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Eclipse Platform
Release 3.0

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org.eclipse.swt.graphics
Class GC

java.lang.Object
  org.eclipse.swt.graphics.GC

public final class GC

extends Object

Class GC is where all of the drawing capabilities that are supported by SWT are located. Instances are used to draw on either an Image, a Control, or directly on a Display.

Styles:

LEFT_TO_RIGHT, RIGHT_TO_LEFT

The SWT drawing coordinate system is the two-dimensional space with the origin (0,0) at the top left corner of the drawing area and with (x,y) values increasing to the right and downward respectively.

Application code must explicitly invoke the GC.dispose() method to release the operating system resources managed by each instance when those instances are no longer required. This is particularly important on Windows95 and Windows98 where the operating system has a limited number of device contexts available.

Note: Only one of LEFT_TO_RIGHT and RIGHT_TO_LEFT may be specified.

See Also:

PaintEvent

Field Summary

int	handle the handle to the OS device context (Warning: This field is platform dependent)

Constructor Summary

GC(Drawable drawable)
Constructs a new instance of this class which has been configured to draw on the specified drawable.

GC(Drawable drawable, int style)
Constructs a new instance of this class which has been configured to draw on the specified drawable.

Method Summary

void	copyArea(Image image, int x, int y) Copies a rectangular area of the receiver at the specified position into the image, which must be of type SWT.BITMAP.
void	copyArea(int srcX, int srcY, int width, int height, int destX, int destY) Copies a rectangular area of the receiver at the source position onto the receiver at the destination position.
void	dispose() Disposes of the operating system resources associated with the graphics context.
void	drawArc(int x, int y, int width, int height, int startAngle, int arcAngle) Draws the outline of a circular or elliptical arc within the specified rectangular area.
void	drawFocus(int x, int y, int width, int height) Draws a rectangle, based on the specified arguments, which has the appearance of the platform's focus rectangle if the platform supports such a notion, and otherwise draws a simple rectangle in the receiver's foreground color.
void	drawImage(Image image, int x, int y) Draws the given image in the receiver at the specified coordinates.
void	drawImage(Image image, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY, int destWidth, int destHeight) Copies a rectangular area from the source image into a (potentially different sized) rectangular area in the receiver.
void	drawLine(int x1, int y1, int x2, int y2) Draws a line, using the foreground color, between the points (x1, y1) and (x2, y2).
void	drawOval(int x, int y, int width, int height) Draws the outline of an oval, using the foreground color, within the specified rectangular area.
void	drawPoint(int x, int y) Draws a pixel, using the foreground color, at the specified point (x, y).
void	drawPolygon(int[] pointArray) Draws the closed polygon which is defined by the specified array of integer coordinates, using the receiver's foreground color.
void	drawPolyline(int[] pointArray) Draws the polyline which is defined by the specified array of integer coordinates, using the receiver's foreground color.
void	drawRectangle(int x, int y, int width, int height) Draws the outline of the rectangle specified by the arguments, using the receiver's foreground color.
void	drawRectangle(Rectangle rect) Draws the outline of the specified rectangle, using the receiver's foreground color.
void	drawRoundRectangle(int x, int y, int width, int height, int arcWidth, int arcHeight) Draws the outline of the round-cornered rectangle specified by the arguments, using the receiver's foreground color.
void	drawString(String string, int x, int y) Draws the given string, using the receiver's current font and foreground color.
void	drawString(String string, int x, int y, boolean isTransparent) Draws the given string, using the receiver's current font and foreground color.
void	drawText(String string, int x, int y) Draws the given string, using the receiver's current font and foreground color.
void	drawText(String string, int x, int y, boolean isTransparent) Draws the given string, using the receiver's current font and foreground color.
void	drawText(String string, int x, int y, int flags) Draws the given string, using the receiver's current font and foreground color.
boolean	equals(Object object) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
void	fillArc(int x, int y, int width, int height, int startAngle, int arcAngle) Fills the interior of a circular or elliptical arc within the specified rectangular area, with the receiver's background color.
void	fillGradientRectangle(int x, int y, int width, int height, boolean vertical) Fills the interior of the specified rectangle with a gradient sweeping from left to right or top to bottom progressing from the receiver's foreground color to its background color.
