Package org.apache.xmlgraphics.java2d
Class GraphicContext
java.lang.Object
org.apache.xmlgraphics.java2d.GraphicContext
- All Implemented Interfaces:
Cloneable
Handles the attributes in a graphic context:
+ Composite
+ Font
+ Paint
+ Stroke
+ Clip
+ RenderingHints
+ AffineTransform
+ Composite
+ Font
+ Paint
+ Stroke
+ Clip
+ RenderingHints
+ AffineTransform
- Version:
- $Id$ Originally authored by Vincent Hardy and Christophe Jolif.
-
Field Summary
FieldsModifier and TypeFieldDescriptionprotected Color
Current background color.protected Shape
Current clipprotected Composite
Current Compositeprotected AffineTransform
Default Transform to be used for creating FontRenderContext.protected Font
Current Fontprotected Color
Current foreground colorprotected RenderingHints
Current set of RenderingHintsprotected Paint
Current Paintprotected Stroke
Current Strokeprotected AffineTransform
Current AffineTransform.protected List
Transform stackprotected boolean
Defines whether the transform stack is valid or not. -
Constructor Summary
ConstructorsModifierConstructorDescriptionDefault constructorGraphicContext
(AffineTransform defaultDeviceTransform) protected
GraphicContext
(GraphicContext template) Copy constructor. -
Method Summary
Modifier and TypeMethodDescriptionvoid
addRenderingHints
(Map hints) Sets the values of an arbitrary number of preferences for the rendering algorithms.void
Intersects the currentClip
with the interior of the specifiedShape
and sets theClip
to the resulting intersection.void
clipRect
(int x, int y, int width, int height) Intersects the current clip with the specified rectangle.clone()
Returns the background color used for clearing a region.getClip()
Gets the current clipping area.Returns the bounding rectangle of the current clipping area.getColor()
Gets this graphics context's current color.Returns the currentComposite
in theGraphics2D
context.getFont()
Gets the current font.Get the rendering context of theFont
within thisGraphics2D
context.getPaint()
Returns the currentPaint
of theGraphics2D
context.getRenderingHint
(RenderingHints.Key hintKey) Returns the value of a single preference for the rendering algorithms.Gets the preferences for the rendering algorithms.Returns the currentStroke
in theGraphics2D
context.Returns a copy of the currentTransform
in theGraphics2D
context.protected void
Marks the GraphicContext's isNewTransformStack to true as a memento that the current transform stack was reset since it was last read.boolean
Checks the status of the transform stack.void
rotate
(double theta) Concatenates the currentGraphics2D
Transform
with a rotation transform.void
rotate
(double theta, double x, double y) Concatenates the currentGraphics2D
Transform
with a translated rotation transform.void
scale
(double sx, double sy) Concatenates the currentGraphics2D
Transform
with a scaling transformation Subsequent rendering is resized according to the specified scaling factors relative to the previous scaling.void
setBackground
(Color color) Sets the background color for theGraphics2D
context.void
setClip
(int x, int y, int width, int height) Sets the current clip to the rectangle specified by the given coordinates.void
Sets the current clipping area to an arbitrary clip shape.void
Sets this graphics context's current color to the specified color.void
setComposite
(Composite comp) Sets theComposite
for theGraphics2D
context.void
Sets this graphics context's font to the specified font.void
Sets thePaint
attribute for theGraphics2D
context.void
setRenderingHint
(RenderingHints.Key hintKey, Object hintValue) Sets the value of a single preference for the rendering algorithms.void
setRenderingHints
(Map hints) Replaces the values of all preferences for the rendering algorithms with the specifiedhints
.void
Sets theStroke
for theGraphics2D
context.void
Sets theTransform
in theGraphics2D
context.void
shear
(double shx, double shy) Concatenates the currentGraphics2D
Transform
with a shearing transform.void
Composes anAffineTransform
object with theTransform
in thisGraphics2D
according to the rule last-specified-first-applied.void
translate
(double tx, double ty) Concatenates the currentGraphics2D
Transform
with a translation transform.void
translate
(int x, int y) Translates the origin of the graphics context to the point (x, y) in the current coordinate system.void
Marks the GraphicContext's isNewTransformStack to false as a memento that the current transform stack was read and has not been reset.
