Path Markup Syntax
Paths are discussed in Shapes and Basic Drawing in WPF Overview and the Geometry Overview, however, this topic describes in detail the powerful and complex mini-language you can use to specify path geometries more compactly using Extensible Application Markup Language (XAML).
This topic contains the following sections.
Prerequisites
To understand this topic, you should be familiar with the basic features of Geometry objects. For more information, see the Geometry Overview.
StreamGeometry and PathFigureCollection Mini-Languages
WPF provides two classes that provide mini-languages for describing geometric paths: StreamGeometry and PathFigureCollection.
You use the StreamGeometry mini-language when setting a property of type Geometry, such as the Clip property of a UIElement or the Data property of a Path element. The following example uses attribute syntax to create a StreamGeometry.
<Path Stroke="Black" Fill="Gray" Data="M 10,100 C 10,300 300,-200 300,100" />You use the PathFigureCollection mini-language when setting the Figures property of a PathGeometry. The following example uses a attribute syntax to create a PathFigureCollection for a PathGeometry.
<Path Stroke="Black" Fill="Gray"> <Path.Data> <PathGeometry Figures="M 10,100 C 10,300 300,-200 300,100" /> </Path.Data> </Path>
As you can see from the preceding examples, the two mini-languages are very similar. It's always possible to use a PathGeometry in any situation where you could use a StreamGeometry; so which one should you use? Use a StreamGeometry when you don't need to modify the path after creating it; use a PathGeometry if you do need to modify the path.
For more information about the differences between PathGeometry and StreamGeometry objects, see the Geometry Overview.
A Note about White Space
For brevity, a single space is shown in the syntax sections that follow, but multiple spaces are also acceptable wherever a single space is shown.
Two numbers don’t actually have to be separated by a comma or whitespace, but this can only be done when the resulting string is unambiguous. For instance, 2..3 is actually two numbers: "2." And ".3". Similarly, 2-3 is "2" and "-3". Spaces are not required before or after commands, either.
Syntax
The Extensible Application Markup Language (XAML) attribute usage syntax for a StreamGeometry is composed of an optional FillRule value and one or more figure descriptions.
StreamGeometry XAML Attribute Usage |
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<object property="[fillRule] figureDescription[figureDescription]*" ... /> |
The Extensible Application Markup Language (XAML) attribute usage syntax for a PathFigureCollection is composed of one or more figure descriptions.
PathFigureCollection XAML Attribute Usage |
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<object property="figureDescription[figureDescription]*" ... /> |
Term |
Description |
|---|---|
fillRule |
Specifies whether the StreamGeometry uses the EvenOdd or Nonzero FillRule. If you omit this command, the subpath uses the default behavior, which is EvenOdd. If you specify this command, you must place it first. |
figureDescription |
A figure composed of a move command, draw commands, and an optional close command. moveCommanddrawCommands [closeCommand] |
moveCommand |
A move command that specifies the start point of the figure. See the Move Command section. |
drawCommands |
One or more drawing commands that describe the figure's contents. See the Draw Commands section. |
closeCommand |
An optional close command that closes figure. See the Close Command section. |
Move Command
Specifies the start point of a new figure.
Syntax |
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M startPoint - or - m startPoint |
Term |
Description |
|---|---|
startPoint |
The start point of a new figure. |
An uppercase M indicates that startPoint is an absolute value; a lowercase m indicates that startPoint is an offset to the previous point, or (0,0) if none exists. If you list multiple points after the move command, a line is drawn to those points though you specified the line command.
Draw Commands
A draw command can consist of several shape commands. The following shape commands are available: line, horizontal line, vertical line, cubic Bezier curve, quadratic Bezier curve, smooth cubic Bezier curve, smooth quadratic Bezier curve, and elliptical arc.
You enter each command by using either an uppercase or a lowercase letter: uppercase letters denote absolute values and lowercase letters denote relative values: the control points for that segment are relative to the end point of the preceding example. When sequentially entering more than one command of the same type, you can omit the duplicate command entry; for example, L 100,200 300,400 is equivalent to L 100,200 L 300,400. The following table describes the move and draw commands.
Line Command
Creates a straight line between the current point and the specified end point. l 20 30 and L 20,30 are examples of valid line commands.
Syntax |
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L endPoint - or - l endPoint |
Term |
Description |
|---|---|
endPoint |
The end point of the line. |
Horizontal Line Command
Creates a horizontal line between the current point and the specified x-coordinate. H 90 is an example of a valid horizontal line command.