void	fillOval(int x, int y, int width, int height) Fills the interior of an oval, within the specified rectangular area, with the receiver's background color.
void	fillPolygon(int[] pointArray) Fills the interior of the closed polygon which is defined by the specified array of integer coordinates, using the receiver's background color.
void	fillRectangle(int x, int y, int width, int height) Fills the interior of the rectangle specified by the arguments, using the receiver's background color.
void	fillRectangle(Rectangle rect) Fills the interior of the specified rectangle, using the receiver's background color.
void	fillRoundRectangle(int x, int y, int width, int height, int arcWidth, int arcHeight) Fills the interior of the round-cornered rectangle specified by the arguments, using the receiver's background color.
int	getAdvanceWidth(char ch) Returns the advance width of the specified character in the font which is currently selected into the receiver.
Color	getBackground() Returns the background color.
int	getCharWidth(char ch) Returns the width of the specified character in the font selected into the receiver.
Rectangle	getClipping() Returns the bounding rectangle of the receiver's clipping region.
void	getClipping(Region region) Sets the region managed by the argument to the current clipping region of the receiver.
Font	getFont() Returns the font currently being used by the receiver to draw and measure text.
FontMetrics	getFontMetrics() Returns a FontMetrics which contains information about the font currently being used by the receiver to draw and measure text.
Color	getForeground() Returns the receiver's foreground color.
int	getLineStyle() Returns the receiver's line style, which will be one of the constants SWT.LINE_SOLID, SWT.LINE_DASH, SWT.LINE_DOT, SWT.LINE_DASHDOT or SWT.LINE_DASHDOTDOT.
int	getLineWidth() Returns the width that will be used when drawing lines for all of the figure drawing operations (that is, drawLine, drawRectangle, drawPolyline, and so forth.
int	getStyle() Returns the receiver's style information.
boolean	getXORMode() Returns true if this GC is drawing in the mode where the resulting color in the destination is the exclusive or of the color values in the source and the destination, and false if it is drawing in the mode where the destination color is being replaced with the source color value.
int	hashCode() Returns an integer hash code for the receiver.
boolean	isClipped() Returns true if the receiver has a clipping region set into it, and false otherwise.
boolean	isDisposed() Returns true if the GC has been disposed, and false otherwise.
void	setBackground(Color color) Sets the background color.
void	setClipping(int x, int y, int width, int height) Sets the area of the receiver which can be changed by drawing operations to the rectangular area specified by the arguments.
void	setClipping(Rectangle rect) Sets the area of the receiver which can be changed by drawing operations to the rectangular area specified by the argument.
void	setClipping(Region region) Sets the area of the receiver which can be changed by drawing operations to the region specified by the argument.
void	setFont(Font font) Sets the font which will be used by the receiver to draw and measure text to the argument.
void	setForeground(Color color) Sets the foreground color.
void	setLineStyle(int lineStyle) Sets the receiver's line style to the argument, which must be one of the constants SWT.LINE_SOLID, SWT.LINE_DASH, SWT.LINE_DOT, SWT.LINE_DASHDOT or SWT.LINE_DASHDOTDOT.
void	setLineWidth(int lineWidth) Sets the width that will be used when drawing lines for all of the figure drawing operations (that is, drawLine, drawRectangle, drawPolyline, and so forth.
void	setXORMode(boolean xor) If the argument is true, puts the receiver in a drawing mode where the resulting color in the destination is the exclusive or of the color values in the source and the destination, and if the argument is false, puts the receiver in a drawing mode where the destination color is replaced with the source color value.
Point	stringExtent(String string) Returns the extent of the given string.
Point	textExtent(String string) Returns the extent of the given string.
Point	textExtent(String string, int flags) Returns the extent of the given string.
String	toString() Returns a string containing a concise, human-readable description of the receiver.
static GC	win32_new(Drawable drawable, GCData data) Invokes platform specific functionality to allocate a new graphics context.
static GC	win32_new(int hDC, GCData data) Invokes platform specific functionality to wrap a graphics context.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

handle

public int handle

the handle to the OS device context (Warning: This field is platform dependent)

Constructor Detail

GC

public GC(Drawable drawable)

Constructs a new instance of this class which has been configured to draw on the specified drawable. Sets the foreground and background color in the GC to match those in the drawable.

