Graphics2D
class extends the
Graphics
class to provide more sophisticated
control over geometry, coordinate transformations, color management,
and text layout. This is the fundamental class for rendering
2-dimensional shapes, text and images on the Java(tm) platform.
Graphics2D
object are specified
in a device-independent coordinate system called User Space, which is
used by applications. The Graphics2D
object contains
an AffineTransform
object as part of its rendering state
that defines how to convert coordinates from user space to
device-dependent coordinates in Device Space.
Coordinates in device space usually refer to individual device pixels
and are aligned on the infinitely thin gaps between these pixels.
Some Graphics2D
objects can be used to capture rendering
operations for storage into a graphics metafile for playback on a
concrete device of unknown physical resolution at a later time. Since
the resolution might not be known when the rendering operations are
captured, the Graphics2D
Transform
is set up
to transform user coordinates to a virtual device space that
approximates the expected resolution of the target device. Further
transformations might need to be applied at playback time if the
estimate is incorrect.
Some of the operations performed by the rendering attribute objects
occur in the device space, but all Graphics2D
methods take
user space coordinates.
Every Graphics2D
object is associated with a target that
defines where rendering takes place. A
GraphicsConfiguration
object defines the characteristics
of the rendering target, such as pixel format and resolution.
The same rendering target is used throughout the life of a
Graphics2D
object.
When creating a Graphics2D
object, the
GraphicsConfiguration
specifies the default transform for
the target of the Graphics2D
(a
Component
or Image
). This default transform maps the
user space coordinate system to screen and printer device coordinates
such that the origin maps to the upper left hand corner of the
target region of the device with increasing X coordinates extending
to the right and increasing Y coordinates extending downward.
The scaling of the default transform is set to identity for those devices
that are close to 72 dpi, such as screen devices.
The scaling of the default transform is set to approximately 72 user
space coordinates per square inch for high resolution devices, such as
printers. For image buffers, the default transform is the
Identity
transform.
Graphics2D
rendering attributes.
The renderer can optimize many of these steps, either by caching the
results for future calls, by collapsing multiple virtual steps into
a single operation, or by recognizing various attributes as common
simple cases that can be eliminated by modifying other parts of the
operation.
The steps in the rendering process are:
Clip
.
The Clip
is specified by a Shape
in user
space and is controlled by the program using the various clip
manipulation methods of Graphics
and
Graphics2D
. This user clip
is transformed into device space by the current
Transform
and combined with the
device clip, which is defined by the visibility of windows and
device extents. The combination of the user clip and device clip
defines the composite clip, which determines the final clipping
region. The user clip is not modified by the rendering
system to reflect the resulting composite clip.
Graphics2D
context.
Shape
operations
draw(Shape)
operation, then
the createStrokedShape
method on the current Stroke
attribute in the
Graphics2D
context is used to construct a new
Shape
object that contains the outline of the specified
Shape
.
Shape
is transformed from user space to device space
using the current Transform
in the Graphics2D
context.
Shape
is extracted using the
getPathIterator
method of
Shape
, which returns a
PathIterator
object that iterates along the boundary of the Shape
.
Graphics2D
object cannot handle the curved segments
that the PathIterator
object returns then it can call the
alternate
getPathIterator
method of Shape
, which flattens the Shape
.
Graphics2D
context
is queried for a PaintContext
, which specifies the
colors to render in device space.
String
:
String
, then the current
Font
in the Graphics2D
context is asked to
convert the Unicode characters in the String
into a set of
glyphs for presentation with whatever basic layout and shaping
algorithms the font implements.
TextLayout
implements more sophisticated glyph layout algorithms that
perform Unicode bi-directional layout adjustments automatically
for multiple fonts of differing writing directions.
GlyphVector
object already contains the appropriate
font-specific glyph codes with explicit coordinates for the position of
each glyph.
Font
is queried to obtain outlines for the
indicated glyphs. These outlines are treated as shapes in user space
relative to the position of each glyph that was determined in step 1.
Shape
operations.
Paint
is queried for a
PaintContext
, which specifies
the colors to render in device space.
Image
Operations
Image
.
