Class SVGRadialGradientPaint
- All Implemented Interfaces:
Paint
,Transparency
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 radius of the circle will cause the rings of the gradient pattern to be centered on the point just inside the edge of the circle in the direction of the focus point. The rendering will internally use this modified location as if it were the specified focus point.
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
object
takes when it is filling the space outside the circle's radius by
setting CycleMethod
to either REFLECTION
or REPEAT
.
The gradient color proportions are equal for any particular line drawn
from the focus point. The following figure shows that the distance AB
is equal to the distance BC, and the distance AD is equal to the distance DE.
If the gradient and graphics rendering transforms are uniformly scaled and the user sets the focus so that it coincides with the center of the circle, the gradient color proportions are equal for any line drawn from the center. The following figure shows the distances AB, BC, AD, and DE. They are all equal.
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 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:
- Since:
- 1.6
- See Also:
-
Field Summary
FieldsModifier and TypeFieldDescriptionprivate final @NotNull Point2D
Center of the circle defining the 100% gradient stop X coordinate.private final @NotNull Point2D
Focus point which defines the 0% gradient stop X coordinate.private final float
Radius of the innermost circle defining the circular area of the 0% gradient stop.private final float
Radius of the outermost circle defining the 100% gradient stop.Fields inherited from class com.github.weisj.jsvg.renderer.jdk.SVGMultipleGradientPaint
colors, colorSpace, cycleMethod, fastGradientArraySize, fractions, gradient, gradients, gradientTransform, isSimpleLookup, model, normalizedIntervals, transparency
Fields inherited from interface java.awt.Transparency
BITMASK, OPAQUE, TRANSLUCENT
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Constructor Summary
ConstructorsConstructorDescriptionSVGRadialGradientPaint
(@NotNull Point2D center, float radius, @NotNull Point2D focus, float focusRadius, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace, @NotNull AffineTransform gradientTransform) Constructs aRadialGradientPaint
. -
Method Summary
Modifier and TypeMethodDescriptioncreateContext
(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints) Methods inherited from class com.github.weisj.jsvg.renderer.jdk.SVGMultipleGradientPaint
getTransparency
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Field Details
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focus
Focus point which defines the 0% gradient stop X coordinate. -
center
Center of the circle defining the 100% gradient stop X coordinate. -
radius
private final float radiusRadius of the outermost circle defining the 100% gradient stop. -
focusRadius
private final float focusRadiusRadius of the innermost circle defining the circular area of the 0% gradient stop.
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Constructor Details
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SVGRadialGradientPaint
public SVGRadialGradientPaint(@NotNull @NotNull Point2D center, float radius, @NotNull @NotNull Point2D focus, float focusRadius, float[] fractions, Color[] colors, MultipleGradientPaint.CycleMethod cycleMethod, MultipleGradientPaint.ColorSpaceType colorSpace, @NotNull @NotNull AffineTransform gradientTransform) Constructs aRadialGradientPaint
.- Parameters:
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 mappedfocusRadius
- the radius around the focus defining the circle in 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
- eitherNO_CYCLE
,REFLECT
, orREPEAT
colorSpace
- which color space to use for interpolation, eitherSRGB
orLINEAR_RGB
gradientTransform
- transform to apply to the gradient- Throws:
NullPointerException
- if one of the points is null, orfractions
array is null, orcolors
array is null, orcycleMethod
is null, orcolorSpace
is null, orgradientTransform
is nullIllegalArgumentException
- ifradius
is non-positive, orfractions.length != colors.length
, orcolors
is less than 2 in size, or afractions
value is less than 0.0 or greater than 1.0, or thefractions
are not provided in strictly increasing order
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Method Details
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createContext
public PaintContext createContext(ColorModel cm, Rectangle deviceBounds, Rectangle2D userBounds, AffineTransform transform, RenderingHints hints)
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