/**
 * This module is responsible for enabling an element to display images with cornerstone
 */
var cornerstone = (function (cornerstone) {

    "use strict";

    if(cornerstone === undefined) {
        cornerstone = {};
    }

    function setCanvasSize(element, canvas)
    {
        // the device pixel ratio is 1.0 for normal displays and > 1.0
        // for high DPI displays like Retina
        /*

        This functionality is disabled due to buggy behavior on systems with mixed DPI's.  If the canvas
        is created on a display with high DPI (e.g. 2.0) and then the browser window is dragged to
        a different display with a different DPI (e.g. 1.0), the canvas is not recreated so the pageToPixel
        produces incorrect results.  I couldn't find any way to determine when the DPI changed other than
        by polling which is not very clean.  If anyone has any ideas here, please let me know, but for now
        we will disable this functionality.  We may want
        to add a mechanism to optionally enable this functionality if we can determine it is safe to do
        so (e.g. iPad or iPhone or perhaps enumerate the displays on the system.  I am choosing
        to be cautious here since I would rather not have bug reports or safety issues related to this
        scenario.

        var devicePixelRatio = window.devicePixelRatio;
        if(devicePixelRatio === undefined) {
            devicePixelRatio = 1.0;
        }
        */

        canvas.width = element.clientWidth;
        canvas.height = element.clientHeight;
        canvas.style.width = element.clientWidth + "px";
        canvas.style.height = element.clientHeight + "px";
    }

    /**
     * resizes an enabled element and optionally fits the image to window
     * @param element
     * @param fitToWindow true to refit, false to leave viewport parameters as they are
     */
    function resize(element, fitToWindow) {

        var enabledElement = cornerstone.getEnabledElement(element);

        setCanvasSize(element, enabledElement.canvas);

        if(enabledElement.image === undefined ) {
            return;
        }

        if(fitToWindow === true) {
            cornerstone.fitToWindow(element);
        }
        else {
            cornerstone.updateImage(element);
        }
    }

    // module/private exports
    cornerstone.resize = resize;

    return cornerstone;
}(cornerstone));