This bounding box is specified in Image Space, which is the
Image
object's local coordinate system.
AffineTransform
is passed to
drawImage(Image, AffineTransform, ImageObserver)
,
the AffineTransform
is used to transform the bounding
box from image space to user space. If no AffineTransform
is supplied, the bounding box is treated as if it is already in user space.
Image
is transformed from user
space into device space using the current Transform
.
Note that the result of transforming the bounding box does not
necessarily result in a rectangular region in device space.
Image
object determines what colors to render,
sampled according to the source to destination
coordinate mapping specified by the current Transform
and the
optional image transform.
Graphics2D
rendering attributes are:
Paint
Component
.
Font
Font
of the Component
.
Stroke
Transform
GraphicsConfiguration
of the Component
.
Composite
Clip
Clip
, the output is clipped to the
Component
.
The Java 2D(tm) (Java(tm) 2 platform) API supports antialiasing renderers. A pen with a width of one pixel does not need to fall completely on pixel N as opposed to pixel N+1. The pen can fall partially on both pixels. It is not necessary to choose a bias direction for a wide pen since the blending that occurs along the pen traversal edges makes the sub-pixel position of the pen visible to the user. On the other hand, when antialiasing is turned off by setting the KEY_ANTIALIASING hint key to the VALUE_ANTIALIAS_OFF hint value, the renderer might need to apply a bias to determine which pixel to modify when the pen is straddling a pixel boundary, such as when it is drawn along an integer coordinate in device space. While the capabilities of an antialiasing renderer make it no longer necessary for the rendering model to specify a bias for the pen, it is desirable for the antialiasing and non-antialiasing renderers to perform similarly for the common cases of drawing one-pixel wide horizontal and vertical lines on the screen. To ensure that turning on antialiasing by setting the KEY_ANTIALIASING hint key to VALUE_ANTIALIAS_ON does not cause such lines to suddenly become twice as wide and half as opaque, it is desirable to have the model specify a path for such lines so that they completely cover a particular set of pixels to help increase their crispness.
Java 2D API maintains compatibility with JDK 1.1 rendering
behavior, such that legacy operations and existing renderer
behavior is unchanged under Java 2D API. Legacy
methods that map onto general draw
and
fill
methods are defined, which clearly indicates
how Graphics2D
extends Graphics
based
on settings of Stroke
and Transform
attributes and rendering hints. The definition
performs identically under default attribute settings.
For example, the default Stroke
is a
BasicStroke
with a width of 1 and no dashing and the
default Transform for screen drawing is an Identity transform.
The following two rules provide predictable rendering behavior whether aliasing or antialiasing is being used.
BasicStroke
object may be "normalized" to provide consistent rendering of the
outlines when positioned at various points on the drawable and
whether drawn with aliased or antialiased rendering. This
normalization process is controlled by the
KEY_STROKE_CONTROL
hint.
The exact normalization algorithm is not specified, but the goals
of this normalization are to ensure that lines are rendered with
consistent visual appearance regardless of how they fall on the
pixel grid and to promote more solid horizontal and vertical
lines in antialiased mode so that they resemble their non-antialiased
counterparts more closely. A typical normalization step might
promote antialiased line endpoints to pixel centers to reduce the
amount of blending or adjust the subpixel positioning of
non-antialiased lines so that the floating point line widths
round to even or odd pixel counts with equal likelihood. This
process can move endpoints by up to half a pixel (usually towards
positive infinity along both axes) to promote these consistent
results.
The following definitions of general legacy methods perform identically to previously specified behavior under default attribute settings:
fill
operations, including fillRect
,
fillRoundRect
, fillOval
,
fillArc
, fillPolygon
, and
clearRect
, #fill(Shape) fill
can now be called
with the desired Shape
. For example, when filling a
rectangle:
fill(new Rectangle(x, y, w, h));is called.
drawLine
,
drawRect
, drawRoundRect
,
drawOval
, drawArc
, drawPolyline
,
and drawPolygon
, #draw(Shape) draw
can now be
called with the desired Shape
. For example, when drawing a
rectangle:
draw(new Rectangle(x, y, w, h));is called.
draw3DRect
and fill3DRect
methods were
implemented in terms of the drawLine
and
fillRect
methods in the Graphics
class which
would predicate their behavior upon the current Stroke
and Paint
objects in a Graphics2D
context.
