source: Dev/trunk/src/client/dojox/gfx/_base.js

define(["dojo/_base/kernel", "dojo/_base/lang", "dojo/_base/Color", "dojo/_base/sniff", "dojo/_base/window",
            "dojo/_base/array","dojo/dom", "dojo/dom-construct","dojo/dom-geometry"],
function(kernel, lang, Color, has, win, arr, dom, domConstruct, domGeom){
        // module:
        //              dojox/gfx
        // summary:
        //              This module contains common core Graphics API used by different graphics renderers.

        var g = lang.getObject("dojox.gfx", true),
                b = g._base = {};
        
        // candidates for dojox.style (work on VML and SVG nodes)
        g._hasClass = function(/*DomNode*/node, /*String*/classStr){
                // summary:
                //              Returns whether or not the specified classes are a portion of the
                //              class list currently applied to the node.
                
                // return (new RegExp('(^|\\s+)'+classStr+'(\\s+|$)')).test(node.className)     // Boolean
                var cls = node.getAttribute("className");
                return cls && (" " + cls + " ").indexOf(" " + classStr + " ") >= 0;  // Boolean
        };
        g._addClass = function(/*DomNode*/node, /*String*/classStr){
                // summary:
                //              Adds the specified classes to the end of the class list on the
                //              passed node.
                var cls = node.getAttribute("className") || "";
                if(!cls || (" " + cls + " ").indexOf(" " + classStr + " ") < 0){
                        node.setAttribute("className", cls + (cls ? " " : "") + classStr);
                }
        };
        g._removeClass = function(/*DomNode*/node, /*String*/classStr){
                // summary:
                //              Removes classes from node.
                var cls = node.getAttribute("className");
                if(cls){
                        node.setAttribute(
                                "className",
                                cls.replace(new RegExp('(^|\\s+)' + classStr + '(\\s+|$)'), "$1$2")
                        );
                }
        };

        // candidate for dojox.html.metrics (dynamic font resize handler is not implemented here)

        //              derived from Morris John's emResized measurer
        b._getFontMeasurements = function(){
                // summary:
                //              Returns an object that has pixel equivilents of standard font
                //              size values.
                var heights = {
                        '1em': 0, '1ex': 0, '100%': 0, '12pt': 0, '16px': 0, 'xx-small': 0,
                        'x-small': 0, 'small': 0, 'medium': 0, 'large': 0, 'x-large': 0,
                        'xx-large': 0
                };
                var p;

                if(has("ie")){
                        //              we do a font-size fix if and only if one isn't applied already.
                        // NOTE: If someone set the fontSize on the HTML Element, this will kill it.
                        win.doc.documentElement.style.fontSize="100%";
                }

                //              set up the measuring node.
                var div = domConstruct.create("div", {style: {
                                position: "absolute",
                                left: "0",
                                top: "-100px",
                                width: "30px",
                                height: "1000em",
                                borderWidth: "0",
                                margin: "0",
                                padding: "0",
                                outline: "none",
                                lineHeight: "1",
                                overflow: "hidden"
                        }}, win.body());

                //              do the measurements.
                for(p in heights){
                        div.style.fontSize = p;
                        heights[p] = Math.round(div.offsetHeight * 12/16) * 16/12 / 1000;
                }

                win.body().removeChild(div);
                return heights; //object
        };

        var fontMeasurements = null;

        b._getCachedFontMeasurements = function(recalculate){
                if(recalculate || !fontMeasurements){
                        fontMeasurements = b._getFontMeasurements();
                }
                return fontMeasurements;
        };

        // candidate for dojox.html.metrics

        var measuringNode = null, empty = {};
        b._getTextBox = function(       /*String*/ text,
                                                                /*Object*/ style,
                                                                /*String?*/ className){
                var m, s, al = arguments.length;
                var i, box;
                if(!measuringNode){
                        measuringNode = domConstruct.create("div", {style: {
                                position: "absolute",
                                top: "-10000px",
                                left: "0",
                                visibility: "hidden"
                        }}, win.body());
                }
                m = measuringNode;
                // reset styles
                m.className = "";
                s = m.style;
                s.borderWidth = "0";
                s.margin = "0";
                s.padding = "0";
                s.outline = "0";
                // set new style
                if(al > 1 && style){
                        for(i in style){
                                if(i in empty){ continue; }
                                s[i] = style[i];
                        }
                }
                // set classes
                if(al > 2 && className){
                        m.className = className;
                }
                // take a measure
                m.innerHTML = text;

