Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class Graphics - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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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 intersects the bounding rectangle of 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(java.awt.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(java.awt.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(), java.awt.Graphics#drawChars(java.lang.String, int, int), java.awt.Graphics#drawString(byte[], int, int, int, int), java.awt.Graphics#drawBytes(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()

getClipBounds

public abstract Rectangle 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 using setClip(null), this method returns null. 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:: getClip(), clipRect(int, int, int, int), setClip(int, int, int, int), setClip(Shape)

clipRect

public abstract 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 using 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.

Parameters:: x - the x coordinate of the rectangle to intersect the clip with; y - the y coordinate of the rectangle to intersect the clip with; width - the width of the rectangle to intersect the clip with; height - the height of the rectangle to intersect the clip with
See Also:: setClip(int, int, int, int), setClip(Shape)

setClip

public abstract 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:: clipRect(int, int, int, int), setClip(Shape)

getClip

public abstract Shape 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 using setClip(null), this method returns null.

Returns:: a Shape object representing the current clipping area, or null if no clip is set.
Since:: JDK1.1
See Also:: getClipBounds(), clipRect(int, int, int, int), setClip(int, int, int, int), setClip(Shape)

setClip

public abstract void setClip(Shape clip)

Sets the current clipping area to an arbitrary clip shape. Not all objects that implement the 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.

Parameters:: clip - the Shape to use to set the clip
Since:: JDK1.1
See Also:: getClip(), clipRect(int, int, int, int), setClip(int, int, int, int)

copyArea

public 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. 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.

Parameters:: x - the x coordinate of the source rectangle.; y - the y coordinate of the source rectangle.; width - the width of the source rectangle.; height - the height of the source rectangle.; dx - the horizontal distance to copy the pixels.; dy - the vertical distance to copy the pixels.

drawLine

public 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.

Parameters:: x1 - the first point's x coordinate.; y1 - the first point's y coordinate.; x2 - the second point's x coordinate.; y2 - the second point's y coordinate.

fillRect

public abstract void fillRect(int x,
                              int y,
                              int width,
                              int height)

Fills the specified rectangle. The left and right edges of the rectangle are at 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.

Parameters:: x - the x coordinate of the rectangle to be filled.; y - the y coordinate of the rectangle to be filled.; width - the width of the rectangle to be filled.; height - the height of the rectangle to be filled.
See Also:: clearRect(int, int, int, int), drawRect(int, int, int, int)

drawRect

public void drawRect(int x,
                     int y,
                     int width,
                     int height)

Draws the outline of the specified rectangle. The left and right edges of the rectangle are at 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.

Parameters:: x - the x coordinate of the rectangle to be drawn.; y - the y coordinate of the rectangle to be drawn.; width - the width of the rectangle to be drawn.; height - the height of the rectangle to be drawn.
See Also:: fillRect(int, int, int, int), clearRect(int, int, int, int)

clearRect

public 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. This operation does not use the current paint mode.

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.

Parameters:: x - the x coordinate of the rectangle to clear.; y - the y coordinate of the rectangle to clear.; width - the width of the rectangle to clear.; height - the height of the rectangle to clear.
See Also:: fillRect(int, int, int, int), drawRect(int, int, int, int), setColor(java.awt.Color), setPaintMode(), setXORMode(java.awt.Color)

drawRoundRect

public 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. The left and right edges of the rectangle are at x and x + width, respectively. The top and bottom edges of the rectangle are at y and y + height.

Parameters:: x - the x coordinate of the rectangle to be drawn.; y - the y coordinate of the rectangle to be drawn.; width - the width of the rectangle to be drawn.; height - the height of the rectangle to be drawn.; arcWidth - the horizontal diameter of the arc at the four corners.; arcHeight - the vertical diameter of the arc at the four corners.
See Also:: fillRoundRect(int, int, int, int, int, int)

fillRoundRect

public 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. The left and right edges of the rectangle are at x and x + width - 1, respectively. The top and bottom edges of the rectangle are at y and y + height - 1.

