org.eclipse.swt.widgets.Label Maven / Gradle / Ivy
/*******************************************************************************
* Copyright (c) 2002, 2013 Innoopract Informationssysteme GmbH and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Innoopract Informationssysteme GmbH - initial API and implementation
* EclipseSource - ongoing development
******************************************************************************/
package org.eclipse.swt.widgets;
import org.eclipse.rap.rwt.RWT;
import org.eclipse.rap.rwt.internal.textsize.TextSizeUtil;
import org.eclipse.rap.rwt.internal.theme.IThemeAdapter;
import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.internal.widgets.MarkupValidator;
import org.eclipse.swt.internal.widgets.labelkit.LabelThemeAdapter;
/**
* Instances of this class represent a non-selectable
* user interface object that displays a string or image.
* When SEPARATOR is specified, displays a single
* vertical or horizontal line.
*
* Shadow styles are hints and may not be honoured
* by the platform. To create a separator label
* with the default shadow style for the platform,
* do not specify a shadow style.
*
*
* - Styles:
* - SEPARATOR, HORIZONTAL, VERTICAL
* - SHADOW_IN, SHADOW_OUT, SHADOW_NONE
* - CENTER, LEFT, RIGHT, WRAP
* - Events:
* - (none)
*
*
* Note: Only one of SHADOW_IN, SHADOW_OUT and SHADOW_NONE may be specified.
* SHADOW_NONE is a HINT. Only one of HORIZONTAL and VERTICAL may be specified.
* Only one of CENTER, LEFT and RIGHT may be specified.
*
* IMPORTANT: This class is intended to be subclassed only
* within the SWT implementation.
*
*
*
* Note: Unlike in SWT, setting an image clears the text of the
* label and vice versa. Thus, after calling setText(), the method
* getImage() will return null, and after calling
* setImage(), getText will return the empty string.
*
* @since 1.0
*/
// TODO [rh] check what should happen with style == SEPARATOR and setForeground
public class Label extends Control {
private String text = "";
private Image image;
boolean markupEnabled;
private boolean markupValidationDisabled;
/**
* 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.
*
*
* @param parent a composite control which will be the parent of the new instance (cannot be null)
* @param style the style of control to construct
*
* @exception IllegalArgumentException
* - ERROR_NULL_ARGUMENT - if the parent is null
*
* @exception SWTException
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent
* - ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass
*
*
* @see SWT#SEPARATOR
* @see SWT#HORIZONTAL
* @see SWT#VERTICAL
* @see SWT#SHADOW_IN
* @see SWT#SHADOW_OUT
* @see SWT#SHADOW_NONE
* @see SWT#CENTER
* @see SWT#LEFT
* @see SWT#RIGHT
* @see SWT#WRAP
* @see Widget#checkSubclass
* @see Widget#getStyle
*/
public Label( Composite parent, int style ) {
super( parent, checkStyle( style ) );
}
@Override
void initState() {
state |= THEME_BACKGROUND;
}
/**
* Sets the receiver's text.
*
* This method sets the widget label. The label may include
* the mnemonic character and line delimiters.
*
*
* 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.
*
*
* @param text the new text
*
* @exception IllegalArgumentException
* - ERROR_NULL_ARGUMENT - if the text is null
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setText( String text ) {
checkWidget();
if( text == null ) {
SWT.error( SWT.ERROR_NULL_ARGUMENT );
}
if( ( style & SWT.SEPARATOR ) == 0 ) {
if( markupEnabled && !markupValidationDisabled ) {
MarkupValidator.getInstance().validate( text );
}
this.text = text;
image = null;
}
}
/**
* Returns the receiver's text, which will be an empty
* string if it has never been set or if the receiver is
* a SEPARATOR label.
*
* @return the receiver's text
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public String getText() {
checkWidget();
return text;
}
/**
* Sets the receiver's image to the argument, which may be
* null indicating that no image should be displayed.
*
* @param image the image to display on the receiver (may be null)
*
* @exception IllegalArgumentException
* - ERROR_INVALID_ARGUMENT - if the image has been disposed
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
// TODO [rst] Clarify or remove this comment:
// TODO: The LCA does not yet handle images. So, setting an image currently
public void setImage( Image image ) {
checkWidget();
if( ( style & SWT.SEPARATOR ) == 0 ) {
this.image = image;
text = "";
}
}
/**
* Returns the receiver's image if it has one, or null
* if it does not.