This class overrides those implementations with versions that use
the current Color
exclusively, overriding the current
Paint
and which uses fillRect
to describe
the exact same behavior as the preexisting methods regardless of the
setting of the current Stroke
.
Graphics
class defines only the setColor
method to control the color to be painted. Since the Java 2D API extends
the Color
object to implement the new Paint
interface, the existing
setColor
method is now a convenience method for setting the
current Paint
attribute to a Color
object.
setColor(c)
is equivalent to setPaint(c)
.
The Graphics
class defines two methods for controlling
how colors are applied to the destination.
setPaintMode
method is implemented as a convenience
method to set the default Composite
, equivalent to
setComposite(new AlphaComposite.SrcOver)
.
setXORMode(Color xorcolor)
method is implemented
as a convenience method to set a special Composite
object that
ignores the Alpha
components of source colors and sets the
destination color to the value:
dstpixel = (PixelOf(srccolor) ^ PixelOf(xorcolor) ^ dstpixel);
Map
object are modified.
All other preferences not present in the specified
object are left unmodified.
Hint categories include controls for rendering quality and
overall time/quality trade-off in the rendering process.
Refer to the RenderingHints
class for definitions of
some common keys and values.
Beginning with Java 1.1, the background color
of offscreen images may be system dependent. Applications should
use setColor
followed by fillRect
to
ensure that an offscreen image is cleared to a specific color.
Clip
with the interior of the
specified Shape
and sets the Clip
to the
resulting intersection. The specified Shape
is
transformed with the current Graphics2D
Transform
before being intersected with the current
Clip
. This method is used to make the current
Clip
smaller.
To make the Clip
larger, use setClip
.
The user clip modified by this method is independent of the
clipping associated with device bounds and visibility. If no clip has
previously been set, or if the clip has been cleared using
setClip
with a null
argument, the specified Shape
becomes the new
user clip.setClip(null)
,
the specified rectangle becomes the new clip.
This method sets the user clip, which is independent of the
clipping associated with device bounds and window visibility.
This method can only be used to make the current clip smaller.
To set the current clip larger, use any of the setClip methods.
Rendering operations have no effect outside of the clipping area.dx
and dy
. From the point specified
by x
and y
, this method
copies downwards and to the right. To copy an area of the
component to the left or upwards, specify a negative value for
dx
or dy
.
If a portion of the source rectangle lies outside the bounds
of the component, or is obscured by another window or component,
copyArea
will be unable to copy the associated
pixels. The area that is omitted can be refreshed by calling
the component's paint
method.Graphics
object that is
a copy of this Graphics
object.Graphics
object based on this
Graphics
object, but with a new translation and clip area.
The new Graphics
object has its origin
translated to the specified point (x, y).
Its clip area is determined by the intersection of the original
clip area with the specified rectangle. The arguments are all
interpreted in the coordinate system of the original
Graphics
object. The new graphics context is
identical to the original, except in two respects:
0
, 0
) in the
new graphics context is the same as (x, y) in
the original graphics context.
0
, 0
), and its size
is specified by the width
and height
arguments.
Graphics
object cannot be used after
dispose
has been called.
When a Java program runs, a large number of Graphics
objects can be created within a short time frame.
Although the finalization process of the garbage collector
also disposes of the same system resources, it is preferable
to manually free the associated resources by calling this
method rather than to rely on a finalization process which
may not run to completion for a long period of time.
Graphics objects which are provided as arguments to the
paint
and update
methods
of components are automatically released by the system when
those methods return. For efficiency, programmers should
call dispose
when finished using
a Graphics
object only if it was created
directly from a component or another Graphics
object.
Shape
using the settings of the
current Graphics2D
context. The rendering attributes
applied include the Clip
, Transform
,
Paint
, Composite
and
Stroke
attributes.
The colors used for the highlighting effect are determined
based on the current color.
