OpenJDK 27 · java.awt.RadialGradientPaintContext · APIdia, the JavaDoc alternative

Field Summary

Modifier and Type	Field and Description
private float	centerX Variables representing center and focus points.
private float	centerY Variables representing center and focus points.
private float	constA Constant part of X, Y user space coordinates.
private float	constB Constant part of X, Y user space coordinates.
private float	focusX Variables representing center and focus points.
private float	focusY Variables representing center and focus points.
private float	gDeltaDelta Constant second order delta for simple loop.
private boolean	isNonCyclic True when (cycleMethod == NO_CYCLE).
private boolean	isSimpleFocus True when (focus == center).
private float	radius Radius of the outermost circle defining the 100% gradient stop.
private float	radiusSq Radius of the gradient circle squared.
private static final float	SCALEBACK Amount for offset when clamping focus.
private static final int	SQRT_LUT_SIZE
private static float[]	sqrtLut
private float	trivial This value represents the solution when focusX == X.

Inherited from java.awt.MultipleGradientPaintContext:: a00 a01 a02 a10 a11 a12 cached cachedModel colorSpace cycleMethod fastGradientArraySize gradient GRADIENT_SIZE GRADIENT_SIZE_INDEX isSimpleLookup model saved

Constructor Summary

Access Constructor and Description

Access	Constructor and Description
pack-priv	RadialGradientPaintContext(RadialGradientPaint the `RadialGradientPaint` from which this context is created paint, ColorModel the `ColorModel` that receives the `Paint` data (this is used only as a hint) cm, Rectangle 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 `AffineTransform` from user space into device space (gradientTransform should be concatenated with this) t, RenderingHints the hints that the context object uses to choose between rendering alternatives hints, float the center X coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle. cx, float the center Y coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle. cy, float the radius of the circle defining the extents of the color gradient r, float the X coordinate in user space to which the first color is mapped fx, float the Y coordinate in user space to which the first color is mapped fy, float[] the fractions specifying the gradient distribution fractions, Color[] the gradient colors colors, MultipleGradientPaint.CycleMethod either NO_CYCLE, REFLECT, or REPEAT cycleMethod, MultipleGradientPaint.ColorSpaceType which colorspace to use for interpolation, either SRGB or LINEAR_RGB colorSpace) Constructor for RadialGradientPaintContext.

pack-priv

RadialGradientPaintContext(RadialGradientPaint

the RadialGradientPaint from which this context is created

paint, ColorModel

the ColorModel that receives the Paint data (this is used only as a hint)

cm, Rectangle

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 AffineTransform from user space into device space (gradientTransform should be concatenated with this)

t, RenderingHints

the hints that the context object uses to choose between rendering alternatives

hints, float

the center X coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

cx, float

the center Y coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.

cy, float

the radius of the circle defining the extents of the color gradient

r, float

the X coordinate in user space to which the first color is mapped

fx, float

the Y coordinate in user space to which the first color is mapped

fy, float[]

the fractions specifying the gradient distribution

fractions, Color[]

the gradient colors

colors, MultipleGradientPaint.CycleMethod

either NO_CYCLE, REFLECT, or REPEAT

cycleMethod, MultipleGradientPaint.ColorSpaceType

which colorspace to use for interpolation, either SRGB or LINEAR_RGB

colorSpace)

Constructor for RadialGradientPaintContext.

Method Summary

Modifier and Type	Method and Description
private void	cyclicCircularGradientFillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h) Fill the raster, cycling the gradient colors when a point falls outside of the perimeter of the 100% stop circle.
protected void	fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h) Implements abstract java.awt.MultipleGradientPaintContext.fillRaster. Return a Raster containing the colors generated for the graphics operation.
private void	simpleNonCyclicFillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h) This code works in the simplest of cases, where the focus == center point, the gradient is noncyclic, and the gradient lookup method is fast (single array index, no conversion necessary).

Inherited from java.awt.MultipleGradientPaintContext:: dispose getColorModel getRaster indexIntoGradientsArrays

Field Detail

centerX	back to summary
private float centerX Variables representing center and focus points.

centerY	back to summary
private float centerY Variables representing center and focus points.

constA	back to summary
private float constA Constant part of X, Y user space coordinates.

constB	back to summary
private float constB Constant part of X, Y user space coordinates.

focusX	back to summary
private float focusX Variables representing center and focus points.

focusY	back to summary
private float focusY Variables representing center and focus points.

gDeltaDelta	back to summary
private float gDeltaDelta Constant second order delta for simple loop.

isNonCyclic	back to summary
private boolean isNonCyclic True when (cycleMethod == NO_CYCLE).

isSimpleFocus	back to summary
private boolean isSimpleFocus True when (focus == center).

radius	back to summary
private float radius Radius of the outermost circle defining the 100% gradient stop.

radiusSq	back to summary
private float radiusSq Radius of the gradient circle squared.

