Wt  3.3.9
Classes | Public Member Functions | List of all members
Wt::WPainterPath Class Reference

A path defining a shape. More...

#include <Wt/WPainterPath>

Inheritance diagram for Wt::WPainterPath:
Inheritance graph
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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.
 
WPainterPathoperator= (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 WT_CXX11ONLY(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(...);
path.lineTo(10, 20);
path.lineTo(30, 20);
path.closeSubPath();
painter.setPen(Wt::red);
painter.setBrush(Wt::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

Wt::WPainterPath::WPainterPath ( )

Default constructor.

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

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

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
WExceptionif the path is JavaScript bound
See also
addEllipse(double, double, double, double), arcTo()
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
WExceptionif the path is JavaScript bound
See also
addEllipse(const WRectF&), arcTo()
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
WExceptionif the path is JavaScript bound
See also
connectPath(const WPainterPath&)
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
WExceptionif the path is JavaScript bound
See also
moveTo(), lineTo()
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
WExceptionif the path is JavaScript bound
See also
addRect(double, double, double, double)
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
WExceptionif the path is JavaScript bound
See also
addRect(const WRectF&)
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
WExceptionif the path is JavaScript bound
See also
arcTo()
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
WExceptionif the path is JavaScript bound
See also
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
WExceptionif the path is JavaScript bound
See also
arcMoveTo()
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
WExceptionif the path is JavaScript bound
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
WExceptionif the path is JavaScript bound
See also
connectPath(const WPainterPath&)
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.

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.

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
WExceptionif the path is JavaScript bound
See also
cubicTo(double, double, double, double, double, double)
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
WExceptionif the path is JavaScript bound
See also
cubicTo(const WPointF&, const WPointF&, const WPointF&)
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.

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.

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.

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
WExceptionif the path is JavaScript bound
See also
lineTo(double, double)
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
WExceptionif the path is JavaScript bound
See also
lineTo(const WPointF&)
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
WExceptionif the path is JavaScript bound
See also
closeSubPath(), moveTo(double, double), setOpenSubPathsEnabled(bool)
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
WExceptionif the path is JavaScript bound
See also
closeSubPath(), moveTo(const WPointF&), setOpenSubPathsEnabled(bool)
bool Wt::WPainterPath::openSubPathsEnabled ( ) const

Returns whether open subpaths are enabled.

See also
setOpenSubPathsEnabled(bool)
bool Wt::WPainterPath::operator!= ( const WPainterPath path) const

Comparison operator.

Returns true if the paths are different.

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

Comparison operator.

Returns true if the paths are exactly the same.

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
WExceptionif the path is JavaScript bound
See also
quadTo(double, double, double, double)
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
WExceptionif the path is JavaScript bound
See also
quadTo(const WPointF&, const WPointF&)
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()

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