Actionscript Image with clickable spots - actionscript-3

Question

Can any one help in suggesting a solution for the following:
i have a large image, consider it as a map, i want to put this image in a viewer that is smaller than the image and i have to be able to scroll the image by clicking and dragging it.
and i want to put in this image a clickable spots in a specified x and y coordinated, and be able to click the spots.
when clicking any spot in the image, the image will be changed with a new spots.. and so on..
can you help in suggesting what is the best object to load the image in and be able to do all the mentioned points.
Thanks in advance.

Answer 1

This is easier than you think. You have a few goals to consider:
"i want to put this image in a viewer that is smaller than the image": You dont need anything special to do this. The concept of this is simply that you have a mask overlay where you want the large image visible.
var viewer:Sprite = new Sprite; //200x200
var imageMask:Sprite = new Sprite; //200x200
var imageContainer:Sprite = new Sprite; //400x500
imageContainer.mask = imageMask;
viewer.addChild(imageContainer);
//this will allow you to visibly see only 200x200 of the
//imageContainer at any time
"i have to be able to scroll the image by clicking and dragging it": This is a little more logic as the imageContainer will have to move in the -(negative) direction of the mouse. Add some listeners to check for mouse actions, and drag as required.
var allowDrag:Boolean = false;
imageContainer.addEventListener(MouseEvent.MOUSE_DOWN, onMouseDown);
imageContainer.addEventListener(MouseEvent.MOUSE_UP, onMouseUp);
imageContainer.addEventListener(MouseEvent.MOUSE_MOVE, onMouseMove);
function onMouseDown(e:Event):void{
allowDrag = true;
}
function onMouseUp(e:Event):void{
allowDrag = false;
}
function onMouseMove(e:Event):void{
//return if not dragging
if(!allowDrag) return;
//move the imageContainer in a -(negative) direction of the mouse
//use an index relative to the size of the viewer and imageContainer
var speed:Number = 0.5;
imageContainer.x -= (viewer.width/imageContainer.width)*speed;
imageContainer.y -= (viewer.height/imageContainer.height)*speed;
//clean the positions so the image remains within the viewer
if(imageContainer.x > 0) imageContainer.x = 0;
if(imageContainer.x < -viewer.width) imageContainer.x = -viewer.width;
if(imageContainer.y > 0) imageContainer.y = 0;
if(imageContainer.y < -viewer.height) imageContainer.y = -viewer.height;
}
"i want to put in this image a clickable spots in a specified x and y coordinated, and be able to click the spots": This also requires a little more thinking. In this case what you want to do is create [hotspots] on the image that are clickable, when clicked = do actions.
//USAGE
//define the click area coords
var clickCoords:Rectangle = new Rectangle();
clickCoords.x = 10; //starts at x 10
clickCoords.y = 10; //starts at y 10
clickCoords.width = 100; //100 wide
clickCoords.height = 100; //100 tall
//add the click listener
var clickArea:Sprite = hotSpot(imageContainer,clickCoords);
clickArea.addEventListener(MouseEvent.CLICK, onHotSoptClick);
//hot spot factory
function hotSpot(target:Sprite,coords:Rectangle):Sprite{
//create the hotspot
var hs:Sprite = new Sprite;
hs.graphics.beginFill(0,0);
hs.graphics.drawRect(0,0,coords.width,coords.height);
hs.graphics.endFill();
//add the hotspot to the target
hs.x = coords.x;
hs.y = coords.y;
target.addChild(hs);
}
function onHotSoptClick(e:MouseEvent):void{
//do something
}
IMPORTANT:
You may want to keep a list of hot spots you create so you can do garbage cleanup, and you plan on dynamically generating hotspots per image... then YOU MUST keep an active list of hot spots and remove when not in use.

Answer 2

You can catch the events MouseDown, MouseUp, MouseMove, MouseOut, on your viewing window, this way you can control exactly what do you want to do.
Here is the pseudo-code:
reset()
{
isDown=false;
downPointX=0;
downPointY=0;
distanceX=0;
distanceY=0;
}
onMouseDown()
{
isDown=true;
downPointX=mouseX;
downPointY=mouseY;
}
onMouseUp()
{
if(distanceX+distanceY==0 and isDown)
click(downPointX,downPointY);
reset();
}
onMouseMove()
{
if isDown then
distanceX=mouseX-downPointX;
distanceY=mouseY-downPointY;
drag(distanceX,distanceY);
endif;
}
onMouseOut()
{
reset();
}
drag(distanceX,distanceY)
{
change your map coordinates
}
click(downPointX,downPointY)
{
if(inSpot(downPointX,downPointY)==true)
changeMap();
endif;
}
changeMap()
{
change your maps and spots
}
avoid implementing any event for your spots sprites or you can get unexpected results.
You can check these for more information
http://help.adobe.com/en_US/FlashPlatform/reference/actionscript/3/flash/display/Sprite.html#eventSummary