/*******************************************************************************

 * Copyright (c) 2000, 2007 IBM Corporation and others.

 * Portion Copyright (c) 2008 Nokia Corporation and/or its subsidiary(-ies).

 * 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

 *     Nokia Corporation - Qt implementation

 *******************************************************************************/

package org.eclipse.swt.widgets;

import org.eclipse.swt.SWT;

import org.eclipse.swt.internal.qt.OS;

import org.eclipse.swt.internal.qt.WidgetState;

import org.eclipse.swt.graphics.Image;

import org.eclipse.swt.graphics.Internal_GfxPackageSupport;

import org.eclipse.swt.graphics.Point;

/**

 * 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.

 * <dl>

 * <dt><b>Styles:</b></dt>

 * <dd>SEPARATOR, HORIZONTAL, VERTICAL</dd>

 * <dd>SHADOW_IN, SHADOW_OUT, SHADOW_NONE</dd>

 * <dd>CENTER, LEFT, RIGHT, WRAP</dd>

 * <dt><b>Events:</b></dt>

 * <dd>(none)</dd>

 * </dl>

 * <p>

 * 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.

 * </p>

 * <p>

 * IMPORTANT: This class is intended to be subclassed <em>only</em> within the

 * SWT implementation.

 * </p>

 */

public class Label extends Control {

    Image image;

    /**

     * 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 composite control which will be the parent of the new

     *            instance (cannot be null)

     * @param style

     *            the style of control 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>

     *                <li>ERROR_INVALID_SUBCLASS - if this class is not an

     *                allowed subclass</li>

     *                </ul>

     *

     * @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) {

        this(parent, checkStyle(style), false);

    }

    /**

     * <p>

     * <b>IMPORTANT:</b> This constructor is <em>not</em> part of the SWT

     * public API. It should never be referenced from application code.

     * </p>

     */

    protected Label(Composite parent, int style, boolean isExtended) {

        super(parent, checkStyle(style), 0, null, isExtended);

    }

    static int checkStyle(int style) {

        style |= SWT.NO_FOCUS;

        if ((style & SWT.SEPARATOR) != 0) {

            style = checkBits(style, SWT.HORIZONTAL, SWT.VERTICAL, 0, 0, 0, 0);

            return checkBits(style, SWT.SHADOW_NONE, SWT.SHADOW_OUT,

                    SWT.SHADOW_IN, 0, 0, 0)

                    | SWT.BORDER;

        }

        return checkBits(style, SWT.LEFT, SWT.CENTER, SWT.RIGHT, 0, 0, 0);

    }

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

        if (wHint != SWT.DEFAULT && wHint < 0)

            wHint = SWT.DEFAULT;

        if (hHint != SWT.DEFAULT && hHint < 0)

            hHint = SWT.DEFAULT;

        if ((style & SWT.SEPARATOR) != 0 || image != null

                || (style & SWT.SINGLE) != 0

                || (wHint == SWT.DEFAULT && hHint == SWT.DEFAULT)

                || (wHint != SWT.DEFAULT && hHint != SWT.DEFAULT)) {

            return super.computeSize(wHint, hHint, changed);

        }

        checkWidget();

        if (changed) {

            OS.QWidget_updateGeometry(handle);

        }

        /**

         * ComputeSize in super class is not able to handle the situation that

         * preferred height depends on the width. So ask QLabel for preferred

         * height or width.

         */

        int border = getBorderWidth();

        if (wHint != SWT.DEFAULT)

            wHint += 2 * border;

        if (hHint != SWT.DEFAULT)

            hHint += 2 * border;

        Point minimumSize = OS.QWidget_minimumSize(handle);

        if (minimumSize.x < 2 * border)

            minimumSize.x = 2 * border;

        if (minimumSize.y < 2 * border)

            minimumSize.y = 2 * border;

        int width = minimumSize.x;

        int height = minimumSize.y;

        if (wHint > width)

            width = wHint;

        if (hHint > height)

            height = hHint;

        /**

         * OS.QWidget_heightForWidth is also used for 'width for height'. In

         * that case, the result may not be accurate.

         */

        int givenLength = wHint != SWT.DEFAULT ? width : height;

        int defaultLength = OS.QWidget_heightForWidth(handle, givenLength);

        if (defaultLength >= 0) {

            if (wHint == SWT.DEFAULT)

                width = defaultLength;

            else

                height = defaultLength;

        }

        return new Point(width, height);

    }

    void createHandle_pp(int index) {

        if ((style & SWT.SEPARATOR) != 0) {

            handle = OS.QFrame_new();

        } else {

            handle = OS.QLabel_new();

            /**

             * Ampresands for keyboard shortcuts are not processed at all and

             * there won't be a shortcut unless buddy is set. The parent is

             * used. Shortcut event can then be cancelled and focus moved

             * manually. This way buddy doesn't ever need to be updated.

             */

            OS.QLabel_setBuddy(handle, parent.handle);

        }

        setStyle(style);

        frameHandle = topHandle = handle;

        state |= WidgetState.HANDLE;

        if ((style & SWT.SEPARATOR) != 0)

            return;

        setAlignment(style);

    }

    /**

     * Returns a value which describes the position of the text or image in the

     * receiver. The value will be one of <code>LEFT</code>,

     * <code>RIGHT</code> or <code>CENTER</code> unless the receiver is a

     * <code>SEPARATOR</code> label, in which case, <code>NONE</code> is

     * returned.

