You can try playing with the scrollRect property.
Here's a minimal example:
package {
import flash.display.Sprite;
import flash.display.DisplayObject;
import flash.events.Event;
import flash.display.Shape;
import flash.geom.Rectangle;
public class CamTest extends Sprite {
private var world:Sprite;
private var view:Rectangle = new Rectangle(0,0,300,300);//only display a portion
private var ease:Number = .075;
public function CamTest() {
addEventListener(Event.ADDED_TO_STAGE,init);
}
private function init(e:Event):void{
world = addChild(new Sprite) as Sprite;//add a container
for(var i:int = 0 ; i < 100; i++) world.addChild(getRandomShape());//populate it with random shapes
stage.addEventListener(Event.ENTER_FRAME,update);//loop
}
private function update(e:Event):void{
view.x += (mouseX-view.x) * ease;//ease the pan positions
view.y += (mouseY-view.y) * ease;//might want to map mouse coords
world.scrollRect = view;//re-apply the scrollRect
}
//dummy shapes, not important
private function getRandomShape():Shape{
var s:Shape = new Shape();
var np:int = (int)(3+Math.random()*9);//random points
var ai:Number = Math.PI / (np * .5);//angle increment
s.graphics.lineStyle(1+Math.random() * 7);
for(var i:int = 0 ; i <= np; i++) {
var a:Number = ai*i;
var r:Number = 20+Math.random() * 10 - Math.random() * 10;
var x:Number = Math.cos(a) * r;
var y:Number = Math.sin(a) * r;
if(i == 0) s.graphics.moveTo(x,y);
s.graphics.lineTo(x,y);
}
s.x = Math.random() * 1000;
s.y = Math.random() * 1000;
return s;
}
}
}
If your world is dense you might want to consider using bitmap sprites/blitting.
Here's a minimal example using BitmapData's copyPixels() method:
package {
import flash.display.MovieClip;
import flash.display.BitmapData;
import flash.display.Bitmap;
import flash.display.BitmapDataChannel;
import flash.geom.Point;
import flash.events.Event;
import flash.geom.Rectangle;
public class CamTest2 extends MovieClip {
private var world:BitmapData = new BitmapData(1000,1000,false,0xFFFFFF);
private var render:BitmapData = new BitmapData(300,300,false,0xFFFFFF);
private var view:Rectangle = new Rectangle(0,0,render.width,render.height);//only display a portion
private var zero:Point = new Point();
private var ease:Number = .075;
public function CamTest2() {
init();
}
private function init() {
world.perlinNoise(200, 180, 6,(int)(Math.random() * 10), false, true, BitmapDataChannel.RED, false, null);//random world
addChild(new Bitmap(render));
addEventListener(Event.ENTER_FRAME,update);
}
private function update(e:Event):void{
//update pan
view.x += (mouseX-view.x) * ease;//ease the pan positions
view.y += (mouseY-view.y) * ease;//might want to map mouse coords
//render based on updated view rect
render.lock();
render.copyPixels(world,view,zero);
render.unlock();
}
}
}
You should also look into actionscript game engines that already implement cameras like Flixel or Starling