*
* @return the receiver's image
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public Image getImage() {
checkWidget();
return image;
}
/**
* Controls how text and images will be displayed in the receiver.
* The argument should be one of LEFT, RIGHT
* or CENTER. If the receiver is a SEPARATOR
* label, the argument is ignored and the alignment is not changed.
*
* @param alignment the new alignment
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public void setAlignment( int alignment ) {
checkWidget();
if( ( style & SWT.SEPARATOR ) == 0
&& ( alignment & ( SWT.LEFT | SWT.RIGHT | SWT.CENTER ) ) != 0 )
{
style &= ~( SWT.LEFT | SWT.RIGHT | SWT.CENTER );
style |= alignment & ( SWT.LEFT | SWT.RIGHT | SWT.CENTER );
}
}
/**
* Returns a value which describes the position of the
* text or image in the receiver. The value will be one of
* LEFT, RIGHT or CENTER
* unless the receiver is a SEPARATOR label, in
* which case, NONE is returned.
*
* @return the alignment
*
* @exception SWTException
* - ERROR_WIDGET_DISPOSED - if the receiver has been disposed
* - ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver
*
*/
public int getAlignment() {
checkWidget();
int result;
if( ( style & SWT.SEPARATOR ) != 0 ) {
result = 0;
} else if( ( style & SWT.LEFT ) != 0 ) {
result = SWT.LEFT;
} else if( ( style & SWT.CENTER ) != 0 ) {
result = SWT.CENTER;
} else if( ( style & SWT.RIGHT ) != 0 ) {
result = SWT.RIGHT;
} else {
result = SWT.LEFT;
}
return result;
}
@Override
public Point computeSize( int wHint, int hHint, boolean changed ) {
checkWidget();
int width = 0;
int height = 0;
if( ( style & SWT.SEPARATOR ) != 0 ) {
int lineWidth = getSeparatorLineWidth();
if( ( style & SWT.HORIZONTAL ) != 0 ) {
width = DEFAULT_WIDTH;
height = lineWidth;
} else {
width = lineWidth;
height = DEFAULT_HEIGHT;
}
} else if( image != null ) {
Rectangle rect = image.getBounds();
width = rect.width;
height = rect.height;
} else if( text.length() > 0 ) {
int wrapWidth = 0;
if( ( style & SWT.WRAP ) != 0 && wHint != SWT.DEFAULT ) {
wrapWidth = wHint;
}
Point extent;
if( markupEnabled ) {
extent = TextSizeUtil.markupExtent( getFont(), text, wrapWidth );
} else {
extent = TextSizeUtil.textExtent( getFont(), text, wrapWidth );
}
width = extent.x;
height = extent.y + 2;
} else {
height = TextSizeUtil.getCharHeight( getFont() );
}
if( wHint != SWT.DEFAULT ) {
width = wHint;
}
if( hHint != SWT.DEFAULT ) {
height = hHint;
}
int border = getBorderWidth();
width += border * 2;
height += border * 2;
return new Point( width, height );
}
@Override
String getNameText() {
return getText();
}
@Override
public void setData( String key, Object value ) {
if( RWT.MARKUP_ENABLED.equals( key ) && !markupEnabled ) {
markupEnabled = Boolean.TRUE.equals( value );
} else if( MarkupValidator.MARKUP_VALIDATION_DISABLED.equals( key ) ) {
markupValidationDisabled = Boolean.TRUE.equals( value );
}
super.setData( key, value );
}
//////////////////
// Helping methods
private static int checkStyle( int style ) {
int result = style;
result |= SWT.NO_FOCUS;
if( ( style & SWT.SEPARATOR ) != 0 ) {
result = checkBits( result, SWT.VERTICAL, SWT.HORIZONTAL, 0, 0, 0, 0 );
result = checkBits ( result,
SWT.SHADOW_OUT,
SWT.SHADOW_IN,
SWT.SHADOW_NONE,
0,
0,
0 );
}
result = checkBits( result, SWT.LEFT, SWT.CENTER, SWT.RIGHT, 0, 0, 0 );
return result;
}
private int getSeparatorLineWidth() {
LabelThemeAdapter themeAdapter = ( LabelThemeAdapter )getAdapter( IThemeAdapter.class );
return themeAdapter.getSeparatorLineWidth( this );
}
}