# Yahoo! UI Library

### dom 3.0.0b1

Yahoo! UI Library > dom > dom-screen.js (source view)
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    (function(Y) {

    /**
     * Adds position and region management functionality to DOM.
     * @module dom
     * @submodule dom-screen
     * @for DOM
     */

    var DOCUMENT_ELEMENT = 'documentElement',
        COMPAT_MODE = 'compatMode',
        POSITION = 'position',
        FIXED = 'fixed',
        RELATIVE = 'relative',
        LEFT = 'left',
        TOP = 'top',
        _BACK_COMPAT = 'BackCompat',
        MEDIUM = 'medium',
        BORDER_LEFT_WIDTH = 'borderLeftWidth',
        BORDER_TOP_WIDTH = 'borderTopWidth',
        GET_BOUNDING_CLIENT_RECT = 'getBoundingClientRect',
        GET_COMPUTED_STYLE = 'getComputedStyle',

        // TODO: how about thead/tbody/tfoot/tr?
        // TODO: does caption matter?
        RE_TABLE = /^t(?:able|d|h)$/i;

    Y.mix(Y.DOM, {
        /**
         * Returns the inner height of the viewport (exludes scrollbar).
         * @method winHeight
         * @return {Number} The current height of the viewport.
         */
        winHeight: function(node) {
            var h = Y.DOM._getWinSize(node).height;
            Y.log('winHeight returning ' + h, 'info', 'dom-screen');
            return h;
        },

        /**
         * Returns the inner width of the viewport (exludes scrollbar).
         * @method winWidth
         * @return {Number} The current width of the viewport.
         */
        winWidth: function(node) {
            var w = Y.DOM._getWinSize(node).width;
            Y.log('winWidth returning ' + w, 'info', 'dom-screen');
            return w;
        },

        /**
         * Document height
         * @method docHeight
         * @return {Number} The current height of the document.
         */
        docHeight:  function(node) {
            var h = Y.DOM._getDocSize(node).height;
            Y.log('docHeight returning ' + h, 'info', 'dom-screen');
            return Math.max(h, Y.DOM._getWinSize(node).height);
        },

        /**
         * Document width
         * @method docWidth
         * @return {Number} The current width of the document.
         */
        docWidth:  function(node) {
            var w = Y.DOM._getDocSize(node).width;
            Y.log('docWidth returning ' + w, 'info', 'dom-screen');
            return Math.max(w, Y.DOM._getWinSize(node).width);
        },

        /**
         * Amount page has been scroll horizontally
         * @method docScrollX
         * @return {Number} The current amount the screen is scrolled horizontally.
         */
        docScrollX: function(node) {
            var doc = Y.DOM._getDoc(node);
            return Math.max(doc[DOCUMENT_ELEMENT].scrollLeft, doc.body.scrollLeft);
        },

        /**
         * Amount page has been scroll vertically
         * @method docScrollY
         * @return {Number} The current amount the screen is scrolled vertically.
         */
        docScrollY:  function(node) {
            var doc = Y.DOM._getDoc(node);
            return Math.max(doc[DOCUMENT_ELEMENT].scrollTop, doc.body.scrollTop);
        },

        /**
         * Gets the current position of an element based on page coordinates.
         * Element must be part of the DOM tree to have page coordinates
         * (display:none or elements not appended return false).
         * @method getXY
         * @param element The target element
         * @return {Array} The XY position of the element

         TODO: test inDocument/display?
         */
        getXY: function() {
            if (document[DOCUMENT_ELEMENT][GET_BOUNDING_CLIENT_RECT]) {
                return function(node) {
                    var xy = null,
                        scrollLeft,
                        scrollTop,
                        box,
                        off1, off2,
                        bLeft, bTop,
                        mode,
                        doc;

                    if (node) {
                        if (Y.DOM.inDoc(node)) {
                            scrollLeft = Y.DOM.docScrollX(node);
                            scrollTop = Y.DOM.docScrollY(node);
                            box = node[GET_BOUNDING_CLIENT_RECT]();
                            doc = Y.DOM._getDoc(node);
                            xy = [box.left, box.top];