                if(m.getBoundingClientRect){
                        var bcr = m.getBoundingClientRect();
                        box = {l: bcr.left, t: bcr.top, w: bcr.width || (bcr.right - bcr.left), h: bcr.height || (bcr.bottom - bcr.top)};
                }else{
                        box = domGeom.getMarginBox(m);
                }
                m.innerHTML = "";
                return box;
        };

        b._computeTextLocation = function(/*g.defaultTextShape*/textShape, /*Number*/width, /*Number*/height, /*Boolean*/fixHeight) {
                var loc = {}, align = textShape.align;
                switch (align) {
                        case 'end':
                                loc.x = textShape.x - width;
                                break;
                        case 'middle':
                                loc.x = textShape.x - width / 2;
                                break;
                        default:
                                loc.x = textShape.x;
                                break;
                }
                var c = fixHeight ? 0.75 : 1;
                loc.y = textShape.y - height*c; // **rough** approximation of the ascent...
                return loc;
        };
        b._computeTextBoundingBox = function(/*shape.Text*/s){
                // summary:
                //              Compute the bbox of the given shape.Text instance. Note that this method returns an
                //              approximation of the bbox, and should be used when the underlying renderer cannot provide precise metrics.
                if(!g._base._isRendered(s)){
                        return {x:0, y:0, width:0, height:0};
                }
                var loc, textShape = s.getShape(),
                        font = s.getFont() || g.defaultFont,
                        w = s.getTextWidth(),
                        h = g.normalizedLength(font.size);
                loc = b._computeTextLocation(textShape, w, h, true);
                return {
                        x: loc.x,
                        y: loc.y,
                        width: w,
                        height: h
                };
        };
        b._isRendered = function(/*Shape*/s){
                var p = s.parent;
                while(p && p.getParent){
                        p = p.parent;
                }
                return p !== null;
        };

        // candidate for dojo.dom

        var uniqueId = 0;
        b._getUniqueId = function(){
                // summary:
                //              returns a unique string for use with any DOM element
                var id;
                do{
                        id = kernel._scopeName + "xUnique" + (++uniqueId);
                }while(dom.byId(id));
                return id;
        };

        // IE10

        b._fixMsTouchAction = function(/*dojox/gfx/shape.Surface*/surface){
                var r = surface.rawNode;
                if (typeof r.style.msTouchAction != 'undefined')
                        r.style.msTouchAction = "none";
        };

        /*=====
        g.Stroke = {
                // summary:
                //              A stroke defines stylistic properties that are used when drawing a path.

                // color: String
                //              The color of the stroke, default value 'black'.
                color: "black",

                // style: String
                //              The style of the stroke, one of 'solid', ... . Default value 'solid'.
                style: "solid",

                // width: Number
                //              The width of a stroke, default value 1.
                width: 1,

                // cap: String
                //              The endcap style of the path. One of 'butt', 'round', ... . Default value 'butt'.
                cap: "butt",

                // join: Number
                //              The join style to use when combining path segments. Default value 4.
                join: 4
        };
        
        g.Fill = {
                // summary:
                //              Defines how to fill a shape. Four types of fills can be used: solid, linear gradient, radial gradient and pattern.
                //              See dojox/gfx.LinearGradient, dojox/gfx.RadialGradient and dojox/gfx.Pattern respectively for more information about the properties supported by each type.
                
                // type: String?
                //              The type of fill. One of 'linear', 'radial', 'pattern' or undefined. If not specified, a solid fill is assumed.
                type:"",
                
                // color: String|dojo/Color?
                //              The color of a solid fill type.
                color:null,
                
        };
        
        g.LinearGradient = {
                // summary:
                //              An object defining the default stylistic properties used for Linear Gradient fills.
                //              Linear gradients are drawn along a virtual line, which results in appearance of a rotated pattern in a given direction/orientation.