Parameters:: x - the x coordinate of the rectangle to be filled.; y - the y coordinate of the rectangle to be filled.; width - the width of the rectangle to be filled.; height - the height of the rectangle to be filled.; arcWidth - the horizontal diameter of the arc at the four corners.; arcHeight - the vertical diameter of the arc at the four corners.
See Also:: drawRoundRect(int, int, int, int, int, int)

draw3DRect

public void draw3DRect(int x,
                       int y,
                       int width,
                       int height,
                       boolean raised)

Draws a 3-D highlighted outline of the specified rectangle. The edges of the rectangle are highlighted so that they appear to be beveled and lit from the upper left corner.

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.

Parameters:: x - the x coordinate of the rectangle to be drawn.; y - the y coordinate of the rectangle to be drawn.; width - the width of the rectangle to be drawn.; height - the height of the rectangle to be drawn.; raised - a boolean that determines whether the rectangle appears to be raised above the surface or sunk into the surface.
See Also:: fill3DRect(int, int, int, int, boolean)

fill3DRect

public void fill3DRect(int x,
                       int y,
                       int width,
                       int height,
                       boolean raised)

Paints a 3-D highlighted rectangle filled with the current color. The edges of the rectangle will be highlighted so that it appears as if the edges were beveled and lit from the upper left corner. The colors used for the highlighting effect will be determined from the current color.

Parameters:: x - the x coordinate of the rectangle to be filled.; y - the y coordinate of the rectangle to be filled.; width - the width of the rectangle to be filled.; height - the height of the rectangle to be filled.; raised - a boolean value that determines whether the rectangle appears to be raised above the surface or etched into the surface.
See Also:: draw3DRect(int, int, int, int, boolean)

drawOval

public abstract void drawOval(int x,
                              int y,
                              int width,
                              int height)

Draws the outline of an oval. The result is a circle or ellipse that fits within the rectangle specified by the x, y, width, and height arguments.

The oval covers an area that is width + 1 pixels wide and height + 1 pixels tall.

Parameters:: x - the x coordinate of the upper left corner of the oval to be drawn.; y - the y coordinate of the upper left corner of the oval to be drawn.; width - the width of the oval to be drawn.; height - the height of the oval to be drawn.
See Also:: fillOval(int, int, int, int)

fillOval

public abstract void fillOval(int x,
                              int y,
                              int width,
                              int height)

Fills an oval bounded by the specified rectangle with the current color.

Parameters:: x - the x coordinate of the upper left corner of the oval to be filled.; y - the y coordinate of the upper left corner of the oval to be filled.; width - the width of the oval to be filled.; height - the height of the oval to be filled.
See Also:: drawOval(int, int, int, int)

drawArc

public 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.

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.

Parameters:: x - the x coordinate of the upper-left corner of the arc to be drawn.; y - the y coordinate of the upper-left corner of the arc to be drawn.; width - the width of the arc to be drawn.; height - the height of the arc to be drawn.; startAngle - the beginning angle.; arcAngle - the angular extent of the arc, relative to the start angle.
See Also:: fillArc(int, int, int, int, int, int)

fillArc

public 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.

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.

Parameters:: x - the x coordinate of the upper-left corner of the arc to be filled.; y - the y coordinate of the upper-left corner of the arc to be filled.; width - the width of the arc to be filled.; height - the height of the arc to be filled.; startAngle - the beginning angle.; arcAngle - the angular extent of the arc, relative to the start angle.
See Also:: drawArc(int, int, int, int, int, int)

drawPolyline

public abstract void drawPolyline(int[] xPoints,
                                  int[] yPoints,
                                  int nPoints)

Draws a sequence of connected lines defined by arrays of x and y coordinates. Each pair of (x, y) coordinates defines a point. The figure is not closed if the first point differs from the last point.

Parameters:: xPoints - an array of x points; yPoints - an array of y points; nPoints - the total number of points
Since:: JDK1.1
See Also:: drawPolygon(int[], int[], int)

drawPolygon

public abstract void drawPolygon(int[] xPoints,
                                 int[] yPoints,
                                 int nPoints)

Draws a closed polygon defined by arrays of x and y coordinates. Each pair of (x, y) coordinates defines a point.

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.

