Package org.eclipse.swt.graphics

Class Pattern

java.lang.Object

org.eclipse.swt.graphics.Resource

org.eclipse.swt.graphics.Pattern

public class Pattern
extends Resource

Instances of this class represent patterns to use while drawing. Patterns can be specified either as bitmaps or gradients.

Application code must explicitly invoke the Pattern.dispose() method to release the operating system resources managed by each instance when those instances are no longer required.

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

Since:

3.1

See Also:

• Path, Pattern snippets
• SWT Example: GraphicsExample
• Sample code and further information

Field Summary

Fields

Modifier and Type	Field	Description
long	handle	the OS resource for the Pattern (Warning: This field is platform dependent)

Constructor Summary

Constructors

Constructor	Description
Pattern(Device device, float x1, float y1, float x2, float y2, Color color1, int alpha1, Color color2, int alpha2)	Constructs a new Pattern that represents a linear, two color gradient.
Pattern(Device device, float x1, float y1, float x2, float y2, Color color1, Color color2)	Constructs a new Pattern that represents a linear, two color gradient.
Pattern(Device device, Image image)	Constructs a new Pattern given an image.

Method Summary

Modifier and Type	Method	Description
boolean	isDisposed()	Returns true if the Pattern has been disposed, and false otherwise.
String	toString()	Returns a string containing a concise, human-readable description of the receiver.

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

dispose, getDevice, setNonDisposeHandler

Methods inherited from class java.lang.Object

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

Field Details

handle

public long handle

the OS resource for the Pattern (Warning: This field is platform dependent)

IMPORTANT: This field is not part of the SWT public API. 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 accessed from application code.

Restriction:

This field is not intended to be referenced by clients.

Constructor Details

Pattern

public Pattern(Device device,
 Image image)

Constructs a new Pattern given an image. Drawing with the resulting pattern will cause the image to be tiled over the resulting area.

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

You must dispose the pattern when it is no longer required.

Parameters:

device - the device on which to allocate the pattern

image - the image that the pattern will draw

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the device is null and there is no current device, or the image is null
• ERROR_INVALID_ARGUMENT - if the image has been disposed

SWTException -

• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

SWTError -

• ERROR_NO_HANDLES if a handle for the pattern could not be obtained

See Also:

• Resource.dispose()

Pattern

public Pattern(Device device,
 float x1,
 float y1,
 float x2,
 float y2,
 Color color1,
 Color color2)

Constructs a new Pattern that represents a linear, two color gradient. Drawing with the pattern will cause the resulting area to be tiled with the gradient specified by the arguments.

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

You must dispose the pattern when it is no longer required.

Parameters:

device - the device on which to allocate the pattern

x1 - the x coordinate of the starting corner of the gradient

y1 - the y coordinate of the starting corner of the gradient

x2 - the x coordinate of the ending corner of the gradient

y2 - the y coordinate of the ending corner of the gradient

color1 - the starting color of the gradient

color2 - the ending color of the gradient

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the device is null and there is no current device, or if either color1 or color2 is null
• ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed

SWTException -

• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

SWTError -

• ERROR_NO_HANDLES if a handle for the pattern could not be obtained

See Also:

• Resource.dispose()

Pattern

public Pattern(Device device,
 float x1,
 float y1,
 float x2,
 float y2,
 Color color1,
 int alpha1,
 Color color2,
 int alpha2)

Constructs a new Pattern that represents a linear, two color gradient. Drawing with the pattern will cause the resulting area to be tiled with the gradient specified by the arguments.

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

You must dispose the pattern when it is no longer required.

Parameters:

device - the device on which to allocate the pattern

x1 - the x coordinate of the starting corner of the gradient

y1 - the y coordinate of the starting corner of the gradient

x2 - the x coordinate of the ending corner of the gradient

y2 - the y coordinate of the ending corner of the gradient

color1 - the starting color of the gradient

alpha1 - the starting alpha value of the gradient

color2 - the ending color of the gradient

alpha2 - the ending alpha value of the gradient

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the device is null and there is no current device, or if either color1 or color2 is null
• ERROR_INVALID_ARGUMENT - if either color1 or color2 has been disposed

SWTException -

• ERROR_NO_GRAPHICS_LIBRARY - if advanced graphics are not available

SWTError -

• ERROR_NO_HANDLES if a handle for the pattern could not be obtained

Since:

3.2

See Also:

• Resource.dispose()

Method Details

isDisposed

public boolean isDisposed()

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

This method gets the dispose state for the Pattern. When a Pattern has been disposed, it is an error to invoke any other method (except Resource.dispose()) using the Pattern.

Specified by:

isDisposed in class Resource

Returns:

true when the Pattern is disposed, and false otherwise

toString

public String toString()

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

Overrides:

toString in class Object

Returns:

a string representation of the receiver