                // type: String
                //              Specifies this object is a Linear Gradient, value 'linear'
                type: "linear",

                // x1: Number
                //              The X coordinate of the start of the virtual line along which the gradient is drawn, default value 0.
                x1: 0,

                // y1: Number
                //              The Y coordinate of the start of the virtual line along which the gradient is drawn, default value 0.
                y1: 0,

                // x2: Number
                //              The X coordinate of the end of the virtual line along which the gradient is drawn, default value 100.
                x2: 100,

                // y2: Number
                //              The Y coordinate of the end of the virtual line along which the gradient is drawn, default value 100.
                y2: 100,

                // colors: Array
                //              An array of colors at given offsets (from the start of the line).  The start of the line is
                //              defined at offest 0 with the end of the line at offset 1.
                //              Default value, [{ offset: 0, color: 'black'},{offset: 1, color: 'white'}], is a gradient from black to white.
                colors: []
        };
        
        g.RadialGradient = {
                // summary:
                //              Specifies the properties for RadialGradients using in fills patterns.

                // type: String
                //              Specifies this is a RadialGradient, value 'radial'
                type: "radial",

                // cx: Number
                //              The X coordinate of the center of the radial gradient, default value 0.
                cx: 0,

                // cy: Number
                //              The Y coordinate of the center of the radial gradient, default value 0.
                cy: 0,

                // r: Number
                //              The radius to the end of the radial gradient, default value 100.
                r: 100,

                // colors: Array
                //              An array of colors at given offsets (from the center of the radial gradient).
                //              The center is defined at offest 0 with the outer edge of the gradient at offset 1.
                //              Default value, [{ offset: 0, color: 'black'},{offset: 1, color: 'white'}], is a gradient from black to white.
                colors: []
        };
        
        g.Pattern = {
                // summary:
                //              An object specifying the default properties for a Pattern using in fill operations.

                // type: String
                //              Specifies this object is a Pattern, value 'pattern'.
                type: "pattern",

                // x: Number
                //              The X coordinate of the position of the pattern, default value is 0.
                x: 0,

                // y: Number
                //              The Y coordinate of the position of the pattern, default value is 0.
                y: 0,

                // width: Number
                //              The width of the pattern image, default value is 0.
                width: 0,

                // height: Number
                //              The height of the pattern image, default value is 0.
                height: 0,

                // src: String
                //              A url specifying the image to use for the pattern.
                src: ""
        };

        g.Text = {
                //      summary:
                //              A keyword argument object defining both the text to be rendered in a VectorText shape,
                //              and specifying position, alignment, and fitting.
                //      text: String
                //              The text to be rendered.
                //      x: Number?
                //              The left coordinate for the text's bounding box.
                //      y: Number?
                //              The top coordinate for the text's bounding box.
                //      width: Number?
                //              The width of the text's bounding box.
                //      height: Number?
                //              The height of the text's bounding box.
                //      align: String?
                //              The alignment of the text, as defined in SVG. Can be "start", "end" or "middle".
                //      fitting: Number?
                //              How the text is to be fitted to the bounding box. Can be 0 (no fitting), 1 (fitting based on
                //              passed width of the bounding box and the size of the font), or 2 (fit text to the bounding box,
                //              and ignore any size parameters).
                //      leading: Number?
                //              The leading to be used between lines in the text.
                //      decoration: String?
                //              Any text decoration to be used.
        };

        g.Font = {
                // summary:
                //              An object specifying the properties for a Font used in text operations.
        
                // type: String
                //              Specifies this object is a Font, value 'font'.
                type: "font",
        
                // style: String
                //              The font style, one of 'normal', 'bold', default value 'normal'.
                style: "normal",
        
                // variant: String
                //              The font variant, one of 'normal', ... , default value 'normal'.
                variant: "normal",
        
                // weight: String
                //              The font weight, one of 'normal', ..., default value 'normal'.
                weight: "normal",
        
                // size: String
                //              The font size (including units), default value '10pt'.
                size: "10pt",
        
                // family: String
                //              The font family, one of 'serif', 'sanserif', ..., default value 'serif'.
                family: "serif"
        };

        =====*/

        lang.mixin(g, {
                // summary:
                //              defines constants, prototypes, and utility functions for the core Graphics API

                // default shapes, which are used to fill in missing parameters
                defaultPath: {
                        // summary:
                        //              Defines the default Path prototype object.

                        // type: String
                        //              Specifies this object is a Path, default value 'path'.
                        type: "path", 

                        // path: String
                        //              The path commands. See W32C SVG 1.0 specification.
                        //              Defaults to empty string value.
                        path: ""
                },
                defaultPolyline: {
                        // summary:
                        //              Defines the default PolyLine prototype.

