java.lang.Objectjava.awt.MultipleGradientPaint
java.awt.LinearGradientPaint
public final class LinearGradientPaint
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
should take when filling color outside the start and end points.
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)
Nested Class Summary |
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Nested classes/interfaces inherited from class java.awt.MultipleGradientPaint |
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MultipleGradientPaint.ColorSpaceType, MultipleGradientPaint.CycleMethod |
Field Summary |
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Fields inherited from interface java.awt.Transparency |
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BITMASK, OPAQUE, TRANSLUCENT |
Constructor Summary | |
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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. |
|
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. |
|
LinearGradientPaint(Point2D start,
Point2D end,
float[] fractions,
Color[] colors)
Constructs a LinearGradientPaint with a default
NO_CYCLE repeating method and SRGB color space. |
|
LinearGradientPaint(Point2D start,
Point2D end,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a LinearGradientPaint with a default SRGB
color space. |
|
LinearGradientPaint(Point2D start,
Point2D end,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod,
MultipleGradientPaint.ColorSpaceType colorSpace,
AffineTransform gradientTransform)
Constructs a LinearGradientPaint . |
Method Summary | |
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PaintContext |
createContext(ColorModel cm,
Rectangle deviceBounds,
Rectangle2D userBounds,
AffineTransform transform,
RenderingHints hints)
Creates and returns a PaintContext used to
generate the color pattern. |
Point2D |
getEndPoint()
Returns a copy of the end point of the gradient axis. |
Point2D |
getStartPoint()
Returns a copy of the start point of the gradient axis. |
Methods inherited from class java.awt.MultipleGradientPaint |
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getColors, getColorSpace, getCycleMethod, getFractions, getTransform, getTransparency |
Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
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public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors)
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 value
NullPointerException
- 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)
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 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(Point2D start, Point2D end, float[] fractions, Color[] colors)
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 value
NullPointerException
- if one of the points is null,
or 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(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod)
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 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(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace, AffineTransform gradientTransform)
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 gradient
NullPointerException
- 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 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 orderMethod Detail |
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public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints)
PaintContext
used to
generate the color pattern.
Since the ColorModel argument to createContext is only a
hint, implementations of Paint should accept a null argument
for ColorModel. Note that if the application does not
prefer a specific ColorModel, the null ColorModel argument
will give the Paint implementation full leeway in using the
most efficient ColorModel it prefers for its raster processing.
Since the API documentation was not specific about this in
releases before 1.4, there may be implementations of
Paint
that do not accept a null
ColorModel
argument.
If a developer is writing code which passes a null
ColorModel
argument to the
createContext
method of Paint
objects from arbitrary sources it would be wise to code defensively
by manufacturing a non-null ColorModel
for those
objects which throw a NullPointerException
.
cm
- the ColorModel
that receives the
Paint
data. This is used only as a hint.deviceBounds
- the device space bounding box
of the graphics primitive being rendereduserBounds
- the user space bounding box
of the graphics primitive being renderedtransform
- the AffineTransform
from user
space into device spacehints
- the hint that the context object uses to
choose between rendering alternatives
PaintContext
for
generating color patternsPaintContext
public Point2D getStartPoint()
Point2D
object that is a copy of the point
that anchors the first color of this LinearGradientPaint
public Point2D getEndPoint()
Point2D
object that is a copy of the point
that anchors the last color of this LinearGradientPaint