Path Class Reference

A path is a sequence of lines and curves that may either form a closed shape or be open-ended. More...

Classes
class	Iterator
	Iterates the lines and curves that a path contains. More...
Public Member Functions
	Path ()
	Creates an empty path.
	Path (const Path &other)
	Creates a copy of another path.
	~Path ()
	Destructor.
Path &	operator= (const Path &other)
	Copies this path from another one.
bool	isEmpty () const throw ()
	Returns true if the path doesn't contain any lines or curves.
const Rectangle< float >	getBounds () const throw ()
	Returns the smallest rectangle that contains all points within the path.
const Rectangle< float >	getBoundsTransformed (const AffineTransform &transform) const throw ()
	Returns the smallest rectangle that contains all points within the path after it's been transformed with the given tranasform matrix.
bool	contains (float x, float y, float tolerence=10.0f) const
	Checks whether a point lies within the path.
bool	intersectsLine (float x1, float y1, float x2, float y2, float tolerence=10.0f)
	Checks whether a line crosses the path.
void	clear () throw ()
	Removes all lines and curves, resetting the path completely.
void	startNewSubPath (float startX, float startY)
	Begins a new subpath with a given starting position.
void	closeSubPath ()
	Closes a the current sub-path with a line back to its start-point.
void	lineTo (float endX, float endY)
	Adds a line from the shape's last position to a new end-point.
void	quadraticTo (float controlPointX, float controlPointY, float endPointX, float endPointY)
	Adds a quadratic bezier curve from the shape's last position to a new position.
void	cubicTo (float controlPoint1X, float controlPoint1Y, float controlPoint2X, float controlPoint2Y, float endPointX, float endPointY)
	Adds a cubic bezier curve from the shape's last position to a new position.
const Point< float >	getCurrentPosition () const
	Returns the last point that was added to the path by one of the drawing methods.
void	addRectangle (float x, float y, float width, float height)
	Adds a rectangle to the path.
void	addRectangle (const Rectangle< int > &rectangle)
	Adds a rectangle to the path.
void	addRoundedRectangle (float x, float y, float width, float height, float cornerSize)
	Adds a rectangle with rounded corners to the path.
void	addRoundedRectangle (float x, float y, float width, float height, float cornerSizeX, float cornerSizeY)
	Adds a rectangle with rounded corners to the path.
void	addTriangle (float x1, float y1, float x2, float y2, float x3, float y3)
	Adds a triangle to the path.
void	addQuadrilateral (float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4)
	Adds a quadrilateral to the path.
void	addEllipse (float x, float y, float width, float height)
	Adds an ellipse to the path.
void	addArc (float x, float y, float width, float height, float fromRadians, float toRadians, bool startAsNewSubPath=false)
	Adds an elliptical arc to the current path.
void	addCentredArc (float centreX, float centreY, float radiusX, float radiusY, float rotationOfEllipse, float fromRadians, float toRadians, bool startAsNewSubPath=false)
	Adds an arc which is centred at a given point, and can have a rotation specified.
void	addPieSegment (float x, float y, float width, float height, float fromRadians, float toRadians, float innerCircleProportionalSize)
	Adds a "pie-chart" shape to the path.
void	addLineSegment (float startX, float startY, float endX, float endY, float lineThickness)
	Adds a line with a specified thickness.
void	addArrow (float startX, float startY, float endX, float endY, float lineThickness, float arrowheadWidth, float arrowheadLength)
	Adds a line with an arrowhead on the end.
void	addStar (float centreX, float centreY, int numberOfPoints, float innerRadius, float outerRadius, float startAngle=0.0f)
	Adds a star shape to the path.
void	addBubble (float bodyX, float bodyY, float bodyW, float bodyH, float cornerSize, float arrowTipX, float arrowTipY, int whichSide, float arrowPositionAlongEdgeProportional, float arrowWidth)
	Adds a speech-bubble shape to the path.
void	addPath (const Path &pathToAppend)
	Adds another path to this one.
void	addPath (const Path &pathToAppend, const AffineTransform &transformToApply)
	Adds another path to this one, transforming it on the way in.
void	swapWithPath (Path &other)
	Swaps the contents of this path with another one.
void	applyTransform (const AffineTransform &transform) throw ()
	Applies a 2D transform to all the vertices in the path.
void	scaleToFit (float x, float y, float width, float height, bool preserveProportions) throw ()
	Rescales this path to make it fit neatly into a given space.
const AffineTransform	getTransformToScaleToFit (float x, float y, float width, float height, bool preserveProportions, const Justification &justificationType=Justification::centred) const
	Returns a transform that can be used to rescale the path to fit into a given space.
const Path	createPathWithRoundedCorners (float cornerRadius) const
	Creates a version of this path where all sharp corners have been replaced by curves.
void	setUsingNonZeroWinding (bool isNonZeroWinding) throw ()
	Changes the winding-rule to be used when filling the path.
bool	isUsingNonZeroWinding () const
	Returns the flag that indicates whether the path should use a non-zero winding rule.
void	loadPathFromStream (InputStream &source)
	Loads a stored path from a data stream.
void	loadPathFromData (const void *data, int numberOfBytes)
	Loads a stored path from a block of data.
void	writePathToStream (OutputStream &destination) const
	Stores the path by writing it out to a stream.
const String	toString () const
	Creates a string containing a textual representation of this path.
void	restoreFromString (const String &stringVersion)
	Restores this path from a string that was created with the toString() method.