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Field Details
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defaultTransform
Default Transform to be used for creating FontRenderContext. -
transform
Current AffineTransform. This is the concatenation of the original AffineTransform (i.e., last setTransform invocation) and the following transform invocations, as captured by originalTransform and the transformStack. -
transformStack
Transform stack -
transformStackValid
protected boolean transformStackValidDefines whether the transform stack is valid or not. This is for use by the class clients. The client should validate the stack every time it starts using it. The stack becomes invalid when a new transform is set.- See Also:
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paint
Current Paint -
stroke
Current Stroke -
composite
Current Composite -
clip
Current clip -
hints
Current set of RenderingHints -
font
Current Font -
background
Current background color. -
foreground
Current foreground color
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Constructor Details
-
GraphicContext
public GraphicContext()Default constructor -
GraphicContext
- Parameters:
defaultDeviceTransform
- Default affine transform applied to map the user space to the user space.
-
GraphicContext
Copy constructor.- Parameters:
template
- the instance to make a copy of
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Method Details
-
clone
-
getColor
Gets this graphics context's current color.- Returns:
- this graphics context's current color.
- See Also:
-
setColor
Sets this graphics context's current color to the specified color. All subsequent graphics operations using this graphics context use this specified color.- Parameters:
c
- the new rendering color.- See Also:
-
getFont
Gets the current font.- Returns:
- this graphics context's current font.
- See Also:
-
setFont
Sets this graphics context's font to the specified font. All subsequent text operations using this graphics context use this font.- Parameters:
font
- the font.- See Also:
-
getClipBounds
Returns the bounding rectangle of the current clipping area. This method refers to the user clip, which is independent of the clipping associated with device bounds and window visibility. If no clip has previously been set, or if the clip has been cleared usingsetClip(null)
, this method returnsnull
. The coordinates in the rectangle are relative to the coordinate system origin of this graphics context.- Returns:
- the bounding rectangle of the current clipping area,
or
null
if no clip is set. - Since:
- JDK1.1
- See Also:
-
clipRect
public void clipRect(int x, int y, int width, int height) Intersects the current clip with the specified rectangle. The resulting clipping area is the intersection of the current clipping area and the specified rectangle. If there is no current clipping area, either because the clip has never been set, or the clip has been cleared usingsetClip(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.- Parameters:
x
- the x coordinate of the rectangle to intersect the clip withy
- the y coordinate of the rectangle to intersect the clip withwidth
- the width of the rectangle to intersect the clip withheight
- the height of the rectangle to intersect the clip with- See Also:
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setClip
public void setClip(int x, int y, int width, int height) Sets the current clip to the rectangle specified by the given coordinates. This method sets the user clip, which is independent of the clipping associated with device bounds and window visibility. Rendering operations have no effect outside of the clipping area.- Parameters:
x
- the x coordinate of the new clip rectangle.y
- the y coordinate of the new clip rectangle.width
- the width of the new clip rectangle.height
- the height of the new clip rectangle.- Since:
- JDK1.1
- See Also:
-
getClip
Gets the current clipping area. This method returns the user clip, which is independent of the clipping associated with device bounds and window visibility. If no clip has previously been set, or if the clip has been cleared usingsetClip(null)
, this method returnsnull
.- Returns:
- a
Shape
object representing the current clipping area, ornull
if no clip is set. - Since:
- JDK1.1
- See Also:
-
setClip
Sets the current clipping area to an arbitrary clip shape. Not all objects that implement theShape
interface can be used to set the clip. The onlyShape
objects that are guaranteed to be supported areShape
objects that are obtained via thegetClip
method and viaRectangle
objects. This method sets the user clip, which is independent of the clipping associated with device bounds and window visibility.- Parameters:
clip
- theShape
to use to set the clip- Since:
- JDK1.1
- See Also:
-
setComposite
Sets theComposite
for theGraphics2D
context. TheComposite
is used in all drawing methods such asdrawImage
,drawString
,draw
, andfill
. 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 aComponent
on the display screen and theComposite
is a custom object rather than an instance of theAlphaComposite
class, and if there is a security manager, itscheckPermission
method is called with anAWTPermission("readDisplayPixels")
permission.- Parameters:
comp
- theComposite
object to be used for rendering- Throws:
SecurityException
- if a customComposite
