org.waveprotocol.wave.client.widget.popup.ListRelativePopupPositioner.java Source code

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Here is the source code for org.waveprotocol.wave.client.widget.popup.ListRelativePopupPositioner.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.waveprotocol.wave.client.widget.popup;

import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.Style;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.dom.client.Style.Visibility;
import com.google.gwt.user.client.ui.RootPanel;
import org.waveprotocol.wave.client.scheduler.ScheduleCommand;
import org.waveprotocol.wave.client.scheduler.Scheduler;

/**
 * Class for positioning a popup relative to an element residing in a horizontal or vertical list.
 *
 */
public class ListRelativePopupPositioner implements RelativePopupPositioner {
    /** Offset to use when positioning popup */
    private static final int PIXEL_OFFSET = 10;

    /** Strategy instance for vertical-list positioning. */
    public static final ListRelativePopupPositioner VERTICAL = new ListRelativePopupPositioner(false);

    /** Strategy instance for horizontal-list positioning. */
    public static final ListRelativePopupPositioner HORIZONTAL = new ListRelativePopupPositioner(true);

    private final boolean inHorizontalList;

    /**
     * Create a new ListRelativePopupPostioner.
     *
     * @param inHorizontalList True if the relative element is in a horizontal list.
     */
    private ListRelativePopupPositioner(boolean inHorizontalList) {
        this.inHorizontalList = inHorizontalList;
    }

    /**
     * {@inheritDoc}
     */
    public void setPopupPositionAndMakeVisible(final Element relative, final Element p) {
        ScheduleCommand.addCommand(new Scheduler.Task() {
            public void execute() {
                Style s = p.getStyle();
                int horizontalCenter = RootPanel.get().getOffsetWidth() / 2;
                int verticalCenter = RootPanel.get().getOffsetHeight() / 2;
                int left = relative.getAbsoluteLeft();
                int right = relative.getAbsoluteRight();
                int top = relative.getAbsoluteTop();
                int bottom = relative.getAbsoluteBottom();
                if (inHorizontalList) {
                    // Place popup above or below relative
                    if (right > horizontalCenter) {
                        // Place popup left of relative's right
                        s.setRight(RootPanel.get().getOffsetWidth() - right + PIXEL_OFFSET, Unit.PX);
                        if (top < verticalCenter) {
                            // Place popup below bottom of relative
                            s.setTop(bottom, Unit.PX);
                        } else {
                            // Place popup above top of relative
                            s.setBottom(RootPanel.get().getOffsetHeight() - top, Unit.PX);
                        }
                    } else {
                        // Place popup right of relative's left
                        s.setLeft(left + PIXEL_OFFSET, Unit.PX);
                        if (top < verticalCenter) {
                            // Place popup below bottom of relative
                            s.setTop(bottom, Unit.PX);
                        } else {
                            // Place popup above top of relative
                            s.setBottom(RootPanel.get().getOffsetHeight() - top, Unit.PX);
                        }
                    }
                } else {
                    // Place popup on left or right side of relative
                    if (right > horizontalCenter) {
                        // Place popup left of relative's left
                        s.setRight(RootPanel.get().getOffsetWidth() - left, Unit.PX);
                        if (top < verticalCenter) {
                            // Place popup below top of relative
                            s.setTop(top + PIXEL_OFFSET, Unit.PX);
                        } else {
                            // Place popup above bottom of relative
                            s.setBottom(RootPanel.get().getOffsetHeight() - bottom + PIXEL_OFFSET, Unit.PX);
                        }
                    } else {
                        // Place popup right of relative's right
                        s.setLeft(right, Unit.PX);
                        if (top < verticalCenter) {
                            // Place popup below top of relative
                            s.setTop(top + PIXEL_OFFSET, Unit.PX);
                        } else {
                            // Place popup above bottom of relative
                            s.setBottom(RootPanel.get().getOffsetHeight() - bottom + PIXEL_OFFSET, Unit.PX);
                        }
                    }
                }
                p.getStyle().setVisibility(Visibility.VISIBLE);
            }
        });
    }
}