You must dispose the graphics context when it is no longer required.

Parameters:

drawable - the drawable to draw on

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the drawable is null
• ERROR_NULL_ARGUMENT - if there is no current device
• ERROR_INVALID_ARGUMENT - if the drawable is an image that is not a bitmap or an icon - if the drawable is an image or printer that is already selected into another graphics context

SWTError -

• ERROR_NO_HANDLES if a handle could not be obtained for gc creation

GC

public GC(Drawable drawable,
          int style)

Constructs a new instance of this class which has been configured to draw on the specified drawable. Sets the foreground and background color in the GC to match those in the drawable.

You must dispose the graphics context when it is no longer required.

Parameters:

drawable - the drawable to draw on

style - the style of GC to construct

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the drawable is null
• ERROR_NULL_ARGUMENT - if there is no current device
• ERROR_INVALID_ARGUMENT - if the drawable is an image that is not a bitmap or an icon - if the drawable is an image or printer that is already selected into another graphics context

SWTError -

• ERROR_NO_HANDLES if a handle could not be obtained for gc creation

Since:

2.1.2

Method Detail

copyArea

public void copyArea(Image image,
                     int x,
                     int y)

Copies a rectangular area of the receiver at the specified position into the image, which must be of type SWT.BITMAP.

Parameters:

image - the image to copy into

x - the x coordinate in the receiver of the area to be copied

y - the y coordinate in the receiver of the area to be copied

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the image is null
• ERROR_INVALID_ARGUMENT - if the image is not a bitmap or has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

copyArea

public void copyArea(int srcX,
                     int srcY,
                     int width,
                     int height,
                     int destX,
                     int destY)

Copies a rectangular area of the receiver at the source position onto the receiver at the destination position.

Parameters:

srcX - the x coordinate in the receiver of the area to be copied

srcY - the y coordinate in the receiver of the area to be copied

width - the width of the area to copy

height - the height of the area to copy

destX - the x coordinate in the receiver of the area to copy to

destY - the y coordinate in the receiver of the area to copy to

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

dispose

public void dispose()

Disposes of the operating system resources associated with the graphics context. Applications must dispose of all GCs which they allocate.

drawArc

public void drawArc(int x,
                    int y,
                    int width,
                    int height,
                    int startAngle,
                    int arcAngle)

Draws the outline of a circular or elliptical arc within the specified rectangular area.

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.

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawFocus

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

Draws a rectangle, based on the specified arguments, which has the appearance of the platform's focus rectangle if the platform supports such a notion, and otherwise draws a simple rectangle in the receiver's foreground color.

Parameters:

x - the x coordinate of the rectangle

y - the y coordinate of the rectangle

width - the width of the rectangle

height - the height of the rectangle

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawRectangle(int, int, int, int)

drawImage

public void drawImage(Image image,
                      int x,
                      int y)

Draws the given image in the receiver at the specified coordinates.

Parameters:

image - the image to draw

x - the x coordinate of where to draw

y - the y coordinate of where to draw

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the image is null
• ERROR_INVALID_ARGUMENT - if the image has been disposed
• ERROR_INVALID_ARGUMENT - if the given coordinates are outside the bounds of the image
  SWTError -

  • ERROR_NO_HANDLES - if no handles are available to perform the operation

  SWTException -

  • ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawImage

public void drawImage(Image image,
                      int srcX,
                      int srcY,
                      int srcWidth,
                      int srcHeight,
                      int destX,
                      int destY,
                      int destWidth,
                      int destHeight)

Copies a rectangular area from the source image into a (potentially different sized) rectangular area in the receiver. If the source and destination areas are of differing sizes, then the source area will be stretched or shrunk to fit the destination area as it is copied. The copy fails if any part of the source rectangle lies outside the bounds of the source image, or if any of the width or height arguments are negative.