Detailed Description

A path is a sequence of lines and curves that may either form a closed shape or be open-ended.

To use a path, you can create an empty one, then add lines and curves to it to create shapes, then it can be rendered by a Graphics context or used for geometric operations.

e.g.

    Path myPath;

    myPath.startNewSubPath (10.0f, 10.0f);          // move the current position to (10, 10)
    myPath.lineTo (100.0f, 200.0f);                 // draw a line from here to (100, 200)
    myPath.quadraticTo (0.0f, 150.0f, 5.0f, 50.0f); // draw a curve that ends at (5, 50)
    myPath.closeSubPath();                          // close the subpath with a line back to (10, 10)

    // add an ellipse as well, which will form a second sub-path within the path..
    myPath.addEllipse (50.0f, 50.0f, 40.0f, 30.0f);

    // double the width of the whole thing..
    myPath.applyTransform (AffineTransform::scale (2.0f, 1.0f));

    // and draw it to a graphics context with a 5-pixel thick outline.
    g.strokePath (myPath, PathStrokeType (5.0f));

A path object can actually contain multiple sub-paths, which may themselves be open or closed.

See also:: PathFlatteningIterator, PathStrokeType, Graphics

Constructor & Destructor Documentation

Path::Path ( )

Creates an empty path.

Path::Path ( const Path & other )

Creates a copy of another path.

Path::~Path ( )

Destructor.

Member Function Documentation

Path& Path::operator= ( const Path & other )

Copies this path from another one.

bool Path::isEmpty ( ) const throw ()

Returns true if the path doesn't contain any lines or curves.

const Rectangle<float> Path::getBounds ( ) const throw ()

Returns the smallest rectangle that contains all points within the path.

const Rectangle<float> Path::getBoundsTransformed ( const AffineTransform & transform ) const throw ()

Returns the smallest rectangle that contains all points within the path after it's been transformed with the given tranasform matrix.

bool Path::contains	(	float	x,
		float	y,
		float	tolerence = `10.0f`
	)			const

Checks whether a point lies within the path.

This is only relevent for closed paths (see closeSubPath()), and may produce false results if used on a path which has open sub-paths.

The path's winding rule is taken into account by this method.

The tolerence parameter is passed to the PathFlatteningIterator that is used to trace the path - for more info about it, see the notes for the PathFlatteningIterator constructor.

See also:: closeSubPath, setUsingNonZeroWinding

bool Path::intersectsLine	(	float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	tolerence = `10.0f`
	)

Checks whether a line crosses the path.

This will return positive if the line crosses any of the paths constituent lines or curves. It doesn't take into account whether the line is inside or outside the path, or whether the path is open or closed.

The tolerence parameter is passed to the PathFlatteningIterator that is used to trace the path - for more info about it, see the notes for the PathFlatteningIterator constructor.

void Path::clear ( ) throw ()

Removes all lines and curves, resetting the path completely.

void Path::startNewSubPath	(	float	startX,
		float	startY
	)

Begins a new subpath with a given starting position.

This will move the path's current position to the co-ordinates passed in and make it ready to draw lines or curves starting from this position.

After adding whatever lines and curves are needed, you can either close the current sub-path using closeSubPath() or call startNewSubPath() to move to a new sub-path, leaving the old one open-ended.

See also:: lineTo, quadraticTo, cubicTo, closeSubPath

void Path::closeSubPath ( )

Closes a the current sub-path with a line back to its start-point.

When creating a closed shape such as a triangle, don't use 3 lineTo() calls - instead use two lineTo() calls, followed by a closeSubPath() to join the final point back to the start.

