/**
* 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.common.util;
import com.google.gwt.dom.client.Element;
/**
* Provides layout properties of elements. In particular, reveals such
* properties in fractional units, on browsers that have sub-pixel rendering.
*
*/
public interface Measurer {
/**
* Gets the position of the top of an element's offset box, either relative to
* the top of another element, or relative to the viewport.
*
* @param base element whose top defines the origin, or {@code null} for the
* top of the viewport being the origin
* @param e element to measure
* @return the top position of {@code e}, relative to the top of {@code base}.
*/
double top(Element base, Element e);
/**
* Gets the position of the left of an element's offset box, either relative to
* the left of another element, or relative to the viewport.
*
* @param base element whose top defines the origin, or {@code null} for the
* left of the viewport being the origin
* @param e element to measure
* @return the left position of {@code e}, relative to the left of {@code base}.
*/
double left(Element base, Element e);
/**
* Gets the position of the bottom of an element's offset box, either relative
* to the top of another element, or relative to the viewport.
*
* @param base element whose top defines the origin, or {@code null} for the
* top of the viewport being the origin
* @param e element to measure
* @return the bottom position of {@code e}, relative to the top of {@code
* base}.
*/
double bottom(Element base, Element e);
/** @return the (offset) height of an element. */
double height(Element e);
/** @return the top of an element relative to its offset parent. */
double offsetTop(Element e);
/** @return the bottom of an element relative to its offset parent. */
double offsetBottom(Element e);
}