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Java™ Platform Standard Ed. 6 |
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java.lang.Objectjava.awt.MultipleGradientPaint
java.awt.RadialGradientPaint
public final class RadialGradientPaint
The RadialGradientPaint class provides a way to fill a shape with
a circular radial color gradient pattern. The user may specify 2 or more
gradient colors, and this paint will provide an interpolation between
each color.
The user must specify the circle controlling the gradient pattern, which is described by a center point and a radius. The user can also specify a separate focus point within that circle, which controls the location of the first color of the gradient. By default the focus is set to be the center of the circle.
This paint will map the first color of the gradient to the focus point, and the last color to the perimeter of the circle, interpolating smoothly for any in-between colors specified by the user. Any line drawn from the focus point to the circumference will thus span all the gradient colors.
Specifying a focus point outside of the circle's radius will result in the focus being set to the intersection point of the focus-center line and the perimeter of the circle.
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 RadialGradientPaint
should take when filling color outside the bounds of the circle's radius.
If no cycle method is specified, NO_CYCLE will be chosen by
default, which means the the last keyframe color 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
RadialGradientPaint, where the center and focus points are
the same:
Point2D center = new Point2D.Float(50, 50);
float radius = 25;
float[] dist = {0.0f, 0.2f, 1.0f};
Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};
RadialGradientPaint p =
new RadialGradientPaint(center, radius, dist, colors);
This image demonstrates the example code above, with default (centered) focus for each of the three cycle methods:
It is also possible to specify a non-centered focus point, as in the following code:
Point2D center = new Point2D.Float(50, 50);
float radius = 25;
Point2D focus = new Point2D.Float(40, 40);
float[] dist = {0.0f, 0.2f, 1.0f};
Color[] colors = {Color.RED, Color.WHITE, Color.BLUE};
RadialGradientPaint p =
new RadialGradientPaint(center, radius, focus,
dist, colors,
CycleMethod.NO_CYCLE);
This image demonstrates the previous example code, with non-centered focus for each of the three cycle methods:
Paint,
Graphics2D.setPaint(java.awt.Paint)| Nested Class Summary |
|---|
| Nested classes/interfaces inherited from class java.awt.MultipleGradientPaint |
|---|
MultipleGradientPaint.ColorSpaceType, MultipleGradientPaint.CycleMethod |
| Field Summary |
|---|
| Fields inherited from interface java.awt.Transparency |
|---|
BITMASK, OPAQUE, TRANSLUCENT |
| Constructor Summary | |
|---|---|
RadialGradientPaint(float cx,
float cy,
float radius,
float[] fractions,
Color[] colors)
Constructs a RadialGradientPaint with a default
NO_CYCLE repeating method and SRGB color space,
using the center as the focus point. |
|
RadialGradientPaint(float cx,
float cy,
float radius,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a RadialGradientPaint with a default
SRGB color space, using the center as the focus point. |
|
RadialGradientPaint(float cx,
float cy,
float radius,
float fx,
float fy,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a RadialGradientPaint with a default
SRGB color space. |
|
RadialGradientPaint(Point2D center,
float radius,
float[] fractions,
Color[] colors)
Constructs a RadialGradientPaint with a default
NO_CYCLE repeating method and SRGB color space,
using the center as the focus point. |
|
RadialGradientPaint(Point2D center,
float radius,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a RadialGradientPaint with a default
SRGB color space, using the center as the focus point. |
|
RadialGradientPaint(Point2D center,
float radius,
Point2D focus,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a RadialGradientPaint with a default
SRGB color space. |
|
RadialGradientPaint(Point2D center,
float radius,
Point2D focus,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod,
MultipleGradientPaint.ColorSpaceType colorSpace,
AffineTransform gradientTransform)
Constructs a RadialGradientPaint. |
|
RadialGradientPaint(Rectangle2D gradientBounds,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
Constructs a RadialGradientPaint with a default
SRGB color space. |
|
| Method Summary | |
|---|---|
PaintContext |
createContext(ColorModel cm,
Rectangle deviceBounds,
Rectangle2D userBounds,
AffineTransform transform,
RenderingHints hints)
Creates and returns a PaintContext used to
generate the color pattern. |
Point2D |
getCenterPoint()
Returns a copy of the center point of the radial gradient. |
Point2D |
getFocusPoint()
Returns a copy of the end point of the gradient axis. |
float |
getRadius()
Returns the radius of the circle defining the radial gradient. |
| Methods inherited from class java.awt.MultipleGradientPaint |
|---|
getColors, getColorSpace, getCycleMethod, getFractions, getTransform, getTransparency |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
|---|
public RadialGradientPaint(float cx,
float cy,
float radius,
float[] fractions,
Color[] colors)
RadialGradientPaint with a default
NO_CYCLE repeating method and SRGB color space,
using the center as the focus point.
cx - the X coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.cy - the Y coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.radius - the radius of the circle defining the extents of the
color gradientfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.