object is being used to render to the screen and a security manager is set and itscheckPermission
method does not allow the operation.- See Also:
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setPaint
Sets thePaint
attribute for theGraphics2D
context. Calling this method with anull
Paint
object does not have any effect on the currentPaint
attribute of thisGraphics2D
.- Parameters:
paint
- thePaint
object to be used to generate color during the rendering process, ornull
- See Also:
-
setStroke
Sets theStroke
for theGraphics2D
context.- Parameters:
s
- theStroke
object to be used to stroke aShape
during the rendering process- See Also:
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setRenderingHint
Sets the value of a single preference for the rendering algorithms. Hint categories include controls for rendering quality and overall time/quality trade-off in the rendering process. Refer to theRenderingHints
class for definitions of some common keys and values.- Parameters:
hintKey
- the key of the hint to be set.hintValue
- the value indicating preferences for the specified hint category.- See Also:
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getRenderingHint
Returns the value of a single preference for the rendering algorithms. Hint categories include controls for rendering quality and overall time/quality trade-off in the rendering process. Refer to theRenderingHints
class for definitions of some common keys and values.- Parameters:
hintKey
- the key corresponding to the hint to get.- Returns:
- an object representing the value for the specified hint key.
Some of the keys and their associated values are defined in the
RenderingHints
class. - See Also:
-
setRenderingHints
Replaces the values of all preferences for the rendering algorithms with the specifiedhints
. The existing values for all rendering hints are discarded and the new set of known hints and values are initialized from the specifiedMap
object. Hint categories include controls for rendering quality and overall time/quality trade-off in the rendering process. Refer to theRenderingHints
class for definitions of some common keys and values.- Parameters:
hints
- the rendering hints to be set- See Also:
-
addRenderingHints
Sets the values of an arbitrary number of preferences for the rendering algorithms. Only values for the rendering hints that are present in the specifiedMap
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 theRenderingHints
class for definitions of some common keys and values.- Parameters:
hints
- the rendering hints to be set- See Also:
-
getRenderingHints
Gets the preferences for the rendering algorithms. Hint categories include controls for rendering quality and overall time/quality trade-off in the rendering process. Returns all of the hint key/value pairs that were ever specified in one operation. Refer to theRenderingHints
class for definitions of some common keys and values.- Returns:
- a reference to an instance of
RenderingHints
that contains the current preferences. - See Also:
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translate
public void translate(int x, int y) Translates the origin of the graphics context to the point (x, y) in the current coordinate system. Modifies this graphics context so that its new origin corresponds to the point (x, y) in this graphics context's original coordinate system. All coordinates used in subsequent rendering operations on this graphics context will be relative to this new origin.- Parameters:
x
- the x coordinate.y
- the y coordinate.
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translate
public void translate(double tx, double ty) Concatenates the currentGraphics2D
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 anAffineTransform
represented by the following matrix:[ 1 0 tx ] [ 0 1 ty ] [ 0 0 1 ]
- Parameters:
tx
- the distance to translate along the x-axisty
- the distance to translate along the y-axis
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rotate
public void rotate(double theta) Concatenates the currentGraphics2D
Transform
with a rotation transform. Subsequent rendering is rotated by the specified radians relative to the previous origin. This is equivalent to callingtransform(R)
, where R is anAffineTransform
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.- Parameters:
theta
- the angle of rotation in radians
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rotate
public void rotate(double theta, double x, double y) Concatenates the currentGraphics2D
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.- Parameters:
theta
- the angle of rotation in radiansx
- x coordinate of the origin of the rotationy
- y coordinate of the origin of the rotation
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scale
public void scale(double sx, double sy) Concatenates the currentGraphics2D
Transform
with a scaling transformation Subsequent rendering is resized according to the specified scaling factors relative to the previous scaling. This is equivalent to callingtransform(S)
, where S is anAffineTransform
represented by the following matrix:[ sx 0 0 ] [ 0 sy 0 ] [ 0 0 1 ]
- Parameters:
sx
- the amount by which X coordinates in subsequent rendering operations are multiplied relative to previous rendering operations.sy
- the amount by which Y coordinates in subsequent rendering operations are multiplied relative to previous rendering operations.
