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Eclipse Platform
Release 3.0

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org.eclipse.swt.custom
Class CLabel

java.lang.Object
  org.eclipse.swt.widgets.Widget
      org.eclipse.swt.widgets.Control
          org.eclipse.swt.widgets.Scrollable
              org.eclipse.swt.widgets.Composite
                  org.eclipse.swt.widgets.Canvas
                      org.eclipse.swt.custom.CLabel

All Implemented Interfaces:

Drawable

public class CLabel

extends Canvas

A Label which supports aligned text and/or an image and different border styles.

If there is not enough space a CLabel uses the following strategy to fit the information into the available space:

         ignores the indent in left align mode
         ignores the image and the gap
         shortens the text by replacing the center portion of the label with an ellipsis
         shortens the text by removing the center portion of the label
 

Styles:

LEFT, RIGHT, CENTER, SHADOW_IN, SHADOW_OUT, SHADOW_NONE

Events:

IMPORTANT: This class is not intended to be subclassed.

Field Summary

Fields inherited from class org.eclipse.swt.widgets.Control

handle

Constructor Summary

CLabel(Composite parent, int style)
Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.

Method Summary

Point	computeSize(int wHint, int hHint, boolean changed) Returns the preferred size of the receiver.
int	getAlignment() Returns the alignment.
Image	getImage() Return the CLabel's image or null.
String	getText() Return the Label's text.
String	getToolTipText() Returns the receiver's tool tip text, or null if it has not been set.
void	setAlignment(int align) Set the alignment of the CLabel.
void	setBackground(Color color) Sets the receiver's background color to the color specified by the argument, or to the default system color for the control if the argument is null.
void	setBackground(Color[] colors, int[] percents) Specify a gradient of colours to be drawn in the background of the CLabel.
void	setBackground(Color[] colors, int[] percents, boolean vertical) Specify a gradient of colours to be drawn in the background of the CLabel.
void	setBackground(Image image) Set the image to be drawn in the background of the label.
void	setFont(Font font) Sets the font that the receiver will use to paint textual information to the font specified by the argument, or to the default font for that kind of control if the argument is null.
void	setImage(Image image) Set the label's Image.
void	setText(String text) Set the label's text.
void	setToolTipText(String string) Sets the receiver's tool tip text to the argument, which may be null indicating that no tool tip text should be shown.
protected String	shortenText(GC gc, String t, int width) Shorten the given text t so that its length doesn't exceed the given width.

Methods inherited from class org.eclipse.swt.widgets.Canvas

getCaret, scroll, setCaret

Methods inherited from class org.eclipse.swt.widgets.Composite

checkSubclass, getChildren, getLayout, getTabList, layout, layout, setFocus, setLayout, setTabList

Methods inherited from class org.eclipse.swt.widgets.Scrollable

computeTrim, getClientArea, getHorizontalBar, getVerticalBar

Methods inherited from class org.eclipse.swt.widgets.Control

addControlListener, addFocusListener, addHelpListener, addKeyListener, addMouseListener, addMouseMoveListener, addMouseTrackListener, addPaintListener, addTraverseListener, computeSize, forceFocus, getAccessible, getBackground, getBorderWidth, getBounds, getEnabled, getFont, getForeground, getLayoutData, getLocation, getMenu, getMonitor, getParent, getShell, getSize, getVisible, internal_dispose_GC, internal_new_GC, isEnabled, isFocusControl, isReparentable, isVisible, moveAbove, moveBelow, pack, pack, redraw, redraw, removeControlListener, removeFocusListener, removeHelpListener, removeKeyListener, removeMouseListener, removeMouseMoveListener, removeMouseTrackListener, removePaintListener, removeTraverseListener, setBounds, setBounds, setCapture, setCursor, setEnabled, setForeground, setLayoutData, setLocation, setLocation, setMenu, setParent, setRedraw, setSize, setSize, setVisible, toControl, toControl, toDisplay, toDisplay, traverse, update

Methods inherited from class org.eclipse.swt.widgets.Widget

addDisposeListener, addListener, checkWidget, dispose, getData, getData, getDisplay, getStyle, isDisposed, isListening, notifyListeners, removeDisposeListener, removeListener, removeListener, setData, setData, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

CLabel

public CLabel(Composite parent,
              int style)

Constructs a new instance of this class given its parent and a style value describing its behavior and appearance.

The style value is either one of the style constants defined in class SWT which is applicable to instances of this class, or must be built by bitwise OR'ing together (that is, using the int "|" operator) two or more of those SWT style constants. The class description lists the style constants that are applicable to the class. Style bits are also inherited from superclasses.

Parameters:

parent - a widget which will be the parent of the new instance (cannot be null)

style - the style of widget to construct

Throws:

IllegalArgumentException -

• ERROR_NULL_ARGUMENT - if the parent is null

SWTException -

• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent

See Also:

SWT.LEFT, SWT.RIGHT, SWT.CENTER, SWT.SHADOW_IN, SWT.SHADOW_OUT, SWT.SHADOW_NONE, Widget.getStyle()

Method Detail

computeSize

public Point computeSize(int wHint,
                         int hHint,
                         boolean changed)

Description copied from class: Control

Returns the preferred size of the receiver.

