public final class LinearGradientPaint extends MultipleGradientPaint
The LinearGradientPaint
class provides a way to fill 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 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}this will be converted to a gradient with the following keyframes:
{Color.BLUE, Color.BLUE, Color.RED, Color.RED}, {0f, .3f, .7f, 1f}
The user may also select what action the LinearGradientPaint
object takes when it is filling the space outside the start and end points by setting CycleMethod
to either REFLECTION
or REPEAT
. The distances between any two colors in any of the reflected or repeated copies of the gradient are the same as the distance between those same two colors between the start and end points. Note that some minor variations in distances may occur due to sampling at the granularity of a pixel. If no cycle method is specified, 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 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 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:
Paint
, Graphics2D.setPaint(java.awt.Paint)
MultipleGradientPaint.ColorSpaceType, MultipleGradientPaint.CycleMethod
BITMASK, OPAQUE, TRANSLUCENT
public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors)
Constructs a LinearGradientPaint
with a default NO_CYCLE
repeating method and SRGB
color space.
startX
- the X coordinate of the gradient axis start point in user spacestartY
- the Y coordinate of the gradient axis start point in user spaceendX
- the X coordinate of the gradient axis end point in user spaceendY
- the Y coordinate of the gradient axis end point in user spacefractions
- numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradientcolors
- array of colors corresponding to each fractional valueNullPointerException
- if fractions
array is null, or colors
array is null,IllegalArgumentException
- if start and end points are the same points, or fractions.length != colors.length
, or colors
is less than 2 in size, or a fractions
value is less than 0.0 or greater than 1.0, or the fractions
are not provided in strictly increasing orderpublic LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a LinearGradientPaint
with a default SRGB
color space.
startX
- the X coordinate of the gradient axis start point in user spacestartY
- the Y coordinate of the gradient axis start point in user spaceendX
- the X coordinate of the gradient axis end point in user spaceendY
- the Y coordinate of the gradient axis end point in user spacefractions
- numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradientcolors
- array of colors corresponding to each fractional valuecycleMethod
- either NO_CYCLE
, REFLECT
, or REPEAT
NullPointerException
- if fractions
array is null, or colors
array is null, or cycleMethod
is nullIllegalArgumentException
- if start and end points are the same points, or fractions.length != colors.length
, or colors
is less than 2 in size, or a fractions
value is less than 0.0 or greater than 1.0, or the fractions
are not provided in strictly increasing orderpublic LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors)
Constructs a LinearGradientPaint
with a default NO_CYCLE
repeating method and SRGB
color space.
start
- the gradient axis start Point2D
in user spaceend
- the gradient axis end Point2D
in user spacefractions
- numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradientcolors
- array of colors corresponding to each fractional valueNullPointerException
- if one of the points is null, or fractions
array is null, or colors
array is nullIllegalArgumentException
- if start and end points are the same points, or fractions.length != colors.length
, or colors
is less than 2 in size, or a fractions
value is less than 0.0 or greater than 1.0, or the fractions
are not provided in strictly increasing orderpublic LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a LinearGradientPaint
with a default SRGB
color space.
start
- the gradient axis start Point2D
in user spaceend
- the gradient axis end Point2D
in user spacefractions
- numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradientcolors
- array of colors corresponding to each fractional valuecycleMethod
- either NO_CYCLE
, REFLECT
, or REPEAT
NullPointerException
- if one of the points is null, or fractions
array is null, or colors
array is null, or cycleMethod
is nullIllegalArgumentException
- if start and end points are the same points, or fractions.length != colors.length
, or colors
is less than 2 in size, or a fractions
value is less than 0.0 or greater than 1.0, or the fractions
are not provided in strictly increasing order@ConstructorProperties(value={"startPoint","endPoint","fractions","colors","cycleMethod","colorSpace","transform"}) public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace, AffineTransform gradientTransform)
Constructs a LinearGradientPaint
.
start
- the gradient axis start Point2D
in user spaceend
- the gradient axis end Point2D
in user spacefractions
- numbers ranging from 0.0 to 1.0 specifying the distribution of colors along the gradientcolors
- array of colors corresponding to each fractional valuecycleMethod
- either NO_CYCLE
, REFLECT
, or REPEAT
colorSpace
- which color space to use for interpolation, either SRGB
or LINEAR_RGB
gradientTransform
- transform to apply to the gradientNullPointerException
- if one of the points is null, or fractions
array is null, or colors
array is null, or cycleMethod
is null, or colorSpace
is null, or gradientTransform
is nullIllegalArgumentException
- if start and end points are the same points, or fractions.length != colors.length
, or colors
is less than 2 in size, or a fractions
value is less than 0.0 or greater than 1.0, or the fractions
are not provided in strictly increasing orderpublic PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints)
Creates and returns a PaintContext
used to generate a linear color gradient pattern. See the specification
of the method in the Paint
interface for information on null parameter handling.
cm
- the preferred ColorModel
which represents the most convenient format for the caller to receive the pixel data, or null
if there is no preference.deviceBounds
- the device space bounding box of the graphics primitive being rendered.userBounds
- the user space bounding box of the graphics primitive being rendered.transform
- the AffineTransform
from user space into device space.hints
- the set of hints that the context object can use to choose between rendering alternatives.PaintContext
for generating color patterns.Paint
, PaintContext
, ColorModel
, Rectangle
, Rectangle2D
, AffineTransform
, RenderingHints
public Point2D getStartPoint()
Returns a copy of the start point of the gradient axis.
Point2D
object that is a copy of the point that anchors the first color of this LinearGradientPaint
public Point2D getEndPoint()
Returns a copy of the end point of the gradient axis.
Point2D
object that is a copy of the point that anchors the last color of this LinearGradientPaint
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