- All Implemented Interfaces:
Painter<JComponent>
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Nested Class Summary
Modifier and TypeClassDescriptionprotected static class
A class encapsulating state useful when painting. -
Constructor Summary
ModifierConstructorDescriptionprotected
Create a new AbstractRegionPainter -
Method Summary
Modifier and TypeMethodDescriptionprotected void
Configures the given Graphics2D.protected final float
decodeAnchorX
(float x, float dx) Decodes and returns a float value representing the actual pixel location for the anchor point given the encoded X value of the control point, and the offset distance to the anchor from that control point.protected final float
decodeAnchorY
(float y, float dy) Decodes and returns a float value representing the actual pixel location for the anchor point given the encoded Y value of the control point, and the offset distance to the anchor from that control point.protected final Color
decodeColor
(Color color1, Color color2, float midPoint) Decodes and returns a color, which is derived from a offset between two other colors.protected final Color
decodeColor
(String key, float hOffset, float sOffset, float bOffset, int aOffset) Decodes and returns a color, which is derived from a base color in UI defaults.protected final LinearGradientPaint
decodeGradient
(float x1, float y1, float x2, float y2, float[] midpoints, Color[] colors) Given parameters for creating a LinearGradientPaint, this method will create and return a linear gradient paint.protected final RadialGradientPaint
decodeRadialGradient
(float x, float y, float r, float[] midpoints, Color[] colors) Given parameters for creating a RadialGradientPaint, this method will create and return a radial gradient paint.protected final float
decodeX
(float x) Decodes and returns a float value representing the actual pixel location for the given encoded X value.protected final float
decodeY
(float y) Decodes and returns a float value representing the actual pixel location for the given encoded y value.protected abstract void
doPaint
(Graphics2D g, JComponent c, int width, int height, Object[] extendedCacheKeys) Actually performs the painting operation.protected final Color
getComponentColor
(JComponent c, String property, Color defaultColor, float saturationOffset, float brightnessOffset, int alphaOffset) Get a color property from the given JComponent.protected Object[]
Get any extra attributes which the painter implementation would like to include in the image cache lookups.protected abstract AbstractRegionPainter.PaintContext
Gets the PaintContext for this painting operation.final void
paint
(Graphics2D g, JComponent c, int w, int h) Renders to the givenGraphics2D
object.
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Constructor Details
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AbstractRegionPainter
protected AbstractRegionPainter()Create a new AbstractRegionPainter
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Method Details
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paint
Renders to the given
Graphics2D
object. Implementations of this method may modify state on theGraphics2D
, and are not required to restore that state upon completion. In most cases, it is recommended that the caller pass in a scratch graphics object. TheGraphics2D
must never be null.State on the graphics object may be honored by the
paint
method, but may not be. For instance, setting the antialiasing rendering hint on the graphics may or may not be respected by thePainter
implementation.The supplied object parameter acts as an optional configuration argument. For example, it could be of type
Component
. APainter
that expected it could then read state from thatComponent
and use the state for painting. For example, an implementation may read the backgroundColor and use that.Generally, to enhance reusability, most standard
Painter
s ignore this parameter. They can thus be reused in any context. Theobject
may be null. Implementations must not throw a NullPointerException if the object parameter is null.Finally, the
width
andheight
arguments specify the width and height that thePainter
should paint into. More specifically, the specified width and height instruct the painter that it should paint fully within this width and height. Any specified clip on theg
param will further constrain the region.For example, suppose I have a
Painter
implementation that draws a gradient. The gradient goes from white to black. It "stretches" to fill the painted region. Thus, if I use thisPainter
to paint a 500 x 500 region, the far left would be black, the far right would be white, and a smooth gradient would be painted between. I could then, without modification, reuse thePainter
to paint a region that is 20x20 in size. This region would also be black on the left, white on the right, and a smooth gradient painted between.- Specified by:
paint
in interfacePainter<JComponent>
- Parameters:
g
- The Graphics2D to render to. This must not be null.c
- an optional configuration parameter. This may be null.w
- width of the area to paint.h
- height of the area to paint.
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getExtendedCacheKeys
Get any extra attributes which the painter implementation would like to include in the image cache lookups. This is checked for every call of the paint(g, c, w, h) method.- Parameters:
c
- The component on the current paint call- Returns:
- Array of extra objects to be included in the cache key
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getPaintContext
Gets the PaintContext for this painting operation. This method is called on every paint, and so should be fast and produce no garbage. The PaintContext contains information such as cache hints. It also contains data necessary for decoding points at runtime, such as the stretching insets, the canvas size at which the encoded points were defined, and whether the stretching insets are inverted.
This method allows for subclasses to package the painting of different states with possibly different canvas sizes, etc, into one AbstractRegionPainter implementation.
- Returns:
- a PaintContext associated with this paint operation.
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configureGraphics
Configures the given Graphics2D. Often, rendering hints or compositing rules are applied to a Graphics2D object prior to painting, which should affect all of the subsequent painting operations. This method provides a convenient hook for configuring the Graphics object prior to rendering, regardless of whether the render operation is performed to an intermediate buffer or directly to the display.
- Parameters:
g
- The Graphics2D object to configure. Will not be null.
