Question

It’s not too hard to track down how to programmatically convert path strings into path objects in WPF, but is there a built-in function to convert a geometry or path back to a string in the mini-language?

Answer 1

Edit: Looking at this just now i thought that there should be a class called GeometryConverter which should be able to do this, and indeed there is. Just create one of those and use ConvertToString on the geometry you want to convert.

---

You can use the XamlWriter class to output objects as XAML, geometry will automatically be reduced to the mini-language.

e.g. if this is your input:

<DrawingImage x:Name="segmentsDrawing">
    <DrawingImage.Drawing>
        <DrawingGroup>

            <GeometryDrawing Brush="Red">
                <GeometryDrawing.Pen>
                    <Pen Brush="Black" />
                </GeometryDrawing.Pen>
                <GeometryDrawing.Geometry>
                    <PathGeometry>
                        <PathFigure StartPoint="100,100">
                            <PathFigure.Segments>
                                <LineSegment Point="100,0"/>
                                <ArcSegment Point="186.6,150"  SweepDirection="Clockwise" Size="100,100"/>
                                <LineSegment Point="100,100"/>
                            </PathFigure.Segments>
                        </PathFigure>
                    </PathGeometry>
                </GeometryDrawing.Geometry>
            </GeometryDrawing>

            <GeometryDrawing Brush="Blue">
                <GeometryDrawing.Pen>
                    <Pen Brush="Black"/>
                </GeometryDrawing.Pen>
                <GeometryDrawing.Geometry>
                    <PathGeometry>
                        <PathFigure StartPoint="100,100">
                            <PathFigure.Segments>
                                <LineSegment Point="186.6,150"/>
                                <ArcSegment Point="13.4,150" SweepDirection="Clockwise" Size="100,100"/>
                                <LineSegment Point="100,100"/>
                            </PathFigure.Segments>
                        </PathFigure>
                    </PathGeometry>
                </GeometryDrawing.Geometry>
            </GeometryDrawing>

            <GeometryDrawing Brush="Green">
                <GeometryDrawing.Pen>
                    <Pen Brush="Black"/>
                </GeometryDrawing.Pen>
                <GeometryDrawing.Geometry>
                    <PathGeometry>
                        <PathFigure StartPoint="100,100">
                            <PathFigure.Segments>
                                <LineSegment Point="13.4,150"/>
                                <ArcSegment Point="100,0" SweepDirection="Clockwise" Size="100,100"/>
                                <LineSegment Point="100,100"/>
                            </PathFigure.Segments>
                        </PathFigure>
                    </PathGeometry>
                </GeometryDrawing.Geometry>
            </GeometryDrawing>
        </DrawingGroup>
    </DrawingImage.Drawing>
</DrawingImage>

…and you serialize it…

XmlTextWriter writer = new XmlTextWriter(@"C:\Users\Public\Test.xml", new UTF8Encoding());
writer.Formatting = Formatting.Indented;
writer.Indentation = 1;
writer.IndentChar = '\t';
XamlWriter.Save(segmentsDrawing, writer);

…you get the following:

<DrawingImage xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
    <DrawingImage.Drawing>
        <DrawingGroup>
            <DrawingGroup.Children>
                <GeometryDrawing Brush="#FFFF0000">
                    <GeometryDrawing.Pen>
                        <Pen Brush="#FF000000" />
                    </GeometryDrawing.Pen>
                    <GeometryDrawing.Geometry>
                        <PathGeometry Figures="M100,100L100,0A100,100,0,0,1,186.6,150L100,100" />
                    </GeometryDrawing.Geometry>
                </GeometryDrawing>
                <GeometryDrawing Brush="#FF0000FF">
                    <GeometryDrawing.Pen>
                        <Pen Brush="#FF000000" />
                    </GeometryDrawing.Pen>
                    <GeometryDrawing.Geometry>
                        <PathGeometry Figures="M100,100L186.6,150A100,100,0,0,1,13.4,150L100,100" />
                    </GeometryDrawing.Geometry>
                </GeometryDrawing>
                <GeometryDrawing Brush="#FF008000">
                    <GeometryDrawing.Pen>
                        <Pen Brush="#FF000000" />
                    </GeometryDrawing.Pen>
                    <GeometryDrawing.Geometry>
                        <PathGeometry Figures="M100,100L13.4,150A100,100,0,0,1,100,0L100,100" />
                    </GeometryDrawing.Geometry>
                </GeometryDrawing>
            </DrawingGroup.Children>
        </DrawingGroup>
    </DrawingImage.Drawing>
</DrawingImage>

All the PathGeometry is now in mini-language. If you want to use this right away in your application i suppose you could write it to a MemoryStream and get the data from it by creating a XmlDocument from it.