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§1.20 Class Graphics

public  abstract  class  java.awt.Graphics
    extends  java.lang.Object  (I-§1.12)
{
        // Constructors
    protected Graphics();	§1.20.1

        // Methods
    public abstract void clearRect(int  x, int  y, 	§1.20.2
                                            int width, int  height);
    public abstract void clipRect(int  x, int  y, 	§1.20.3
                                           int width, int height);
    public abstract void	§1.20.4
        copyArea(int  x, int  y, int  width,
                    int  height, int  dx, int  dy);
    public abstract Graphics create();	§1.20.5
    public Graphics create(int  x, int  y,	§1.20.6
                        int  width, int  height);
    public abstract void dispose();	§1.20.7
    public void draw3DRect(int  x, int  y, int  width,	§1.20.8
                                      int  height, boolean  raised);
    public abstract voiddrawArc(int  x, int  y, int  width,	§1.20.9
                                              int  height, int  startAngle,
                            int  arcAngle);
    public void drawBytes(byte  data[], int  offset,	§1.20.10
                                int  length, int  x, int  y);
    public void drawChars(char  data[], int  offset,	§1.20.11
                                int  length, int  x, int  y);
    public abstract boolean	§1.20.12
        drawImage(Image  img, int  x, int  y,  Color  bgcolor,
                    ImageObserver  observer);
    public abstract boolean	§1.20.13
        drawImage(Image  img, int  x, int  y,
                    ImageObserver  observer);
    public abstract boolean	§1.20.14
        drawImage(Image  img, int  x, int  y,
                            int  width, int  height, Color  bgcolor,
                            ImageObserver  observer);
    public abstract boolean	§1.20.15
        drawImage(Image  img, int  x, int  y,
                  int  width, int  height,
                                    ImageObserver  observer);
    public abstract void drawLine(int  x1, int  y1,	§1.20.16
              int  x2,  int  y2);
    public abstract void drawOval(int  x, int  y,	§1.20.17
                                    int width, int  height);
    public abstract void	§1.20.18
        drawPolygon(int  xPoints[], int yPoints[], 
                                int  nPoints);
    public void drawPolygon(Polygon  p);	§1.20.19
    public void drawRect(int  x, int  y,	§1.20.20
                   int  width, int  height);
    public abstract void	§1.20.21
        drawRoundRect(int  x, int  y, int  width,
              int  height, int  arcWidth,
                  int  arcHeight);
    public abstract void	§1.20.22
        drawString(String  str, int  x, int  y);
    public void	§1.20.23
        fill3DRect(int  x, int  y, int  width,
                              int  height, boolean  raised);
    public abstract void	§1.20.24
        fillArc(int  x, int  y, int  width,
                        int  height, int  startAngle,
                        int  arcAngle);
    public abstract void	§1.20.25
        fillOval(int  x, int  y, int  width, int  height);
    public abstract void	§1.20.26
        fillPolygon(int  xPoints[], int  yPoints[], int  nPoints);
    public void fillPolygon(Polygon  p);	§1.20.27
    public abstract void	§1.20.28
        fillRect(int  x, int  y, int  width,  int  height);
    public abstract void	§1.20.29
        fillRoundRect(int  x, int  y, int  width, int height, 
                                    int  arcWidth,  int  arcHeight);
    public void finalize();	§1.20.30
    public abstract Rectangle getClipRect();	§1.20.31
    public abstract Color getColor();	§1.20.32
    public abstract Font getFont();	§1.20.33
    public FontMetrics getFontMetrics();	§1.20.34
    public abstract FontMetrics getFontMetrics(Font  f);	§1.20.35
    public abstract void setColor(Color  c);	§1.20.36
    public abstract void setFont(Font  font);	§1.20.37
    public abstract void setPaintMode();	§1.20.38
    public abstract void setXORMode(Color  c1);	§1.20.39
    public String toString();	§1.20.40
    public abstract void   translate(int  x, int  y);	§1.20.41
}

The Graphics class is the abstract base class for all graphics contexts which allow an application to draw onto components or onto off-screen images.