Parameters:: xPoints - a an array of x coordinates.; yPoints - a an array of y coordinates.; nPoints - a the total number of points.
See Also:: fillPolygon(int[], int[], int), drawPolyline(int[], int[], int)

drawPolygon

public void drawPolygon(Polygon p)

Draws the outline of a polygon defined by the specified Polygon object.

Parameters:: p - the polygon to draw.
See Also:: fillPolygon(int[], int[], int), drawPolyline(int[], int[], int)

fillPolygon

public abstract void fillPolygon(int[] xPoints,
                                 int[] yPoints,
                                 int nPoints)

Fills a closed polygon defined by arrays of x and y coordinates.

The area inside the polygon is defined using an even-odd fill rule, also known as the alternating rule.

Parameters:: xPoints - a an array of x coordinates.; yPoints - a an array of y coordinates.; nPoints - a the total number of points.
See Also:: drawPolygon(int[], int[], int)

fillPolygon

public void fillPolygon(Polygon p)

Fills the polygon defined by the specified Polygon object with the graphics context's current color.

The area inside the polygon is defined using an even-odd fill rule, also known as the alternating rule.

Parameters:: p - the polygon to fill.
See Also:: drawPolygon(int[], int[], int)

drawString

public 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. The baseline of the first character is at position (x, y) in this graphics context's coordinate system.

Parameters:: str - the string to be drawn.; x - the x coordinate.; y - the y coordinate.
See Also:: drawBytes(byte[], int, int, int, int), drawChars(char[], int, int, int, int)

drawString

public abstract void drawString(AttributedCharacterIterator iterator,
                                int x,
                                int y)

Draws the text given by the specified iterator, using this graphics context's current color. The iterator has to specify a font for each character. The baseline of the first character is at position (x, y) in this graphics context's coordinate system.

Parameters:: iterator - the iterator whose text is to be drawn; x - the x coordinate.; y - the y coordinate.
See Also:: drawBytes(byte[], int, int, int, int), drawChars(char[], int, int, int, int)

drawChars

public 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. The baseline of the first character is at position (x, y) in this graphics context's coordinate system.

Parameters:: data - the array of characters to be drawn; offset - the start offset in the data; length - the number of characters to be drawn; x - the x coordinate of the baseline of the text; y - the y coordinate of the baseline of the text
See Also:: drawBytes(byte[], int, int, int, int), drawString(java.lang.String, int, int)

drawBytes

public 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. The baseline of the first character is at position (x, y) in this graphics context's coordinate system.

Parameters:: data - the data to be drawn; offset - the start offset in the data; length - the number of bytes that are drawn; x - the x coordinate of the baseline of the text; y - the y coordinate of the baseline of the text
See Also:: drawChars(char[], int, int, int, int), drawString(java.lang.String, int, int)

drawImage

public abstract boolean drawImage(Image img,
                                  int x,
                                  int y,
                                  ImageObserver observer)

Draws as much of the specified image as is currently available. The image is drawn with its top-left corner at (x, y) in this graphics context's coordinate space. Transparent pixels in the image do not affect whatever pixels are already there.

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 not yet been completely loaded, then drawImage returns false. As more of the image becomes available, the process that draws the image notifies the specified image observer.

Parameters:: img - the specified image to be drawn.; x - the x coordinate.; y - the y coordinate.; observer - object to be notified as more of the image is converted.
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

drawImage

public 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.

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 draws 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.

Parameters:: img - the specified image to be drawn.; x - the x coordinate.; y - the y coordinate.; width - the width of the rectangle.; height - the height of the rectangle.; observer - object to be notified as more of the image is converted.
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

drawImage

public abstract boolean drawImage(Image img,
                                  int x,
                                  int y,
                                  Color bgcolor,
                                  ImageObserver observer)

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 not yet been completely loaded, then drawImage returns false. As more of the image becomes available, the process that draws the image notifies the specified image observer.

Parameters:: img - the specified image to be drawn.; x - the x coordinate.; y - the y coordinate.; bgcolor - the background color to paint under the non-opaque portions of the image.; observer - object to be notified as more of the image is converted.
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

drawImage

public 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.

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 draws the image notifies the specified image observer.

