package com.esri.viewer
{
import com.esri.ags.Map;
import com.esri.ags.esri_internal;
import com.esri.ags.events.ExtentEvent;
import com.esri.ags.events.MapEvent;
import com.esri.ags.geometry.Extent;
import com.esri.ags.utils.ProjUtils;
import flash.system.Capabilities;
use namespace esri_internal;
public class ConstrainedMap extends Map
{
private var m_cExtent:Extent = new Extent(Number.NEGATIVE_INFINITY, Number.NEGATIVE_INFINITY,
Number.POSITIVE_INFINITY, Number.POSITIVE_INFINITY);
private var m_initialScale:Number = Number.POSITIVE_INFINITY;
private var m_initialExtent:Extent = new Extent(
Number.NEGATIVE_INFINITY, Number.NEGATIVE_INFINITY,
Number.POSITIVE_INFINITY, Number.POSITIVE_INFINITY);
private var lastDy:Number = 0;
public function set constrainedExtent(value:Extent):void
{
m_cExtent = value;
}
public function get constrainedExtent():Extent
{
return m_cExtent;
}
public function ConstrainedMap()
{
this.openHandCursorVisible = true;
this.extent = m_cExtent.esri_internal::duplicate();
this.addEventListener(MapEvent.LOAD, loadHandler );
}
override public function set extent(value:Extent):void
{
const newScale:Number = ProjUtils.convertExtentToScale(value, width, Capabilities.screenDPI);
// trace( newScale.toFixed(0), m_initialScale.toFixed(0));
// Make sure we do not go over the initial extent.
if( newScale > m_initialScale )
{
super.extent = m_initialExtent.esri_internal::duplicate();;
}
else
{
super.extent = value;
}
}
private function loadHandler(event:MapEvent):void
{
this.removeEventListener(MapEvent.LOAD, loadHandler);
// Note the low priority listener.
this.addEventListener(ExtentEvent.EXTENT_CHANGE, extentChangeHandlerOnce, false, -99);
this.addEventListener(ExtentEvent.EXTENT_CHANGE, extentChangeHandler);
}
/**
* Handler used _once_ to get the initial map scale and extent.
*/
private function extentChangeHandlerOnce(event:ExtentEvent):void
{
this.removeEventListener(ExtentEvent.EXTENT_CHANGE, extentChangeHandlerOnce);
m_initialScale = ProjUtils.convertExtentToScale(m_cExtent, width, Capabilities.screenDPI);
m_initialExtent = m_cExtent;
}
private function extentChangeHandler(event:ExtentEvent):void
{
if(extent.contains(m_initialExtent))
{
return;
}
var dx:Number, dy:Number;
if(m_initialExtent.xmax < extent.xmax)
{
dx = extent.xmax - m_initialExtent.xmax;
}
else if(m_initialExtent.xmin > extent.xmin)
{
dx = extent.xmin - m_initialExtent.xmin;
}
else
{
dx = 0.0;
}
if(m_initialExtent.ymax < extent.ymax)
{
dy = extent.ymax - m_initialExtent.ymax;
}
else if(m_initialExtent.ymin > extent.ymin)
{
dy = extent.ymin - m_initialExtent.ymin;
}
else
{
dy = 0;
}
//trace( dx.toFixed(0), dy.toFixed(0));
if(dx.toFixed(0) !== "0." || dy.toFixed(0) !== "0.")
{
// Make sure the extent is set on the next display cycle.
callLater(callLaterHandler, [dx,dy]);
}
}
private function callLaterHandler(dx:Number, dy:Number):void
{
if(Math.abs(dy).toFixed(0) == Math.abs(lastDy).toFixed(0)){
//trace("exiting extent change");
return;
}
extent = new Extent(extent.xmin - dx, extent.ymin - dy, extent.xmax - dx, extent.ymax - dy);
lastDy = dy;
}
}
}
This has code to avoid the earthquake effect.