SCALEBACK	back to summary
private static final float SCALEBACK Amount for offset when clamping focus.

SQRT_LUT_SIZE	back to summary
private static final int SQRT_LUT_SIZE

sqrtLut	back to summary
private static float[] sqrtLut

trivial	back to summary
private float trivial This value represents the solution when focusX == X. It is called trivial because it is easier to calculate than the general case.

Constructor Detail

RadialGradientPaintContext back to summary

RadialGradientPaintContext	back to summary
pack-priv RadialGradientPaintContext(RadialGradientPaint paint, ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform t, RenderingHints hints, float cx, float cy, float r, float fx, float fy, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace) Constructor for RadialGradientPaintContext. Parameters paint:RadialGradientPaint the `RadialGradientPaint` from which this context is created cm:ColorModel the `ColorModel` that receives the `Paint` data (this is used only as a hint) deviceBounds:Rectangle the device space bounding box of the graphics primitive being rendered userBounds:Rectangle2D the user space bounding box of the graphics primitive being rendered t:AffineTransform the `AffineTransform` from user space into device space (gradientTransform should be concatenated with this) hints:RenderingHints the hints that the context object uses to choose between rendering alternatives cx:float the center X coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle. cy:float the center Y coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle. r:float the radius of the circle defining the extents of the color gradient fx:float the X coordinate in user space to which the first color is mapped fy:float the Y coordinate in user space to which the first color is mapped fractions:float[] the fractions specifying the gradient distribution colors:Color[] the gradient colors cycleMethod:MultipleGradientPaint.CycleMethod either NO_CYCLE, REFLECT, or REPEAT colorSpace:MultipleGradientPaint.ColorSpaceType which colorspace to use for interpolation, either SRGB or LINEAR_RGB

pack-priv RadialGradientPaintContext(RadialGradientPaint paint, ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform t, RenderingHints hints, float cx, float cy, float r, float fx, float fy, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace)

Constructor for RadialGradientPaintContext.

Parameters

paint:RadialGradientPaint: the RadialGradientPaint from which this context is created
cm:ColorModel: the ColorModel that receives the Paint data (this is used only as a hint)
deviceBounds:Rectangle: the device space bounding box of the graphics primitive being rendered
userBounds:Rectangle2D: the user space bounding box of the graphics primitive being rendered
t:AffineTransform: the AffineTransform from user space into device space (gradientTransform should be concatenated with this)
hints:RenderingHints: the hints that the context object uses to choose between rendering alternatives
cx:float: the center X coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
cy:float: the center Y coordinate in user space of the circle defining the gradient. The last color of the gradient is mapped to the perimeter of this circle.
r:float: the radius of the circle defining the extents of the color gradient
fx:float: the X coordinate in user space to which the first color is mapped
fy:float: the Y coordinate in user space to which the first color is mapped
fractions:float[]: the fractions specifying the gradient distribution
colors:Color[]: the gradient colors
cycleMethod:MultipleGradientPaint.CycleMethod: either NO_CYCLE, REFLECT, or REPEAT
colorSpace:MultipleGradientPaint.ColorSpaceType: which colorspace to use for interpolation, either SRGB or LINEAR_RGB

Method Detail

cyclicCircularGradientFillRaster	back to summary
private void cyclicCircularGradientFillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h) Fill the raster, cycling the gradient colors when a point falls outside of the perimeter of the 100% stop circle. This calculation first computes the intersection point of the line from the focus through the current point in the raster, and the perimeter of the gradient circle. Then it determines the percentage distance of the current point along that line (focus is 0%, perimeter is 100%). Equation of a circle centered at (a,b) with radius r: (x-a)^2 + (y-b)^2 = r^2 Equation of a line with slope m and y-intercept b: y = mx + b Replacing y in the circle equation and solving using the quadratic formula produces the following set of equations. Constant factors have been extracted out of the inner loop.

cyclicCircularGradientFillRaster

back to summary

private void cyclicCircularGradientFillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h)

Fill the raster, cycling the gradient colors when a point falls outside of the perimeter of the 100% stop circle. This calculation first computes the intersection point of the line from the focus through the current point in the raster, and the perimeter of the gradient circle. Then it determines the percentage distance of the current point along that line (focus is 0%, perimeter is 100%). Equation of a circle centered at (a,b) with radius r: (x-a)^2 + (y-b)^2 = r^2 Equation of a line with slope m and y-intercept b: y = mx + b Replacing y in the circle equation and solving using the quadratic formula produces the following set of equations. Constant factors have been extracted out of the inner loop.

fillRaster	back to summary
protected void fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h) Implements abstract java.awt.MultipleGradientPaintContext.fillRaster. Return a Raster containing the colors generated for the graphics operation.

fillRaster

back to summary

protected void fillRaster(int[] pixels, int off, int adjust, int x, int y, int w, int h)

Implements abstract java.awt.MultipleGradientPaintContext.fillRaster.

Return a Raster containing the colors generated for the graphics operation.