org.bioversityinternational.cisf.client.tools.Elements.java Source code

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Here is the source code for org.bioversityinternational.cisf.client.tools.Elements.java

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/*
 * Copyright 2009 Johnson Consulting Services
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package org.bioversityinternational.cisf.client.tools;

import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Style;
import com.google.gwt.user.client.Command;
import com.google.gwt.user.client.DeferredCommand;
import com.google.gwt.user.client.Timer;
import com.google.gwt.user.client.ui.UIObject;

/**
 * Utility class for DOM element manipulations, UIObject effects, etc.
 *
 * @author wilj
 *
 */
public class Elements {

    public interface FadeCallback {
        public void onFadeComplete();

        public void onFadeStart();
    }

    /**
     * Causes an element to "fade in" via opacity.  Make sure that element to fade is not visible before calling this method.
     * When the callback is invoked with onFadeStart, the element can be set to visible as it is entirely transparent.
     * When onFadeComplete is called, the element will be entirely opaque.
     * @param target the UIObject to be faded in
     * @param milliseconds how long the fade effect should take to process
     * @param callback the callback to be invoked on fade progress
     */
    public static void fadeIn(final UIObject target, final int milliseconds, final FadeCallback callback) {
        final Element e = target.getElement();
        final int interval = milliseconds / 50;
        setOpacity(e, 0);
        DeferredCommand.addCommand(new Command() {

            public void execute() {
                callback.onFadeStart();

                final Timer t = new Timer() {
                    int pct = 0;

                    @Override
                    public void run() {
                        pct += 2;
                        setOpacity(e, pct);
                        if (pct == 100) {
                            this.cancel();
                            callback.onFadeComplete();
                        }
                    }
                };
                t.scheduleRepeating(interval);

            }
        });
    }

    /**
     * Causes an element to "fade out" via opacity.
     * When onFadeComplete is called, the element will be entirely transparent.
     * @param target the UIObject to be faded out
     * @param milliseconds how long the fade effect should take to process
     * @param callback the callback to be invoked on fade progress
     */
    public static void fadeOut(final UIObject target, final int milliseconds, final FadeCallback callback) {
        final Element e = target.getElement();
        final int interval = milliseconds / 50;
        DeferredCommand.addCommand(new Command() {

            public void execute() {
                callback.onFadeStart();

                final Timer t = new Timer() {
                    int pct = 100;

                    @Override
                    public void run() {
                        pct -= 2;
                        setOpacity(e, pct);
                        if (pct == 0) {
                            this.cancel();
                            callback.onFadeComplete();
                        }
                    }
                };
                t.scheduleRepeating(interval);

            }
        });
    }

    /**
     * Sets a DOM element's opacity
     * @param e
     * @param percent
     */
    public static void setOpacity(final Element e, final int percent) {
        final Style s = e.getStyle();
        final double d = ((double) percent / (double) 100);
        s.setProperty("opacity", String.valueOf(d));
        s.setProperty("MozOpacity", String.valueOf(d));
        s.setProperty("KhtmlOpacity", String.valueOf(d));
        s.setProperty("filter", "alpha(opacity=" + percent + ")");
    }

    /**
     * Enables/disables text selection for the specified element.
     * Code borrowed/modified from:
     * <a href="http://forgetmenotes.blogspot.com/2009/05/gwt-disable-text-selection-in-table.html">http://forgetmenotes.blogspot.com/2009/05/gwt-disable-text-selection-in-table.html</a>
     * @param e
     * @param selectable
     */
    public static native void setTextSelectable(Element e,
            boolean selectable)/*-{
                                                                                                             }-*/;
}