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java.lang.Objectorg.eclipse.swt.graphics.Device
public abstract class Device
This class is the abstract superclass of all device objects, such as the Display device and the Printer device. Devices can have a graphics context (GC) created for them, and they can be drawn on by sending messages to the associated GC.
| Field Summary | |
|---|---|
protected static Device |
CurrentDevice
|
static boolean |
DEBUG
|
protected static Runnable |
DeviceFinder
|
int |
hPalette
Palette (Warning: This field is platform dependent) IMPORTANT: This field is not part of the SWT public API. |
| Constructor Summary | |
|---|---|
Device()
Constructs a new instance of this class. |
|
Device(DeviceData data)
Constructs a new instance of this class. |
|
| Method Summary | |
|---|---|
protected void |
checkDevice()
Throws an SWTException if the receiver can not
be accessed by the caller. |
protected void |
create(DeviceData data)
Creates the device in the operating system. |
protected void |
destroy()
Destroys the device in the operating system and releases the device's handle. |
void |
dispose()
Disposes of the operating system resources associated with the receiver. |
Rectangle |
getBounds()
Returns a rectangle describing the receiver's size and location. |
Rectangle |
getClientArea()
Returns a rectangle which describes the area of the receiver which is capable of displaying data. |
int |
getDepth()
Returns the bit depth of the screen, which is the number of bits it takes to represent the number of unique colors that the screen is currently capable of displaying. |
DeviceData |
getDeviceData()
Returns a DeviceData based on the receiver. |
Point |
getDPI()
Returns a point whose x coordinate is the horizontal dots per inch of the display, and whose y coordinate is the vertical dots per inch of the display. |
FontData[] |
getFontList(String faceName,
boolean scalable)
Returns FontData objects which describe
the fonts that match the given arguments. |
Color |
getSystemColor(int id)
Returns the matching standard color for the given constant, which should be one of the color constants specified in class SWT. |
Font |
getSystemFont()
Returns a reasonable font for applications to use. |
boolean |
getWarnings()
Returns true if the underlying window system prints out
warning messages on the console, and setWarnings
had previously been called with true. |
protected void |
init()
Initializes any internal resources needed by the device. |
abstract void |
internal_dispose_GC(int hDC,
GCData data)
Invokes platform specific functionality to dispose a GC handle. |
abstract int |
internal_new_GC(GCData data)
Invokes platform specific functionality to allocate a new GC handle. |
boolean |
isDisposed()
Returns true if the device has been disposed,
and false otherwise. |
protected void |
release()
Releases any internal resources back to the operating system and clears all fields except the device handle. |
void |
setWarnings(boolean warnings)
If the underlying window system supports printing warning messages to the console, setting warnings to false prevents these
messages from being printed. |
| Methods inherited from class java.lang.Object |
|---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
|---|
public static boolean DEBUG
public int hPalette
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.
protected static Device CurrentDevice
protected static Runnable DeviceFinder
| Constructor Detail |
|---|
public Device()
You must dispose the device when it is no longer required.
create(org.eclipse.swt.graphics.DeviceData),
init()public Device(DeviceData data)
You must dispose the device when it is no longer required.
data - the DeviceData which describes the receivercreate(org.eclipse.swt.graphics.DeviceData),
init(),
DeviceData| Method Detail |
|---|
protected void checkDevice()
SWTException if the receiver can not
be accessed by the caller. This may include both checks on
the state of the receiver and more generally on the entire
execution context. This method should be called by
device implementors to enforce the standard SWT invariants.
Currently, it is an error to invoke any method (other than
isDisposed() and dispose()) on a
device that has had its dispose() method called.
In future releases of SWT, there may be more or fewer error checks and exceptions may be thrown for different reasons.
SWTException - protected void create(DeviceData data)
This method is called before init.
Subclasses are supposed to reimplement this method and not
call the super implementation.
data - the DeviceData which describes the receiverinit()protected void destroy()
This method is called after release.
Subclasses are supposed to reimplement this method and not
call the super implementation.
dispose(),
release()public void dispose()
true when sent the message
isDisposed().
release(),
destroy(),
checkDevice()public Rectangle getBounds()
SWTException - public DeviceData getDeviceData()
DeviceData based on the receiver.
Modifications made to this DeviceData will not
affect the receiver.
DeviceData containing the device's data and attributes
SWTException - DeviceDatapublic Rectangle getClientArea()
SWTException - getBounds()public int getDepth()
SWTException - public Point getDPI()
SWTException -
public FontData[] getFontList(String faceName,
boolean scalable)
FontData objects which describe
the fonts that match the given arguments. If the
faceName is null, all fonts will be returned.
faceName - the name of the font to look for, or nullscalable - if true only scalable fonts are returned, otherwise only non-scalable fonts are returned.
SWTException - public Color getSystemColor(int id)
SWT. Any value other
than one of the SWT color constants which is passed
in will result in the color black. This color should
not be freed because it was allocated by the system,
not the application.
id - the color constant
SWTException - SWTpublic Font getSystemFont()
Typically, applications which want the default look should simply not set the font on the widgets they create. Widgets are always created with the correct default font for the class of user-interface component they represent.
SWTException - public boolean getWarnings()
true if the underlying window system prints out
warning messages on the console, and setWarnings
had previously been called with true.
trueif warnings are being handled, and false otherwise
SWTException - protected void init()
This method is called after create.
If subclasses reimplement this method, they must
call the super implementation.
create(org.eclipse.swt.graphics.DeviceData)public abstract int internal_new_GC(GCData data)
IMPORTANT: This method is not part of the public
API for Device. 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.
internal_new_GC in interface Drawabledata - the platform specific GC data
public abstract void internal_dispose_GC(int hDC,
GCData data)
IMPORTANT: This method is not part of the public
API for Device. 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.
internal_dispose_GC in interface DrawablehDC - the platform specific GC handledata - the platform specific GC datapublic boolean isDisposed()
true if the device has been disposed,
and false otherwise.
This method gets the dispose state for the device. When a device has been disposed, it is an error to invoke any other method using the device.
true when the device is disposed and false otherwiseprotected void release()
When a device is destroyed, resources that were acquired
on behalf of the programmer need to be returned to the
operating system. For example, if the device allocated a
font to be used as the system font, this font would be
freed in release. Also,to assist the garbage
collector and minimize the amount of memory that is not
reclaimed when the programmer keeps a reference to a
disposed device, all fields except the handle are zero'd.
The handle is needed by destroy.
destroy.
If subclasses reimplement this method, they must
call the super implementation.
dispose(),
destroy()public void setWarnings(boolean warnings)
false prevents these
messages from being printed. If the argument is true then
message printing is not blocked.
warnings - trueif warnings should be printed, and false otherwise
SWTException -
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