/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation 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:
 *     IBM Corporation - initial API and implementation
 * Port to the D programming language:
 *     Frank Benoit <benoit@tionex.de>
 *******************************************************************************/
module org.eclipse.swt.custom.CLabel;


import org.eclipse.swt.SWT;
import org.eclipse.swt.SWTException;
import org.eclipse.swt.accessibility.ACC;
import org.eclipse.swt.accessibility.Accessible;
import org.eclipse.swt.accessibility.AccessibleAdapter;
import org.eclipse.swt.accessibility.AccessibleControlAdapter;
import org.eclipse.swt.accessibility.AccessibleControlEvent;
import org.eclipse.swt.accessibility.AccessibleEvent;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.events.TraverseEvent;
import org.eclipse.swt.events.TraverseListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.graphics.TextLayout;
import org.eclipse.swt.widgets.Canvas;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;

import java.lang.all;
import java.nonstandard.UnsafeUtf;

/**
 * A Label which supports aligned text and/or an image and different border styles.
 * <p>
 * If there is not enough space a CLabel uses the following strategy to fit the
 * information into the available space:
 * <pre>
 *      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
 * </pre>
 * <p>
 * <dl>
 * <dt><b>Styles:</b>
 * <dd>LEFT, RIGHT, CENTER, SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd>
 * <dt><b>Events:</b>
 * <dd></dd>
 * </dl>
 *
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: CustomControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 */
public class CLabel : Canvas {

    alias Canvas.computeSize computeSize;

    /** Gap between icon and text */
    private static const int GAP = 5;
    /** Left and right margins */
    private static const int INDENT = 3;
    /** a string inserted in the middle of text that has been shortened */
    private static const String ELLIPSIS = "..."; //$NON-NLS-1$ // could use the ellipsis glyph on some platforms "\u2026"
    /** the alignment. Either CENTER, RIGHT, LEFT. Default is LEFT*/
    private int align_ = SWT.LEFT;
    private int hIndent = INDENT;
    private int vIndent = INDENT;
    /** the current text */
    private String text;
    /** the current icon */
    private Image image;
    // The tooltip is used for two purposes - the application can set
    // a tooltip or the tooltip can be used to display the full text when the
    // the text has been truncated due to the label being too short.
    // The appToolTip stores the tooltip set by the application.  Control.tooltiptext
    // contains whatever tooltip is currently being displayed.
    private String appToolTipText;

    private Image backgroundImage;
    private Color[] gradientColors;
    private int[] gradientPercents;
    private bool gradientVertical;
    private Color background;

    private static int DRAW_FLAGS = SWT.DRAW_MNEMONIC | SWT.DRAW_TAB | SWT.DRAW_TRANSPARENT | SWT.DRAW_DELIMITER;

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * lists the style constants that are applicable to the class.
 * Style bits are also inherited from superclasses.
 * </p>
 *
 * @param parent a widget which will be the parent of the new instance (cannot be null)
 * @param style the style of widget to construct
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 * </ul>
 *
 * @see SWT#LEFT
 * @see SWT#RIGHT
 * @see SWT#CENTER
 * @see SWT#SHADOW_IN
 * @see SWT#SHADOW_OUT
 * @see SWT#SHADOW_NONE
 * @see #getStyle()
 */
public this(Composite parent, int style) {
    super(parent, checkStyle(style));
    if ((style & (SWT.CENTER | SWT.RIGHT)) is 0) style |= SWT.LEFT;
    if ((style & SWT.CENTER) !is 0) align_ = SWT.CENTER;
    if ((style & SWT.RIGHT) !is 0)  align_ = SWT.RIGHT;
    if ((style & SWT.LEFT) !is 0)   align_ = SWT.LEFT;

    addPaintListener(new class() PaintListener{
        public void paintControl(PaintEvent event) {
            onPaint(event);
        }
    });

    addDisposeListener(new class() DisposeListener{
        public void widgetDisposed(DisposeEvent event) {
            onDispose(event);
        }
    });

    addTraverseListener(new class() TraverseListener {
        public void keyTraversed(TraverseEvent event) {
            if (event.detail is SWT.TRAVERSE_MNEMONIC) {
                onMnemonic(event);
            }
        }
    });

    initAccessible();

