Package com.itextpdf.svg.renderers.path.impl

Class QuadraticCurveTo

java.lang.Object

com.itextpdf.svg.renderers.path.impl.AbstractPathShape

com.itextpdf.svg.renderers.path.impl.QuadraticCurveTo

All Implemented Interfaces:

IControlPointCurve, IPathShape

Direct Known Subclasses:

QuadraticSmoothCurveTo

public class QuadraticCurveTo
extends AbstractPathShape
implements IControlPointCurve

Implements quadratic Bezier curveTo(Q) attribute of SVG's path element.

Field Summary

Fields

Modifier and Type	Field	Description
(package private) static int	ARGUMENT_SIZE

Fields inherited from class com.itextpdf.svg.renderers.path.impl.AbstractPathShape

context, coordinates, copier, properties, relative

Constructor Summary

Constructors

Constructor	Description
QuadraticCurveTo()	Creates new QuadraticCurveTo instance.
QuadraticCurveTo(boolean relative)	Creates new QuadraticCurveTo instance.
QuadraticCurveTo(boolean relative, IOperatorConverter copier)	Creates new QuadraticCurveTo instance.

Method Summary

Modifier and Type	Method	Description
private static void	addTValueToList(double t, java.util.List<java.lang.Double> tValuesList)	Check that t is in the range [0, 1] and add it to list
private static double	calculateExtremeCoordinate(double t, double p0, double p1, double p2)
void	draw()	Draws a quadratic Bezier curve from the current point to (x,y) using (x1,y1) as the control point
private static double[]	getBezierMinMaxPoints(double x0, double y0, double x1, double y1, double x2, double y2)	The algorithm is similar to cubic curve in the method CurveTo#getBezierMinMaxPoints, but the initial function is f(t) = (1 - t)^2*P0 + 2*(1-t)*t*P1 + t^2*P2, 0 <= t <= 1
private static double[]	getExtremeTValues(double x0, double y0, double x1, double y1, double x2, double y2)	Calculate values of t at which the function reaches its extreme points.
Point	getLastControlPoint()	Returns coordinates of the last control point (the one closest to the ending point) in the Bezier curve, in SVG space coordinates
Rectangle	getPathShapeRectangle(Point lastPoint)	Get bounding rectangle of the current path shape.
private static double	getTValue(double p0, double p1, double p2)
void	setCoordinates(java.lang.String[] inputCoordinates, Point startPoint)	This method sets the coordinates for the path painting operator and does internal preprocessing, if necessary

Methods inherited from class com.itextpdf.svg.renderers.path.impl.AbstractPathShape

applyTransform, createPoint, draw, getEndingPoint, isRelative, parseHorizontalLength, parseVerticalLength, setContext, setParent, setTransform

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

ARGUMENT_SIZE

static final int ARGUMENT_SIZE

See Also:

Constant Field Values

Constructor Detail

QuadraticCurveTo

public QuadraticCurveTo()

Creates new QuadraticCurveTo instance.

QuadraticCurveTo

public QuadraticCurveTo(boolean relative)

Creates new QuadraticCurveTo instance.

Parameters:

relative - true in case it is a relative operator, false if it is an absolute operator

QuadraticCurveTo

public QuadraticCurveTo(boolean relative,
                        IOperatorConverter copier)

Creates new QuadraticCurveTo instance.

Parameters:

relative - true in case it is a relative operator, false if it is an absolute operator

copier - IOperatorConverter copier for converting relative coordinates to absolute coordinates

Method Detail

draw

public void draw()

Draws a quadratic Bezier curve from the current point to (x,y) using (x1,y1) as the control point

Specified by:

draw in class AbstractPathShape

setCoordinates

public void setCoordinates(java.lang.String[] inputCoordinates,
                           Point startPoint)

Description copied from interface: IPathShape

This method sets the coordinates for the path painting operator and does internal preprocessing, if necessary

Specified by:

setCoordinates in interface IPathShape

Parameters:

inputCoordinates - an array containing point values for path coordinates

startPoint - the ending point of the previous operator, or, in broader terms, the point that the coordinates should be absolutized against, for relative operators

getLastControlPoint

public Point getLastControlPoint()

Description copied from interface: IControlPointCurve

Returns coordinates of the last control point (the one closest to the ending point) in the Bezier curve, in SVG space coordinates

Specified by:

getLastControlPoint in interface IControlPointCurve

Returns:

coordinates of the last control point in SVG space coordinates

getPathShapeRectangle

public Rectangle getPathShapeRectangle(Point lastPoint)

Description copied from class: AbstractPathShape

Get bounding rectangle of the current path shape.

Specified by:

getPathShapeRectangle in interface IPathShape

Overrides:

getPathShapeRectangle in class AbstractPathShape

Parameters:

lastPoint - start point for this shape

Returns:

calculated rectangle

getBezierMinMaxPoints

private static double[] getBezierMinMaxPoints(double x0,
                                              double y0,
                                              double x1,
                                              double y1,
                                              double x2,
                                              double y2)

The algorithm is similar to cubic curve in the method CurveTo#getBezierMinMaxPoints, but the initial function is f(t) = (1 - t)^2*P0 + 2*(1-t)*t*P1 + t^2*P2, 0 <= t <= 1

Parameters:

x0 - x coordinate of the starting point

y0 - y coordinate of the starting point

x1 - x coordinate of the control point

y1 - y coordinate of the control point

x2 - x coordinate of the ending point

y2 - y coordinate of the ending point

Returns:

array of {xMin, yMin, xMax, yMax} values

getExtremeTValues

private static double[] getExtremeTValues(double x0,
                                          double y0,
                                          double x1,
                                          double y1,
                                          double x2,
                                          double y2)

Calculate values of t at which the function reaches its extreme points. To do this, we get the derivative of the function and equate it to 0: f'(t) = 2a*t + b. t can only be in the range [0, 1] and it discarded otherwise.

Parameters:

x0 - x coordinate of the starting point

y0 - y coordinate of the starting point

x1 - x coordinate of the control point

y1 - y coordinate of the control point

x2 - x coordinate of the ending point

y2 - y coordinate of the ending point

Returns:

array of theta values corresponding to extreme points

addTValueToList

private static void addTValueToList(double t,
                                    java.util.List<java.lang.Double> tValuesList)

Check that t is in the range [0, 1] and add it to list

Parameters:

t - value of t

tValuesList - list storing t values

getTValue

private static double getTValue(double p0,
                                double p1,
                                double p2)

calculateExtremeCoordinate

private static double calculateExtremeCoordinate(double t,
                                                 double p0,
                                                 double p1,
                                                 double p2)