Parameters:: img - the specified image to be drawn.; x - the x coordinate.; y - the y coordinate.; width - the width of the rectangle.; height - the height of the rectangle.; bgcolor - the background color to paint under the non-opaque portions of the image.; observer - object to be notified as more of the image is converted.
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

drawImage

public 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. Transparent pixels do not affect whatever pixels are already there.

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 draws 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.

Parameters:: img - the specified image to be drawn; dx1 - the x coordinate of the first corner of the destination rectangle.; dy1 - the y coordinate of the first corner of the destination rectangle.; dx2 - the x coordinate of the second corner of the destination rectangle.; dy2 - the y coordinate of the second corner of the destination rectangle.; sx1 - the x coordinate of the first corner of the source rectangle.; sy1 - the y coordinate of the first corner of the source rectangle.; sx2 - the x coordinate of the second corner of the source rectangle.; sy2 - the y coordinate of the second corner of the source rectangle.; observer - object to be notified as more of the image is scaled and converted.
Since:: JDK1.1
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

drawImage

public 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.

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.

Parameters:: img - the specified image to be drawn; dx1 - the x coordinate of the first corner of the destination rectangle.; dy1 - the y coordinate of the first corner of the destination rectangle.; dx2 - the x coordinate of the second corner of the destination rectangle.; dy2 - the y coordinate of the second corner of the destination rectangle.; sx1 - the x coordinate of the first corner of the source rectangle.; sy1 - the y coordinate of the first corner of the source rectangle.; sx2 - the x coordinate of the second corner of the source rectangle.; sy2 - the y coordinate of the second corner of the source rectangle.; bgcolor - the background color to paint under the non-opaque portions of the image.; observer - object to be notified as more of the image is scaled and converted.
Since:: JDK1.1
See Also:: Image, ImageObserver, ImageObserver.imageUpdate(java.awt.Image, int, int, int, int, int)

dispose

public abstract void dispose()

Disposes of this graphics context and releases any system resources that it is using. A Graphics object cannot be used after disposehas 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.

See Also:: finalize(), Component.paint(java.awt.Graphics), Component.update(java.awt.Graphics), Component.getGraphics(), create()

finalize

public void finalize()

Disposes of this graphics context once it is no longer referenced.

Overrides:: finalize in class Object

See Also:: dispose()

toString

public String toString()

Returns a String object representing this Graphics object's value.

Overrides:: toString in class Object

Returns:: a string representation of this graphics context.

getClipRect

public Rectangle getClipRect()

Deprecated. As of JDK version 1.1, replaced by getClipBounds().

hitClip

public boolean hitClip(int x,
                       int y,
                       int width,
                       int height)

Returns true if the specified rectangular area intersects the bounding rectangle of the current clipping area. The coordinates in the rectangle are relative to the coordinate system origin of this graphics context.

Parameters:: x - the x coordinate of the rectangle to test against the clip; y - the y coordinate of the rectangle to test against the clip; width - the width of the rectangle to test against the clip; height - the height of the rectangle to test against the clip

getClipBounds

public Rectangle getClipBounds(Rectangle r)

Returns the bounding rectangle of the current clipping area. The coordinates in the rectangle are relative to the coordinate system origin of this graphics context. This method differs from getClipBounds in that an existing rectangle is used instead of allocating a new one. 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 using setClip(null), this method returns the specified Rectangle.

Parameters:: r - the rectangle where the current clipping area is copied to. Any current values in this rectangle are overwritten.
Returns:: the bounding rectangle of the current clipping area.

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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 intersects the bounding rectangle of 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.

Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class Graphics - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

java.awt Class Graphics

Graphics

create

create

translate

getColor

setColor

setPaintMode

setXORMode

getFont

setFont

getFontMetrics

getFontMetrics

getClipBounds

clipRect

setClip

getClip

setClip

copyArea

drawLine

fillRect

drawRect

clearRect

drawRoundRect

fillRoundRect

draw3DRect

fill3DRect

drawOval

fillOval

drawArc

fillArc

drawPolyline

drawPolygon

drawPolygon

fillPolygon

fillPolygon

drawString

drawString

drawChars

drawBytes

drawImage

drawImage

drawImage

drawImage

drawImage

drawImage

dispose

finalize

toString

getClipRect

hitClip

getClipBounds

java.awt
Class Graphics