Module javafx.graphics

Package javafx.scene.paint

Class LinearGradient

java.lang.Object

javafx.scene.paint.Paint

javafx.scene.paint.LinearGradient

public final class LinearGradient
extends Paint

The LinearGradient class fills a shape with a linear color gradient pattern. The user may specify two or more gradient colors, and this Paint will provide an interpolation between each color.

The application provides an array of Stops specifying how to distribute the colors along the gradient. The Stop#offset variable must be the range 0.0 to 1.0 and act like keyframes along the gradient. The offsets mark where the gradient should be exactly a particular color.

If the proportional variable is set to true then the start and end points of the gradient should be specified relative to the unit square (0.0->1.0) and will be stretched across the shape. If the proportional variable is set to false, then the start and end points should be specified in the local coordinate system of the shape and the gradient will not be stretched at all.

The two filled rectangles in the example below will render the same. The one on the left uses proportional coordinates to specify the end points of the gradient. The one on the right uses absolute coordinates. Both of them fill the specified rectangle with a horizontal gradient that varies from black to red

// object bounding box relative (proportional = true)
Stop[] stops = new Stop[] { new Stop(0, Color.BLACK), new Stop(1, Color.RED)};
LinearGradient lg1 = new LinearGradient(0, 0, 1, 0, true, CycleMethod.NO_CYCLE, stops);
Rectangle r1 = new Rectangle(0, 0, 100, 100);
r1.setFill(lg1);

// user space relative (proportional: = false)
LinearGradient lg2 = new LinearGradient(125, 0, 225, 0, false, CycleMethod.NO_CYCLE, stops);
Rectangle r2 = new Rectangle(125, 0, 100, 100);
r2.setFill(lg2);

Since:

JavaFX 2.0

Constructor Summary

Constructors

Constructor	Description
LinearGradient(double startX, double startY, double endX, double endY, boolean proportional, CycleMethod cycleMethod, List<Stop> stops)	Creates a new instance of LinearGradient.
LinearGradient(double startX, double startY, double endX, double endY, boolean proportional, CycleMethod cycleMethod, Stop... stops)	Creates a new instance of LinearGradient.

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object obj)	Indicates whether some other object is "equal to" this one.
CycleMethod	getCycleMethod()	Defines which of the following cycle method is applied to the LinearGradient: CycleMethod.NO_CYCLE, CycleMethod.REFLECT, or CycleMethod.REPEAT.
double	getEndX()	Defines the X coordinate of the gradient axis end point.
double	getEndY()	Defines the Y coordinate of the gradient axis end point.
double	getStartX()	Defines the X coordinate of the gradient axis start point.
double	getStartY()	Defines the Y coordinate of the gradient axis start point.
List<Stop>	getStops()	A sequence of 2 or more Stop values specifying how to distribute the colors along the gradient.
int	hashCode()	Returns a hash code for this LinearGradient object.
boolean	isOpaque()	Gets whether this Paint is completely opaque.
boolean	isProportional()	Indicates whether start and end locations are proportional or absolute.
String	toString()	Returns a string representation of this LinearGradient object.
static LinearGradient	valueOf(String value)	Creates a linear gradient value from a string representation.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

LinearGradient

public LinearGradient(double startX, double startY, double endX, double endY, boolean proportional, CycleMethod cycleMethod, Stop... stops)

Creates a new instance of LinearGradient.

Parameters:

startX - the X coordinate of the gradient axis start point

startY - the Y coordinate of the gradient axis start point

endX - the X coordinate of the gradient axis end point

endY - the Y coordinate of the gradient axis end point

proportional - whether the coordinates are proportional to the shape which this gradient fills

cycleMethod - cycle method applied to the gradient

stops - the gradient's color specification

LinearGradient

public LinearGradient(double startX, double startY, double endX, double endY, boolean proportional, CycleMethod cycleMethod, List<Stop> stops)

Creates a new instance of LinearGradient.

Parameters:

startX - the X coordinate of the gradient axis start point

startY - the Y coordinate of the gradient axis start point

endX - the X coordinate of the gradient axis end point

endY - the Y coordinate of the gradient axis end point

proportional - whether the coordinates are proportional to the shape which this gradient fills

cycleMethod - cycle method applied to the gradient

stops - the gradient's color specification

Method Details

getStartX

public final double getStartX()

Defines the X coordinate of the gradient axis start point. If proportional is true (the default), this value specifies a point on a unit square that will be scaled to match the size of the the shape that the gradient fills. (

Default value:

0.0

Returns:

the X coordinate of the gradient axis start point

getStartY

public final double getStartY()

Defines the Y coordinate of the gradient axis start point. If proportional is true (the default), this value specifies a point on a unit square that will be scaled to match the size of the the shape that the gradient fills.