                                if (Y.UA.ie) {
                                    off1 = 2;
                                    off2 = 2;
                                    mode = doc[COMPAT_MODE];
                                    bLeft = Y.DOM[GET_COMPUTED_STYLE](doc[DOCUMENT_ELEMENT], BORDER_LEFT_WIDTH);
                                    bTop = Y.DOM[GET_COMPUTED_STYLE](doc[DOCUMENT_ELEMENT], BORDER_TOP_WIDTH);

                                    if (Y.UA.ie === 6) {
                                        if (mode !== _BACK_COMPAT) {
                                            off1 = 0;
                                            off2 = 0;
                                        }
                                    }

                                    if ((mode == _BACK_COMPAT)) {
                                        if (bLeft !== MEDIUM) {
                                            off1 = parseInt(bLeft, 10);
                                        }
                                        if (bTop !== MEDIUM) {
                                            off2 = parseInt(bTop, 10);
                                        }
                                    }

                                    xy[0] -= off1;
                                    xy[1] -= off2;

                                }

                            if ((scrollTop || scrollLeft)) {
                                xy[0] += scrollLeft;
                                xy[1] += scrollTop;
                            }
                        } else { // default to current offsets
                            xy = Y.DOM._getOffset(node);
                        }
                    }
                    return xy;
                };
            } else {
                return function(node) { // manually calculate by crawling up offsetParents
                    //Calculate the Top and Left border sizes (assumes pixels)
                    var xy = null,
                        parentNode,
                        bCheck,
                        scrollTop,
                        scrollLeft;

                    if (node) {
                        if (Y.DOM.inDoc(node)) {
                            xy = [node.offsetLeft, node.offsetTop];
                            parentNode = node;
                            // TODO: refactor with !! or just falsey
                            bCheck = ((Y.UA.gecko || Y.UA.webkit > 519) ? true : false);

                            // TODO: worth refactoring for TOP/LEFT only?
                            while ((parentNode = parentNode.offsetParent)) {
                                xy[0] += parentNode.offsetLeft;
                                xy[1] += parentNode.offsetTop;
                                if (bCheck) {
                                    xy = Y.DOM._calcBorders(parentNode, xy);
                                }
                            }

                            // account for any scrolled ancestors
                            if (Y.DOM.getStyle(node, POSITION) != FIXED) {
                                parentNode = node;

                                while ((parentNode = parentNode.parentNode)) {
                                    scrollTop = parentNode.scrollTop;
                                    scrollLeft = parentNode.scrollLeft;

                                    //Firefox does something funky with borders when overflow is not visible.
                                    if (Y.UA.gecko && (Y.DOM.getStyle(parentNode, 'overflow') !== 'visible')) {
                                            xy = Y.DOM._calcBorders(parentNode, xy);
                                    }

                                    if (scrollTop || scrollLeft) {
                                        xy[0] -= scrollLeft;
                                        xy[1] -= scrollTop;
                                    }
                                }
                                xy[0] += Y.DOM.docScrollX(node);
                                xy[1] += Y.DOM.docScrollY(node);

                            } else {
                                //Fix FIXED position -- add scrollbars
                                xy[0] += Y.DOM.docScrollX(node);
                                xy[1] += Y.DOM.docScrollY(node);
                            }
                        } else {
                            xy = Y.DOM._getOffset(node);
                        }
                    }

                    return xy;
                };
            }
        }(),// NOTE: Executing for loadtime branching

        _getOffset: function(node) {
            var pos,
                xy = null;

            if (node) {
                pos = Y.DOM.getStyle(node, POSITION);
                xy = [
                    parseInt(Y.DOM[GET_COMPUTED_STYLE](node, LEFT), 10),
                    parseInt(Y.DOM[GET_COMPUTED_STYLE](node, TOP), 10)
                ];

                if ( isNaN(xy[0]) ) { // in case of 'auto'
                    xy[0] = parseInt(Y.DOM.getStyle(node, LEFT), 10); // try inline
                    if ( isNaN(xy[0]) ) { // default to offset value
                        xy[0] = (pos === RELATIVE) ? 0 : node.offsetLeft || 0;
                    }
                }

                if ( isNaN(xy[1]) ) { // in case of 'auto'
                    xy[1] = parseInt(Y.DOM.getStyle(node, TOP), 10); // try inline
                    if ( isNaN(xy[1]) ) { // default to offset value
                        xy[1] = (pos === RELATIVE) ? 0 : node.offsetTop || 0;
                    }
                }
            }

            return xy;