                        // type: String
                        //              Specifies this object is a PolyLine, default value 'polyline'.
                        type: "polyline",

                        // points: Array
                        //              An array of point objects [{x:0,y:0},...] defining the default polyline's line segments. Value is an empty array [].
                        points: []
                },
                defaultRect: {
                        // summary:
                        //              Defines the default Rect prototype.

                        // type: String
                        //              Specifies this default object is a type of Rect. Value is 'rect'
                        type: "rect",

                        // x: Number
                        //              The X coordinate of the default rectangles position, value 0.
                        x: 0,

                        // y: Number
                        //              The Y coordinate of the default rectangle's position, value 0.
                        y: 0,

                        // width: Number
                        //              The width of the default rectangle, value 100.
                        width: 100,

                        // height: Number
                        //              The height of the default rectangle, value 100.
                        height: 100,

                        // r: Number
                        //              The corner radius for the default rectangle, value 0.
                        r: 0
                },
                defaultEllipse: {
                        // summary:
                        //              Defines the default Ellipse prototype.

                        // type: String
                        //              Specifies that this object is a type of Ellipse, value is 'ellipse'
                        type: "ellipse",

                        // cx: Number
                        //              The X coordinate of the center of the ellipse, default value 0.
                        cx: 0,

                        // cy: Number
                        //              The Y coordinate of the center of the ellipse, default value 0.
                        cy: 0,

                        // rx: Number
                        //              The radius of the ellipse in the X direction, default value 200.
                        rx: 200,

                        // ry: Number
                        //              The radius of the ellipse in the Y direction, default value 200.
                        ry: 100
                },
                defaultCircle: {
                        // summary:
                        //              An object defining the default Circle prototype.

                        // type: String
                        //              Specifies this object is a circle, value 'circle'
                        type: "circle",

                        // cx: Number
                        //              The X coordinate of the center of the circle, default value 0.
                        cx: 0,
                        // cy: Number
                        //              The Y coordinate of the center of the circle, default value 0.
                        cy: 0,

                        // r: Number
                        //              The radius, default value 100.
                        r: 100
                },
                defaultLine: {
                        // summary:
                        //              An object defining the default Line prototype.

                        // type: String
                        //              Specifies this is a Line, value 'line'
                        type: "line",

                        // x1: Number
                        //              The X coordinate of the start of the line, default value 0.
                        x1: 0,

                        // y1: Number
                        //              The Y coordinate of the start of the line, default value 0.
                        y1: 0,

                        // x2: Number
                        //              The X coordinate of the end of the line, default value 100.
                        x2: 100,

                        // y2: Number
                        //              The Y coordinate of the end of the line, default value 100.
                        y2: 100
                },
                defaultImage: {
                        // summary:
                        //              Defines the default Image prototype.

                        // type: String
                        //              Specifies this object is an image, value 'image'.
                        type: "image",

                        // x: Number
                        //              The X coordinate of the image's position, default value 0.
                        x: 0,

                        // y: Number
                        //              The Y coordinate of the image's position, default value 0.
                        y: 0,

                        // width: Number
                        //              The width of the image, default value 0.
                        width: 0,

                        // height: Number
                        //              The height of the image, default value 0.
                        height: 0,

                        // src: String
                        //              The src url of the image, defaults to empty string.
                        src: ""
                },
                defaultText: {
                        // summary:
                        //              Defines the default Text prototype.

                        // type: String
                        //              Specifies this is a Text shape, value 'text'.
                        type: "text",

                        // x: Number
                        //              The X coordinate of the text position, default value 0.
                        x: 0,

                        // y: Number
                        //              The Y coordinate of the text position, default value 0.
                        y: 0,

                        // text: String
                        //              The text to be displayed, default value empty string.
                        text: "",

                        // align:       String
                        //              The horizontal text alignment, one of 'start', 'end', 'center'. Default value 'start'.
                        align: "start",

                        // decoration: String
                        //              The text decoration , one of 'none', ... . Default value 'none'.
                        decoration: "none",

                        // rotated: Boolean
                        //              Whether the text is rotated, boolean default value false.
                        rotated: false,

                        // kerning: Boolean
                        //              Whether kerning is used on the text, boolean default value true.
                        kerning: true
                },
                defaultTextPath: {
                        // summary:
                        //              Defines the default TextPath prototype.