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doPaint
protected abstract void doPaint(Graphics2D g, JComponent c, int width, int height, Object[] extendedCacheKeys) Actually performs the painting operation. Subclasses must implement this method. The graphics object passed may represent the actual surface being rendered to, or it may be an intermediate buffer. It has also been pre-translated. Simply render the component as if it were located at 0, 0 and had a width ofwidth
and a height ofheight
. For performance reasons, you may want to read the clip from the Graphics2D object and only render within that space.- Parameters:
g
- The Graphics2D surface to paint toc
- The JComponent related to the drawing event. For example, if the region being rendered is Button, thenc
will be a JButton. If the region being drawn is ScrollBarSlider, then the component will be JScrollBar. This value may be null.width
- The width of the region to paint. Note that in the case of painting the foreground, this value may differ from c.getWidth().height
- The height of the region to paint. Note that in the case of painting the foreground, this value may differ from c.getHeight().extendedCacheKeys
- The result of the call to getExtendedCacheKeys()
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decodeX
protected final float decodeX(float x) Decodes and returns a float value representing the actual pixel location for the given encoded X value.- Parameters:
x
- an encoded x value (0...1, or 1...2, or 2...3)- Returns:
- the decoded x value
- Throws:
IllegalArgumentException
- ifx < 0
orx > 3
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decodeY
protected final float decodeY(float y) Decodes and returns a float value representing the actual pixel location for the given encoded y value.- Parameters:
y
- an encoded y value (0...1, or 1...2, or 2...3)- Returns:
- the decoded y value
- Throws:
IllegalArgumentException
- ify < 0
ory > 3
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decodeAnchorX
protected final float decodeAnchorX(float x, float dx) Decodes and returns a float value representing the actual pixel location for the anchor point given the encoded X value of the control point, and the offset distance to the anchor from that control point.- Parameters:
x
- an encoded x value of the bezier control point (0...1, or 1...2, or 2...3)dx
- the offset distance to the anchor from the control point x- Returns:
- the decoded x location of the control point
- Throws:
IllegalArgumentException
- ifx < 0
orx > 3
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decodeAnchorY
protected final float decodeAnchorY(float y, float dy) Decodes and returns a float value representing the actual pixel location for the anchor point given the encoded Y value of the control point, and the offset distance to the anchor from that control point.- Parameters:
y
- an encoded y value of the bezier control point (0...1, or 1...2, or 2...3)dy
- the offset distance to the anchor from the control point y- Returns:
- the decoded y position of the control point
- Throws:
IllegalArgumentException
- ify < 0
ory > 3
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decodeColor
protected final Color decodeColor(String key, float hOffset, float sOffset, float bOffset, int aOffset) Decodes and returns a color, which is derived from a base color in UI defaults.- Parameters:
key
- A key corresponding to the value in the UI Defaults table of UIManager where the base color is definedhOffset
- The hue offset used for derivation.sOffset
- The saturation offset used for derivation.bOffset
- The brightness offset used for derivation.aOffset
- The alpha offset used for derivation. Between 0...255- Returns:
- The derived color, whose color value will change if the parent uiDefault color changes.
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decodeColor
Decodes and returns a color, which is derived from a offset between two other colors.- Parameters:
color1
- The first colorcolor2
- The second colormidPoint
- The offset between color 1 and color 2, a value of 0.0 is color 1 and 1.0 is color 2;- Returns:
- The derived color
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decodeGradient
protected final LinearGradientPaint decodeGradient(float x1, float y1, float x2, float y2, float[] midpoints, Color[] colors) Given parameters for creating a LinearGradientPaint, this method will create and return a linear gradient paint. One primary purpose for this method is to avoid creating a LinearGradientPaint where the start and end points are equal. In such a case, the end y point is slightly increased to avoid the overlap.- Parameters:
x1
- x1y1
- y1x2
- x2y2
- y2midpoints
- the midpointscolors
- the colors- Returns:
- a valid LinearGradientPaint. This method never returns null.
- Throws:
NullPointerException
- ifmidpoints
array is null, orcolors
array is null,IllegalArgumentException
- if start and end points are the same points, ormidpoints.length != colors.length
, orcolors
is less than 2 in size, or amidpoints
value is less than 0.0 or greater than 1.0, or themidpoints
are not provided in strictly increasing order
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decodeRadialGradient
protected final RadialGradientPaint decodeRadialGradient(float x, float y, float r, float[] midpoints, Color[] colors) Given parameters for creating a RadialGradientPaint, this method will create and return a radial gradient paint. One primary purpose for this method is to avoid creating a RadialGradientPaint where the radius is non-positive. In such a case, the radius is just slightly increased to avoid 0.- Parameters:
x
- x-coordinatey
- y-coordinater
- radiusmidpoints
- the midpointscolors
- the colors- Returns:
- a valid RadialGradientPaint. This method never returns null.
- Throws:
NullPointerException
- ifmidpoints
array is null, orcolors
array is nullIllegalArgumentException
- ifr
is non-positive, ormidpoints.length != colors.length
, orcolors
is less than 2 in size, or amidpoints
value is less than 0.0 or greater than 1.0, or themidpoints
are not provided in strictly increasing order
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getComponentColor
protected final Color getComponentColor(JComponent c, String property, Color defaultColor, float saturationOffset, float brightnessOffset, int alphaOffset) Get a color property from the given JComponent. First checks for agetXXX()
method and if that fails checks for a client property with keyproperty
. If that still fails to return a Color thendefaultColor
is returned.- Parameters:
c
- The component to get the color property fromproperty
- The name of a bean style property or client propertydefaultColor
- The color to return if no color was obtained from the component.saturationOffset
- additively modifies the HSB saturation component of the color returned (ignored if default color is returned).brightnessOffset
- additively modifies the HSB brightness component of the color returned (ignored if default color is returned).alphaOffset
- additively modifies the ARGB alpha component of the color returned (ignored if default color is returned).- Returns:
- The color that was obtained from the component or defaultColor
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