com.google.gwt.event.dom.client.MouseWheelEvent Maven / Gradle / Ivy
/*
* Copyright 2008 Google Inc.
*
* 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 com.google.gwt.event.dom.client;
import com.google.gwt.dom.client.BrowserEvents;
/**
* Represents a native mouse wheel event.
*/
public class MouseWheelEvent extends MouseEvent {
/**
* Event type for mouse wheel events. Represents the meta-data associated with
* this event.
*/
private static final Type TYPE = new Type(
BrowserEvents.MOUSEWHEEL, new MouseWheelEvent());
static {
/**
* Hidden type used to ensure DOMMouseScroll gets registered in the type map.
* This is the special name used on Mozilla browsers for what everyone else
* calls 'mousewheel'.
*/
new Type("DOMMouseScroll", new MouseWheelEvent());
}
/**
* Gets the event type associated with mouse wheel events.
*
* @return the handler type
*/
public static Type getType() {
return TYPE;
}
/**
* Protected constructor, use
* {@link DomEvent#fireNativeEvent(com.google.gwt.dom.client.NativeEvent, com.google.gwt.event.shared.HasHandlers)}
* to fire mouse wheel events.
*/
protected MouseWheelEvent() {
}
@Override
public final Type getAssociatedType() {
return TYPE;
}
/**
* Get the change in the mouse wheel position along the Y-axis; positive if
* the mouse wheel is moving north (toward the top of the screen) or negative
* if the mouse wheel is moving south (toward the bottom of the screen).
*
* Note that delta values are not normalized across browsers or OSes.
*
* @return the delta of the mouse wheel along the y axis
*/
public int getDeltaY() {
return getNativeEvent().getMouseWheelVelocityY();
}
/**
* Convenience method that returns true if {@link #getDeltaY()}
* is a negative value (ie, the velocity is directed toward the top of the
* screen).
*
* @return true if the velocity is directed toward the top of the screen
*/
public boolean isNorth() {
return getDeltaY() < 0;
}
/**
* Convenience method that returns true if {@link #getDeltaY()}
* is a positive value (ie, the velocity is directed toward the bottom of the
* screen).
*
* @return true if the velocity is directed toward the bottom of the screen
*/
public boolean isSouth() {
return getDeltaY() > 0;
}
@Override
protected void dispatch(MouseWheelHandler handler) {
handler.onMouseWheel(this);
}
}