The resulting rectangle covers an area that is
width + 1
pixels wide
by height + 1
pixels tall. This method
uses the current Color
exclusively and ignores
the current Paint
.
The resulting arc begins at startAngle
and extends
for arcAngle
degrees, using the current color.
Angles are interpreted such that 0 degrees
is at the 3 o'clock position.
A positive value indicates a counter-clockwise rotation
while a negative value indicates a clockwise rotation.
The center of the arc is the center of the rectangle whose origin
is (x, y) and whose size is specified by the
width
and height
arguments.
The resulting arc covers an area
width + 1
pixels wide
by height + 1
pixels tall.
The angles are specified relative to the non-square extents of the bounding rectangle such that 45 degrees always falls on the line from the center of the ellipse to the upper right corner of the bounding rectangle. As a result, if the bounding rectangle is noticeably longer in one axis than the other, the angles to the start and end of the arc segment will be skewed farther along the longer axis of the bounds.
Graphics2D
context's rendering attributes.
The rendering attributes applied include the Clip
,
Transform
, Paint
, and
Composite
attributes. The GlyphVector
specifies individual glyphs from a Font
.
The GlyphVector
can also contain the glyph positions.
This is the fastest way to render a set of characters to the
screen.BufferedImage
that is
filtered with a
BufferedImageOp
.
The rendering attributes applied include the Clip
,
Transform
and Composite
attributes. This is equivalent to:
img1 = op.filter(img, null); drawImage(img1, new AffineTransform(1f,0f,0f,1f,x,y), null);
Transform
in the Graphics2D
.
The specified transformation is applied to the image before the
transform attribute in the Graphics2D
context is applied.
The rendering attributes applied include the Clip
,
Transform
, and Composite
attributes.
Note that no rendering is done if the specified transform is
noninvertible.This operation is equivalent to filling a rectangle of the width and height of the specified image with the given color and then drawing the image on top of it, but possibly more efficient.
This method returns immediately in all cases, even if the complete image has not yet been loaded, and it has not been dithered and converted for the current output device.
If the image has completely loaded and its pixels are
no longer being changed, then
drawImage
returns true
.
Otherwise, drawImage
returns false
and as more of
the image becomes available
or it is time to draw another frame of animation,
the process that loads the image notifies
the specified image observer.
This method returns immediately in all cases, even if the complete image has not yet been loaded, and it has not been dithered and converted for the current output device.
If the image has completely loaded and its pixels are
no longer being changed, then
drawImage
returns true
.
Otherwise, drawImage
returns false
and as more of
the image becomes available
or it is time to draw another frame of animation,
the process that loads the image notifies
the specified image observer.
The image is drawn inside the specified rectangle of this graphics context's coordinate space, and is scaled if necessary. Transparent pixels are drawn in the specified background color. This operation is equivalent to filling a rectangle of the width and height of the specified image with the given color and then drawing the image on top of it, but possibly more efficient.
This method returns immediately in all cases, even if the
entire image has not yet been scaled, dithered, and converted
for the current output device.
If the current output representation is not yet complete then
drawImage
returns false
. As more of
the image becomes available, the process that loads the image notifies
the specified image observer.
A scaled version of an image will not necessarily be available immediately just because an unscaled version of the image has been constructed for this output device. Each size of the image may be cached separately and generated from the original data in a separate image production sequence.
The image is drawn inside the specified rectangle of this graphics context's coordinate space, and is scaled if necessary. Transparent pixels do not affect whatever pixels are already there.
This method returns immediately in all cases, even if the
entire image has not yet been scaled, dithered, and converted
for the current output device.
If the current output representation is not yet complete, then
drawImage
returns false
. As more of
the image becomes available, the process that loads the image notifies
the image observer by calling its imageUpdate
method.
A scaled version of an image will not necessarily be available immediately just because an unscaled version of the image has been constructed for this output device. Each size of the image may be cached separately and generated from the original data in a separate image production sequence.
Transparent pixels are drawn in the specified background color. This operation is equivalent to filling a rectangle of the width and height of the specified image with the given color and then drawing the image on top of it, but possibly more efficient.
