com.sencha.gxt.core.client.dom.DefaultScrollSupport.java Source code

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Here is the source code for com.sencha.gxt.core.client.dom.DefaultScrollSupport.java

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/**
 * Sencha GXT 4.0.0 - Sencha for GWT
 * Copyright (c) 2006-2015, Sencha Inc.
 *
 * licensing@sencha.com
 * http://www.sencha.com/products/gxt/license/
 *
 * ================================================================================
 * Open Source License
 * ================================================================================
 * This version of Sencha GXT is licensed under the terms of the Open Source GPL v3
 * license. You may use this license only if you are prepared to distribute and
 * share the source code of your application under the GPL v3 license:
 * http://www.gnu.org/licenses/gpl.html
 *
 * If you are NOT prepared to distribute and share the source code of your
 * application under the GPL v3 license, other commercial and oem licenses
 * are available for an alternate download of Sencha GXT.
 *
 * Please see the Sencha GXT Licensing page at:
 * http://www.sencha.com/products/gxt/license/
 *
 * For clarification or additional options, please contact:
 * licensing@sencha.com
 * ================================================================================
 *
 *
 * ================================================================================
 * Disclaimer
 * ================================================================================
 * THIS SOFTWARE IS DISTRIBUTED "AS-IS" WITHOUT ANY WARRANTIES, CONDITIONS AND
 * REPRESENTATIONS WHETHER EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE
 * IMPLIED WARRANTIES AND CONDITIONS OF MERCHANTABILITY, MERCHANTABLE QUALITY,
 * FITNESS FOR A PARTICULAR PURPOSE, DURABILITY, NON-INFRINGEMENT, PERFORMANCE AND
 * THOSE ARISING BY STATUTE OR FROM CUSTOM OR USAGE OF TRADE OR COURSE OF DEALING.
 * ================================================================================
 */
package com.sencha.gxt.core.client.dom;

import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.client.Element;
import com.google.gwt.user.client.ui.UIObject;

public class DefaultScrollSupport implements ScrollSupport {

    private XElement scrollElement;

    private ScrollMode scrollMode = ScrollMode.NONE;

    public DefaultScrollSupport(Element scrollElement) {
        this.scrollElement = scrollElement.cast();
    }

    @Override
    public void ensureVisible(UIObject item) {
        Element element = item.getElement();
        ensureVisibleImpl(scrollElement, element);
    }

    @Override
    public int getHorizontalScrollPosition() {
        return scrollElement.getScrollLeft();
    }

    @Override
    public int getMaximumHorizontalScrollPosition() {
        return ScrollImplHelper.getMaximumHorizontalScrollPosition(scrollElement);
    }

    @Override
    public int getMaximumVerticalScrollPosition() {
        return scrollElement.getScrollHeight() - scrollElement.getClientHeight();
    }

    @Override
    public int getMinimumHorizontalScrollPosition() {
        return ScrollImplHelper.getMinimumHorizontalScrollPosition(scrollElement);
    }

    @Override
    public int getMinimumVerticalScrollPosition() {
        return 0;
    }

    public XElement getScrollElement() {
        return scrollElement;
    }

    @Override
    public ScrollMode getScrollMode() {
        return scrollMode;
    }

    @Override
    public int getVerticalScrollPosition() {
        return scrollElement.getScrollTop();
    }

    @Override
    public void scrollToBottom() {
        setVerticalScrollPosition(getMaximumVerticalScrollPosition());
    }

    @Override
    public void scrollToLeft() {
        setHorizontalScrollPosition(getMinimumHorizontalScrollPosition());
    }

    @Override
    public void scrollToRight() {
        setHorizontalScrollPosition(getMaximumHorizontalScrollPosition());
    }

    @Override
    public void scrollToTop() {
        setVerticalScrollPosition(getMinimumVerticalScrollPosition());
    }

    @Override
    public void setHorizontalScrollPosition(int position) {
        scrollElement.setScrollLeft(position);
    }

    @Override
    public void setScrollMode(ScrollMode scrollMode) {
        this.scrollMode = scrollMode;
        switch (scrollMode) {
        case AUTO:
        case ALWAYS:
        case NONE:
            scrollElement.getStyle().setProperty("overflowX", scrollMode.value().toLowerCase());
            scrollElement.getStyle().setProperty("overflowY", scrollMode.value().toLowerCase());
            break;
        case AUTOX:
            scrollElement.getStyle().setProperty("overflowX", scrollMode.value().toLowerCase());
            scrollElement.getStyle().setProperty("overflowY", "hidden");
            break;
        case AUTOY:
            scrollElement.getStyle().setProperty("overflowY", scrollMode.value().toLowerCase());
            scrollElement.getStyle().setProperty("overflowX", "hidden");
            break;
        }
    }

    @Override
    public void setVerticalScrollPosition(int position) {
        scrollElement.setScrollTop(position);
    }

    private native void ensureVisibleImpl(Element scroll, Element e) /*-{
                                                                     if (!e)
                                                                     return;
                                                                         
                                                                     var item = e;
                                                                     var realOffset = 0;
                                                                     while (item && (item != scroll)) {
                                                                     realOffset += item.offsetTop;
                                                                     item = item.offsetParent;
                                                                     }
                                                                         
                                                                     scroll.scrollTop = realOffset - scroll.offsetHeight / 2;
                                                                     }-*/;

}