Windows Phone 7: How to parse Bezier Path string like in XAML?
bezier, c#, silverlight, windows-phone-7, xaml
Solution
We don't currently expose an API for the path mini-language parser. It's internal to the XAML parser.
You can, however, create Path objects dynamically based on mini-language strings, using the XamlReader:
Path path = XamlReader.Load("<Path xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' Stroke='Blue' Data='M 0 0 Q 10 10 20 0'/>") as Path;
Note that this won't actually expose the details of the geometry through the API to you, but you can display the resulting Path in your app.
Problem
I have a need to parse Bezier Path Strings, but apparently the `System.Windows.Media.Geometry`version in the .Net CF framework doesn't have the `Parse()` method that is available in it's normal counterpart. However, entering the following XAML does work, so there must be a way the system parses the Path Data String. `<Path Stroke="Blue" Data="M 0 0 Q 10 10 20 0"/>` Any clue on how I can initiate this parsing myself with a custom string outside XAML? I ofcourse could also try to write my own parser using regex or so, but I would prefer not to handle this myself, since the framework clearly is capable of it. Update When using the suggested XAMLReader, I get a strange Exception when I set a StrokeThickness to the newly created `Path`: ``` path.StrokeThickness = strokeWidth; //ArgumentException ??? (strokeWidth = 6) ``` When I change codepath to render using my manual parser, everything works correctly. Am I missing something here? Nothing changes except the parser. Manually Generating Data: ``` //"M {0} {1} Q {2} {3} {4} {5}" String regex_input = @"M (\d+) (\d+) Q (\d+) (\d+) (\d+) (\d+)"; Regex regex = new Regex(regex_input); Match match = regex.Match(pathData); int startx = int.Parse(match.Groups[1].Value); int starty = int.Parse(match.Groups[2].Value); int controlx = int.Parse(match.Groups[3].Value); int controly = int.Parse(match.Groups[4].Value); int endx = int.Parse(match.Groups[5].Value); int endy = int.Parse(match.Groups[6].Value); PathGeometry geo = new PathGeometry(); PathFigure figure = new PathFigure(); figure.StartPoint = new Point(startx, starty); QuadraticBezierSegment quad = new QuadraticBezierSegment(); quad.Point1 = new Point(controlx, controly); quad.Point2 = new Point(endx, endy); figure.Segments.Add(quad); geo.Figures.Add(figure); path.Data = geo; ``` Using XamlReader ``` String formattedXAMLInput = String.Format("<Path xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation' Stroke='Black' Data='{0}'/>", pathData); Path xamlpath = (Path)XamlReader.Load(formattedXAMLInput); Geometry xamldata = xamlpath.Data; path.Data = xamldata; ```