Class LinearGradientPaint
- All Implemented Interfaces:
Paint
,Transparency
LinearGradientPaint
class provides a way to fill
a Shape
with a linear color gradient pattern. The user may
specify 2 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).
For example:
Point2D start = new Point2D.Float(0, 0);
Point2D end = new Point2D.Float(100,100);
float[] dist = {0.0, 0.2, 1.0};
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%.
In the event that the user does not set the first keyframe value equal
to 0 and 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}, {.3, .7}
this will be converted to a gradient with the following keyframes:
{Color.blue, Color.blue, Color.red, Color.red}, {0, .3, .7, 1}
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, so the endpoint colors will be used to fill the remaining area.
The following image demonstrates the options NO_CYCLE and REFLECT.
The colorSpace parameter allows the user to specify in which colorspace the interpolation should be performed, default sRGB or linearized RGB.
- See Also:
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Nested Class Summary
Nested classes/interfaces inherited from class org.apache.batik.ext.awt.MultipleGradientPaint
MultipleGradientPaint.ColorSpaceEnum, MultipleGradientPaint.CycleMethodEnum
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Field Summary
Fields inherited from class org.apache.batik.ext.awt.MultipleGradientPaint
colors, colorSpace, cycleMethod, fractions, gradientTransform, LINEAR_RGB, NO_CYCLE, REFLECT, REPEAT, SRGB, transparency
Fields inherited from interface java.awt.Transparency
BITMASK, OPAQUE, TRANSLUCENT
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Constructor Summary
ConstructorsConstructorDescriptionLinearGradientPaint
(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors) Constructs anLinearGradientPaint
with the default NO_CYCLE repeating method and SRGB colorspace.LinearGradientPaint
(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod) Constructs anLinearGradientPaint
with default SRGB colorspace.LinearGradientPaint
(Point2D start, Point2D end, float[] fractions, Color[] colors) Constructs aLinearGradientPaint
with the default NO_CYCLE repeating method and SRGB colorspace.LinearGradientPaint
(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace) Constructs aLinearGradientPaint
.LinearGradientPaint
(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace, AffineTransform gradientTransform) Constructs aLinearGradientPaint
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Method Summary
Modifier and TypeMethodDescriptioncreateContext
(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints) Creates and returns a PaintContext used to generate the color pattern, for use by the internal rendering engine.Returns a copy of the end point of the gradient axisReturns a copy of the start point of the gradient axisMethods inherited from class org.apache.batik.ext.awt.MultipleGradientPaint
getColors, getColorSpace, getCycleMethod, getFractions, getTransform, getTransparency
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Constructor Details
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LinearGradientPaint
public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors) Constructs an
LinearGradientPaint
with the default NO_CYCLE repeating method and SRGB colorspace.- Parameters:
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- Throws:
IllegalArgumentException
- if start and end points are the same points, or if fractions.length != colors.length, or if colors is less than 2 in size.
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LinearGradientPaint
public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod) Constructs an
LinearGradientPaint
with default SRGB colorspace.- Parameters:
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- Throws:
IllegalArgumentException
- if start and end points are the same points, or if fractions.length != colors.length, or if colors is less than 2 in size.
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LinearGradientPaint
Constructs a
LinearGradientPaint
with the default NO_CYCLE repeating method and SRGB colorspace.- Parameters:
start
- the gradient axis startPoint
in user spaceend
- the gradient axis endPoint
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- Throws:
NullPointerException
- if one of the points is nullIllegalArgumentException
- if start and end points are the same points, or if fractions.length != colors.length, or if colors is less than 2 in size.
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LinearGradientPaint
public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace) Constructs a
LinearGradientPaint
.- Parameters:
start
- the gradient axis startPoint
in user spaceend
- the gradient axis endPoint
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 REPEATcolorSpace
- which colorspace to use for interpolation, either SRGB or LINEAR_RGB- Throws:
NullPointerException
- if one of the points is nullIllegalArgumentException
- if start and end points are the same points, or if fractions.length != colors.length, or if colors is less than 2 in size.
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LinearGradientPaint
public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethodEnum cycleMethod, MultipleGradientPaint.ColorSpaceEnum colorSpace, AffineTransform gradientTransform) Constructs a
LinearGradientPaint
.- Parameters:
start
- the gradient axis startPoint
in user spaceend
- the gradient axis endPoint
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 REPEATcolorSpace
- which colorspace to use for interpolation, either SRGB or LINEAR_RGBgradientTransform
- transform to apply to the gradient- Throws:
NullPointerException
- if one of the points is null, or gradientTransform is nullIllegalArgumentException
- if start and end points are the same points, or if fractions.length != colors.length, or if colors is less than 2 in size.
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Method Details
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createContext
public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints) Creates and returns a PaintContext used to generate the color pattern, for use by the internal rendering engine.- Parameters:
cm
-ColorModel
that receives thePaint
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
- theAffineTransform
from user space into device spacehints
- the hints that the context object uses to choose between rendering alternatives- Returns:
- the
PaintContext
that generates color patterns. - See Also:
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getStartPoint
Returns a copy of the start point of the gradient axis- Returns:
- a
Point2D
object that is a copy of the point that anchors the first color of thisLinearGradientPaint
.
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getEndPoint
Returns a copy of the end point of the gradient axis- Returns:
- a
Point2D
object that is a copy of the point that anchors the last color of thisLinearGradientPaint
.
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