Unless otherwise stated, all graphics operations performed with a graphics context object only modify bits within the graphic context's clipping region (II-§1.20.3). All drawing or writing is done in the current color (II-§1.20.36) using the current paint mode (II-§1.20.38, §1.20.39) and in the current font (II-§1.20.37).

Graphics

protected Graphics()

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 (II-§1.20.5) or are created by a component (II-§1.10.17).

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 screen ¹. This operation does not use the current paint mode (II-§1.20.38, §1.20.39).

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: fillRect (II-§1.20.28)
drawRect (II-§1.20.20).

clipRect

public abstract void

clipRect(int  x, int  y, int  width, int  height)

Sets a clipping rectangle for this graphics context. The resulting clipping area is the intersection of the current clipping area and the specified rectangle.

Graphics operations performed with this graphics context have no effect outside the clipping area.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: getClipRect (II-§1.20.31).

copyArea

public abstract void

copyArea(int  x, int  y, int  width, int  height,

                  int  dx, int  dy)

Copies an area. The source is the rectangle with origin

, and size specified by the width and height arguments. The destination is the rectangle with origin

and the same width and height.

The clipping rectangle of this graphics context affects only the destination, not the source.

Parameters:: x -the x-coordinate of the source; y -the y-coordinate of the source; width -the width; height -the height; dx -the horizontal distance; dy -the vertical distance

create

public abstract Graphics create()

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 context The new graphics context is identical to this graphics context, except in two respects:

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 (II-§1.20.41).

dispose

public abstract void dispose()

Disposes of this graphics context.

The graphics context cannot be used after being disposed.

See Also:: finalize (II-§1.20.30).

draw3DRect

public void draw3DRect(int  x, int  y, int  width,

                                              int  height, boolean  raised)

Draws a highlighted 3-D rectangle.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; raised -if true, the rectangle appears raised; if false, it appears lowered

drawArc

public abstract void

drawArc(int  x, int  y, int  width, int  height,

                int  startAngle, int  arcAngle)

Draws a single circular or elliptical arc.

The center of the arc is the center of the rectangle whose origin is

and whose size is specified by the width and height arguments.

The two axes of the arc are given by the width and height arguments.

The arc is drawn from startAngle to startAngle + arcAngle. The start angle and arc angle are in degrees, not radians.

A start angle of 0 indicates the 3-o'clock position. A positive arc angle indicates a counter-clockwise rotation; a negative arc angle indicates a clockwise rotation.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; startAngle -the beginning angle; arcAngle -the angle of the arc (relative to startAngle).
See Also:: fillArc (II-§1.20.24).

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

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; y -the y coordinate
See Also:: drawString (II-§1.20.22)
drawChars (II-§1.20.11).

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

in the 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; y -the y coordinate
See Also:: drawString (II-§1.20.22)
drawBytes (II-§1.20.10).

drawImage

public abstract boolean

drawImage(Image  img, int  x, int  y, Color  bgcolor,

                    ImageObserver  observer)

Draws the specified image with its top left corner at

in this graphics context's coordinate space. Transparent pixels in the image are drawn in the specified background color.

If the image has not yet been completely loaded, the image observer's imageUpdate (II-§2.11.9) method is notified as more of the image becomes available.

Parameters:: img -the specified image to be drawn; x -the x coordinate; y -the y coordinate; bgcolor -the background color; observer -object to notify when the image is loaded.
Returns:: true if all bits of the image are available; false otherwise.
See Also:: Image (II-§1.24)
ImageObserver (II-§2.11).

drawImage

public abstract boolean

drawImage(Image  img, int  x, int  y, ImageObserver  observer)

Draws the specified image with its top left corner at

in this graphics context's coordinate space. Transparent pixels in the image do not affect whatever pixels are already there.

If the image has not yet been completely loaded, the image observer's imageUpdate (II-§2.11.9) method is notified as more of the image becomes available.

Parameters:: img -the specified image to be drawn; x -the x coordinate; y -the y coordinate; observer -object to notify when the image is loaded
Returns:: true if all bits of the image are available; false otherwise.
See Also:: Image (II-§1.24)
ImageObserver (II-§2.11).

drawImage

public abstract boolean

drawImage(Image  img, int  x, int  y, int  width,

                    int  height, Color  bgcolor, ImageObserver  observer)

Draws the specified image inside the specified rectangle of this graphics context's coordinate space. The image is scaled if necessary. Transparent pixels in the image are drawn in the specified background color.

