A path defining a shape. More...

#include <Wt/WPainterPath.h>

Inheritance diagram for Wt::WPainterPath:

Classes
class	Segment
	A segment. More...

Public Member Functions
	WPainterPath ()
	Default constructor. More...

	WPainterPath (const WPointF &startPoint)
	Construct a new path, and set the initial position. More...

	WPainterPath (const WPainterPath &path)
	Copy constructor.

WPainterPath &	operator= (const WPainterPath &path)
	Assignment operator.

WPointF	currentPosition () const
	Returns the current position. More...

bool	isEmpty () const
	Returns whether the path is empty. More...

bool	operator== (const WPainterPath &path) const
	Comparison operator. More...

bool	operator!= (const WPainterPath &path) const
	Comparison operator. More...

void	closeSubPath ()
	Closes the last sub path. More...

void	moveTo (const WPointF &point)
	Moves the current position to a new location. More...

void	moveTo (double x, double y)
	Moves the current position to a new location. More...

void	lineTo (const WPointF &point)
	Draws a straight line. More...

void	lineTo (double x, double y)
	Draws a straight line. More...

void	cubicTo (const WPointF &c1, const WPointF &c2, const WPointF &endPoint)
	Draws a cubic bezier curve. More...

void	cubicTo (double c1x, double c1y, double c2x, double c2y, double endPointx, double endPointy)
	Draws a cubic bezier curve. More...

void	arcTo (double cx, double cy, double radius, double startAngle, double spanAngle)
	Draws an arc. More...

void	arcMoveTo (double cx, double cy, double radius, double angle)
	Moves to a point on an arc. More...

void	arcMoveTo (double x, double y, double width, double height, double angle)
	Move to a point on an arc. More...

void	quadTo (const WPointF &c, const WPointF &endPoint)
	Draws a quadratic bezier curve. More...

void	quadTo (double cx, double cy, double endPointx, double endPointy)
	Draws a quadratic bezier curve. More...

void	addEllipse (const WRectF &boundingRectangle)
	Draws an ellipse. More...

void	addEllipse (double x, double y, double width, double height)
	Draws an ellipse. More...

void	addRect (const WRectF &rectangle)
	Draws a rectangle. More...

void	addRect (double x, double y, double width, double height)
	Draws a rectangle. More...

void	addPolygon (const std::vector< WPointF > &points)
	Adds a polygon. More...

void	addPath (const WPainterPath &path)
	Adds a path. More...

void	connectPath (const WPainterPath &path)
	Adds a path, connecting. More...

WRectF	controlPointRect (const WTransform &transform=WTransform::Identity) const
	Returns the bounding box of the control points. More...

WPainterPath	crisp () const
	Returns a copy of the path where straight lines are moved to be rendered crisply. More...

void	setOpenSubPathsEnabled (bool enabled=true)
	Disables automatically closing subpaths on moveTo. More...

bool	openSubPathsEnabled () const
	Returns whether open subpaths are enabled. More...

virtual std::string	jsValue () const override
	Returns a JavaScript representation of the value of this object. More...

Public Member Functions inherited from Wt::WJavaScriptExposableObject
bool	isJavaScriptBound () const
	Returns whether this object is JavaScript bound. More...

std::string	jsRef () const
	Returns a JavaScript reference to this object. More...

Detailed Description

A path defining a shape.

A painter path represents a (complex) path that may be composed of lines, arcs and bezier curve segments, and painted onto a paint device using WPainter::drawPath().

The path that is composed in a painter path may consist of multiple closed sub-paths. Only the last sub-path can be left open.

To compose a path, this class maintains a current position, which is the starting point for the next drawing operation. An operation may draw a line (see lineTo()), arc (see arcTo()), or bezier curve (see quadTo() and cubicTo()) from the current position to a new position. A new sub path may be started by moving the current position to a new location (see moveTo()), which automatically closes the previous sub path.

When sub paths overlap, the result is undefined (it is dependent on the underlying painting device).

