Sintaxe de Marcação de Caminho
Paths are discussed in Visão geral de Formas e Desenho básico no WPF and the Visão Geral de Geometria, 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. Para obter mais informações, consulte o Visão Geral de Geometria.
StreamGeometry and PathFigureCollection Mini-Languages
WPFfornece duas classes que fornecem os idiomas mini-para descrever geométricos caminhos: 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 Visão Geral de Geometria.
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. Por exemplo, 2..3 é na verdade dois números: "2." E ". 3". Da mesma forma, 2-3 é "2" e "-" (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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<objeto propriedade="fillRulefigureDescriptionfigureDescription]*" ... /> |
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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<objeto propriedade="figureDescriptionfigureDescription]*" ... /> |
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. |
maiúsculasM indica que startPoint é um valor absoluto; um em minúsculas m indica que startPoint é um deslocamento para o ponto anterior, ou (0,0) se não houver nenhum. 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. Os comandos de forma a seguir estão disponíveis: linhahorizontal linha, vertical linha, curva de Bezier cúbica, curva de Bezier quadrática, curva de Bezier cúbica suave, curva de Bezier quadrática suave e arco elíptico.
Cada comando digitado usando uma letra em minúsculas ou maiúsculas : letrasmaiúsculas indicam valores absolutos e letras em minúsculas denotam valores relativos: os pontos de controle para esse segmento são relativo ao ponto final do exemplo anterior. 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
Cria uma linha reta entre o ponto atual e o ponto de extremidade especificado. l 20 30e L 20,30 são exemplos de válido line comandos.
Syntax |
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L ponto de extremidade - or - l ponto de extremidade |
Term |
Description |
|---|---|
ponto de extremidade |
The end point of the line. |
Horizontal Line Command
Cria uma linha horizontal entre o ponto atual e o especificado coordenada X. H 90é um exemplo de um comando de linha de horizontal válido .
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
Cria uma linha vertical entre o ponto atual e a coordenada y especificado-. v 90é um exemplo de um comando de linha de vertical válido .
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
Cria uma curva de Bezier cúbica entre o ponto atual e o ponto de extremidade especificado, usando os dois pontos de controle especificado (controlPoint1 e controlPoint2). C 100,200 200,400 300,200é um exemplo de um comando válido da curva.
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
Cria uma curva de Bezier quadrática entre o ponto atual e o ponto de extremidade especificado usando o ponto de controle especificado (controlPoint). q 100,200 300,200é um exemplo de um comando de curva de Bezier quadrático válido .
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 |
|---|
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.
Consulte também
Referência
Conceitos
Visão geral de Formas e Desenho básico no WPF