If the image has not yet been completely loaded, the image observer's imageUpdate (II-§2.11.9) method is notified as more of the image becomes available.

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 -background color for the image; observer -object to notify when the image is loaded
Returns:: true if all bits of the image are available; false otherwise.
See Also:: Image (II-§1.24)
ImageObserver (II-§2.11).

drawImage

public abstract boolean

drawImage(Image  img, int  x, int  y, int  width,

                    int  height, ImageObserver  observer)

Draws the specified image inside the specified rectangle of this graphics context's coordinate space. The image is scaled if necessary. Transparent pixels in the image do not affect whatever pixels are already there.

If the image has not yet been completely loaded, the image observer's imageUpdate (II-§2.11.9) method is notified as more of the image becomes available.

Parameters:: img -the specified image to be drawn; x -the x coordinate; y -the y coordinate; width -the width of the rectangle; bgcolor -background color for the image; observer -object to notify when the image is loaded
Returns:: true if all bits of the image are available; false otherwise.
See Also:: Image (II-§1.24)
ImageObserver (II-§2.11).

drawLine

public abstract void

drawLine(int  x1, int  y1, int  x2, int  y2)

Draws a line from

in this graphics context's coordinate system.

The line is drawn below and to the right of the logical coordinates.

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

drawOval

public abstract void

drawOval(int  x, int  y, int  width, int  height)

Draws a circle or an ellipse such that it fits within the rectangle specified by the x, y, width and height arguments.

The center of the oval is the center of the rectangle whose origin is

is this graphics context's coordinate system and whose size is specified by the width and height arguments.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: fillOval (II-§1.20.25).

drawPolygon

public abstract void

drawPolygon(int  xPoints[], int  yPoints[], int  nPoints)

Draws a closed polygon defined by an array of x points and y points.

This method draws the polygon defined by npoint line segments, where the first npoint-1 line segments are lines segments from

, for

. The last line segment starts at the final point and ends at the first point.

Parameters:: xPoints -an array of x points; yPoints -an array of y points; nPoints -the total number of points
See Also:: fillPolygon (II-§1.20.26).

drawPolygon

public void drawPolygon(Polygon  p)

Draws a polygon defined by the specified polygon argument.

Parameters:: p -a polygon
See Also:: fillPolygon (II-§1.20.26).

drawRect

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

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

and

respectively. The top and bottom edges of the rectangle are at

and

. respectively.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: fillRect (II-§1.20.28)
clearRect (II-§1.20.2).

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

and

respectively. The top and bottom edges of the rectangle are at

and

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; 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 (II-§1.20.29).

drawString

public abstract void drawString(String  str, int  x, int  y)

Draws the string using this graphics context's current font and color. The baseline of the first character is at position

in the graphics context's coordinate system.

Parameters:: str -the string to be drawn; x -the x coordinate; y -the y coordinate
See Also:: drawChars (II-§1.20.11)
drawBytes (II-§1.20.10).

fill3DRect

public void fill3DRect(int  x, int  y, int  width,

                                              int  height, boolean  raised)

Draws a highlighted 3-D rectangle that is filled with this graphics context's current color.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; raised -if true, the rectangle is raised; if false, it is lowered

fillArc

public abstract void

fillArc(int  x, int  y, int  width, int  height,

                int  startAngle, int  arcAngle)

Draws a single circular or elliptical arc that is filled with this graphics context's current color. The result is a pie shape.

The center of the arc is the center of the rectangle whose origin is

and whose size is specified by the width and height arguments.

The two axes of the arc are given by the width and height arguments.

The arc is drawn from startAngle to startAngle + arcAngle. The start angle and arc angle are in degrees, not radians.