Usage example:

Wt::WPainter painter(...);
 
Wt::WPainterPath path(Wt::WPointF(10, 10));
path.lineTo(10, 20);
path.lineTo(30, 20);
path.closeSubPath();
 
painter.setPen(Wt::StandardColor::Red);
painter.setBrush(Wt::StandardColor::Blue);
painter.drawPath(path);

JavaScript exposability

A WPainterPath is JavaScript exposable. If a WPainterPath is JavaScript bound, it can be accessed in your custom JavaScript code through its handle's jsRef().

A WPainterPath is represented in JavaScript as an array of segments, where each segment is defined by a three element array: [x,y,type], where type is the integer representation of the type of a segment.

For example, a 10 by 10 square with the top left at (10,10) is represented as:

[
 [10,10,0], // move to (10,10)
 [20,10,1], // line to (20,10)
 [20,20,1], // line to (20,20)
 [10,20,1], // line to (10,20)
 [10,10,1]  // line to (10,10)
]

Warning: A WPainterPath that is JavaScript exposed should be modified only through its handle. Any attempt at modifying it will cause an exception to be thrown.

See also: WPainter::drawPath(), WPaintedWidget::createJSPainterPath()

Constructor & Destructor Documentation

◆ WPainterPath() [1/2]

Wt::WPainterPath::WPainterPath ( )

Default constructor.

Creates an empty path, and sets the current position to (0, 0).

◆ WPainterPath() [2/2]

Wt::WPainterPath::WPainterPath ( const WPointF & startPoint )

Construct a new path, and set the initial position.

Creates an empty path, and sets the current position to startPoint.

Member Function Documentation

◆ addEllipse() [1/2]

void Wt::WPainterPath::addEllipse ( const WRectF & boundingRectangle )

Draws an ellipse.

This method closes the current sub path, and adds an ellipse that is bounded by the rectangle boundingRectangle.

Note: some renderers only support circles (width == height)

Exceptions

WException if the path is JavaScript bound

See also: addEllipse(double, double, double, double), arcTo()

◆ addEllipse() [2/2]

void Wt::WPainterPath::addEllipse	(	double	x,
		double	y,
		double	width,
		double	height
	)

Draws an ellipse.

This method closes the current sub path, and adds an ellipse that is bounded by the rectangle defined by top left position (x, y), and size width x height.

Note: Some renderers only support circles (width == height)

Exceptions

WException if the path is JavaScript bound

See also: addEllipse(const WRectF&), arcTo()

◆ addPath()

void Wt::WPainterPath::addPath ( const WPainterPath & path )

Adds a path.

Adds an entire path to the current path. If the path's begin position is different from the current position, the last sub path is first closed, unless open subpaths are enabled, otherwise the last sub path is extended with the path's first sub path.

Exceptions

WException if the path is JavaScript bound

See also: connectPath(const WPainterPath&)

◆ addPolygon()

void Wt::WPainterPath::addPolygon ( const std::vector< WPointF > & points )

Adds a polygon.

If the first point is different from the current position, the last sub path is first closed, unless open subpaths are enabled, otherwise the last sub path is extended with the polygon.

Exceptions

WException if the path is JavaScript bound

See also: moveTo(), lineTo()

◆ addRect() [1/2]

void Wt::WPainterPath::addRect ( const WRectF & rectangle )

Draws a rectangle.

This method closes the current sub path, unless open subpaths are enabled, and adds a rectangle that is defined by rectangle.

Exceptions

WException if the path is JavaScript bound

See also: addRect(double, double, double, double)

◆ addRect() [2/2]

void Wt::WPainterPath::addRect	(	double	x,
		double	y,
		double	width,
		double	height
	)

Draws a rectangle.

This method closes the current sub path, unless open subpaths are enabled, and adds a rectangle that is defined by top left position (x, y), and size width x height.

Exceptions

WException if the path is JavaScript bound

See also: addRect(const WRectF&)

◆ arcMoveTo() [1/2]

void Wt::WPainterPath::arcMoveTo	(	double	cx,
		double	cy,
		double	radius,
		double	angle
	)

Moves to a point on an arc.

Moves to a point on a circle. The circle is defined with center (cx, cy) and radius, and the point is at angle degrees measured counter-clockwise starting from the 3 o'clock position.