Syntax |
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H x - or - h x |
Term |
Description |
|---|---|
x |
The x-coordinate of the end point of the line. |
Vertical Line Command
Creates a vertical line between the current point and the specified y-coordinate. v 90 is an example of a valid vertical line command.
Syntax |
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V y - or - v y |
Term |
Description |
|---|---|
y |
The y-coordinate of the end point of the line. |
Cubic Bezier Curve Command
Creates a cubic Bezier curve between the current point and the specified end point by using the two specified control points (controlPoint1 and controlPoint2). C 100,200 200,400 300,200 is an example of a valid curve command.
Syntax |
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C controlPoint1 controlPoint2 endPoint - or - c controlPoint1 controlPoint2 endPoint |
Term |
Description |
|---|---|
controlPoint1 |
The first control point of the curve, which determines the starting tangent of the curve. |
controlPoint2 |
The second control point of the curve, which determines the ending tangent of the curve. |
endPoint |
The point to which the curve is drawn. |
Quadratic Bezier Curve Command
Creates a quadratic Bezier curve between the current point and the specified end point by using the specified control point (controlPoint). q 100,200 300,200 is an example of a valid quadratic Bezier curve command.
Syntax |
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Q controlPoint endPoint - or - q controlPoint endPoint |
Term |
Description |
|---|---|
controlPoint |
The control point of the curve, which determines the starting and ending tangents of the curve. |
endPoint |
The point to which the curve is drawn. |
Smooth cubic Bezier curve Command
Creates a cubic Bezier curve between the current point and the specified end point. The first control point is assumed to be the reflection of the second control point of the previous command relative to the current point. If there is no previous command or if the previous command was not a cubic Bezier curve command or a smooth cubic Bezier curve command, assume the first control point is coincident with the current point. The second control point, the control point for the end of the curve, is specified by controlPoint2. For example, S 100,200 200,300 is a valid smooth cubic Bezier curve command.
Syntax |
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S controlPoint2 endPoint - or - s controlPoint2 endPoint |
Term |
Description |
|---|---|
controlPoint2 |
The control point of the curve, which determines the ending tangent of the curve. |
endPoint |
The point to which the curve is drawn. |
Smooth quadratic Bezier curve Command
Creates a quadratic Bezier curve between the current point and the specified end point. The control point is assumed to be the reflection of the control point of the previous command relative to the current point. If there is no previous command or if the previous command was not a quadratic Bezier curve command or a smooth quadratic Bezier curve command, the control point is coincident with the current point.
Syntax |
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T controlPoint endPoint - or - t controlPoint endPoint |
Term |
Description |
|---|---|
controlPoint |
The control point of the curve, which determines the starting and tangent of the curve. |
endPoint |
The point to which the curve is drawn. |
Elliptical Arc Command
Creates an elliptical arc between the current point and the specified end point.
Syntax |
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A size rotationAngle isLargeArcFlag sweepDirectionFlag endPoint - or - a size rotationAngle isLargeArcFlag sweepDirectionFlag endPoint |
Term |
Description |
|---|---|
size |
The x- and y-radius of the arc. |
rotationAngle |
The rotation of the ellipse, in degrees. |
isLargeArcFlag |
Set to 1 if the angle of the arc should be 180 degrees or greater; otherwise, set to 0. |
sweepDirectionFlag |
Set to 1 if the arc is drawn in a positive-angle direction; otherwise, set to 0. |
endPoint |
The point to which the arc is drawn. |
The Close Command
Ends the current figure and creates a line that connects the current point to the starting point of the figure. This command creates a line-join (corner) between the last segment and the first segment of the figure.
Syntax |
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Z - or - z |
Point Syntax
Describes the x- and y-coordinates of a point.
Syntax |
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x,y - or - x y |
Term |
Description |
|---|---|
x |
The x-coordinate of the point. |
y |
The y-coordinate of the point. |
Special Values
Instead of a standard numerical value, you can also use the following special values. These values are case-sensitive.
Infinity
Represents Double.PositiveInfinity.-Infinity
Represents Double.NegativeInfinity.NaN
Represents Double.NaN.
You may also use scientific notation. For example, +1.e17 is a valid value.
See Also
Reference
Concepts
Shapes and Basic Drawing in WPF Overview