}
/**
 * Check the style bits to ensure that no invalid styles are applied.
 */
private static int checkStyle (int style) {
    if ((style & SWT.BORDER) !is 0) style |= SWT.SHADOW_IN;
    int mask = SWT.SHADOW_IN | SWT.SHADOW_OUT | SWT.SHADOW_NONE | SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
    style = style & mask;
    return style |= SWT.NO_FOCUS | SWT.DOUBLE_BUFFERED;
}

//protected void checkSubclass () {
//  String name = getClass().getName ();
//  String validName = CLabel.class.getName();
//  if (validName != (name)) {
//      SWT.error (SWT.ERROR_INVALID_SUBCLASS);
//  }
//}

public override Point computeSize(int wHint, int hHint, bool changed) {
    checkWidget();
    Point e = getTotalSize(image, text);
    if (wHint is SWT.DEFAULT){
        e.x += 2*hIndent;
    } else {
        e.x = wHint;
    }
    if (hHint is SWT.DEFAULT) {
        e.y += 2*vIndent;
    } else {
        e.y = hHint;
    }
    return e;
}
/**
 * Draw a rectangle in the given colors.
 */
private void drawBevelRect(GC gc, int x, int y, int w, int h, Color topleft, Color bottomright) {
    gc.setForeground(bottomright);
    gc.drawLine(x+w, y,   x+w, y+h);
    gc.drawLine(x,   y+h, x+w, y+h);

    gc.setForeground(topleft);
    gc.drawLine(x, y, x+w-1, y);
    gc.drawLine(x, y, x,     y+h-1);
}
/*
 * Return the lowercase of the first non-'&' character following
 * an '&' character in the given string. If there are no '&'
 * characters in the given string, return '\0'.
 */
dchar _findMnemonic (String str) {
    if (str is null) return '\0';
    size_t index = 0;
    auto length = str.length;
    do {
        while (index < length && str[index] !is '&') index++;
        if (++index >= length) return '\0';
        if (str[index] !is '&') return Character.toLowerCase( str.dcharAt(index) );
        index++;
    } while (index < length);
    return '\0';
}
/**
 * Returns the alignment.
 * The alignment style (LEFT, CENTER or RIGHT) is returned.
 *
 * @return SWT.LEFT, SWT.RIGHT or SWT.CENTER
 */
public int getAlignment() {
    //checkWidget();
    return align_;
}
/**
 * Return the CLabel's image or <code>null</code>.
 *
 * @return the image of the label or null
 */
public Image getImage() {
    //checkWidget();
    return image;
}
/**
 * Compute the minimum size.
 */
private Point getTotalSize(Image image, String text) {
    Point size = new Point(0, 0);

    if (image !is null) {
        Rectangle r = image.getBounds();
        size.x += r.width;
        size.y += r.height;
    }

    GC gc = new GC(this);
    if (text !is null && text.length > 0) {
        Point e = gc.textExtent(text, DRAW_FLAGS);
        size.x += e.x;
        size.y = Math.max(size.y, e.y);
        if (image !is null) size.x += GAP;
    } else {
        size.y = Math.max(size.y, gc.getFontMetrics().getHeight());
    }
    gc.dispose();

    return size;
}
public override int getStyle () {
    int style = super.getStyle();
    switch (align_) {
        case SWT.RIGHT: style |= SWT.RIGHT; break;
        case SWT.CENTER: style |= SWT.CENTER; break;
        case SWT.LEFT: style |= SWT.LEFT; break;
        default:
    }
    return style;
}