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shear
public void shear(double shx, double shy) Concatenates the currentGraphics2D
Transform
with a shearing transform. Subsequent renderings are sheared by the specified multiplier relative to the previous position. This is equivalent to callingtransform(SH)
, where SH is anAffineTransform
represented by the following matrix:[ 1 shx 0 ] [ shy 1 0 ] [ 0 0 1 ]
- Parameters:
shx
- the multiplier by which coordinates are shifted in the positive X axis direction as a function of their Y coordinateshy
- the multiplier by which coordinates are shifted in the positive Y axis direction as a function of their X coordinate
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transform
Composes anAffineTransform
object with theTransform
in thisGraphics2D
according to the rule last-specified-first-applied. If the currentTransform
is Cx, the result of composition with Tx is a newTransform
Cx'. Cx' becomes the currentTransform
for thisGraphics2D
. Transforming a point p by the updatedTransform
Cx' is equivalent to first transforming p by Tx and then transforming the result by the originalTransform
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.- Parameters:
tx
- theAffineTransform
object to be composed with the currentTransform
- See Also:
-
setTransform
Sets theTransform
in theGraphics2D
context.- Parameters:
tx
- theAffineTransform
object to be used in the rendering process- See Also:
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validateTransformStack
public void validateTransformStack()Marks the GraphicContext's isNewTransformStack to false as a memento that the current transform stack was read and has not been reset. Only the setTransform method can override this memento. -
isTransformStackValid
public boolean isTransformStackValid()Checks the status of the transform stack.- Returns:
- true if the transform stack is valid
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getTransformStack
- Returns:
- array containing the successive transforms that were concatenated with the original one.
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invalidateTransformStack
protected void invalidateTransformStack()Marks the GraphicContext's isNewTransformStack to true as a memento that the current transform stack was reset since it was last read. Only validateTransformStack can override this memento -
getTransform
Returns a copy of the currentTransform
in theGraphics2D
context.- Returns:
- the current
AffineTransform
in theGraphics2D
context. - See Also:
-
getPaint
Returns the currentPaint
of theGraphics2D
context.- Returns:
- the current
Graphics2D
Paint
, which defines a color or pattern. - See Also:
-
getComposite
Returns the currentComposite
in theGraphics2D
context.- Returns:
- the current
Graphics2D
Composite
, which defines a compositing style. - See Also:
-
setBackground
Sets the background color for theGraphics2D
context. The background color is used for clearing a region. When aGraphics2D
is constructed for aComponent
, the background color is inherited from theComponent
. Setting the background color in theGraphics2D
context only affects the subsequentclearRect
calls and not the background color of theComponent
. To change the background of theComponent
, use appropriate methods of theComponent
.- Parameters:
color
- the background color that isused in subsequent calls toclearRect
- See Also:
-
getBackground
Returns the background color used for clearing a region.- Returns:
- the current
Graphics2D
Color
, which defines the background color. - See Also:
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getStroke
Returns the currentStroke
in theGraphics2D
context.- Returns:
- the current
Graphics2D
Stroke
, which defines the line style. - See Also:
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clip
Intersects the currentClip
with the interior of the specifiedShape
and sets theClip
to the resulting intersection. The specifiedShape
is transformed with the currentGraphics2D
Transform
before being intersected with the currentClip
. This method is used to make the currentClip
smaller. To make theClip
larger, usesetClip
. 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 usingsetClip
with anull
argument, the specifiedShape
becomes the new user clip.- Parameters:
s
- theShape
to be intersected with the currentClip
. Ifs
isnull
, this method clears the currentClip
.
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getFontRenderContext
Get the rendering context of theFont
within thisGraphics2D
context. TheFontRenderContext
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 asFont
andTextLayout
. 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.- Returns:
- a reference to an instance of FontRenderContext.
- Since:
- JDK1.2
- See Also:
-