Parameters:

image - the source image

srcX - the x coordinate in the source image to copy from

srcY - the y coordinate in the source image to copy from

srcWidth - the width in pixels to copy from the source

srcHeight - the height in pixels to copy from the source

destX - the x coordinate in the destination to copy to

destY - the y coordinate in the destination to copy to

destWidth - the width in pixels of the destination rectangle

destHeight - the height in pixels of the destination rectangle

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the image is null
• ERROR_INVALID_ARGUMENT - if the image has been disposed
• ERROR_INVALID_ARGUMENT - if any of the width or height arguments are negative.
• ERROR_INVALID_ARGUMENT - if the source rectangle is not contained within the bounds of the source image

SWTError -

• ERROR_NO_HANDLES - if no handles are available to perform the operation

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawLine

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

Draws a line, using the foreground color, between the points (x1, y1) and (x2, y2).

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawOval

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

Draws the outline of an oval, using the foreground color, within the specified rectangular area.

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawPoint

public void drawPoint(int x,
                      int y)

Draws a pixel, using the foreground color, at the specified point (x, y).

Note that the receiver's line attributes do not affect this operation.

Parameters:

x - the point's x coordinate

y - the point's y coordinate

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

3.0

drawPolygon

public void drawPolygon(int[] pointArray)

Draws the closed polygon which is defined by the specified array of integer coordinates, using the receiver's foreground color. The array contains alternating x and y values which are considered to represent points which are the vertices of the polygon. Lines are drawn between each consecutive pair, and between the first pair and last pair in the array.

Parameters:

pointArray - an array of alternating x and y values which are the vertices of the polygon

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT if pointArray is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawPolyline

public void drawPolyline(int[] pointArray)

Draws the polyline which is defined by the specified array of integer coordinates, using the receiver's foreground color. The array contains alternating x and y values which are considered to represent points which are the corners of the polyline. Lines are drawn between each consecutive pair, but not between the first pair and last pair in the array.

Parameters:

pointArray - an array of alternating x and y values which are the corners of the polyline

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the point array is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawRectangle

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

Draws the outline of the rectangle specified by the arguments, using the receiver's foreground color. 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.

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawRectangle

public void drawRectangle(Rectangle rect)

Draws the outline of the specified rectangle, using the receiver's foreground color. The left and right edges of the rectangle are at rect.x and rect.x + rect.width. The top and bottom edges are at rect.y and rect.y + rect.height.

Parameters:

rect - the rectangle to draw

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the rectangle is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawRoundRectangle

public void drawRoundRectangle(int x,
                               int y,
                               int width,
                               int height,
                               int arcWidth,
                               int arcHeight)

Draws the outline of the round-cornered rectangle specified by the arguments, using the receiver's foreground color. 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 roundness of the corners is specified by the arcWidth and arcHeight arguments.

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawString

public void drawString(String string,
                       int x,
                       int y)

Draws the given string, using the receiver's current font and foreground color. No tab expansion or carriage return processing will be performed. The background of the rectangular area where the string is being drawn will be filled with the receiver's background color.

Parameters:

string - the string to be drawn

x - the x coordinate of the top left corner of the rectangular area where the string is to be drawn

y - the y coordinate of the top left corner of the rectangular area where the string is to be drawn

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawString

public void drawString(String string,
                       int x,
                       int y,
                       boolean isTransparent)

Draws the given string, using the receiver's current font and foreground color. No tab expansion or carriage return processing will be performed. If isTransparent is true, then the background of the rectangular area where the string is being drawn will not be modified, otherwise it will be filled with the receiver's background color.