        },

        /**
         * Gets the current X position of an element based on page coordinates.
         * Element must be part of the DOM tree to have page coordinates
         * (display:none or elements not appended return false).
         * @method getX
         * @param element The target element
         * @return {Int} The X position of the element
         */

        getX: function(node) {
            return Y.DOM.getXY(node)[0];
        },

        /**
         * Gets the current Y position of an element based on page coordinates.
         * Element must be part of the DOM tree to have page coordinates
         * (display:none or elements not appended return false).
         * @method getY
         * @param element The target element
         * @return {Int} The Y position of the element
         */

        getY: function(node) {
            return Y.DOM.getXY(node)[1];
        },

        /**
         * Set the position of an html element in page coordinates.
         * The element must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
         * @method setXY
         * @param element The target element
         * @param {Array} xy Contains X & Y values for new position (coordinates are page-based)
         * @param {Boolean} noRetry By default we try and set the position a second time if the first fails
         */
        setXY: function(node, xy, noRetry) {
            var setStyle = Y.DOM.setStyle,
                pos,
                delta,
                newXY,
                currentXY;

            if (node && xy) {
                pos = Y.DOM.getStyle(node, POSITION);

                delta = Y.DOM._getOffset(node);

                if (pos == 'static') { // default to relative
                    pos = RELATIVE;
                    setStyle(node, POSITION, pos);
                }

                currentXY = Y.DOM.getXY(node);

                if (xy[0] !== null) {
                    setStyle(node, LEFT, xy[0] - currentXY[0] + delta[0] + 'px');
                }

                if (xy[1] !== null) {
                    setStyle(node, TOP, xy[1] - currentXY[1] + delta[1] + 'px');
                }

                if (!noRetry) {
                    newXY = Y.DOM.getXY(node);
                    if (newXY[0] !== xy[0] || newXY[1] !== xy[1]) {
                        Y.DOM.setXY(node, xy, true);
                    }
                }

                Y.log('setXY setting position to ' + xy, 'info', 'dom-screen');
            } else {
                Y.log('setXY failed to set ' + node + ' to ' + xy, 'info', 'dom-screen');
            }
        },

        /**
         * Set the X position of an html element in page coordinates, regardless of how the element is positioned.
         * The element(s) must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
         * @method setX
         * @param element The target element
         * @param {Int} x The X values for new position (coordinates are page-based)
         */
        setX: function(node, x) {
            return Y.DOM.setXY(node, [x, null]);
        },

        /**
         * Set the Y position of an html element in page coordinates, regardless of how the element is positioned.
         * The element(s) must be part of the DOM tree to have page coordinates (display:none or elements not appended return false).
         * @method setY
         * @param element The target element
         * @param {Int} y The Y values for new position (coordinates are page-based)
         */
        setY: function(node, y) {
            return Y.DOM.setXY(node, [null, y]);
        },

        _calcBorders: function(node, xy2) {
            var t = parseInt(Y.DOM[GET_COMPUTED_STYLE](node, BORDER_TOP_WIDTH), 10) || 0,
                l = parseInt(Y.DOM[GET_COMPUTED_STYLE](node, BORDER_LEFT_WIDTH), 10) || 0;
            if (Y.UA.gecko) {
                if (RE_TABLE.test(node.tagName)) {
                    t = 0;
                    l = 0;
                }
            }
            xy2[0] += l;
            xy2[1] += t;
            return xy2;
        },

        _getWinSize: function(node) {
            var doc = Y.DOM._getDoc(),
                win = doc.defaultView || doc.parentWindow,
                mode = doc[COMPAT_MODE],
                h = win.innerHeight,
                w = win.innerWidth,
                root = doc[DOCUMENT_ELEMENT];

            if ( mode && !Y.UA.opera ) { // IE, Gecko
                if (mode != 'CSS1Compat') { // Quirks
                    root = doc.body;
                }
                h = root.clientHeight;
                w = root.clientWidth;
            }
            return { height: h, width: w };
        },

        _getDocSize: function(node) {
            var doc = Y.DOM._getDoc(),
                root = doc[DOCUMENT_ELEMENT];

            if (doc[COMPAT_MODE] != 'CSS1Compat') {
                root = doc.body;
            }

            return { height: root.scrollHeight, width: root.scrollWidth };
        }
    });
    })(Y);

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