                        // type: String
                        //              Specifies this is a TextPath, value 'textpath'.
                        type: "textpath",

                        // text: String
                        //              The text to be displayed, default value empty string.
                        text: "",

                        // align: String
                        //              The horizontal text alignment, one of 'start', 'end', 'center'. Default value 'start'.
                        align: "start",

                        // decoration: String
                        //              The text decoration , one of 'none', ... . Default value 'none'.
                        decoration: "none",

                        // rotated: Boolean
                        //              Whether the text is rotated, boolean default value false.
                        rotated: false,

                        // kerning: Boolean
                        //              Whether kerning is used on the text, boolean default value true.
                        kerning: true
                },

                // default stylistic attributes
                defaultStroke: {
                        // summary:
                        //              A stroke defines stylistic properties that are used when drawing a path.
                        //              This object defines the default Stroke prototype.
                        // type: String
                        //              Specifies this object is a type of Stroke, value 'stroke'.
                        type: "stroke",

                        // color: String
                        //              The color of the stroke, default value 'black'.
                        color: "black",

                        // style: String
                        //              The style of the stroke, one of 'solid', ... . Default value 'solid'.
                        style: "solid",

                        // width: Number
                        //              The width of a stroke, default value 1.
                        width: 1,

                        // cap: String
                        //              The endcap style of the path. One of 'butt', 'round', ... . Default value 'butt'.
                        cap: "butt",

                        // join: Number
                        //              The join style to use when combining path segments. Default value 4.
                        join: 4
                },
                defaultLinearGradient: {
                        // summary:
                        //              An object defining the default stylistic properties used for Linear Gradient fills.
                        //              Linear gradients are drawn along a virtual line, which results in appearance of a rotated pattern in a given direction/orientation.

                        // type: String
                        //              Specifies this object is a Linear Gradient, value 'linear'
                        type: "linear",

                        // x1: Number
                        //              The X coordinate of the start of the virtual line along which the gradient is drawn, default value 0.
                        x1: 0,

                        // y1: Number
                        //              The Y coordinate of the start of the virtual line along which the gradient is drawn, default value 0.
                        y1: 0,

                        // x2: Number
                        //              The X coordinate of the end of the virtual line along which the gradient is drawn, default value 100.
                        x2: 100,

                        // y2: Number
                        //              The Y coordinate of the end of the virtual line along which the gradient is drawn, default value 100.
                        y2: 100,

                        // colors: Array
                        //              An array of colors at given offsets (from the start of the line).  The start of the line is
                        //              defined at offest 0 with the end of the line at offset 1.
                        //              Default value, [{ offset: 0, color: 'black'},{offset: 1, color: 'white'}], is a gradient from black to white.
                        colors: [
                                { offset: 0, color: "black" }, { offset: 1, color: "white" }
                        ]
                },
                defaultRadialGradient: {
                        // summary:
                        //              An object specifying the default properties for RadialGradients using in fills patterns.

                        // type: String
                        //              Specifies this is a RadialGradient, value 'radial'
                        type: "radial",

                        // cx: Number
                        //              The X coordinate of the center of the radial gradient, default value 0.
                        cx: 0,

                        // cy: Number
                        //              The Y coordinate of the center of the radial gradient, default value 0.
                        cy: 0,

                        // r: Number
                        //              The radius to the end of the radial gradient, default value 100.
                        r: 100,

                        // colors: Array
                        //              An array of colors at given offsets (from the center of the radial gradient).
                        //              The center is defined at offest 0 with the outer edge of the gradient at offset 1.
                        //              Default value, [{ offset: 0, color: 'black'},{offset: 1, color: 'white'}], is a gradient from black to white.
                        colors: [
                                { offset: 0, color: "black" }, { offset: 1, color: "white" }
                        ]
                },
                defaultPattern: {
                        // summary:
                        //              An object specifying the default properties for a Pattern using in fill operations.

                        // type: String
                        //              Specifies this object is a Pattern, value 'pattern'.
                        type: "pattern",

                        // x: Number
                        //              The X coordinate of the position of the pattern, default value is 0.
                        x: 0,

                        // y: Number
                        //              The Y coordinate of the position of the pattern, default value is 0.
                        y: 0,

                        // width: Number
                        //              The width of the pattern image, default value is 0.
                        width: 0,

                        // height: Number
                        //              The height of the pattern image, default value is 0.
                        height: 0,

                        // src: String
                        //              A url specifying the image to use for the pattern.
                        src: ""
                },
                defaultFont: {
                        // summary:
                        //              An object specifying the default properties for a Font used in text operations.

