToString(), NumberStyles.Float, CultureInfo.InvariantCulture);
#endif
state.Position = state.CharsPosition;
state.CurrNumState = state.NewNumState;
return(MarkState(true, ref state));
}
else if (state.NewNumState != state.CurrNumState && state.CurrNumState == NumState.Separator)
{
state.Position = state.CharsPosition;
}
if (state.NewNumState == NumState.Invalid)
{
result = float.MinValue;
return(MarkState(false, ref state));
}
state.CurrNumState = state.NewNumState;
++state.CharsPosition;
}
if (state.CurrNumState == NumState.Separator || !state.HasMore || state.Position >= charsLength)
{
result = float.MinValue;
return(MarkState(false, ref state));
}
else
{
#if NETSTANDARD2_1 || NETCORE || NETCOREAPP2_1 || NETCOREAPP3_1 || NET5_0
result = float.Parse(chars.Slice(state.Position, charsLength - state.Position), NumberStyles.Float, CultureInfo.InvariantCulture);
#else
result = float.Parse(chars.Slice(state.Position, charsLength - state.Position).ToString(), NumberStyles.Float, CultureInfo.InvariantCulture);
#endif
state.Position = charsLength;
return(MarkState(true, ref state));
}
}
public static bool TryGetBool(out bool result, ref ReadOnlySpan <char> chars, ref CoordinateParserState state)
{
var charsLength = chars.Length;
while (state.CharsPosition < charsLength && state.HasMore)
{
switch (state.CurrNumState)
{
case NumState.Separator:
var currentChar = chars[state.CharsPosition];
if (IsCoordSeparator(currentChar))
{
state.NewNumState = NumState.Separator;
}
else if (currentChar == '0')
{
result = false;
state.NewNumState = NumState.Separator;
state.Position = state.CharsPosition + 1;
return(MarkState(true, ref state));
}
else if (currentChar == '1')
{
result = true;
state.NewNumState = NumState.Separator;
state.Position = state.CharsPosition + 1;
return(MarkState(true, ref state));
}
else
{
result = false;
return(MarkState(false, ref state));
}
break;
default:
result = false;
return(MarkState(false, ref state));
}
++state.CharsPosition;
}
result = false;
return(MarkState(false, ref state));
}
private static bool MarkState(bool hasMode, ref CoordinateParserState state)
{
state.HasMore = hasMode;
++state.CharsPosition;
return(hasMode);
}
private static void CreatePathSegment(char command, SvgPathSegmentList segments, ref CoordinateParserState state, ref ReadOnlySpan <char> chars)
{
var isRelative = char.IsLower(command);
// http://www.w3.org/TR/SVG11/paths.html#PathDataGeneralInformation
switch (command)
{
case 'M': // moveto
case 'm': // relative moveto
{
if (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state))
{
segments.Add(
new SvgMoveToSegment(
isRelative, new PointF(coords0, coords1)));
}
while (CoordinateParser.TryGetFloat(out coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out coords1, ref chars, ref state))
{
segments.Add(
new SvgLineSegment(
isRelative, new PointF(coords0, coords1)));
}
}
break;
case 'A': // elliptical arc
case 'a': // relative elliptical arc
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords2, ref chars, ref state) &&
CoordinateParser.TryGetBool(out var size, ref chars, ref state) &&
CoordinateParser.TryGetBool(out var sweep, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords3, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords4, ref chars, ref state))
{
// A|a rx ry x-axis-rotation large-arc-flag sweep-flag x y
segments.Add(
new SvgArcSegment(
coords0,
coords1,
coords2,
size ? SvgArcSize.Large : SvgArcSize.Small,
sweep ? SvgArcSweep.Positive : SvgArcSweep.Negative,
isRelative, new PointF(coords3, coords4)));
}
}
break;
case 'L': // lineto
case 'l': // relative lineto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state))
{
segments.Add(
new SvgLineSegment(
isRelative, new PointF(coords0, coords1)));
}
}
break;
case 'H': // horizontal lineto
case 'h': // relative horizontal lineto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state))
{
segments.Add(
new SvgLineSegment(
isRelative, new PointF(coords0, float.NaN)));
}
}
break;
case 'V': // vertical lineto
case 'v': // relative vertical lineto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state))
{
segments.Add(
new SvgLineSegment(
isRelative, new PointF(float.NaN, coords0)));
}
}
break;
case 'Q': // quadratic bézier curveto
case 'q': // relative quadratic bézier curveto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords2, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords3, ref chars, ref state))
{
segments.Add(
new SvgQuadraticCurveSegment(
isRelative,
new PointF(coords0, coords1),
new PointF(coords2, coords3)));
}
}
break;
case 'T': // shorthand/smooth quadratic bézier curveto
case 't': // relative shorthand/smooth quadratic bézier curveto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state))
{
segments.Add(
new SvgQuadraticCurveSegment(
isRelative, new PointF(coords0, coords1)));
}
}
break;
case 'C': // curveto
case 'c': // relative curveto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords2, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords3, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords4, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords5, ref chars, ref state))
{
segments.Add(
new SvgCubicCurveSegment(
isRelative,
new PointF(coords0, coords1),
new PointF(coords2, coords3),
new PointF(coords4, coords5)));
}
}
break;
case 'S': // shorthand/smooth curveto
case 's': // relative shorthand/smooth curveto
{
while (CoordinateParser.TryGetFloat(out var coords0, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords1, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords2, ref chars, ref state) &&
CoordinateParser.TryGetFloat(out var coords3, ref chars, ref state))
{
segments.Add(
new SvgCubicCurveSegment(
isRelative,
new PointF(coords0, coords1),
new PointF(coords2, coords3)));
}
}
break;
case 'Z': // closepath
case 'z': // relative closepath
{
segments.Add(new SvgClosePathSegment(isRelative));
}
break;
}
}