/**
 * Return the Label's text.
 *
 * @return the text of the label or null
 */
public String getText() {
    //checkWidget();
    return text;
}
public override String getToolTipText () {
    checkWidget();
    return appToolTipText;
}
private void initAccessible() {
    Accessible accessible = getAccessible();
    accessible.addAccessibleListener(new class() AccessibleAdapter {
        override
        public void getName(AccessibleEvent e) {
            e.result = getText();
        }

        override
        public void getHelp(AccessibleEvent e) {
            e.result = getToolTipText();
        }

        override
        public void getKeyboardShortcut(AccessibleEvent e) {
            dchar mnemonic = _findMnemonic(this.outer.text);
            if (mnemonic !is '\0') {
                e.result = "Alt+" ~ dcharToString(mnemonic); //$NON-NLS-1$
            }
        }
    });

    accessible.addAccessibleControlListener(new class() AccessibleControlAdapter {
        override
        public void getChildAtPoint(AccessibleControlEvent e) {
            e.childID = ACC.CHILDID_SELF;
        }

        override
        public void getLocation(AccessibleControlEvent e) {
            Rectangle rect = getDisplay().map(getParent(), null, getBounds());
            e.x = rect.x;
            e.y = rect.y;
            e.width = rect.width;
            e.height = rect.height;
        }

        override
        public void getChildCount(AccessibleControlEvent e) {
            e.detail = 0;
        }

        override
        public void getRole(AccessibleControlEvent e) {
            e.detail = ACC.ROLE_LABEL;
        }

        override
        public void getState(AccessibleControlEvent e) {
            e.detail = ACC.STATE_READONLY;
        }
    });
}
void onDispose(DisposeEvent event) {
    gradientColors = null;
    gradientPercents = null;
    backgroundImage = null;
    text = null;
    image = null;
    appToolTipText = null;
}
void onMnemonic(TraverseEvent event) {
    dchar mnemonic = _findMnemonic(text);
    if (mnemonic is '\0') return;
    if (Character.toLowerCase(event.character) !is mnemonic) return;
    Composite control = this.getParent();
    while (control !is null) {
        Control [] children = control.getChildren();
        int index = 0;
        while (index < children.length) {
            if (children [index] is this) break;
            index++;
        }
        index++;
        if (index < children.length) {
            if (children [index].setFocus ()) {
                event.doit = true;
                event.detail = SWT.TRAVERSE_NONE;
            }
        }
        control = control.getParent();
    }
}

void onPaint(PaintEvent event) {
    Rectangle rect = getClientArea();
    if (rect.width is 0 || rect.height is 0) return;

    bool shortenText_ = false;
    String t = text;
    Image img = image;
    int availableWidth = Math.max(0, rect.width - 2*hIndent);
    Point extent = getTotalSize(img, t);
    if (extent.x > availableWidth) {
        img = null;
        extent = getTotalSize(img, t);
        if (extent.x > availableWidth) {
            shortenText_ = true;
        }
    }

    GC gc = event.gc;
    String[] lines = text is null ? null : splitString(text);

    // shorten the text
    if (shortenText_) {
        extent.x = 0;
        for(int i = 0; i < lines.length; i++) {
            Point e = gc.textExtent(lines[i], DRAW_FLAGS);
            if (e.x > availableWidth) {
                lines[i] = shortenText(gc, lines[i], availableWidth);
                extent.x = Math.max(extent.x, getTotalSize(null, lines[i]).x);
            } else {
                extent.x = Math.max(extent.x, e.x);
            }
        }
        if (appToolTipText is null) {
            super.setToolTipText(text);
        }
    } else {
        super.setToolTipText(appToolTipText);
    }

    // determine horizontal position
    int x = rect.x + hIndent;
    if (align_ is SWT.CENTER) {
        x = (rect.width - extent.x)/2;
    }
    if (align_ is SWT.RIGHT) {
        x = rect.width - hIndent - extent.x;
    }