NullPointerException - if fractions array is null,
or colors array is null
IllegalArgumentException - if radius is non-positive,
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
public RadialGradientPaint(Point2D center,
float radius,
float[] fractions,
Color[] colors)
RadialGradientPaint with a default
NO_CYCLE repeating method and SRGB color space,
using the center as the focus point.
center - the center point, in user space, of the circle defining
the gradientradius - the radius of the circle defining the extents of the
color gradientfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.
NullPointerException - if center point is null,
or fractions array is null,
or colors array is null
IllegalArgumentException - if radius is non-positive,
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
public RadialGradientPaint(float cx,
float cy,
float radius,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
RadialGradientPaint with a default
SRGB color space, using the center as the focus point.
cx - the X coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.cy - the Y coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.radius - the radius of the circle defining the extents of the
color gradientfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - either NO_CYCLE, REFLECT,
or REPEAT
NullPointerException - if fractions array is null,
or colors array is null,
or cycleMethod is null
IllegalArgumentException - if radius is non-positive,
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
public RadialGradientPaint(Point2D center,
float radius,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
RadialGradientPaint with a default
SRGB color space, using the center as the focus point.
center - the center point, in user space, of the circle defining
the gradientradius - the radius of the circle defining the extents of the
color gradientfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - either NO_CYCLE, REFLECT,
or REPEAT
NullPointerException - if center point is null,
or fractions array is null,
or colors array is null,
or cycleMethod is null
IllegalArgumentException - if radius is non-positive,
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
public RadialGradientPaint(float cx,
float cy,
float radius,
float fx,
float fy,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
RadialGradientPaint with a default
SRGB color space.
cx - the X coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.cy - the Y coordinate in user space of the center point of the
circle defining the gradient. The last color of the
gradient is mapped to the perimeter of this circle.radius - the radius of the circle defining the extents of the
color gradientfx - the X coordinate of the point in user space to which the
first color is mappedfy - the Y coordinate of the point in user space to which the
first color is mappedfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - either NO_CYCLE, REFLECT,
or REPEAT
NullPointerException - if fractions array is null,
or colors array is null,
or cycleMethod is null
IllegalArgumentException - if radius is non-positive,
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
public RadialGradientPaint(Point2D center,
float radius,
Point2D focus,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
RadialGradientPaint with a default
SRGB color space.
center - the center point, in user space, of the circle defining
the gradient. The last color of the gradient is mapped
to the perimeter of this circle.radius - the radius of the circle defining the extents of the color
gradientfocus - the point in user space to which the first color is mappedfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - 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 radius is non-positive,
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
public RadialGradientPaint(Point2D center,
float radius,
Point2D focus,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod,
MultipleGradientPaint.ColorSpaceType colorSpace,
AffineTransform gradientTransform)
RadialGradientPaint.
center - the center point in user space of the circle defining the
gradient. The last color of the gradient is mapped to
the perimeter of this circle.radius - the radius of the circle defining the extents of the
color gradientfocus - the point in user space to which the first color is mappedfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - either NO_CYCLE, REFLECT,
or REPEATcolorSpace - which color space to use for interpolation,
either SRGB or LINEAR_RGBgradientTransform - 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 radius is non-positive,
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
public RadialGradientPaint(Rectangle2D gradientBounds,
float[] fractions,
Color[] colors,
MultipleGradientPaint.CycleMethod cycleMethod)
RadialGradientPaint with a default
SRGB color space.
The gradient circle of the RadialGradientPaint is defined
by the given bounding box.
This constructor is a more convenient way to express the
following (equivalent) code:
double gw = gradientBounds.getWidth();
double gh = gradientBounds.getHeight();
double cx = gradientBounds.getCenterX();
double cy = gradientBounds.getCenterY();
Point2D center = new Point2D.Double(cx, cy);
AffineTransform gradientTransform = new AffineTransform();
gradientTransform.translate(cx, cy);
gradientTransform.scale(gw / 2, gh / 2);
gradientTransform.translate(-cx, -cy);
RadialGradientPaint gp =
new RadialGradientPaint(center, 1.0f, center,
fractions, colors,
cycleMethod,
ColorSpaceType.SRGB,
gradientTransform);
gradientBounds - the bounding box, in user space, of the circle
defining the outermost extent of the gradientfractions - numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradientcolors - array of colors to use in the gradient. The first color
is used at the focus point, the last color around the
perimeter of the circle.cycleMethod - either NO_CYCLE, REFLECT,
or REPEAT
NullPointerException - if gradientBounds is null,
or fractions array is null,
or colors array is null,
or cycleMethod is null
IllegalArgumentException - if gradientBounds is empty,
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| Method Detail |
|---|
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 patternsPaintContextpublic Point2D getCenterPoint()
Point2D object that is a copy of the center pointpublic Point2D getFocusPoint()
Point2D object that is a copy of the focus pointpublic float getRadius()
|
Java™ Platform Standard Ed. 6 |
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