This ensures that closes shapes are recognised as such, and this is important for tasks like drawing strokes, which needs to know whether to draw end-caps or not.

See also:: startNewSubPath, lineTo, quadraticTo, cubicTo, closeSubPath

void Path::lineTo	(	float	endX,
		float	endY
	)

Adds a line from the shape's last position to a new end-point.

This will connect the end-point of the last line or curve that was added to a new point, using a straight line.

See the class description for an example of how to add lines and curves to a path.

See also:: startNewSubPath, quadraticTo, cubicTo, closeSubPath

void Path::quadraticTo	(	float	controlPointX,
		float	controlPointY,
		float	endPointX,
		float	endPointY
	)

Adds a quadratic bezier curve from the shape's last position to a new position.

This will connect the end-point of the last line or curve that was added to a new point, using a quadratic spline with one control-point.

See the class description for an example of how to add lines and curves to a path.

See also:: startNewSubPath, lineTo, cubicTo, closeSubPath

void Path::cubicTo	(	float	controlPoint1X,
		float	controlPoint1Y,
		float	controlPoint2X,
		float	controlPoint2Y,
		float	endPointX,
		float	endPointY
	)

Adds a cubic bezier curve from the shape's last position to a new position.

This will connect the end-point of the last line or curve that was added to a new point, using a cubic spline with two control-points.

See the class description for an example of how to add lines and curves to a path.

See also:: startNewSubPath, lineTo, quadraticTo, closeSubPath

const Point<float> Path::getCurrentPosition ( ) const

Returns the last point that was added to the path by one of the drawing methods.

void Path::addRectangle	(	float	x,
		float	y,
		float	width,
		float	height
	)

Adds a rectangle to the path.

The rectangle is added as a new sub-path. (Any currently open paths will be left open).

See also:: addRoundedRectangle, addTriangle

void Path::addRectangle ( const Rectangle< int > & rectangle )

Adds a rectangle to the path.

The rectangle is added as a new sub-path. (Any currently open paths will be left open).

See also:: addRoundedRectangle, addTriangle

void Path::addRoundedRectangle	(	float	x,
		float	y,
		float	width,
		float	height,
		float	cornerSize
	)

Adds a rectangle with rounded corners to the path.

The rectangle is added as a new sub-path. (Any currently open paths will be left open).

See also:: addRectangle, addTriangle

void Path::addRoundedRectangle	(	float	x,
		float	y,
		float	width,
		float	height,
		float	cornerSizeX,
		float	cornerSizeY
	)

Adds a rectangle with rounded corners to the path.

The rectangle is added as a new sub-path. (Any currently open paths will be left open).

See also:: addRectangle, addTriangle

void Path::addTriangle	(	float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	x3,
		float	y3
	)

Adds a triangle to the path.

The triangle is added as a new closed sub-path. (Any currently open paths will be left open).

Note that whether the vertices are specified in clockwise or anticlockwise order will affect how the triangle is filled when it overlaps other shapes (the winding order setting will affect this of course).

void Path::addQuadrilateral	(	float	x1,
		float	y1,
		float	x2,
		float	y2,
		float	x3,
		float	y3,
		float	x4,
		float	y4
	)

Adds a quadrilateral to the path.

The quad is added as a new closed sub-path. (Any currently open paths will be left open).

Note that whether the vertices are specified in clockwise or anticlockwise order will affect how the quad is filled when it overlaps other shapes (the winding order setting will affect this of course).

void Path::addEllipse	(	float	x,
		float	y,
		float	width,
		float	height
	)

Adds an ellipse to the path.

The shape is added as a new sub-path. (Any currently open paths will be left open).

See also:: addArc

void Path::addArc	(	float	x,
		float	y,
		float	width,
		float	height,
		float	fromRadians,
		float	toRadians,
		bool	startAsNewSubPath = `false`
	)

Adds an elliptical arc to the current path.

Note that when specifying the start and end angles, the curve will be drawn either clockwise or anti-clockwise according to whether the end angle is greater than the start. This means that sometimes you may need to use values greater than 2*Pi for the end angle.