    // draw a background image behind the text
    try {
        if (backgroundImage !is null) {
            // draw a background image behind the text
            Rectangle imageRect = backgroundImage.getBounds();
            // tile image to fill space
            gc.setBackground(getBackground());
            gc.fillRectangle(rect);
            int xPos = 0;
            while (xPos < rect.width) {
                int yPos = 0;
                while (yPos < rect.height) {
                    gc.drawImage(backgroundImage, xPos, yPos);
                    yPos += imageRect.height;
                }
                xPos += imageRect.width;
            }
        } else if (gradientColors !is null) {
            // draw a gradient behind the text
            Color oldBackground = gc.getBackground();
            if (gradientColors.length is 1) {
                if (gradientColors[0] !is null) gc.setBackground(gradientColors[0]);
                gc.fillRectangle(0, 0, rect.width, rect.height);
            } else {
                Color oldForeground = gc.getForeground();
                Color lastColor = gradientColors[0];
                if (lastColor is null) lastColor = oldBackground;
                int pos = 0;
                for (int i = 0; i < gradientPercents.length; ++i) {
                    gc.setForeground(lastColor);
                    lastColor = gradientColors[i + 1];
                    if (lastColor is null) lastColor = oldBackground;
                    gc.setBackground(lastColor);
                    if (gradientVertical) {
                        int gradientHeight = (gradientPercents[i] * rect.height / 100) - pos;
                        gc.fillGradientRectangle(0, pos, rect.width, gradientHeight, true);
                        pos += gradientHeight;
                    } else {
                        int gradientWidth = (gradientPercents[i] * rect.width / 100) - pos;
                        gc.fillGradientRectangle(pos, 0, gradientWidth, rect.height, false);
                        pos += gradientWidth;
                    }
                }
                if (gradientVertical && pos < rect.height) {
                    gc.setBackground(getBackground());
                    gc.fillRectangle(0, pos, rect.width, rect.height - pos);
                }
                if (!gradientVertical && pos < rect.width) {
                    gc.setBackground(getBackground());
                    gc.fillRectangle(pos, 0, rect.width - pos, rect.height);
                }
                gc.setForeground(oldForeground);
            }
            gc.setBackground(oldBackground);
        } else {
            if (background !is null || (getStyle() & SWT.DOUBLE_BUFFERED) is 0) {
                gc.setBackground(getBackground());
                gc.fillRectangle(rect);
            }
        }
    } catch (SWTException e) {
        if ((getStyle() & SWT.DOUBLE_BUFFERED) is 0) {
            gc.setBackground(getBackground());
            gc.fillRectangle(rect);
        }
    }

    // draw border
    int style = getStyle();
    if ((style & SWT.SHADOW_IN) !is 0 || (style & SWT.SHADOW_OUT) !is 0) {
        paintBorder(gc, rect);
    }

    // draw the image
    if (img !is null) {
        Rectangle imageRect = img.getBounds();
        gc.drawImage(img, 0, 0, imageRect.width, imageRect.height,
                        x, (rect.height-imageRect.height)/2, imageRect.width, imageRect.height);
        x +=  imageRect.width + GAP;
        extent.x -= imageRect.width + GAP;
    }
    // draw the text
    if (lines !is null) {
        int lineHeight = gc.getFontMetrics().getHeight();
        int textHeight = cast(int)/*64bit*/lines.length * lineHeight;
        int lineY = Math.max(vIndent, rect.y + (rect.height - textHeight) / 2);
        gc.setForeground(getForeground());
        for (int i = 0; i < lines.length; i++) {
            int lineX = x;
            if (lines.length > 1) {
                if (align_ is SWT.CENTER) {
                    int lineWidth = gc.textExtent(lines[i], DRAW_FLAGS).x;
                    lineX = x + Math.max(0, (extent.x - lineWidth) / 2);
                }
                if (align_ is SWT.RIGHT) {
                    int lineWidth = gc.textExtent(lines[i], DRAW_FLAGS).x;
                    lineX = Math.max(x, rect.x + rect.width - hIndent - lineWidth);
                }
            }
            gc.drawText(lines[i], lineX, lineY, DRAW_FLAGS);
            lineY += lineHeight;
        }
    }
}
/**
 * Paint the Label's border.
 */
private void paintBorder(GC gc, Rectangle r) {
    Display disp= getDisplay();

