LinearGradientPaint class provides a way to fill
a 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}
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:
java.awt.Paint , java.awt.Graphics2D#setPaint
| Modifier and Type | Field and Description |
|---|---|
| private final Point2D | end
Gradient start and end points. |
| private final Point2D | start
Gradient start and end points. |
| Access | Constructor and Description |
|---|---|
| public | LinearGradientPaint(float
the X coordinate of the gradient axis start point
in user space startX, float the Y coordinate of the gradient axis start point
in user space startY, float the X coordinate of the gradient axis end point
in user space endX, float the Y coordinate of the gradient axis end point
in user space endY, float[] numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradient fractions, Color[] array of colors corresponding to each fractional value colors)Constructs a |
| public | LinearGradientPaint(float
the X coordinate of the gradient axis start point
in user space startX, float the Y coordinate of the gradient axis start point
in user space startY, float the X coordinate of the gradient axis end point
in user space endX, float the Y coordinate of the gradient axis end point
in user space endY, float[] numbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradient fractions, Color[] array of colors corresponding to each fractional value colors, MultipleGradientPaint.either cycleMethodNO_CYCLE, REFLECT,
or REPEATConstructs a |
| public | LinearGradientPaint(Point2D
the gradient axis start start, Point2D Point2D in user spacethe gradient axis end end, float[] Point2D in user spacenumbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradient fractions, Color[] array of colors corresponding to each fractional value colors)Constructs a |
| public | LinearGradientPaint(Point2D
the gradient axis start start, Point2D Point2D in user spacethe gradient axis end end, float[] Point2D in user spacenumbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradient fractions, Color[] array of colors corresponding to each fractional value colors, MultipleGradientPaint.either cycleMethodNO_CYCLE, REFLECT,
or REPEATConstructs a |
| public | LinearGradientPaint(Point2D
the gradient axis start start, Point2D Point2D in user spacethe gradient axis end end, float[] Point2D in user spacenumbers ranging from 0.0 to 1.0 specifying the
distribution of colors along the gradient fractions, Color[] array of colors corresponding to each fractional value colors, MultipleGradientPaint.either cycleMethod,NO_CYCLE, REFLECT,
or REPEATwhich color space to use for interpolation,
either colorSpace,SRGB or LINEAR_RGBtransform to apply to the gradient gradientTransform)Constructs a |
| Modifier and Type | Method and Description |
|---|---|
| public PaintContext | Returns: thePaintContext for
generating color patterns.the preferred cm, Rectangle ColorModel which represents the most convenient
format for the caller to receive the pixel data, or null
if there is no preference.the device space bounding box
of the graphics primitive being rendered. deviceBounds, Rectangle2D the user space bounding box
of the graphics primitive being rendered. userBounds, AffineTransform the transform, RenderingHints AffineTransform from user
space into device space.the set of hints that the context object can use to
choose between rendering alternatives. hints)Implements java. Creates and returns a |
| public Point2D | Returns: aPoint2D object that is a copy of the point
that anchors the last color of this LinearGradientPaintReturns a copy of the end point of the gradient axis. |
| public Point2D | Returns: aPoint2D object that is a copy of the point
that anchors the first color of this LinearGradientPaintReturns a copy of the start point of the gradient axis. |
| end | back to summary |
|---|---|
| private final Point2D end Gradient start and end points. | |
| start | back to summary |
|---|---|
| private final Point2D start Gradient start and end points. | |
| LinearGradientPaint | back to summary |
|---|---|
| public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors) Constructs a
| |
| LinearGradientPaint | back to summary |
|---|---|
| public LinearGradientPaint(float startX, float startY, float endX, float endY, float[] fractions, Color[] colors, MultipleGradientPaint. Constructs a
| |
| LinearGradientPaint | back to summary |
|---|---|
| public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors) Constructs a
| |
| LinearGradientPaint | back to summary |
|---|---|
| public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint. Constructs a
| |
| LinearGradientPaint | back to summary |
|---|---|
| public LinearGradientPaint(Point2D start, Point2D end, float[] fractions, Color[] colors, MultipleGradientPaint. Constructs a
| |
| createContext | back to summary |
|---|---|
| public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints) Implements java. Creates and returns a
| |
| getEndPoint | back to summary |
|---|---|
| public Point2D getEndPoint() Returns a copy of the end point of the gradient axis.
| |
| getStartPoint | back to summary |
|---|---|
| public Point2D getStartPoint() Returns a copy of the start point of the gradient axis.
| |