The preferred size of a control is the size that it would best be displayed at. The width hint and height hint arguments allow the caller to ask a control questions such as "Given a particular width, how high does the control need to be to show all of the contents?" To indicate that the caller does not wish to constrain a particular dimension, the constant SWT.DEFAULT is passed for the hint.

If the changed flag is true, it indicates that the receiver's contents have changed, therefore any caches that a layout manager containing the control may have been keeping need to be flushed. When the control is resized, the changed flag will be false, so layout manager caches can be retained.

Overrides:

computeSize in class Composite

getAlignment

public int getAlignment()

Returns the alignment. The alignment style (LEFT, CENTER or RIGHT) is returned.

Returns:

SWT.LEFT, SWT.RIGHT or SWT.CENTER

getImage

public Image getImage()

Return the CLabel's image or null.

Returns:

the image of the label or null

setToolTipText

public void setToolTipText(String string)

Description copied from class: Control

Sets the receiver's tool tip text to the argument, which may be null indicating that no tool tip text should be shown.

Overrides:

setToolTipText in class Control

Parameters:

string - the new tool tip text (or null)

getText

public String getText()

Return the Label's text.

Returns:

the text of the label or null

getToolTipText

public String getToolTipText()

Description copied from class: Control

Returns the receiver's tool tip text, or null if it has not been set.

Overrides:

getToolTipText in class Control

Returns:

the receiver's tool tip text

setAlignment

public void setAlignment(int align)

Set the alignment of the CLabel. Use the values LEFT, CENTER and RIGHT to align image and text within the available space.

Parameters:

align - the alignment style of LEFT, RIGHT or CENTER

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_INVALID_ARGUMENT - if the value of align is not one of SWT.LEFT, SWT.RIGHT or SWT.CENTER

setBackground

public void setBackground(Color color)

Description copied from class: Control

Sets the receiver's background color to the color specified by the argument, or to the default system color for the control if the argument is null.

Overrides:

setBackground in class Control

Parameters:

color - the new color (or null)

setBackground

public void setBackground(Color[] colors,
                          int[] percents)

Specify a gradient of colours to be drawn in the background of the CLabel.

For example, to draw a gradient that varies from dark blue to blue and then to white and stays white for the right half of the label, use the following call to setBackground:

    clabel.setBackground(new Color[]{display.getSystemColor(SWT.COLOR_DARK_BLUE), 
                                   display.getSystemColor(SWT.COLOR_BLUE),
                                   display.getSystemColor(SWT.COLOR_WHITE), 
                                   display.getSystemColor(SWT.COLOR_WHITE)},
                       new int[] {25, 50, 100});
 

Parameters:

colors - an array of Color that specifies the colors to appear in the gradient in order of appearance from left to right; The value null clears the background gradient; the value null can be used inside the array of Color to specify the background color.

percents - an array of integers between 0 and 100 specifying the percent of the width of the widget at which the color should change; the size of the percents array must be one less than the size of the colors array.

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistant

setBackground

public void setBackground(Color[] colors,
                          int[] percents,
                          boolean vertical)

Specify a gradient of colours to be drawn in the background of the CLabel.

For example, to draw a gradient that varies from dark blue to white in the vertical, direction use the following call to setBackground:

    clabel.setBackground(new Color[]{display.getSystemColor(SWT.COLOR_DARK_BLUE), 
                                   display.getSystemColor(SWT.COLOR_WHITE)},
                         new int[] {100}, true);
 

Parameters:

colors - an array of Color that specifies the colors to appear in the gradient in order of appearance from left/top to right/bottom; The value null clears the background gradient; the value null can be used inside the array of Color to specify the background color.

percents - an array of integers between 0 and 100 specifying the percent of the width/height of the widget at which the color should change; the size of the percents array must be one less than the size of the colors array.

vertical - indicate the direction of the gradient. True is vertical and false is horizontal.

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
• ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistant

Since:

3.0

setBackground

public void setBackground(Image image)

Set the image to be drawn in the background of the label.

Parameters:

image - the image to be drawn in the background

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setFont

public void setFont(Font font)

Description copied from class: Control

Sets the font that the receiver will use to paint textual information to the font specified by the argument, or to the default font for that kind of control if the argument is null.

Overrides:

setFont in class Canvas

setImage

public void setImage(Image image)

Set the label's Image. The value null clears it.

Parameters:

image - the image to be displayed in the label or null

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

setText

public void setText(String text)

Set the label's text. The value null clears it.

Parameters:

text - the text to be displayed in the label or null

Throws:

SWTException -

• ERROR_WIDGET_DISPOSED - if the receiver has been disposed
• ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver

shortenText

protected String shortenText(GC gc,
                             String t,
                             int width)

Shorten the given text t so that its length doesn't exceed the given width. The default implementation replaces characters in the center of the original string with an ellipsis ("..."). Override if you need a different strategy.