This method returns immediately in all cases, even if the
image area to be drawn has not yet been scaled, dithered, and converted
for the current output device.
If the current output representation is not yet complete then
drawImage
returns false
. As more of
the image becomes available, the process that loads the image notifies
the specified image observer.
This method always uses the unscaled version of the image to render the scaled rectangle and performs the required scaling on the fly. It does not use a cached, scaled version of the image for this operation. Scaling of the image from source to destination is performed such that the first coordinate of the source rectangle is mapped to the first coordinate of the destination rectangle, and the second source coordinate is mapped to the second destination coordinate. The subimage is scaled and flipped as needed to preserve those mappings.
This method returns immediately in all cases, even if the
image area to be drawn has not yet been scaled, dithered, and converted
for the current output device.
If the current output representation is not yet complete then
drawImage
returns false
. As more of
the image becomes available, the process that loads the image notifies
the specified image observer.
This method always uses the unscaled version of the image to render the scaled rectangle and performs the required scaling on the fly. It does not use a cached, scaled version of the image for this operation. Scaling of the image from source to destination is performed such that the first coordinate of the source rectangle is mapped to the first coordinate of the destination rectangle, and the second source coordinate is mapped to the second destination coordinate. The subimage is scaled and flipped as needed to preserve those mappings.
(x1, y1)
and (x2, y2)
in this graphics context's coordinate system.x
, y
,
width
, and height
arguments.
The oval covers an area that is
width + 1
pixels wide
and height + 1
pixels tall.
This method draws the polygon defined by nPoint
line
segments, where the first nPoint - 1
line segments are line segments from
(xPoints[i - 1], yPoints[i - 1])
to (xPoints[i], yPoints[i])
, for
1 ≤ i ≤ nPoints
.
The figure is automatically closed by drawing a line connecting
the final point to the first point, if those points are different.
Polygon
object.x
and x + width
.
The top and bottom edges are at
y
and y + height
.
The rectangle is drawn using the graphics context's current color.Transform
in the Graphics2D
.
The specified transformation is applied to the image before the
transform attribute in the Graphics2D
context is applied.
The rendering attributes applied include the Clip
,
Transform
, and Composite
attributes. Note
that no rendering is done if the specified transform is
noninvertible.
Rendering hints set on the Graphics2D
object might
be used in rendering the RenderableImage
.
If explicit control is required over specific hints recognized by a
specific RenderableImage
, or if knowledge of which hints
are used is required, then a RenderedImage
should be
obtained directly from the RenderableImage
and rendered using
drawRenderedImage
.
Transform
in the Graphics2D
.
The specified transformation is applied to the image before the
transform attribute in the Graphics2D
context is applied.
The rendering attributes applied include the Clip
,
Transform
, and Composite
attributes. Note
that no rendering is done if the specified transform is
noninvertible.x
and x + width
,
respectively. The top and bottom edges of the rectangle are at
y
and y + height
.Graphics2D
context's current Paint
. The
iterator must specify a font
for each character. The baseline of the
first character is at position (x, y) in the
User Space.
The rendering attributes applied include the Clip
,
Transform
, Paint
, and
Composite
attributes.
For characters in script systems such as Hebrew and Arabic,
the glyphs can be rendered from right to left, in which case the
coordinate supplied is the location of the leftmost character
on the baseline.Graphics2D
context's current Paint
. The
iterator has to specify a font
for each character. The baseline of the
first character is at position (x, y) in the
User Space.
The rendering attributes applied include the Clip
,
Transform
, Paint
, and
Composite
attributes.
For characters in script systems such as Hebrew and Arabic,
the glyphs can be rendered from right to left, in which case the
coordinate supplied is the location of the leftmost character
on the baseline.String
,
using the current text attribute state in the Graphics2D
context.
The baseline of the first character is at position
(x, y) in the User Space.
The rendering attributes applied include the Clip
,
Transform
, Paint
, Font
and
Composite
attributes. For characters in script systems
such as Hebrew and Arabic, the glyphs can be rendered from right to
left, in which case the coordinate supplied is the location of the
leftmost character on the baseline.String
, using the
current text attribute state in the Graphics2D
context.