Default value:

0.0

Returns:

the Y coordinate of the gradient axis start point

getEndX

public final double getEndX()

Defines the X coordinate of the gradient axis end point. If proportional is true (the default), this value specifies a point on a unit square that will be scaled to match the size of the the shape that the gradient fills.

Default value:

1.0

Returns:

the X coordinate of the gradient axis end point

getEndY

public final double getEndY()

Defines the Y coordinate of the gradient axis end point. If proportional is true (the default), this value specifies a point on a unit square that will be scaled to match the size of the the shape that the gradient fills.

Default value:

1.0

Returns:

the Y coordinate of the gradient axis end point

isProportional

public final boolean isProportional()

Indicates whether start and end locations are proportional or absolute. If this flag is true, the two end points are defined in a coordinate space where coordinates in the range [0..1] are scaled to map onto the bounds of the shape that the gradient fills. If this flag is false, then the coordinates are specified in the local coordinate system of the node.

Default value:

true

Returns:

if true start and end locations are proportional, otherwise absolute

getCycleMethod

public final CycleMethod getCycleMethod()

Defines which of the following cycle method is applied to the LinearGradient: CycleMethod.NO_CYCLE, CycleMethod.REFLECT, or CycleMethod.REPEAT.

Default value:

NO_CYCLE

Returns:

the cycle method applied to this linear gradient

getStops

public final List<Stop> getStops()

A sequence of 2 or more Stop values specifying how to distribute the colors along the gradient. These values must be in the range 0.0 to 1.0. They act like key frames along the gradient: they mark where the gradient should be exactly a particular color.

Each stop in the sequence must have an offset that is greater than the previous stop in the sequence.

The list is unmodifiable and will throw UnsupportedOperationException on each modification attempt.

Default value:

empty

Returns:

the list of stop values

isOpaque

public final boolean isOpaque()

Gets whether this Paint is completely opaque. An opaque paint is one that has no alpha component in any of its colors. It may be possible for a Paint to be opaque and yet return false, if it cannot be easily determined whether the paint is actually opaque. For example, the ImagePattern may not be able to cheaply determine its opacity.

Specified by:

isOpaque in class Paint

Returns:

true if the Paint is opaque, false if it is not opaque or if it cannot be determined.

Since:

JavaFX 8.0

equals

public boolean equals(Object obj)

Indicates whether some other object is "equal to" this one.

Overrides:

equals in class Object

Parameters:

obj - the reference object with which to compare.

Returns:

true if this object is equal to the obj argument; false otherwise.

hashCode

public int hashCode()

Returns a hash code for this LinearGradient object.

Overrides:

hashCode in class Object

Returns:

a hash code for this LinearGradient object.

toString

public String toString()

Returns a string representation of this LinearGradient object.

Overrides:

toString in class Object

Returns:

a string representation of this LinearGradient object.

valueOf

public static LinearGradient valueOf(String value)

Creates a linear gradient value from a string representation.

The format of the string representation is based on JavaFX CSS specification for linear gradient which is

 linear-gradient( [ [from <point> to <point>| [ to <side-or-corner>], ]? [ [ repeat | reflect ], ]? <color-stop>[, <color-stop>]+)
 

where

 <side-or-corner> = [left | right] || [top | bottom]
 <point> = [ [ <length> <length> ] | [ <percentage> | <percentage> ] ]
 <color-stop> = [ <color> [ <percentage> | <length>]? ]
 

Currently length can be only specified in px, the specification of unit can be omited. Format of color representation is the one used in Color.web(String color). The linear-gradient keyword can be omited. For additional information about the format of string representation, see the CSS Reference Guide.

Examples:

 LinearGradient g
      = LinearGradient.valueOf("linear-gradient(from 0% 0% to 100% 100%, red  0% , blue 30%,  black 100%)");
 LinearGradient g
      = LinearGradient.valueOf("from 0% 0% to 100% 100%, red  0% , blue 30%,  black 100%");
 LinearGradient g
      = LinearGradient.valueOf("linear-gradient(from 0px 0px to 200px 0px, #00ff00 0%, 0xff0000 50%, 0x1122ff40 100%)");
 LinearGradient g
      = LinearGradient.valueOf("from 0px 0px to 200px 0px, #00ff00 0%, 0xff0000 50%, 0x1122ff40 100%");
 

Parameters:

value - the string to convert

Returns:

a LinearGradient object holding the value represented by the string argument.

Throws:

NullPointerException - if the value is null

IllegalArgumentException - if the value cannot be parsed

Since:

JavaFX 2.1