Parameters:

string - the string to be drawn

x - the x coordinate of the top left corner of the rectangular area where the string is to be drawn

y - the y coordinate of the top left corner of the rectangular area where the string is to be drawn

isTransparent - if true the background will be transparent, otherwise it will be opaque

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(String string,
                     int x,
                     int y)

Draws the given string, using the receiver's current font and foreground color. Tab expansion and carriage return processing are performed. The background of the rectangular area where the text is being drawn will be filled with the receiver's background color.

Parameters:

string - the string to be drawn

x - the x coordinate of the top left corner of the rectangular area where the text is to be drawn

y - the y coordinate of the top left corner of the rectangular area where the text is to be drawn

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(String string,
                     int x,
                     int y,
                     boolean isTransparent)

Draws the given string, using the receiver's current font and foreground color. Tab expansion and carriage return processing are performed. If isTransparent is true, then the background of the rectangular area where the text is being drawn will not be modified, otherwise it will be filled with the receiver's background color.

Parameters:

string - the string to be drawn

x - the x coordinate of the top left corner of the rectangular area where the text is to be drawn

y - the y coordinate of the top left corner of the rectangular area where the text is to be drawn

isTransparent - if true the background will be transparent, otherwise it will be opaque

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(String string,
                     int x,
                     int y,
                     int flags)

Draws the given string, using the receiver's current font and foreground color. Tab expansion, line delimiter and mnemonic processing are performed according to the specified flags. If flags includes DRAW_TRANSPARENT, then the background of the rectangular area where the text is being drawn will not be modified, otherwise it will be filled with the receiver's background color.

The parameter flags may be a combination of:

DRAW_DELIMITER

draw multiple lines

DRAW_TAB

expand tabs

DRAW_MNEMONIC

underline the mnemonic character

DRAW_TRANSPARENT

transparent background

Parameters:

string - the string to be drawn

x - the x coordinate of the top left corner of the rectangular area where the text is to be drawn

y - the y coordinate of the top left corner of the rectangular area where the text is to be drawn

flags - the flags specifing how to process the text

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

equals

public boolean equals(Object object)

Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.

Parameters:

object - the object to compare with this object

Returns:

true if the object is the same as this object and false otherwise

See Also:

hashCode()

fillArc

public void fillArc(int x,
                    int y,
                    int width,
                    int height,
                    int startAngle,
                    int arcAngle)

Fills the interior of a circular or elliptical arc within the specified rectangular area, with the receiver's background color.

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.

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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawArc(int, int, int, int, int, int)

fillGradientRectangle

public void fillGradientRectangle(int x,
                                  int y,
                                  int width,
                                  int height,
                                  boolean vertical)

Fills the interior of the specified rectangle with a gradient sweeping from left to right or top to bottom progressing from the receiver's foreground color to its background 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, may be negative (inverts direction of gradient if horizontal)

height - the height of the rectangle to be filled, may be negative (inverts direction of gradient if vertical)

vertical - if true sweeps from top to bottom, else sweeps from left to right

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawRectangle(int, int, int, int)

fillOval

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

Fills the interior of an oval, within the specified rectangular area, with the receiver's background 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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawOval(int, int, int, int)

fillPolygon

public void fillPolygon(int[] pointArray)

Fills the interior of the closed polygon which is defined by the specified array of integer coordinates, using the receiver's background color. The array contains alternating x and y values which are considered to represent points which are the vertices of the polygon. Lines are drawn between each consecutive pair, and between the first pair and last pair in the array.

Parameters:

pointArray - an array of alternating x and y values which are the vertices of the polygon

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT if pointArray is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawPolygon(int[])

fillRectangle

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

Fills the interior of the rectangle specified by the arguments, using the receiver's background 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

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawRectangle(int, int, int, int)

fillRectangle

public void fillRectangle(Rectangle rect)

Fills the interior of the specified rectangle, using the receiver's background color.