The baseline of the
first character is at position (x, y) in
the User Space.
The rendering attributes applied include the Clip
,
Transform
, Paint
, Font
and
Composite
attributes. For characters in script
systems such as Hebrew and Arabic, the glyphs can be rendered from
right to left, in which case the coordinate supplied is the
location of the leftmost character on the baseline.
The equals
method implements an equivalence relation
on non-null object references:
x
, x.equals(x)
should return
true
.
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
x
and y
, multiple invocations of
x.equals(y) consistently return true
or consistently return false
, provided no
information used in equals
comparisons on the
objects is modified.
x
,
x.equals(null)
should return false
.
The equals method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.
Shape
using the settings of the
Graphics2D
context. The rendering attributes applied
include the Clip
, Transform
,
Paint
, and Composite
.Color
. This method uses
the current Color
exclusively and ignores the current
Paint
.
The resulting arc begins at startAngle
and extends
for arcAngle
degrees.
Angles are interpreted such that 0 degrees
is at the 3 o'clock position.
A positive value indicates a counter-clockwise rotation
while a negative value indicates a clockwise rotation.
The center of the arc is the center of the rectangle whose origin
is (x, y) and whose size is specified by the
width
and height
arguments.
The resulting arc covers an area
width + 1
pixels wide
by height + 1
pixels tall.
The angles are specified relative to the non-square extents of the bounding rectangle such that 45 degrees always falls on the line from the center of the ellipse to the upper right corner of the bounding rectangle. As a result, if the bounding rectangle is noticeably longer in one axis than the other, the angles to the start and end of the arc segment will be skewed farther along the longer axis of the bounds.
This method draws the polygon defined by nPoint
line
segments, where the first nPoint - 1
line segments are line segments from
(xPoints[i - 1], yPoints[i - 1])
to (xPoints[i], yPoints[i])
, for
1 ≤ i ≤ nPoints
.
The figure is automatically closed by drawing a line connecting
the final point to the first point, if those points are different.
The area inside the polygon is defined using an even-odd fill rule, also known as the alternating rule.
The area inside the polygon is defined using an even-odd fill rule, also known as the alternating rule.
x
and x + width - 1
.
The top and bottom edges are at
y
and y + height - 1
.
The resulting rectangle covers an area
width
pixels wide by
height
pixels tall.
The rectangle is filled using the graphics context's current color.x
and x + width - 1
,
respectively. The top and bottom edges of the rectangle are at
y
and y + height - 1
.setClip(null)
, this method returns
null
.setClip(null)
, this method returns
null
.
The coordinates in the rectangle are relative to the coordinate
system origin of this graphics context.setClip(null)
, this method returns the
specified Rectangle
.Composite
in the
Graphics2D
context.Graphics2D
.Font
within this
Graphics2D
context.
The FontRenderContext
encapsulates application hints such as anti-aliasing and
fractional metrics, as well as target device specific information
such as dots-per-inch. This information should be provided by the
application when using objects that perform typographical
formatting, such as Font
and
TextLayout
. This information should also be provided
by applications that perform their own layout and need accurate
measurements of various characteristics of glyphs such as advance
and line height when various rendering hints have been applied to
the text rendering.Paint
of the
Graphics2D
context.RenderingHints
class for definitions of some common
keys and values.RenderingHints
class for definitions of some common
keys and values.Stroke
in the
Graphics2D
context.Transform
in the
Graphics2D
context.java.util.Hashtable
.
The general contract of hashCode
is:
hashCode
method on each of
the two objects must produce the same integer result.
As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)
Shape
intersects
the specified Rectangle
, which is in device
space. If onStroke
is false, this method checks
whether or not the interior of the specified Shape
intersects the specified Rectangle
. If
onStroke
is true
, this method checks
whether or not the Stroke
of the specified
Shape
outline intersects the specified
Rectangle
.
The rendering attributes taken into account include the
Clip
, Transform
, and Stroke
attributes.wait
methods.
The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. The awakened thread will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object.
This method should only be called by a thread that is the owner of this object's monitor. A thread becomes the owner of the object's monitor in one of three ways:
synchronized
statement
that synchronizes on the object.