Parameters:

	x	the left-hand edge of the rectangle in which the elliptical outline fits
	y	the top edge of the rectangle in which the elliptical outline fits
	width	the width of the rectangle in which the elliptical outline fits
	height	the height of the rectangle in which the elliptical outline fits
	fromRadians	the angle (clockwise) in radians at which to start the arc segment (where 0 is the top-centre of the ellipse)
	toRadians	the angle (clockwise) in radians at which to end the arc segment (where 0 is the top-centre of the ellipse). This angle can be greater than 2Pi, so for example to draw a curve clockwise from the 9 o'clock position to the 3 o'clock position via 12 o'clock, you'd use 1.5Pi and 2.5*Pi as the start and finish points.
	startAsNewSubPath	if true, the arc will begin a new subpath from its starting point; if false, it will be added to the current sub-path, continuing from the current postition

See also:: addCentredArc, arcTo, addPieSegment, addEllipse

void Path::addCentredArc	(	float	centreX,
		float	centreY,
		float	radiusX,
		float	radiusY,
		float	rotationOfEllipse,
		float	fromRadians,
		float	toRadians,
		bool	startAsNewSubPath = `false`
	)

Adds an arc which is centred at a given point, and can have a rotation specified.

Note that when specifying the start and end angles, the curve will be drawn either clockwise or anti-clockwise according to whether the end angle is greater than the start. This means that sometimes you may need to use values greater than 2*Pi for the end angle.

Parameters:

	centreX	the centre x of the ellipse
	centreY	the centre y of the ellipse
	radiusX	the horizontal radius of the ellipse
	radiusY	the vertical radius of the ellipse
	rotationOfEllipse	an angle by which the whole ellipse should be rotated about its centre, in radians (clockwise)
	fromRadians	the angle (clockwise) in radians at which to start the arc segment (where 0 is the top-centre of the ellipse)
	toRadians	the angle (clockwise) in radians at which to end the arc segment (where 0 is the top-centre of the ellipse). This angle can be greater than 2Pi, so for example to draw a curve clockwise from the 9 o'clock position to the 3 o'clock position via 12 o'clock, you'd use 1.5Pi and 2.5*Pi as the start and finish points.
	startAsNewSubPath	if true, the arc will begin a new subpath from its starting point; if false, it will be added to the current sub-path, continuing from the current postition

See also:: addArc, arcTo

void Path::addPieSegment	(	float	x,
		float	y,
		float	width,
		float	height,
		float	fromRadians,
		float	toRadians,
		float	innerCircleProportionalSize
	)

Adds a "pie-chart" shape to the path.

The shape is added as a new sub-path. (Any currently open paths will be left open).

Note that when specifying the start and end angles, the curve will be drawn either clockwise or anti-clockwise according to whether the end angle is greater than the start. This means that sometimes you may need to use values greater than 2*Pi for the end angle.

Parameters:

	x	the left-hand edge of the rectangle in which the elliptical outline fits
	y	the top edge of the rectangle in which the elliptical outline fits
	width	the width of the rectangle in which the elliptical outline fits
	height	the height of the rectangle in which the elliptical outline fits
	fromRadians	the angle (clockwise) in radians at which to start the arc segment (where 0 is the top-centre of the ellipse)
	toRadians	the angle (clockwise) in radians at which to end the arc segment (where 0 is the top-centre of the ellipse)
	innerCircleProportionalSize	if this is > 0, then the pie will be drawn as a curved band around a hollow ellipse at its centre, where this value indicates the inner ellipse's size with respect to the outer one.

See also:: addArc

void Path::addLineSegment	(	float	startX,
		float	startY,
		float	endX,
		float	endY,
		float	lineThickness
	)

Adds a line with a specified thickness.

The line is added as a new closed sub-path. (Any currently open paths will be left open).

See also:: addArrow

void Path::addArrow	(	float	startX,
		float	startY,
		float	endX,
		float	endY,
		float	lineThickness,
		float	arrowheadWidth,
		float	arrowheadLength
	)

Adds a line with an arrowhead on the end.

The arrow is added as a new closed sub-path. (Any currently open paths will be left open).

void Path::addStar	(	float	centreX,
		float	centreY,
		int	numberOfPoints,
		float	innerRadius,
		float	outerRadius,
		float	startAngle = `0.0f`
	)

Adds a star shape to the path.

void Path::addBubble	(	float	bodyX,
		float	bodyY,
		float	bodyW,
		float	bodyH,
		float	cornerSize,
		float	arrowTipX,
		float	arrowTipY,
		int	whichSide,
		float	arrowPositionAlongEdgeProportional,
		float	arrowWidth
	)

Adds a speech-bubble shape to the path.