Parameters:

rect - the rectangle to be filled

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the rectangle is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawRectangle(int, int, int, int)

fillRoundRectangle

public void fillRoundRectangle(int x,
                               int y,
                               int width,
                               int height,
                               int arcWidth,
                               int arcHeight)

Fills the interior of the round-cornered rectangle specified by the arguments, using the receiver's background 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

arcWidth - the horizontal diameter of the arc at the four corners

arcHeight - the vertical diameter of the arc at the four corners

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawRoundRectangle(int, int, int, int, int, int)

getAdvanceWidth

public int getAdvanceWidth(char ch)

Returns the advance width of the specified character in the font which is currently selected into the receiver.

The advance width is defined as the horizontal distance the cursor should move after printing the character in the selected font.

Parameters:

ch - the character to measure

Returns:

the distance in the x direction to move past the character before painting the next

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getBackground

public Color getBackground()

Returns the background color.

Returns:

the receiver's background color

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getCharWidth

public int getCharWidth(char ch)

Returns the width of the specified character in the font selected into the receiver.

The width is defined as the space taken up by the actual character, not including the leading and tailing whitespace or overhang.

Parameters:

ch - the character to measure

Returns:

the width of the character

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getClipping

public Rectangle getClipping()

Returns the bounding rectangle of the receiver's clipping region. If no clipping region is set, the return value will be a rectangle which covers the entire bounds of the object the receiver is drawing on.

Returns:

the bounding rectangle of the clipping region

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getClipping

public void getClipping(Region region)

Sets the region managed by the argument to the current clipping region of the receiver.

Parameters:

region - the region to fill with the clipping region

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the region is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getFont

public Font getFont()

Returns the font currently being used by the receiver to draw and measure text.

Returns:

the receiver's font

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getFontMetrics

public FontMetrics getFontMetrics()

Returns a FontMetrics which contains information about the font currently being used by the receiver to draw and measure text.

Returns:

font metrics for the receiver's font

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getForeground

public Color getForeground()

Returns the receiver's foreground color.

Returns:

the color used for drawing foreground things

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getLineStyle

public int getLineStyle()

Returns the receiver's line style, which will be one of the constants SWT.LINE_SOLID, SWT.LINE_DASH, SWT.LINE_DOT, SWT.LINE_DASHDOT or SWT.LINE_DASHDOTDOT.

Returns:

the style used for drawing lines

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getLineWidth

public int getLineWidth()

Returns the width that will be used when drawing lines for all of the figure drawing operations (that is, drawLine, drawRectangle, drawPolyline, and so forth.

Returns:

the receiver's line width

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getStyle

public int getStyle()

Returns the receiver's style information.

Note that the value which is returned by this method may not match the value which was provided to the constructor when the receiver was created. This can occur when the underlying operating system does not support a particular combination of requested styles.

Returns:

the style bits

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

2.1.2

getXORMode

public boolean getXORMode()

Returns true if this GC is drawing in the mode where the resulting color in the destination is the exclusive or of the color values in the source and the destination, and false if it is drawing in the mode where the destination color is being replaced with the source color value.

Returns:

true true if the receiver is in XOR mode, and false otherwise

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

hashCode

public int hashCode()

Returns an integer hash code for the receiver. Any two objects which return true when passed to equals must return the same value for this method.

Returns:

the receiver's hash

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

equals(java.lang.Object)

isClipped

public boolean isClipped()

Returns true if the receiver has a clipping region set into it, and false otherwise. If this method returns false, the receiver will draw on all available space in the destination. If it returns true, it will draw only in the area that is covered by the region that can be accessed with getClipping(region).

Returns:

true if the GC has a clipping region, and false otherwise

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

isDisposed

public boolean isDisposed()

Returns true if the GC has been disposed, and false otherwise.

This method gets the dispose state for the GC. When a GC has been disposed, it is an error to invoke any other method using the GC.

Returns:

true when the GC is disposed and false otherwise

setBackground

public void setBackground(Color color)

Sets the background color. The background color is used for fill operations and as the background color when text is drawn.

Parameters:

color - the new background color for the receiver

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the color is null
• ERROR_INVALID_ARGUMENT - if the color has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setClipping

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

Sets the area of the receiver which can be changed by drawing operations to the rectangular area specified by the arguments.