Class,
by executing a
synchronized static method of that class.
Only one thread at a time can own an object's monitor.
wait
methods.
The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object. The awakened threads will compete in the usual manner with any other threads that might be actively competing to synchronize on this object; for example, the awakened threads enjoy no reliable privilege or disadvantage in being the next thread to lock this object.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify
method for a
description of the ways in which a thread can become the owner of
a monitor.
Graphics2D
Transform
with a rotation transform.
Subsequent rendering is rotated by the specified radians relative
to the previous origin.
This is equivalent to calling transform(R)
, where R is an
AffineTransform
represented by the following matrix:
[ cos(theta) -sin(theta) 0 ] [ sin(theta) cos(theta) 0 ] [ 0 0 1 ]Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.
Graphics2D
Transform
with a translated rotation
transform. Subsequent rendering is transformed by a transform
which is constructed by translating to the specified location,
rotating by the specified radians, and translating back by the same
amount as the original translation. This is equivalent to the
following sequence of calls:
translate(x, y); rotate(theta); translate(-x, -y);Rotating with a positive angle theta rotates points on the positive x axis toward the positive y axis.
Graphics2D
Transform
with a scaling transformation
Subsequent rendering is resized according to the specified scaling
factors relative to the previous scaling.
This is equivalent to calling transform(S)
, where S is an
AffineTransform
represented by the following matrix:
[ sx 0 0 ] [ 0 sy 0 ] [ 0 0 1 ]
Graphics2D
context.
The background color is used for clearing a region.
When a Graphics2D
is constructed for a
Component
, the background color is
inherited from the Component
. Setting the background color
in the Graphics2D
context only affects the subsequent
clearRect
calls and not the background color of the
Component
. To change the background
of the Component
, use appropriate methods of
the Component
.Shape
interface can be used to set the clip. The only
Shape
objects that are guaranteed to be
supported are Shape
objects that are
obtained via the getClip
method and via
Rectangle
objects. This method sets the
user clip, which is independent of the clipping associated
with device bounds and window visibility.Composite
for the Graphics2D
context.
The Composite
is used in all drawing methods such as
drawImage
, drawString
, draw
,
and fill
. It specifies how new pixels are to be combined
with the existing pixels on the graphics device during the rendering
process.
If this Graphics2D
context is drawing to a
Component
on the display screen and the
Composite
is a custom object rather than an
instance of the AlphaComposite
class, and if
there is a security manager, its checkPermission
method is called with an AWTPermission("readDisplayPixels")
permission.
Paint
attribute for the
Graphics2D
context. Calling this method
with a null
Paint
object does
not have any effect on the current Paint
attribute
of this Graphics2D
.RenderingHints
class for definitions of some common
keys and values.hints
.
The existing values for all rendering hints are discarded and
the new set of known hints and values are initialized from the
specified Map
object.
Hint categories include controls for rendering quality and
overall time/quality trade-off in the rendering process.
Refer to the RenderingHints
class for definitions of
some common keys and values.Stroke
for the Graphics2D
context.Graphics2D
context.
WARNING: This method should never be used to apply a new
coordinate transform on top of an existing transform because the
Graphics2D
might already have a transform that is
needed for other purposes, such as rendering Swing
components or applying a scaling transformation to adjust for the
resolution of a printer.
To add a coordinate transform, use the
transform
, rotate
, scale
,
or shear
methods. The setTransform
method is intended only for restoring the original
Graphics2D
transform after rendering, as shown in this
example:
// Get the current transform AffineTransform saveAT = g2.getTransform(); // Perform transformation g2d.transform(...); // Render g2d.draw(...); // Restore original transform g2d.setTransform(saveAT);
When drawing operations are performed, pixels which are the current color are changed to the specified color, and vice versa.
Pixels that are of colors other than those two colors are changed in an unpredictable but reversible manner; if the same figure is drawn twice, then all pixels are restored to their original values.
Graphics2D
Transform
with a shearing transform.
Subsequent renderings are sheared by the specified
multiplier relative to the previous position.