A start angle of 0 indicates the 3-o'clock position. A positive arc angle indicates a counter-clockwise rotation; a negative arc angle indicates a clockwise rotation.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; startAngle -the beginning angle; arcAngle -the angle of the arc (relative to startAngle).
See Also:: drawArc (II-§1.20.9).

fillOval

public abstract void

fillOval(int  x, int  y, int  width, int  height)

Draws a filled circle or a filled ellipse using this graphics context's current color.

The center of the oval is the center of the rectangle whose origin is

is the graphics context's coordinate system and whose size is specified by the width and height arguments.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: drawOval (II-§1.20.17).

fillPolygon

public abstract void

fillPolygon(int  xPoints[], int  yPoints[], int  nPoints)

Fills a polygon defined by an array of x points and y points with this graphics context's current color.

This method fills the polygon defined by npoint line segments, where the first npoint-1 line segments are lines segments from

, for

. The last line segment starts at the final point and ends at the first point.

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

Parameters:: xPoints -an array of x points; yPoints -an array of y points; nPoints -the total number of points
See Also:: drawPolygon (II-§1.20.18).

fillPolygon

public void fillPolygon(Polygon  p)

Fills a polygon defined by the specified polygon argument with this 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
See Also:: drawPolygon (II-§1.20.19).

fillRect

public abstract void

fillRect(int  x, int  y, int  width, int  height)

Fills the specified rectangle with this graphics context's current color. The left and right edges are at

and

respectively. The top and bottom edges are at

and

respectively.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle
See Also:: drawRect (II-§1.20.20)
clearRect (II-§1.20.2).

fillRoundRect

public abstract void

fillRoundRect(int  x, int  y, int  width, int  height,

                            int  arcWidth, int  arcHeight)

Fills an outlined rounded corner rectangle with this graphics context's current color. The left and right edges are at

and

respectively. The top and bottom edges are at

and

respectively.

Parameters:: x -the x coordinate; y -the y coordinate; width -the width of the rectangle; height -the height of the rectangle; arcWidth -the horizontal diameter of the arc at the four corners; arcHeight -the vertical diameter of the arc at the four corners

Draws a rounded rectangle filled in with the current color.

See Also:: drawRoundRect (II-§1.20.21).

finalize

public void finalize()

The finalize method ensures that this graphics context's dispose method (II-§1.20.7) is called when this graphics context is no longer referenced.

Overrides:: finalize in class Object (I-§1.12.4).

getClipRect

public abstract Rectangle getClipRect()

Returns:: the bounding rectangle of this graphics context's clipping area.
See Also:: clipRect (II-§1.20.3).

getColor

public abstract Color getColor()

Returns:: this graphics context's current color.
See Also:: setColor (II-§1.20.36).

getFont

public abstract Font getFont()

Returns:: this graphics context's current font.
See Also:: setFont (II-§1.20.37).

getFontMetrics

public FontMetrics getFontMetrics()

Returns:: this font metrics of the graphics context's current font.
See Also:: getFont (II-§1.20.33).

getFontMetrics

public abstract FontMetrics getFontMetrics(Font  f)

Parameters:: f -the specified font
Returns:: the font metrics for the specified font.
See Also:: getFont (II-§1.20.33).

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 color
See Also:: Color (II-§1.9)
getColor (II-§1.20.32).

setFont

public abstract void setFont(Font  font)

Sets this graphics context's font to the specified font.

All subsequent text operations (such as drawString (II-§1.20.22), drawBytes (II-§1.20.10), and drawChars (II-§1.20.11)) using this graphics context use this font.

Parameters:: font -the font

setPaintMode

public abstract void setPaintMode()

Sets the paint mode of this graphics context to overwrite the destination with this graphics context's 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.

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 second color

toString

public String toString()

Returns:: a string representation of this graphics context.
Overrides:: toString in class Object (I-§1.12.9).

translate

public abstract void translate(int  x, int  y)

Modifies this graphics context so that its new origin corresponds to the point

in this graphics context's original coordinate system.

Parameters:: x -the x coordinate; y -the y coordinate

¹ In Java 1.0, the background color of offscreen images is white. In Java 1.1, the background color of offscreen images may be system dependent. Applications should use setColor (II-§1.20.36) followed by fillRect (II-§1.20.28) to ensure that an offscreen image is cleared to a specific color.

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