org.eclipse.swt.graphics

Class GC

java.lang.Object

org.eclipse.swt.graphics.Resource

org.eclipse.swt.graphics.GC

public class GC
extends Resource

Class GC is where all of the drawing capabilities that are supported by SWT are located. Instances are used to draw on a Control.

Styles:

LEFT_TO_RIGHT

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.

Since:

1.3

See Also:

Constructor Summary

Constructors

Constructor and Description
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

Modifier and Type	Method and Description
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	drawPath(Path path) Draws the path described by the parameter.
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(java.lang.String string, int x, int y) Draws the given string, using the receiver's current font and foreground color.
void	drawString(java.lang.String string, int x, int y, boolean isTransparent) Draws the given string, using the receiver's current font and foreground color.
void	drawText(java.lang.String string, int x, int y) Draws the given string, using the receiver's current font and foreground color.
void	drawText(java.lang.String string, int x, int y, boolean isTransparent) Draws the given string, using the receiver's current font and foreground color.
void	drawText(java.lang.String string, int x, int y, int flags) Draws the given string, using the receiver's current font and foreground color.
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	fillPath(Path path) Fills the path described by the parameter.
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.
boolean	getAdvanced() Returns true if receiver is using the operating system's advanced graphics subsystem.
int	getAlpha() Returns the receiver's alpha value.
int	getAntialias() Returns the receiver's anti-aliasing setting value, which will be one of SWT.DEFAULT, SWT.OFF or SWT.ON.
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.
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.
LineAttributes	getLineAttributes() Returns the receiver's line attributes.
int	getLineCap() Returns the receiver's line cap style, which will be one of the constants SWT.CAP_FLAT, SWT.CAP_ROUND, or SWT.CAP_SQUARE.
int	getLineJoin() Returns the receiver's line join style, which will be one of the constants SWT.JOIN_MITER, SWT.JOIN_ROUND, or SWT.JOIN_BEVEL.
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.
int	getTextAntialias() Returns the receiver's text drawing anti-aliasing setting value, which will be one of SWT.DEFAULT, SWT.OFF or SWT.ON.
void	getTransform(Transform transform) Sets the parameter to the transform that is currently being used by the receiver.
void	setAdvanced(boolean advanced) Sets the receiver to always use the operating system's advanced graphics subsystem for all graphics operations if the argument is true.
void	setAlpha(int alpha) Sets the receiver's alpha value which must be between 0 (transparent) and 255 (opaque).
void	setAntialias(int antialias) Sets the receiver's anti-aliasing value to the parameter, which must be one of SWT.DEFAULT, SWT.OFF or SWT.ON.
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(Path path) Sets the area of the receiver which can be changed by drawing operations to the path specified by the argument.
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	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	setLineAttributes(LineAttributes attributes) Sets the receiver's line attributes.
void	setLineCap(int lineCap) Sets the receiver's line cap style to the argument, which must be one of the constants SWT.CAP_FLAT, SWT.CAP_ROUND, or SWT.CAP_SQUARE.
void	setLineJoin(int lineJoin) Sets the receiver's line join style to the argument, which must be one of the constants SWT.JOIN_MITER, SWT.JOIN_ROUND, or SWT.JOIN_BEVEL.
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	setTextAntialias(int antialias) Sets the receiver's text anti-aliasing value to the parameter, which must be one of SWT.DEFAULT, SWT.OFF or SWT.ON.
void	setTransform(Transform transform) Sets the transform that is currently being used by the receiver.
Point	stringExtent(java.lang.String string) Returns the extent of the given string.
Point	textExtent(java.lang.String string) Returns the extent of the given string.

Methods inherited from class org.eclipse.swt.graphics.Resource

dispose, getDevice, isDisposed

Methods inherited from class java.lang.Object

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

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 color, background color and font 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:

java.lang.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
• ERROR_THREAD_INVALID_ACCESS if not called from the thread that created the drawable

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 color, background color and font 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:

java.lang.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
• ERROR_THREAD_INVALID_ACCESS if not called from the thread that created the drawable

Method Detail

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:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the font has been disposed

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

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

stringExtent

public Point stringExtent(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

textExtent

public Point textExtent(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

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

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:

java.lang.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

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

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:

java.lang.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

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

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. Specifying null for the rectangle reverts the receiver's clipping area to its original value.

