org.eclipse.scada.swt

Class CLabel

java.lang.Object

Canvas

org.eclipse.scada.swt.CLabel

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.

See Also:

SWT Example: CustomControlExample, Sample code and further information

Constructor Summary

Constructors

Constructor and Description
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

Methods

Modifier and Type	Method and Description
protected java.lang.String	beginShortenText(GC gc, java.lang.String t, int width, int w)
protected java.lang.String	centerShortenText(GC gc, java.lang.String t, int width, int w)
Point	computeSize(int wHint, int hHint, boolean changed)
protected java.lang.String	endShortenText(GC gc, java.lang.String t, int width, int w)
int	getAlignment() Returns the horizontal alignment.
int	getBottomMargin() Return the CLabel's bottom margin.
java.lang.String	getEllipsis() Return the CLabel's ellipsis.
int	getEllipsisAligment() Return the CLabel's ellipsis alignment.
Image	getImage() Return the CLabel's image or null.
int	getLeftMargin() Return the CLabel's left margin.
int	getRightMargin() Return the CLabel's right margin.
int	getStyle()
java.lang.String	getText() Return the Label's text.
java.lang.String	getToolTipText()
int	getTopMargin() Return the CLabel's top margin.
void	setAlignment(int align) Set the horizontal alignment of the CLabel.
void	setBackground(Color color)
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	setBottomMargin(int bottomMargin) Set the label's bottom margin, in pixels.
void	setEllipsis(java.lang.String ellipsis) Set the label's ellipsis
void	setEllipsisAlignment(int ellipsisAlign) Set the alignment of the ellipsis.
void	setFont(Font font)
void	setImage(Image image) Set the label's Image.
void	setLeftMargin(int leftMargin) Set the label's horizontal left margin, in pixels.
void	setMargins(int leftMargin, int topMargin, int rightMargin, int bottomMargin) Set the label's margins, in pixels.
void	setRightMargin(int rightMargin) Set the label's right margin, in pixels.
void	setText(java.lang.String text) Set the label's text.
void	setToolTipText(java.lang.String string)
void	setTopMargin(int topMargin) Set the label's top margin, in pixels.
protected java.lang.String	shortenText(GC gc, java.lang.String t, int width) Shorten the given text t so that its length doesn't exceed the given width.

Methods inherited from class java.lang.Object

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

java.lang.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, getStyle()

Method Detail

computeSize

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

getAlignment

public int getAlignment()

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

Returns:

SWT.LEFT, SWT.RIGHT or SWT.CENTER

getBottomMargin

public int getBottomMargin()

Return the CLabel's bottom margin.

Returns:

the bottom margin of the label

Since:

3.6

getEllipsis

public java.lang.String getEllipsis()

Return the CLabel's ellipsis.

Returns:

the current ellipsis

Since:

TDB

getEllipsisAligment

public int getEllipsisAligment()

Return the CLabel's ellipsis alignment.

Returns:

the current ellipsis alignment

Since:

TDB

getImage

public Image getImage()

Return the CLabel's image or null.

Returns:

the image of the label or null

getLeftMargin

public int getLeftMargin()

Return the CLabel's left margin.

Returns:

the left margin of the label

Since:

3.6

getRightMargin

public int getRightMargin()

Return the CLabel's right margin.

Returns:

the right margin of the label

Since:

3.6

getStyle

public int getStyle()

getText

public java.lang.String getText()

Return the Label's text.

Returns:

the text of the label or null

getToolTipText

public java.lang.String getToolTipText()

getTopMargin

public int getTopMargin()

Return the CLabel's top margin.

Returns:

the top margin of the label

Since:

3.6

setAlignment

public void setAlignment(int align)

Set the horizontal 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)

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 consistent

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 consistent

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

setBottomMargin

public void setBottomMargin(int bottomMargin)

Set the label's bottom margin, in pixels.

Parameters:

bottomMargin - the bottom margin of the label, which must be equal to or greater than zero

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

Since:

3.6

setEllipsis

public void setEllipsis(java.lang.String ellipsis)

Set the label's ellipsis

Parameters:

ellipsis - the ellipsis to use instead of the DEFAULT_ELLIPSIS

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

Since:

TBD

setEllipsisAlignment

public void setEllipsisAlignment(int ellipsisAlign)

Set the alignment of the ellipsis.

Use the values LEFT, CENTER, RIGHT, BEGINNING or END to align the ellipsis in the text.

BEGINNING and END are mapped to LEFT and RIGHT according to the current LEFT_TO_RIGHT and RIGHT_TO_LEFT style.

Parameters:

align - the alignment style of LEFT, RIGHT, CENTER, BEGINNING or END

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

Since:

TBD

setFont

public void setFont(Font font)

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

setLeftMargin

public void setLeftMargin(int leftMargin)

Set the label's horizontal left margin, in pixels.

Parameters:

leftMargin - the left margin of the label, which must be equal to or greater than zero

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

Since:

3.6

setMargins

public void setMargins(int leftMargin,
              int topMargin,
              int rightMargin,
              int bottomMargin)

Set the label's margins, in pixels.

Parameters:

leftMargin - the left margin.

topMargin - the top margin.

rightMargin - the right margin.

bottomMargin - the bottom margin.

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

Since:

3.6

setRightMargin

public void setRightMargin(int rightMargin)

Set the label's right margin, in pixels.

Parameters:

rightMargin - the right margin of the label, which must be equal to or greater than zero

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

Since:

3.6

setText

public void setText(java.lang.String text)

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

Mnemonics are indicated by an '&' that causes the next character to be the mnemonic. When the user presses a key sequence that matches the mnemonic, focus is assigned to the control that follows the label. On most platforms, the mnemonic appears underlined but may be emphasised in a platform specific manner. The mnemonic indicator character '&' can be escaped by doubling it in the string, causing a single '&' to be displayed.

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

setToolTipText

public void setToolTipText(java.lang.String string)

setTopMargin

public void setTopMargin(int topMargin)

Set the label's top margin, in pixels.

Parameters:

topMargin - the top margin of the label, which must be equal to or greater than zero

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

Since:

3.6

shortenText

protected java.lang.String shortenText(GC gc,
                           java.lang.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.

Parameters:

gc - the gc to use for text measurement

t - the text to shorten

width - the width to shorten the text to, in pixels

Returns:

the shortened text

beginShortenText

protected java.lang.String beginShortenText(GC gc,
                                java.lang.String t,
                                int width,
                                int w)

endShortenText

protected java.lang.String endShortenText(GC gc,
                              java.lang.String t,
                              int width,
                              int w)

centerShortenText

protected java.lang.String centerShortenText(GC gc,
                                 java.lang.String t,
                                 int width,
                                 int w)