Exceptions

WException if the path is JavaScript bound

See also: arcTo()

◆ arcMoveTo() [2/2]

void Wt::WPainterPath::arcMoveTo	(	double	x,
		double	y,
		double	width,
		double	height,
		double	angle
	)

Move to a point on an arc.

Moves to a point on an ellipse. The ellipse fits in the rectangle defined by top left position (x, y), and size width x height, and the point is at angle degrees measured counter-clockwise starting from the 3 o'clock position.

Exceptions

WException if the path is JavaScript bound

See also: arcTo()

◆ arcTo()

void Wt::WPainterPath::arcTo	(	double	cx,
		double	cy,
		double	radius,
		double	startAngle,
		double	spanAngle
	)

Draws an arc.

Draws an arc which is a segment of a circle. The circle is defined with center (cx, cy) and radius. The segment starts at startAngle, and spans an angle given by spanAngle. These angles are expressed in degrees, and are measured counter-clockwise starting from the 3 o'clock position.

Implicitly draws a line from the current position to the start of the arc, if the current position is different from the start.

Exceptions

WException if the path is JavaScript bound

See also: arcMoveTo()

◆ closeSubPath()

void Wt::WPainterPath::closeSubPath ( )

Closes the last sub path.

Draws a line from the current position to the start position of the last sub path (which is the end point of the last move operation), and sets the current position to (0, 0).

Exceptions

WException if the path is JavaScript bound

◆ connectPath()

void Wt::WPainterPath::connectPath ( const WPainterPath & path )

Adds a path, connecting.

Adds an entire path to the current path. If the path's begin position is different from the current position, the last sub path is first closed, unless open subpaths are enabled, otherwise the last sub path is extended with the path's first sub path.

Exceptions

WException if the path is JavaScript bound

See also: connectPath(const WPainterPath&)

◆ controlPointRect()

WRectF Wt::WPainterPath::controlPointRect ( const WTransform & transform = WTransform::Identity ) const

Returns the bounding box of the control points.

Returns the bounding box of all control points. This is guaranteed to be a superset of the actual bounding box.

The transform is applied to the path first.

◆ crisp()

WPainterPath Wt::WPainterPath::crisp ( ) const

Returns a copy of the path where straight lines are moved to be rendered crisply.

This is intended to be used on rectangles, or other paths consisting of only straight line, and will nudge every edge a little bit, so that 1px straight lines are rendered as a crisp line.

This will also work if the path is JavaScript bound.

◆ cubicTo() [1/2]

void Wt::WPainterPath::cubicTo	(	const WPointF &	c1,
		const WPointF &	c2,
		const WPointF &	endPoint
	)

Draws a cubic bezier curve.

Draws a cubic bezier curve from the current position to endPoint, which becomes the new current position. The bezier curve uses the two control points c1 and c2.

Exceptions

WException if the path is JavaScript bound

See also: cubicTo(double, double, double, double, double, double)

◆ cubicTo() [2/2]

void Wt::WPainterPath::cubicTo	(	double	c1x,
		double	c1y,
		double	c2x,
		double	c2y,
		double	endPointx,
		double	endPointy
	)

Draws a cubic bezier curve.

This is an overloaded method provided for convenience.

Exceptions

WException if the path is JavaScript bound

See also: cubicTo(const WPointF&, const WPointF&, const WPointF&)

◆ currentPosition()

WPointF Wt::WPainterPath::currentPosition ( ) const

Returns the current position.

Returns the current position, which is the end point of the last move or draw operation, and which well be the start point of the next draw operation.

◆ isEmpty()

bool Wt::WPainterPath::isEmpty ( ) const

Returns whether the path is empty.

Returns true if the path contains no drawing operations. Note that move operations are not considered drawing operations.

◆ jsValue()

std::string Wt::WPainterPath::jsValue ( ) const

overridevirtual

Returns a JavaScript representation of the value of this object.

Note: The value returned will reflect the current server side value of the object. If this object is JavaScript bound, this value may not reflect the actual client side value. If you need access to the client side value, use jsRef() intead.