Parameters:

x - the x coordinate of the clipping rectangle

y - the y coordinate of the clipping rectangle

width - the width of the clipping rectangle

height - the height of the clipping rectangle

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setClipping

public void setClipping(Rectangle rect)

Sets the area of the receiver which can be changed by drawing operations to the rectangular area specified by the argument.

Parameters:

rect - the clipping rectangle

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setClipping

public void setClipping(Region region)

Sets the area of the receiver which can be changed by drawing operations to the region specified by the argument.

Parameters:

region - the clipping region.

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setFont

public void setFont(Font font)

Sets the font which will be used by the receiver to draw and measure text to the argument. If the argument is null, then a default font appropriate for the platform will be used instead.

Parameters:

font - the new font for the receiver, or null to indicate a default font

Throws:

IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the font has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setForeground

public void setForeground(Color color)

Sets the foreground color. The foreground color is used for drawing operations including when text is drawn.

Parameters:

color - the new foreground color for the receiver

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the color is null
• ERROR_INVALID_ARGUMENT - if the color has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setLineStyle

public void setLineStyle(int lineStyle)

Sets the receiver's line style to the argument, which must be one of the constants SWT.LINE_SOLID, SWT.LINE_DASH, SWT.LINE_DOT, SWT.LINE_DASHDOT or SWT.LINE_DASHDOTDOT.

Parameters:

lineStyle - the style to be used for drawing lines

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setLineWidth

public void setLineWidth(int lineWidth)

Sets the width that will be used when drawing lines for all of the figure drawing operations (that is, drawLine, drawRectangle, drawPolyline, and so forth.

Parameters:

lineWidth - the width of a line

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setXORMode

public void setXORMode(boolean xor)

If the argument is true, puts the receiver in a drawing mode where the resulting color in the destination is the exclusive or of the color values in the source and the destination, and if the argument is false, puts the receiver in a drawing mode where the destination color is replaced with the source color value.

Parameters:

xor - if true, then xor mode is used, otherwise source copy mode is used

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

stringExtent

public Point stringExtent(String string)

Returns the extent of the given string. No tab expansion or carriage return processing will be performed.

The extent of a string is the width and height of the rectangular area it would cover if drawn in a particular font (in this case, the current font in the receiver).

Parameters:

string - the string to measure

Returns:

a point containing the extent of the string

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

textExtent

public Point textExtent(String string)

Returns the extent of the given string. Tab expansion and carriage return processing are performed.

The extent of a string is the width and height of the rectangular area it would cover if drawn in a particular font (in this case, the current font in the receiver).

Parameters:

string - the string to measure

Returns:

a point containing the extent of the string

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

textExtent

public Point textExtent(String string,
                        int flags)

Returns the extent of the given string. Tab expansion, line delimiter and mnemonic processing are performed according to the specified flags, which can be a combination of:

DRAW_DELIMITER

draw multiple lines

DRAW_TAB

expand tabs

DRAW_MNEMONIC

underline the mnemonic character

DRAW_TRANSPARENT

transparent background

The extent of a string is the width and height of the rectangular area it would cover if drawn in a particular font (in this case, the current font in the receiver).

Parameters:

string - the string to measure

flags - the flags specifing how to process the text

Returns:

a point containing the extent of the string

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

toString

public String toString()

Returns a string containing a concise, human-readable description of the receiver.

Returns:

a string representation of the receiver

win32_new

public static GC win32_new(Drawable drawable,
                           GCData data)

Invokes platform specific functionality to allocate a new graphics context.

IMPORTANT: This method is not part of the public API for GC. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

Parameters:

drawable - the Drawable for the receiver.

data - the data for the receiver.

Returns:

a new GC

win32_new

public static GC win32_new(int hDC,
                           GCData data)

Invokes platform specific functionality to wrap a graphics context.

IMPORTANT: This method is not part of the public API for GC. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

Parameters:

hDC - the Windows HDC.

data - the data for the receiver.

Returns:

a new GC