java.awt
Class Graphics

java.lang.Object   
  java.awt.Graphics

Direct Known Subclasses:

DebugGraphics , Graphics2D

public abstract class Graphics
extends Object   

The Graphics class is the abstract base class for all graphics contexts that allow an application to draw onto components that are realized on various devices, as well as onto off-screen images.

A Graphics object encapsulates state information needed for the basic rendering operations that Java supports. This state information includes the following properties:

• The Component object on which to draw.
• A translation origin for rendering and clipping coordinates.
• The current clip.
• The current color.
• The current font.
• The current logical pixel operation function (XOR or Paint).
• The current XOR alternation color (see setXORMode(java.awt.Color) ).

Coordinates are infinitely thin and lie between the pixels of the output device. Operations that draw the outline of a figure operate by traversing an infinitely thin path between pixels with a pixel-sized pen that hangs down and to the right of the anchor point on the path. Operations that fill a figure operate by filling the interior of that infinitely thin path. Operations that render horizontal text render the ascending portion of character glyphs entirely above the baseline coordinate.

The graphics pen hangs down and to the right from the path it traverses. This has the following implications:

• If you draw a figure that covers a given rectangle, that figure occupies one extra row of pixels on the right and bottom edges as compared to filling a figure that is bounded by that same rectangle.
• If you draw a horizontal line along the same y coordinate as the baseline of a line of text, that line is drawn entirely below the text, except for any descenders.

All coordinates that appear as arguments to the methods of this Graphics object are considered relative to the translation origin of this Graphics object prior to the invocation of the method.

All rendering operations modify only pixels which lie within the area bounded by the current clip, which is specified by a Shape in user space and is controlled by the program using the Graphics object. This user clip is transformed into device space 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 cannot be modified by the rendering system to reflect the resulting composite clip. The user clip can only be changed through the setClip or clipRect methods. All drawing or writing is done in the current color, using the current paint mode, and in the current font.

Since:

JDK1.0

See Also:

Component , clipRect(int, int, int, int) , setColor(java.awt.Color) , setPaintMode() , setXORMode(java.awt.Color) , setFont(java.awt.Font)

Constructor Summary

protected

Graphics () Constructs a new Graphics object.

Method Summary

abstract void	clearRect (int x, int y, int width, int height) Clears the specified rectangle by filling it with the background color of the current drawing surface.
abstract void	clipRect (int x, int y, int width, int height) Intersects the current clip with the specified rectangle.
abstract void	copyArea (int x, int y, int width, int height, int dx, int dy) Copies an area of the component by a distance specified by dx and dy.
abstract Graphics	create () Creates a new Graphics object that is a copy of this Graphics object.
Graphics	create (int x, int y, int width, int height) Creates a new Graphics object based on this Graphics object, but with a new translation and clip area.
abstract void	dispose () Disposes of this graphics context and releases any system resources that it is using.
void	draw3DRect (int x, int y, int width, int height, boolean raised) Draws a 3-D highlighted outline of the specified rectangle.
abstract void	drawArc (int x, int y, int width, int height, int startAngle, int arcAngle) Draws the outline of a circular or elliptical arc covering the specified rectangle.
void	drawBytes (byte[] data, int offset, int length, int x, int y) Draws the text given by the specified byte array, using this graphics context's current font and color.
void	drawChars (char[] data, int offset, int length, int x, int y) Draws the text given by the specified character array, using this graphics context's current font and color.
abstract boolean	drawImage (Image img, int x, int y, Color bgcolor, ImageObserver observer) Draws as much of the specified image as is currently available.
abstract boolean	drawImage (Image img, int x, int y, ImageObserver observer) Draws as much of the specified image as is currently available.
abstract boolean	drawImage (Image img, int x, int y, int width, int height, Color bgcolor, ImageObserver observer) Draws as much of the specified image as has already been scaled to fit inside the specified rectangle.
abstract boolean	drawImage (Image img, int x, int y, int width, int height, ImageObserver observer) Draws as much of the specified image as has already been scaled to fit inside the specified rectangle.
abstract boolean	drawImage (Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, Color bgcolor, ImageObserver observer) Draws as much of the specified area of the specified image as is currently available, scaling it on the fly to fit inside the specified area of the destination drawable surface.
abstract boolean	drawImage (Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer) Draws as much of the specified area of the specified image as is currently available, scaling it on the fly to fit inside the specified area of the destination drawable surface.
abstract void	drawLine (int x1, int y1, int x2, int y2) Draws a line, using the current color, between the points (x1, y1) and (x2, y2) in this graphics context's coordinate system.
abstract void	drawOval (int x, int y, int width, int height) Draws the outline of an oval.
abstract void	drawPolygon (int[] xPoints, int[] yPoints, int nPoints) Draws a closed polygon defined by arrays of x and y coordinates.
void	drawPolygon (Polygon p) Draws the outline of a polygon defined by the specified Polygon object.
abstract void	drawPolyline (int[] xPoints, int[] yPoints, int nPoints) Draws a sequence of connected lines defined by arrays of x and y coordinates.
void	drawRect (int x, int y, int width, int height) Draws the outline of the specified rectangle.
abstract void	drawRoundRect (int x, int y, int width, int height, int arcWidth, int arcHeight) Draws an outlined round-cornered rectangle using this graphics context's current color.
abstract void	drawString (AttributedCharacterIterator iterator, int x, int y) Draws the text given by the specified iterator, using this graphics context's current color.
abstract void	drawString (String str, int x, int y) Draws the text given by the specified string, using this graphics context's current font and color.
void	fill3DRect (int x, int y, int width, int height, boolean raised) Paints a 3-D highlighted rectangle filled with the current color.
abstract void	fillArc (int x, int y, int width, int height, int startAngle, int arcAngle) Fills a circular or elliptical arc covering the specified rectangle.
abstract void	fillOval (int x, int y, int width, int height) Fills an oval bounded by the specified rectangle with the current color.
abstract void	fillPolygon (int[] xPoints, int[] yPoints, int nPoints) Fills a closed polygon defined by arrays of x and y coordinates.
void	fillPolygon (Polygon p) Fills the polygon defined by the specified Polygon object with the graphics context's current color.
abstract void	fillRect (int x, int y, int width, int height) Fills the specified rectangle.
abstract void	fillRoundRect (int x, int y, int width, int height, int arcWidth, int arcHeight) Fills the specified rounded corner rectangle with the current color.
void	finalize () Disposes of this graphics context once it is no longer referenced.
abstract Shape	getClip () Gets the current clipping area.
abstract Rectangle	getClipBounds () Returns the bounding rectangle of the current clipping area.
Rectangle	getClipBounds (Rectangle r) Returns the bounding rectangle of the current clipping area.
Rectangle	getClipRect () Deprecated. As of JDK version 1.1, replaced by getClipBounds().
abstract Color	getColor () Gets this graphics context's current color.
abstract Font	getFont () Gets the current font.
FontMetrics	getFontMetrics () Gets the font metrics of the current font.
abstract FontMetrics	getFontMetrics (Font f) Gets the font metrics for the specified font.
boolean	hitClip (int x, int y, int width, int height) Returns true if the specified rectangular area might intersect the current clipping area.
abstract void	setClip (int x, int y, int width, int height) Sets the current clip to the rectangle specified by the given coordinates.
abstract void	setClip (Shape clip) Sets the current clipping area to an arbitrary clip shape.
abstract void	setColor (Color c) Sets this graphics context's current color to the specified color.
abstract void	setFont (Font font) Sets this graphics context's font to the specified font.
abstract void	setPaintMode () Sets the paint mode of this graphics context to overwrite the destination with this graphics context's current color.
abstract void	setXORMode (Color c1) Sets the paint mode of this graphics context to alternate between this graphics context's current color and the new specified color.
String	toString () Returns a String object representing this Graphics object's value.
abstract void	translate (int x, int y) Translates the origin of the graphics context to the point (x, y) in the current coordinate system.