Parameters:

rect - the clipping rectangle or null

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

3.0

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

Since:

3.0

setClipping

public void setClipping(Path path)

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

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

path - the clipping path.

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the path has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

3.0

See Also:

Path, getAdvanced(), setAdvanced(boolean)

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

setAlpha

public void setAlpha(int alpha)

Sets the receiver's alpha value which must be between 0 (transparent) and 255 (opaque).

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

alpha - the alpha value

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

getAlpha

public int getAlpha()

Returns the receiver's alpha value. The alpha value is between 0 (transparent) and 255 (opaque).

Returns:

the alpha value

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

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

setLineCap

public void setLineCap(int lineCap)

Sets the receiver's line cap style to the argument, which must be one of the constants SWT.CAP_FLAT, SWT.CAP_ROUND, or SWT.CAP_SQUARE.

Parameters:

lineCap - the cap style to be used for drawing lines

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the style is not valid

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getLineCap

public int getLineCap()

Returns the receiver's line cap style, which will be one of the constants SWT.CAP_FLAT, SWT.CAP_ROUND, or SWT.CAP_SQUARE.

Returns:

the cap style used for drawing lines

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setLineJoin

public void setLineJoin(int lineJoin)

Sets the receiver's line join style to the argument, which must be one of the constants SWT.JOIN_MITER, SWT.JOIN_ROUND, or SWT.JOIN_BEVEL.

Parameters:

lineJoin - the join style to be used for drawing lines

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the style is not valid

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

getLineJoin

public int getLineJoin()

Returns the receiver's line join style, which will be one of the constants SWT.JOIN_MITER, SWT.JOIN_ROUND, or SWT.JOIN_BEVEL.

Returns:

the join style used for drawing lines

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setLineAttributes

public void setLineAttributes(LineAttributes attributes)

Sets the receiver's line attributes.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

attributes - the line attributes

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the attributes is null
• ERROR_INVALID_ARGUMENT - if any of the line attributes is not valid

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

See Also:

LineAttributes

getLineAttributes

public LineAttributes getLineAttributes()

Returns the receiver's line attributes.

Returns:

the line attributes used for drawing lines

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

setAdvanced

public void setAdvanced(boolean advanced)

Sets the receiver to always use the operating system's advanced graphics subsystem for all graphics operations if the argument is true. If the argument is false, the advanced graphics subsystem is no longer used, advanced graphics state is cleared and the normal graphics subsystem is used from now on.

Normally, the advanced graphics subsystem is invoked automatically when any one of the alpha, antialias, patterns, interpolation, paths, clipping or transformation operations in the receiver is requested. When the receiver is switched into advanced mode, the advanced graphics subsystem performs both advanced and normal graphics operations. Because the two subsystems are different, their output may differ. Switching to advanced graphics before any graphics operations are performed ensures that the output is consistent.

Advanced graphics may not be installed for the operating system. In this case, this operation does nothing. Some operating system have only one graphics subsystem, so switching from normal to advanced graphics does nothing. However, switching from advanced to normal graphics will always clear the advanced graphics state, even for operating systems that have only one graphics subsystem.

Parameters:

advanced - the new advanced graphics state

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

1.4

See Also:

setAlpha(int), setAntialias(int), setClipping(Path), setLineAttributes(org.eclipse.swt.graphics.LineAttributes), setTextAntialias(int), setTransform(org.eclipse.swt.graphics.Transform), getAdvanced()

setAntialias

public void setAntialias(int antialias)

Sets the receiver's anti-aliasing value to the parameter, which must be one of SWT.DEFAULT, SWT.OFF or SWT.ON. Note that this controls anti-aliasing for all non-text drawing operations.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

antialias - the anti-aliasing setting

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the parameter is not one of SWT.DEFAULT, SWT.OFF or SWT.ON

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

1.5

See Also:

getAdvanced(), setAdvanced(boolean), setTextAntialias(int)

getAntialias

public int getAntialias()

Returns the receiver's anti-aliasing setting value, which will be one of SWT.DEFAULT, SWT.OFF or SWT.ON. Note that this controls anti-aliasing for all non-text drawing operations.