This is equivalent to calling transform(SH)
, where SH
is an AffineTransform
represented by the following
matrix:
[ 1 shx 0 ] [ shy 1 0 ] [ 0 0 1 ]
String
object representing this
Graphics
object's value.AffineTransform
object with the
Transform
in this Graphics2D
according
to the rule last-specified-first-applied. If the current
Transform
is Cx, the result of composition
with Tx is a new Transform
Cx'. Cx' becomes the
current Transform
for this Graphics2D
.
Transforming a point p by the updated Transform
Cx' is
equivalent to first transforming p by Tx and then transforming
the result by the original Transform
Cx. In other
words, Cx'(p) = Cx(Tx(p)). A copy of the Tx is made, if necessary,
so further modifications to Tx do not affect rendering.Graphics2D
Transform
with a translation transform.
Subsequent rendering is translated by the specified
distance relative to the previous position.
This is equivalent to calling transform(T), where T is an
AffineTransform
represented by the following matrix:
[ 1 0 tx ] [ 0 1 ty ] [ 0 0 1 ]
Graphics2D
context to the
point (x, y) in the current coordinate system.
Modifies the Graphics2D
context so that its new origin
corresponds to the point (x, y) in the
Graphics2D
context's former coordinate system. All
coordinates used in subsequent rendering operations on this graphics
context are relative to this new origin.
The current thread must own this object's monitor. The thread
releases ownership of this monitor and waits until another thread
notifies threads waiting on this object's monitor to wake up
either through a call to the notify
method or the
notifyAll
method. The thread then waits until it can
re-obtain ownership of the monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:
synchronized (obj) { while (<condition does not hold>) obj.wait(); ... // Perform action appropriate to condition }This method should only be called by a thread that is the owner of this object's monitor. See the
notify
method for a
description of the ways in which a thread can become the owner of
a monitor.The current thread must own this object's monitor.
This method causes the current thread (call it T) to place itself in the wait set for this object and then to relinquish any and all synchronization claims on this object. Thread T becomes disabled for thread scheduling purposes and lies dormant until one of four things happens:
A thread can also wake up without being notified, interrupted, or timing out, a so-called spurious wakeup. While this will rarely occur in practice, applications must guard against it by testing for the condition that should have caused the thread to be awakened, and continuing to wait if the condition is not satisfied. In other words, waits should always occur in loops, like this one:
synchronized (obj) { while (<condition does not hold>) obj.wait(timeout); ... // Perform action appropriate to condition }(For more information on this topic, see Section 3.2.3 in Doug Lea's "Concurrent Programming in Java (Second Edition)" (Addison-Wesley, 2000), or Item 50 in Joshua Bloch's "Effective Java Programming Language Guide" (Addison-Wesley, 2001).
If the current thread is interrupted by another thread while it is waiting, then an InterruptedException is thrown. This exception is not thrown until the lock status of this object has been restored as described above.
Note that the wait method, as it places the current thread into the wait set for this object, unlocks only this object; any other objects on which the current thread may be synchronized remain locked while the thread waits.
This method should only be called by a thread that is the owner
of this object's monitor. See the notify
method for a
description of the ways in which a thread can become the owner of
a monitor.
This method is similar to the wait
method of one
argument, but it allows finer control over the amount of time to
wait for a notification before giving up. The amount of real time,
measured in nanoseconds, is given by:
1000000*timeout+nanos
In all other respects, this method does the same thing as the method of one argument. In particular, wait(0, 0) means the same thing as wait(0).
The current thread must own this object's monitor. The thread releases ownership of this monitor and waits until either of the following two conditions has occurred:
notify
method
or the notifyAll
method.
timeout
milliseconds plus nanos
nanoseconds arguments, has
elapsed.
The thread then waits until it can re-obtain ownership of the monitor and resumes execution.
As in the one argument version, interrupts and spurious wakeups are possible, and this method should always be used in a loop:
synchronized (obj) { while (<condition does not hold>) obj.wait(timeout, nanos); ... // Perform action appropriate to condition }This method should only be called by a thread that is the owner of this object's monitor. See the
notify
method for a
description of the ways in which a thread can become the owner of
a monitor.