                        // type: String
                        //              Specifies this object is a Font, value 'font'.
                        type: "font",

                        // style: String
                        //              The font style, one of 'normal', 'bold', default value 'normal'.
                        style: "normal",

                        // variant: String
                        //              The font variant, one of 'normal', ... , default value 'normal'.
                        variant: "normal",

                        // weight: String
                        //              The font weight, one of 'normal', ..., default value 'normal'.
                        weight: "normal",

                        // size: String
                        //              The font size (including units), default value '10pt'.
                        size: "10pt",

                        // family: String
                        //              The font family, one of 'serif', 'sanserif', ..., default value 'serif'.
                        family: "serif"
                },

                getDefault: (function(){
                        // summary:
                        //              Returns a function used to access default memoized prototype objects (see them defined above).
                        var typeCtorCache = {};
                        // a memoized delegate()
                        return function(/*String*/ type){
                                var t = typeCtorCache[type];
                                if(t){
                                        return new t();
                                }
                                t = typeCtorCache[type] = new Function();
                                t.prototype = g[ "default" + type ];
                                return new t();
                        }
                })(),

                normalizeColor: function(/*dojo/Color|Array|string|Object*/ color){
                        // summary:
                        //              converts any legal color representation to normalized
                        //              dojo/Color object
                        // color:
                        //              A color representation.
                        return (color instanceof Color) ? color : new Color(color); // dojo/Color
                },
                normalizeParameters: function(existed, update){
                        // summary:
                        //              updates an existing object with properties from an 'update'
                        //              object
                        // existed: Object
                        //              the target object to be updated
                        // update: Object
                        //              the 'update' object, whose properties will be used to update
                        //              the existed object
                        var x;
                        if(update){
                                var empty = {};
                                for(x in existed){
                                        if(x in update && !(x in empty)){
                                                existed[x] = update[x];
                                        }
                                }
                        }
                        return existed; // Object
                },
                makeParameters: function(defaults, update){
                        // summary:
                        //              copies the original object, and all copied properties from the
                        //              'update' object
                        // defaults: Object
                        //              the object to be cloned before updating
                        // update: Object
                        //              the object, which properties are to be cloned during updating
                        // returns: Object
                        //      new object with new and default properties
                        var i = null;
                        if(!update){
                                // return dojo.clone(defaults);
                                return lang.delegate(defaults);
                        }
                        var result = {};
                        for(i in defaults){
                                if(!(i in result)){
                                        result[i] = lang.clone((i in update) ? update[i] : defaults[i]);
                                }
                        }
                        return result; // Object
                },
                formatNumber: function(x, addSpace){
                        // summary:
                        //              converts a number to a string using a fixed notation
                        // x: Number
                        //              number to be converted
                        // addSpace: Boolean
                        //              whether to add a space before a positive number
                        // returns: String
                        //      the formatted value
                        var val = x.toString();
                        if(val.indexOf("e") >= 0){
                                val = x.toFixed(4);
                        }else{
                                var point = val.indexOf(".");
                                if(point >= 0 && val.length - point > 5){
                                        val = x.toFixed(4);
                                }
                        }
                        if(x < 0){
                                return val; // String
                        }
                        return addSpace ? " " + val : val; // String
                },
                // font operations
                makeFontString: function(font){
                        // summary:
                        //              converts a font object to a CSS font string
                        // font: Object
                        //              font object (see dojox/gfx.defaultFont)
                        return font.style + " " + font.variant + " " + font.weight + " " + font.size + " " + font.family; // Object
                },
                splitFontString: function(str){
                        // summary:
                        //              converts a CSS font string to a font object
                        // description:
                        //              Converts a CSS font string to a gfx font object. The CSS font
                        //              string components should follow the W3C specified order
                        //              (see http://www.w3.org/TR/CSS2/fonts.html#font-shorthand):
                        //              style, variant, weight, size, optional line height (will be
                        //              ignored), and family. Note that the Font.size attribute is limited to numeric CSS length.
                        // str: String
                        //              a CSS font string.
                        // returns: Object
                        //      object in dojox/gfx.defaultFont format
                        var font = g.getDefault("Font");
                        var t = str.split(/\s+/);
                        do{
                                if(t.length < 5){ break; }
                                font.style   = t[0];
                                font.variant = t[1];
                                font.weight  = t[2];
                                var i = t[3].indexOf("/");
                                font.size = i < 0 ? t[3] : t[3].substring(0, i);
                                var j = 4;
                                if(i < 0){
                                        if(t[4] == "/"){
                                                j = 6;
                                        }else if(t[4].charAt(0) == "/"){
                                                j = 5;
                                        }
                                }
                                if(j < t.length){
                                        font.family = t.slice(j).join(" ");
                                }
                        }while(false);
                        return font;    // Object
                },
                // length operations

