Path Markup Syntax
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Silverlight supports a powerful and complex mini-language that you can use to describe geometric paths in Extensible Application Markup Language (XAML).
This topic contains the following sections.
- Prerequisites
- Path Mini-Language
- Move Command
- Draw Commands
- Close Command
- Point Syntax
- Special Values
- Related Topics
Prerequisites
You should be familiar with the basic features of Geometry objects. For more information, see Geometries.
Path Mini-Language
Silverlight provides a mini-language for describing geometric paths as values of attributes in XAML. You use this 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 the path attribute syntax to create a shape.
<Canvas>
<Path Stroke="Black" Fill="Gray"
Data="M 10,100 C 10,300 300,-200 300,100" />
</Canvas>
Separators and 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 do not need to be separated by a comma or white space if the resulting string is unambiguous. For example, 2..3 is interpreted as two numbers: "2." and ".3". Similarly, 2-3 consists of the two numbers "2" and "-3".
Spaces are not required before or after commands.
Syntax
The XAML path syntax consists of an optional FillRule value and one or more figure descriptions.
Path XAML attribute usage |
|---|
<object property="[fillRule] figureDescription[ figureDescription]*" ... /> |
Term |
Description |
|---|---|
fillRule |
Specifies whether the path uses the EvenOdd or NonZero fill rule value:
If you omit this command, the path 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. moveCommand drawCommands [closeCommand] |
moveCommand |
A move command that specifies the start point of the figure. |
drawCommands |
One or more draw commands that describe the figure's contents. |
closeCommand |
An optional close command that closes the figure. |
Move Command
Specifies the start point of a new figure. If a figure was previously started with a move command, but not closed with a close command, the open figure will be ended (not closed) when a new move command is issued.
Syntax |
|---|
M startPoint - or - m startPoint |
Term |
Description |
|---|---|
startPoint |
The start point of the 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 as if you had 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 letter or a lowercase letter: uppercase letters denote absolute values, and lowercase letters denote relative values. The control points for a segment are relative to the end point of the preceding segment. 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.
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 |
|---|
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 |
|---|
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 |
|---|
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 |
|---|
C controlPoint1 controlPoint2 endPoint - or - c controlPoint1 controlPoint2 endPoint |
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 |
|---|
Q controlPoint endPoint - or - q controlPoint endPoint |
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 is not a cubic Bezier curve command or a smooth cubic Bezier curve command, the first control point is assumed to be 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 |
|---|
S controlPoint2 endPoint - or - s controlPoint2 endPoint |
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 is not a quadratic Bezier curve command or a smooth quadratic Bezier curve command, the control point is coincident with the current point.
Syntax |
|---|
T controlPoint endPoint - or - t controlPoint endPoint |
Elliptical Arc Command
Creates an elliptical arc between the current point and the specified end point.
Syntax |
|---|
A size rotationAngle isLargeArcFlag sweepDirectionFlag endPoint - or - a size rotationAngle isLargeArcFlag sweepDirectionFlag endPoint |
Term |
Description |
|---|---|
size |
x, y pair The x-radius 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. |
Close Command
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.
After the figure is closed with the close command, a new figure is implicitly created at the closed figure’s starting point, which is also the point specified by the last move command. This enables drawing with draw commands immediately after closing a figure and allows for more concise syntax when figures, such as a pinwheel pattern, share the same starting point. To use a different figure starting point, specify another move command.
Syntax |
|---|
Z - or - z |
Point Syntax
Point syntax describes the x-coordinate and y-coordinate of a point.
Syntax |
|---|
x,y - or - x y |
Special Values
You can also use the following special values instead of the standard numerical values. These values are case-sensitive.
Value |
Description |
|---|---|
Infinity |
Represents the positive infinity Double value (Double.PositiveInfinity). |
-Infinity |
Represents the negative infinity Double value (Double.NegativeInfinity). |
NaN |
Represents the NaN Double value (Double.NaN). |
You may also use scientific notation. For example, +1.e17 is a valid value.