Implements Wt::WJavaScriptExposableObject.

◆ lineTo() [1/2]

void Wt::WPainterPath::lineTo ( const WPointF & point )

Draws a straight line.

Draws a straight line from the current position to point, which becomes the new current position.

Exceptions

WException if the path is JavaScript bound

See also: lineTo(double, double)

◆ lineTo() [2/2]

void Wt::WPainterPath::lineTo	(	double	x,
		double	y
	)

Draws a straight line.

Draws a straight line from the current position to (x, y), which becomes the new current position.

Exceptions

WException if the path is JavaScript bound

See also: lineTo(const WPointF&)

◆ moveTo() [1/2]

void Wt::WPainterPath::moveTo ( const WPointF & point )

Moves the current position to a new location.

Moves the current position to a new point, implicitly closing the last sub path, unless open subpaths are enabled.

Exceptions

WException if the path is JavaScript bound

See also: closeSubPath(), moveTo(double, double), setOpenSubPathsEnabled(bool)

◆ moveTo() [2/2]

void Wt::WPainterPath::moveTo	(	double	x,
		double	y
	)

Moves the current position to a new location.

Moves the current position to a new point, implicitly closing the last sub path, unless open subpaths are enabled.

Exceptions

WException if the path is JavaScript bound

See also: closeSubPath(), moveTo(const WPointF&), setOpenSubPathsEnabled(bool)

◆ openSubPathsEnabled()

bool Wt::WPainterPath::openSubPathsEnabled ( ) const

Returns whether open subpaths are enabled.

See also: setOpenSubPathsEnabled(bool)

◆ operator!=()

bool Wt::WPainterPath::operator!= ( const WPainterPath & path ) const

Comparison operator.

Returns true if the paths are different.

◆ operator==()

bool Wt::WPainterPath::operator== ( const WPainterPath & path ) const

Comparison operator.

Returns true if the paths are exactly the same.

◆ quadTo() [1/2]

void Wt::WPainterPath::quadTo	(	const WPointF &	c,
		const WPointF &	endPoint
	)

Draws a quadratic bezier curve.

Draws a quadratic bezier curve from the current position to endPoint, which becomes the new current position. The bezier curve uses the single control point c.

Exceptions

WException if the path is JavaScript bound

See also: quadTo(double, double, double, double)

◆ quadTo() [2/2]

void Wt::WPainterPath::quadTo	(	double	cx,
		double	cy,
		double	endPointx,
		double	endPointy
	)

Draws a quadratic bezier curve.

This is an overloaded method provided for convenience.

Exceptions

WException if the path is JavaScript bound

See also: quadTo(const WPointF&, const WPointF&)

◆ setOpenSubPathsEnabled()

void Wt::WPainterPath::setOpenSubPathsEnabled ( bool enabled = true )

Disables automatically closing subpaths on moveTo.

By default, open sub paths are disabled, and moveTo and any operation that relies on moveTo will automatically close the last subpath. Enabling this option disables that feature.

See also: moveTo(), addPath(), connectPath(), addRect()

Classes

Public Member Functions

Detailed Description

JavaScript exposability

Constructor & Destructor Documentation

◆ WPainterPath() [1/2]

◆ WPainterPath() [2/2]

Member Function Documentation

◆ addEllipse() [1/2]

◆ addEllipse() [2/2]

◆ addPath()

◆ addPolygon()

◆ addRect() [1/2]

◆ addRect() [2/2]

◆ arcMoveTo() [1/2]

◆ arcMoveTo() [2/2]

◆ arcTo()

◆ closeSubPath()

◆ connectPath()

◆ controlPointRect()

◆ crisp()

◆ cubicTo() [1/2]

◆ cubicTo() [2/2]

◆ currentPosition()

◆ isEmpty()

◆ jsValue()

◆ lineTo() [1/2]

◆ lineTo() [2/2]

◆ moveTo() [1/2]

◆ moveTo() [2/2]

◆ openSubPathsEnabled()

◆ operator!=()

◆ operator==()

◆ quadTo() [1/2]

◆ quadTo() [2/2]

◆ setOpenSubPathsEnabled()