                // cm_in_pt: Number
                //              points per centimeter (constant)
                cm_in_pt: 72 / 2.54,

                // mm_in_pt: Number
                //              points per millimeter (constant)
                mm_in_pt: 7.2 / 2.54,

                px_in_pt: function(){
                        // summary:
                        //              returns the current number of pixels per point.
                        return g._base._getCachedFontMeasurements()["12pt"] / 12;       // Number
                },

                pt2px: function(len){
                        // summary:
                        //              converts points to pixels
                        // len: Number
                        //              a value in points
                        return len * g.px_in_pt();      // Number
                },

                px2pt: function(len){
                        // summary:
                        //              converts pixels to points
                        // len: Number
                        //              a value in pixels
                        return len / g.px_in_pt();      // Number
                },

                normalizedLength: function(len) {
                        // summary:
                        //              converts any length value to pixels
                        // len: String
                        //              a length, e.g., '12pc'
                        // returns: Number
                        //      pixels
                        if(len.length === 0){ return 0; }
                        if(len.length > 2){
                                var px_in_pt = g.px_in_pt();
                                var val = parseFloat(len);
                                switch(len.slice(-2)){
                                        case "px": return val;
                                        case "pt": return val * px_in_pt;
                                        case "in": return val * 72 * px_in_pt;
                                        case "pc": return val * 12 * px_in_pt;
                                        case "mm": return val * g.mm_in_pt * px_in_pt;
                                        case "cm": return val * g.cm_in_pt * px_in_pt;
                                }
                        }
                        return parseFloat(len); // Number
                },

                // pathVmlRegExp: RegExp
                //              a constant regular expression used to split a SVG/VML path into primitive components
                // tags:
                //              private
                pathVmlRegExp: /([A-Za-z]+)|(\d+(\.\d+)?)|(\.\d+)|(-\d+(\.\d+)?)|(-\.\d+)/g,

                // pathVmlRegExp: RegExp
                //              a constant regular expression used to split a SVG/VML path into primitive components
                // tags:
                //              private
                pathSvgRegExp: /([A-Za-z])|(\d+(\.\d+)?)|(\.\d+)|(-\d+(\.\d+)?)|(-\.\d+)/g,

                equalSources: function(a, b){
                        // summary:
                        //              compares event sources, returns true if they are equal
                        // a: Object
                        //              first event source
                        // b: Object
                        //              event source to compare against a
                        // returns: Boolean
                        //      true, if objects are truthy and the same
                        return a && b && a === b;
                },

                switchTo: function(/*String|Object*/ renderer){
                        // summary:
                        //              switch the graphics implementation to the specified renderer.
                        // renderer:
                        //              Either the string name of a renderer (eg. 'canvas', 'svg, ...) or the renderer
                        //              object to switch to.
                        var ns = typeof renderer == "string" ? g[renderer] : renderer;
                        if(ns){
                                // If more options are added, update the docblock at the end of shape.js!
                                arr.forEach(["Group", "Rect", "Ellipse", "Circle", "Line",
                                                "Polyline", "Image", "Text", "Path", "TextPath",
                                                "Surface", "createSurface", "fixTarget"], function(name){
                                        g[name] = ns[name];
                                });
                                if(typeof renderer == "string"){
                                        g.renderer = renderer;
                                }else{
                                        arr.some(["svg","vml","canvas","canvasWithEvents","silverlight"], function(r){
                                                return (g.renderer = g[r] && g[r].Surface === g.Surface ? r : null);
                                        });
                                }
                        }
                }
        });
        
        /*=====
                g.createSurface = function(parentNode, width, height){
                        // summary:
                        //              creates a surface
                        // parentNode: Node
                        //              a parent node
                        // width: String|Number
                        //              width of surface, e.g., "100px" or 100
                        // height: String|Number
                        //              height of surface, e.g., "100px" or 100
                        // returns: dojox/gfx.Surface
                        //     newly created surface
                };
                g.fixTarget = function(){
                        // tags:
                        //              private
                };
        =====*/
        
        return g; // defaults object api
});