Returns:

the anti-aliasing setting

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

1.5

See Also:

getTextAntialias()

setTextAntialias

public void setTextAntialias(int antialias)

Sets the receiver's text anti-aliasing value to the parameter, which must be one of SWT.DEFAULT, SWT.OFF or SWT.ON. Note that this controls anti-aliasing only for all text drawing operations.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

antialias - the anti-aliasing setting

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the parameter is not one of SWT.DEFAULT, SWT.OFF or SWT.ON

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

1.5

See Also:

getAdvanced(), setAdvanced(boolean), setAntialias(int)

getTextAntialias

public int getTextAntialias()

Returns the receiver's text drawing anti-aliasing setting value, which will be one of SWT.DEFAULT, SWT.OFF or SWT.ON. Note that this controls anti-aliasing only for text drawing operations.

Returns:

the anti-aliasing setting

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

1.5

See Also:

getAntialias()

getAdvanced

public boolean getAdvanced()

Returns true if receiver is using the operating system's advanced graphics subsystem. Otherwise, false is returned to indicate that normal graphics are in use.

Advanced graphics may not be installed for the operating system. In this case, false is always returned. Some operating system have only one graphics subsystem. If this subsystem supports advanced graphics, then true is always returned. If any graphics operation such as alpha, antialias, patterns, interpolation, paths, clipping or transformation has caused the receiver to switch from regular to advanced graphics mode, true is returned. If the receiver has been explicitly switched to advanced mode and this mode is supported, true is returned.

Returns:

the advanced value

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

1.4

See Also:

setAdvanced(boolean)

setTransform

public void setTransform(Transform transform)

Sets the transform that is currently being used by the receiver. If the argument is null, the current transform is set to the identity transform.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

transform - the transform to set

Throws:

java.lang.IllegalArgumentException -

• ERROR_INVALID_ARGUMENT - if the parameter has been disposed

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

3.1

See Also:

Transform, getAdvanced(), setAdvanced(boolean)

getTransform

public void getTransform(Transform transform)

Sets the parameter to the transform that is currently being used by the receiver.

Parameters:

transform - the destination to copy the transform into

Throws:

java.lang.IllegalArgumentException -

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

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

Since:

3.1

See Also:

Transform

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

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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the rectangle 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

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)

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:

java.lang.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)

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)

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)

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, which are respectively the width and height of the ellipse used to draw the corners.

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 width of the arc

arcHeight - the height of the arc

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

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 width of the arc

arcHeight - the height of the arc

Throws:

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

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

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

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)

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

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)

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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT if pointArray is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT if pointArray is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

See Also:

drawPolygon(int[])

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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the point array is null

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

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:

java.lang.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

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

SWTError -

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

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:

java.lang.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

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

SWTError -

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

drawString

public void drawString(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawString

public void drawString(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(java.lang.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:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawText

public void drawText(java.lang.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 specifying how to process the text

Throws:

java.lang.IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the string is null

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed

drawPath

public void drawPath(Path path)

Draws the path described by the parameter.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

path - the path to draw

Throws:

java.lang.IllegalArgumentException -

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

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

2.1

See Also:

Path

fillPath

public void fillPath(Path path)

Fills the path described by the parameter.

This operation requires the operating system's advanced graphics subsystem which may not be available on some platforms.

Parameters:

path - the path to fill

Throws:

java.lang.IllegalArgumentException -

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

SWTException -

• ERROR_GRAPHIC_DISPOSED - if the receiver has been disposed
• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

Since:

2.1

See Also:

Path

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