Handling the pointer move event

When we move the pointer, we perform the following tasks:

• Pointer is down

• Select a bubble in the global variable

• Check whether the bubble can be moved into this position

• Swap two neighbor bubbles

The ready slideBubble handler looks like this:

function slideBubble(pointer, x, y, fromClick) {
    if (window.selectedBubble && pointer.isDown)
    {
        var cursorBubblePosX = getBubblePos(x);
        var cursorBubblePosY = getBubblePos(y);
        if (checkIfBubbleCanBeMovedHere(
            window.selectedBubbleStartPos.x, 
            window.selectedBubbleStartPos.y, 
            cursorBubblePosX, 
            cursorBubblePosY))
        {
            if (cursorBubblePosX !== window.selectedBubble.posX || 
                cursorBubblePosY !== window.selectedBubble.posY)
            {
                bubbles.bringToTop(window.selectedBubble);
                tempShiftedBubble = getBubble(cursorBubblePosX, cursorBubblePosY);                
              ...