    Color c1 = null;
    Color c2 = null;

    int style = getStyle();
    if ((style & SWT.SHADOW_IN) !is 0) {
        c1 = disp.getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
        c2 = disp.getSystemColor(SWT.COLOR_WIDGET_HIGHLIGHT_SHADOW);
    }
    if ((style & SWT.SHADOW_OUT) !is 0) {
        c1 = disp.getSystemColor(SWT.COLOR_WIDGET_LIGHT_SHADOW);
        c2 = disp.getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
    }

    if (c1 !is null && c2 !is null) {
        gc.setLineWidth(1);
        drawBevelRect(gc, r.x, r.y, r.width-1, r.height-1, c1, c2);
    }
}
/**
 * Set the alignment of the CLabel.
 * Use the values LEFT, CENTER and RIGHT to align image and text within the available space.
 *
 * @param align the alignment style of LEFT, RIGHT or CENTER
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the value of align is not one of SWT.LEFT, SWT.RIGHT or SWT.CENTER</li>
 * </ul>
 */
public void setAlignment(int align_) {
    checkWidget();
    if (align_ !is SWT.LEFT && align_ !is SWT.RIGHT && align_ !is SWT.CENTER) {
        SWT.error(SWT.ERROR_INVALID_ARGUMENT);
    }
    if (this.align_ !is align_) {
        this.align_ = align_;
        redraw();
    }
}

public override void setBackground (Color color) {
    super.setBackground (color);
    // Are these settings the same as before?
    if (backgroundImage is null &&
        gradientColors is null &&
        gradientPercents is null) {
        if (color is null) {
            if (background is null) return;
        } else {
            if (color ==/*eq*/ background) return;
        }
    }
    background = color;
    backgroundImage = null;
    gradientColors = null;
    gradientPercents = null;
    redraw ();
}

/**
 * Specify a gradient of colours to be drawn in the background of the CLabel.
 * <p>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:</p>
 * <pre>
 *  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});
 * </pre>
 *
 * @param colors an array of Color that specifies the colors to appear in the gradient
 *               in order of appearance from left to right;  The value <code>null</code>
 *               clears the background gradient; the value <code>null</code> can be used
 *               inside the array of Color to specify the background color.
 * @param 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.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistent</li>
 * </ul>
 */
public void setBackground(Color[] colors, int[] percents) {
    setBackground(colors, percents, false);
}
/**
 * Specify a gradient of colours to be drawn in the background of the CLabel.
 * <p>For example, to draw a gradient that varies from dark blue to white in the vertical,
 * direction use the following call
 * to setBackground:</p>
 * <pre>
 *  clabel.setBackground(new Color[]{display.getSystemColor(SWT.COLOR_DARK_BLUE),
 *                                 display.getSystemColor(SWT.COLOR_WHITE)},
 *                       new int[] {100}, true);
 * </pre>
 *
 * @param 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 <code>null</code>
 *               clears the background gradient; the value <code>null</code> can be used
 *               inside the array of Color to specify the background color.
 * @param 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.
 * @param vertical indicate the direction of the gradient.  True is vertical and false is horizontal.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the values of colors and percents are not consistent</li>
 * </ul>
 *
 * @since 3.0
 */
public void setBackground(Color[] colors, int[] percents, bool vertical) {
    checkWidget();
    if (colors !is null) {
        if (percents is null || percents.length !is colors.length - 1) {
            SWT.error(SWT.ERROR_INVALID_ARGUMENT);
        }
        if (getDisplay().getDepth() < 15) {
            // Don't use gradients on low color displays
            colors = [colors[colors.length - 1]];
            percents = null;
        }
        for (int i = 0; i < percents.length; i++) {
            if (percents[i] < 0 || percents[i] > 100) {
                SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            }
            if (i > 0 && percents[i] < percents[i-1]) {
                SWT.error(SWT.ERROR_INVALID_ARGUMENT);
            }
        }
    }

