LinearGradient (JavaFX 13)

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 `Stop`s 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

    All Methods Static Methods Instance Methods Concrete Methods
    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 Detail

    - #### 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 Detail

    - #### 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