java.awt
class LinearGradientPaint

java.lang.Object java.awt.MultipleGradientPaint java.awt.LinearGradientPaint

All Implemented Interfaces:

Paint

public final class LinearGradientPaint
extends MultipleGradientPaint

The {@code LinearGradientPaint} class provides a way to fill a {@link java.awt.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 user also specifies start and end points which define where in user space the color gradient should begin and end.

The user must provide an array of floats specifying how to distribute the colors along the gradient. These values should range from 0.0 to 1.0 and act like keyframes along the gradient (they mark where the gradient should be exactly a particular color).

In the event that the user does not set the first keyframe value equal to 0 and/or the last keyframe value equal to 1, keyframes will be created at these positions and the first and last colors will be replicated there. So, if a user specifies the following arrays to construct a gradient:

     {Color.BLUE, Color.RED}, {.3f, .7f}
 

     {Color.BLUE, Color.BLUE, Color.RED, Color.RED}, {0f, .3f, .7f, 1f}
 

The user may also select what action the {@code LinearGradientPaint} should take when filling color outside the start and end points. If no cycle method is specified, {@code NO_CYCLE} will be chosen by default, which means the endpoint colors will be used to fill the remaining area.

The colorSpace parameter allows the user to specify in which colorspace the interpolation should be performed, default sRGB or linearized RGB.

The following code demonstrates typical usage of {@code LinearGradientPaint}:

     Point2D start = new Point2D.Float(0, 0);
     Point2D end = new Point2D.Float(50, 50);
     float[] dist = {0.0f, 0.2f, 1.0f};
     Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};
     LinearGradientPaint p =
         new LinearGradientPaint(start, end, dist, colors);
 

This code will create a {@code LinearGradientPaint} which interpolates between red and white for the first 20% of the gradient and between white and blue for the remaining 80%.

This image demonstrates the example code above for each of the three cycle methods:

LinearGradientPaint

public LinearGradientPaint(float startX,
                           float startY,
                           float endX,
                           float endY,
                           float[] fractions,
                           Color[] colors)

Constructs a {@code LinearGradientPaint} with a default {@code NO_CYCLE} repeating method and {@code SRGB} color space.

Parameters:

startX - the X coordinate of the gradient axis start point in user space

startY - the Y coordinate of the gradient axis start point in user space

endX - the X coordinate of the gradient axis end point in user space

endY - the Y coordinate of the gradient axis end point in user space

fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors - array of colors corresponding to each fractional value

LinearGradientPaint

public LinearGradientPaint(float startX,
                           float startY,
                           float endX,
                           float endY,
                           float[] fractions,
                           Color[] colors,
                           MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a {@code LinearGradientPaint} with a default {@code SRGB} color space.

Parameters:

startX - the X coordinate of the gradient axis start point in user space

startY - the Y coordinate of the gradient axis start point in user space

endX - the X coordinate of the gradient axis end point in user space

endY - the Y coordinate of the gradient axis end point in user space

fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors - array of colors corresponding to each fractional value

cycleMethod - either {@code NO_CYCLE}, {@code REFLECT}, or {@code REPEAT}

LinearGradientPaint

public LinearGradientPaint(Point2D start,
                           Point2D end,
                           float[] fractions,
                           Color[] colors)

Constructs a {@code LinearGradientPaint} with a default {@code NO_CYCLE} repeating method and {@code SRGB} color space.

Parameters:

start - the gradient axis start {@code Point2D} in user space

end - the gradient axis end {@code Point2D} in user space

fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors - array of colors corresponding to each fractional value

LinearGradientPaint

public LinearGradientPaint(Point2D start,
                           Point2D end,
                           float[] fractions,
                           Color[] colors,
                           MultipleGradientPaint.CycleMethod cycleMethod)

Constructs a {@code LinearGradientPaint} with a default {@code SRGB} color space.

Parameters:

start - the gradient axis start {@code Point2D} in user space

end - the gradient axis end {@code Point2D} in user space

fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors - array of colors corresponding to each fractional value

cycleMethod - either {@code NO_CYCLE}, {@code REFLECT}, or {@code REPEAT}

LinearGradientPaint

public LinearGradientPaint(Point2D start,
                           Point2D end,
                           float[] fractions,
                           Color[] colors,
                           MultipleGradientPaint.CycleMethod cycleMethod,
                           MultipleGradientPaint.ColorSpaceType colorSpace,
                           AffineTransform gradientTransform)

Constructs a {@code LinearGradientPaint}.

Parameters:

start - the gradient axis start {@code Point2D} in user space

end - the gradient axis end {@code Point2D} in user space

fractions - numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradient

colors - array of colors corresponding to each fractional value

cycleMethod - either {@code NO_CYCLE}, {@code REFLECT}, or {@code REPEAT}

colorSpace - which color space to use for interpolation, either {@code SRGB} or {@code LINEAR_RGB}

gradientTransform - transform to apply to the gradient

createContext

public PaintContext createContext(ColorModel cm,
                                  Rectangle deviceBounds,
                                  Rectangle2D userBounds,
                                  AffineTransform transform,
                                  RenderingHints hints)

{@inheritDoc}

Parameters:

cm

deviceBounds

userBounds

transform

hints

getEndPoint

public Point2D getEndPoint()

Returns a copy of the end point of the gradient axis.

Returns:

a {@code Point2D} object that is a copy of the point that anchors the last color of this {@code LinearGradientPaint}

getStartPoint

public Point2D getStartPoint()

Returns a copy of the start point of the gradient axis.

Returns:

a {@code Point2D} object that is a copy of the point that anchors the first color of this {@code LinearGradientPaint}