    // Are these settings the same as before?
    Color background = getBackground();
    if (backgroundImage is null) {
        if ((gradientColors !is null) && (colors !is null) &&
            (gradientColors.length is colors.length)) {
            bool same = false;
            for (int i = 0; i < gradientColors.length; i++) {
                same = (gradientColors[i] is colors[i]) ||
                    ((gradientColors[i] is null) && (colors[i] is background)) ||
                    ((gradientColors[i] is background) && (colors[i] is null));
                if (!same) break;
            }
            if (same) {
                for (int i = 0; i < gradientPercents.length; i++) {
                    same = gradientPercents[i] is percents[i];
                    if (!same) break;
                }
            }
            if (same && this.gradientVertical is vertical) return;
        }
    } else {
        backgroundImage = null;
    }
    // Store the new settings
    if (colors is null) {
        gradientColors = null;
        gradientPercents = null;
        gradientVertical = false;
    } else {
        gradientColors = new Color[colors.length];
        for (int i = 0; i < colors.length; ++i)
            gradientColors[i] = (colors[i] !is null) ? colors[i] : background;
        gradientPercents = new int[percents.length];
        for (int i = 0; i < percents.length; ++i)
            gradientPercents[i] = percents[i];
        gradientVertical = vertical;
    }
    // Refresh with the new settings
    redraw();
}
/**
 * Set the image to be drawn in the background of the label.
 *
 * @param image the image to be drawn in the background
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setBackground(Image image) {
    checkWidget();
    if (image is backgroundImage) return;
    if (image !is null) {
        gradientColors = null;
        gradientPercents = null;
    }
    backgroundImage = image;
    redraw();

}
public override void setFont(Font font) {
    super.setFont(font);
    redraw();
}
/**
 * Set the label's Image.
 * The value <code>null</code> clears it.
 *
 * @param image the image to be displayed in the label or null
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setImage(Image image) {
    checkWidget();
    if (image !is this.image) {
        this.image = image;
        redraw();
    }
}
/**
 * Set the label's text.
 * The value <code>null</code> clears it.
 *
 * @param text the text to be displayed in the label or null
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setText(String text) {
    checkWidget();
    if (text is null) text = ""; //$NON-NLS-1$
    if ( text !=/*eq*/ this.text) {
        this.text = text;
        redraw();
    }
}
public override void setToolTipText (String string) {
    super.setToolTipText (string);
    appToolTipText = super.getToolTipText();
}
/**
 * Shorten the given text <code>t</code> 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.
 *
 * @param gc the gc to use for text measurement
 * @param t the text to shorten
 * @param width the width to shorten the text to, in pixels
 * @return the shortened text
 */
protected String shortenText(GC gc, String t, int width) {
    if (t is null) return null;
    int w = gc.textExtent(ELLIPSIS, DRAW_FLAGS).x;
    if (width<=w) return t;
    int l = cast(int)/*64bit*/t.length;
    int max = l/2;
    int min = 0;
    int mid = (max+min)/2 - 1;
    if (mid <= 0) return t;
    TextLayout layout = new TextLayout (getDisplay());
    layout.setText(t);
    mid = validateOffset(layout, mid);
    while (min < mid && mid < max) {
        String s1 = t.substring(0, mid);
        String s2 = t.substring(validateOffset(layout, l-mid), l);
        int l1 = gc.textExtent(s1, DRAW_FLAGS).x;
        int l2 = gc.textExtent(s2, DRAW_FLAGS).x;
        if (l1+w+l2 > width) {
            max = mid;
            mid = validateOffset(layout, (max+min)/2);
        } else if (l1+w+l2 < width) {
            min = mid;
            mid = validateOffset(layout, (max+min)/2);
        } else {
            min = max;
        }
    }
    String result = mid is 0 ? t : t.substring(0, mid) ~ ELLIPSIS ~ t.substring(validateOffset(layout, l-mid), l);
    layout.dispose();
    return result;
}
int validateOffset(TextLayout layout, int offset) {
    int nextOffset = layout.getNextOffset(offset, SWT.MOVEMENT_CLUSTER);
    if (nextOffset !is offset) return layout.getPreviousOffset(nextOffset, SWT.MOVEMENT_CLUSTER);
    return offset;
}
private String[] splitString(String text) {
    String[] lines = new String[1];
    int start = 0, pos;
    do {
        pos = text.indexOf('\n', start);
        if (pos is -1) {
            lines[lines.length - 1] = text[start .. $ ];
        } else {
            bool crlf = (pos > 0) && (text[ pos - 1 ] is '\r');
            lines[lines.length - 1] = text[ start .. pos - (crlf ? 1 : 0)];
            start = pos + 1;
            String[] newLines = new String[lines.length+1];
            System.arraycopy(lines, 0, newLines, 0, lines.length);
            lines = newLines;
        }
    } while (pos !is -1);
    return lines;
}
}