     *

     * @return the alignment

     *

     * @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 int getAlignment() {

        checkWidget();

        if ((style & SWT.SEPARATOR) != 0)

            return 0;

        if ((style & SWT.LEFT) != 0)

            return SWT.LEFT;

        if ((style & SWT.CENTER) != 0)

            return SWT.CENTER;

        if ((style & SWT.RIGHT) != 0)

            return SWT.RIGHT;

        return SWT.LEFT;

    }

    /**

     * Returns the receiver's image if it has one, or null if it does not.

     *

     * @return the receiver's image

     *

     * @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 Image getImage() {

        checkWidget();

        return image;

    }

    String getNameText() {

        return getText();

    }

    /**

     * Returns the receiver's text, which will be an empty string if it has

     * never been set or if the receiver is a <code>SEPARATOR</code> label.

     *

     * @return the receiver's text

     *

     * @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 String getText() {

        checkWidget();

        if ((style & SWT.SEPARATOR) != 0)

            return "";

        return OS.QLabel_text(handle);

    }

    void releaseWidget_pp() {

        super.releaseWidget_pp();

        image = null;

    }

    /**

     * Controls how text and images will be displayed in the receiver. The

     * argument should be one of <code>LEFT</code>, <code>RIGHT</code> or

     * <code>CENTER</code>. If the receiver is a <code>SEPARATOR</code>

     * label, the argument is ignored and the alignment is not changed.

     *

     * @param alignment

     *            the new alignment

     *

     * @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 setAlignment(int alignment) {

        checkWidget();

        if ((style & SWT.SEPARATOR) != 0)

            return;

        alignment &= SWT.LEFT | SWT.RIGHT | SWT.CENTER;

        if (alignment == 0)

            return;

        alignment = checkBits(alignment, SWT.LEFT, SWT.RIGHT, SWT.CENTER, 0, 0,

                0);

        style &= ~(SWT.LEFT | SWT.RIGHT | SWT.CENTER);

        style |= alignment & (SWT.LEFT | SWT.RIGHT | SWT.CENTER);

        int qAlign = 0;

        if ((style & SWT.LEFT) != 0) {

            qAlign |= OS.QT_ALIGNLEFT;

        } else if ((style & SWT.CENTER) != 0) {

            qAlign |= OS.QT_ALIGNHCENTER;

        } else if ((style & SWT.RIGHT) != 0) {

            qAlign |= OS.QT_ALIGNRIGHT;

        }

        qAlign |= OS.QT_ALIGNVCENTER;

        OS.QLabel_setAlignment(handle, qAlign);

    }

    void setStandardIcon(int iconType, int iconWidth, int iconHeight) {

        checkWidget();

        if ((style & SWT.SEPARATOR) != 0)

            return;

        int styleHandle = OS.QApplication_style();

        int iconHandle = 0;

        int pixmapHandle = 0;

        try {

            iconHandle = OS.QStyle_standardIcon(styleHandle, iconType);

            pixmapHandle = OS.QIcon_pixmap(iconHandle, iconWidth, iconHeight);

            OS.QLabel_setPixmap(topHandle, pixmapHandle);

        } finally {

            OS.QIcon_delete(iconHandle);

            OS.QPixmap_delete(pixmapHandle);

        }

    }

    void setStyle(int style) {

        int qStyle = 0;

        if ((style & SWT.SEPARATOR) != 0) {

            if ((style & SWT.VERTICAL) != 0) {

                qStyle |= OS.QT_FRAMEVLINE;

            } else {

                qStyle |= OS.QT_FRAMEHLINE;

            }

            if ((style & SWT.SHADOW_IN) != 0) {

                qStyle |= OS.QT_FRAMESUNKEN;

            } else if ((style & SWT.SHADOW_OUT) != 0) {

                qStyle |= OS.QT_FRAMERAISED;

            } else {

                qStyle |= OS.QT_FRAMEPLAIN;

            }

        } else if ((style & SWT.BORDER) != 0) {

            qStyle |= OS.QT_FRAMESTYLEDPANEL;

        } else {

            qStyle |= OS.QT_NOFRAME;

        }

        OS.QFrame_setFrameStyle(handle, qStyle);

        if ((style & SWT.SEPARATOR) != 0) {

            return;

        }

        if ((style & SWT.WRAP) != 0) {

            OS.QLabel_setWordWrap(handle, true);

        }

    }

    /**

     * 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

     *                <ul>

     *                <li>ERROR_INVALID_ARGUMENT - if the image has been

     *                disposed</li>

     *                </ul>

     * @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 ((style & SWT.SEPARATOR) != 0)

            return;

        if (image != null) {

            if (image.isDisposed())

                SWT.error(SWT.ERROR_INVALID_ARGUMENT);

        }

        if (this.image == image)

            return;

        OS.QLabel_setPixmap(handle, image == null ? 0 : Internal_GfxPackageSupport.getPixmapHandle(image));

        this.image = image;

    }

    /**

     * Sets the receiver's text.

     * <p>

     * This method sets the widget label. The label may include the mnemonic

     * character and line delimiters.

     * </p>

     * <p>

     * 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.

     * </p>

     *

     * @param string

     *            the new text

     *

     * @exception IllegalArgumentException

     *                <ul>

     *                <li>ERROR_NULL_ARGUMENT - if the text is null</li>

     *                </ul>

     * @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 string) {

        checkWidget();

        if (string == null)

            error(SWT.ERROR_NULL_ARGUMENT);

        if ((style & SWT.SEPARATOR) != 0)

            return;

        if (image != null) {

            image = null;

            // empty string does not erase image

            if (string.length() < 1) {

                OS.QLabel_setPixmap(handle, 0);

                return;

            }

        }

        OS.QLabel_setText(handle, string);

    }

    boolean isTabGroup() {

        return false;

    }

    boolean isTabItem() {

        return false;

    }

}