Parameters:

	bodyX	the left of the main body area of the bubble
	bodyY	the top of the main body area of the bubble
	bodyW	the width of the main body area of the bubble
	bodyH	the height of the main body area of the bubble
	cornerSize	the amount by which to round off the corners of the main body rectangle
	arrowTipX	the x position that the tip of the arrow should connect to
	arrowTipY	the y position that the tip of the arrow should connect to
	whichSide	the side to connect the arrow to: 0 = top, 1 = left, 2 = bottom, 3 = right
	arrowPositionAlongEdgeProportional	how far along the edge of the main rectangle the arrow's base should be - this is a proportional distance between 0 and 1.0
	arrowWidth	how wide the base of the arrow should be where it joins the main rectangle

void Path::addPath ( const Path & pathToAppend )

Adds another path to this one.

The new path is added as a new sub-path. (Any currently open paths in this path will be left open).

Parameters:

pathToAppend

the path to add

void Path::addPath	(	const Path &	pathToAppend,
		const AffineTransform &	transformToApply
	)

Adds another path to this one, transforming it on the way in.

The new path is added as a new sub-path, its points being transformed by the given matrix before being added.

Parameters:

	pathToAppend	the path to add
	transformToApply	an optional transform to apply to the incoming vertices

void Path::swapWithPath ( Path & other )

Swaps the contents of this path with another one.

The internal data of the two paths is swapped over, so this is much faster than copying it to a temp variable and back.

void Path::applyTransform ( const AffineTransform & transform ) throw ()

Applies a 2D transform to all the vertices in the path.

See also:: AffineTransform, scaleToFit, getTransformToScaleToFit

void Path::scaleToFit	(	float	x,
		float	y,
		float	width,
		float	height,
		bool	preserveProportions
	)			throw ()

Rescales this path to make it fit neatly into a given space.

This is effectively a quick way of calling applyTransform (getTransformToScaleToFit (x, y, w, h, preserveProportions))

Parameters:

	x	the x position of the rectangle to fit the path inside
	y	the y position of the rectangle to fit the path inside
	width	the width of the rectangle to fit the path inside
	height	the height of the rectangle to fit the path inside
	preserveProportions	if true, it will fit the path into the space without altering its horizontal/vertical scale ratio; if false, it will distort the path to fill the specified ratio both horizontally and vertically

See also:: applyTransform, getTransformToScaleToFit

const AffineTransform Path::getTransformToScaleToFit	(	float	x,
		float	y,
		float	width,
		float	height,
		bool	preserveProportions,
		const Justification &	justificationType = `Justification::centred`
	)			const

Returns a transform that can be used to rescale the path to fit into a given space.

Parameters:

	x	the x position of the rectangle to fit the path inside
	y	the y position of the rectangle to fit the path inside
	width	the width of the rectangle to fit the path inside
	height	the height of the rectangle to fit the path inside
	preserveProportions	if true, it will fit the path into the space without altering its horizontal/vertical scale ratio; if false, it will distort the path to fill the specified ratio both horizontally and vertically
	justificationType	if the proportions are preseved, the resultant path may be smaller than the available rectangle, so this describes how it should be positioned within the space.

Returns:: an appropriate transformation

See also:: applyTransform, scaleToFit

const Path Path::createPathWithRoundedCorners ( float cornerRadius ) const

Creates a version of this path where all sharp corners have been replaced by curves.

Wherever two lines meet at an angle, this will replace the corner with a curve of the given radius.

void Path::setUsingNonZeroWinding ( bool isNonZeroWinding ) throw ()

Changes the winding-rule to be used when filling the path.

If set to true (which is the default), then the path uses a non-zero-winding rule to determine which points are inside the path. If set to false, it uses an alternate-winding rule.

The winding-rule comes into play when areas of the shape overlap other areas, and determines whether the overlapping regions are considered to be inside or outside.

Changing this value just sets a flag - it doesn't affect the contents of the path.

See also:: isUsingNonZeroWinding

bool Path::isUsingNonZeroWinding ( ) const

Returns the flag that indicates whether the path should use a non-zero winding rule.

The default for a new path is true.

See also:: setUsingNonZeroWinding

void Path::loadPathFromStream ( InputStream & source )

Loads a stored path from a data stream.

The data in the stream must have been written using writePathToStream().

Note that this will append the stored path to whatever is currently in this path, so you might need to call clear() beforehand.

See also:: loadPathFromData, writePathToStream

void Path::loadPathFromData	(	const void *	data,
		int	numberOfBytes
	)

Loads a stored path from a block of data.

This is similar to loadPathFromStream(), but just reads from a block of data. Useful if you're including stored shapes in your code as a block of static data.