Methods inherited from class java.lang.Object

clone , equals , getClass , hashCode , notify , notifyAll , wait , wait , wait

Constructor Detail

Graphics

protected Graphics()

Constructs a new Graphics object. This constructor is the default contructor for a graphics context.

Since Graphics is an abstract class, applications cannot call this constructor directly. Graphics contexts are obtained from other graphics contexts or are created by calling getGraphics on a component.

See Also:

create() , Component.getGraphics()

Method Detail

create

public abstract Graphics    create()

Creates a new Graphics object that is a copy of this Graphics object.

Returns:

a new graphics context that is a copy of this graphics context.

create

public Graphics    create(int x,
                       int y,
                       int width,
                       int height)

Creates a new 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:

• The new graphics context is translated by (x, y). That is to say, the point (0, 0) in the new graphics context is the same as (x, y) in the original graphics context.
• The new graphics context has an additional clipping rectangle, in addition to whatever (translated) clipping rectangle it inherited from the original graphics context. The origin of the new clipping rectangle is at (0, 0), and its size is specified by the width and height arguments.

Parameters:

x - the x coordinate.

y - the y coordinate.

width - the width of the clipping rectangle.

height - the height of the clipping rectangle.

Returns:

a new graphics context.

See Also:

translate(int, int) , clipRect(int, int, int, int)

translate

public abstract 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.

getColor

public abstract Color    getColor()

Gets this graphics context's current color.

Returns:

this graphics context's current color.

See Also:

Color , setColor(Color)

setColor

public abstract void setColor(Color    c)

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:

Color , getColor()

setPaintMode

public abstract void setPaintMode()

Sets the paint mode of this graphics context to overwrite the destination with this graphics context's current color. This sets the logical pixel operation function to the paint or overwrite mode. All subsequent rendering operations will overwrite the destination with the current color.

setXORMode

public abstract void setXORMode(Color    c1)

Sets the paint mode of this graphics context to alternate between this graphics context's current color and the new specified color. This specifies that logical pixel operations are performed in the XOR mode, which alternates pixels between the current color and a specified XOR color.

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.

Parameters:

c1 - the XOR alternation color

getFont

public abstract Font    getFont()

Gets the current font.

Returns:

this graphics context's current font.

See Also:

Font , setFont(Font)

setFont

public abstract void setFont(Font    font)

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:

getFont() , drawString(java.lang.String, int, int) , drawBytes(byte[], int, int, int, int) , drawChars(char[], int, int, int, int)

getFontMetrics

public FontMetrics    getFontMetrics()

Gets the font metrics of the current font.

Returns:

the font metrics of this graphics context's current font.

See Also:

getFont() , FontMetrics , getFontMetrics(Font)

getFontMetrics

public abstract FontMetrics    getFontMetrics(Font    f)

Gets the font metrics for the specified font.

Parameters:

f - the specified font

Returns:

the font metrics for the specified font.

See Also:

getFont() , FontMetrics , getFontMetrics()