source: Dev/trunk/src/client/dojox/dgauges/TextIndicator.js

define(["dojo/_base/lang", "dojo/_base/declare", "dojo/_base/sniff", "dojo/_base/array", "dojo/on", "dojox/gfx", "./IndicatorBase"],
        function(lang, declare, has, array, on, gfx, IndicatorBase){
        return declare("dojox.dgauges.TextIndicator", IndicatorBase, {
                // summary:
                //              This type of indicator is used to render text.
                //              To render an arbitrary text, set the value property.
                //              To render the value of a value indicator or a range indicator, set the indicator property.
                //              Setting the indicator property takes precedence on setting the value property.
                //              When the indicator property is set, the text is automatically updated on value changes.

                // font: Object
                //              Font used by this element.
                font: null,
                // x: Number
                //              The text anchor x-position. Default is 0.
                x: 0,
                // y: Number
                //              The text anchor y-position. Default is 0.
                y: 0,
                // align: String
                //              An alignment of a text in regards to the anchor position:
                //
                //              - "start": A text's baseline starts at the anchor. 
                //              This is the default value of the align attribute.
                //              - "middle": A text's baseline is centered on the anchor point.
                //              - "end": A text's baseline ends at the anchor point.
                align: "middle",
                // color: Object
                //              The color of the text.
                color: "black",
                // indicator: dojox/dgauges/IndicatorBase
                //              If this property is set, the value of the indicator is automatically
                //              rendered by this text element.
                indicator: null,
                // labelFunc: Object
                //              If set, this method allows to format the value of this text indicator.
                //              A label function takes the text to render as argument and returns a String. 
                labelFunc: null,
                
                constructor: function(){
                        this.addInvalidatingProperties(["indicator"]);

                        var resetProps = ["x", "y", "font", "align", "color", "labelFunc"];
                        array.forEach(resetProps, lang.hitch(this, function(entry){
                                this.watch(entry, this._resetText);
                        }));
                        
                        this.watch("indicator", lang.hitch(this, this._indicatorChanged));
                },

                postscript: function(mixin){
                        // summary:
                        //              Internal method
                        // tags:
                        //              private
                        this.inherited(arguments);
                        if(mixin && mixin.indicator){
                                this._indicatorChanged("indicator", null, mixin.indicator);
                        }
                },
                
                _resetText: function(){
                        // summary:
                        //              Internal method.
                        // tags:
                        //              private
                        this._textCreated = false;
                        this.invalidateRendering();
                },
                
                _valueWatcher: null,
                
                _indicatorChanged: function(name, oldValue, newValue){
                        // summary:
                        //              Internal method.
                        // tags:
                        //              private
                        if(this._valueWatcher){
                                this._valueWatcher.unwatch();
                        }
                        this._valueWatcher = newValue.watch("value", lang.hitch(this, this.refreshRendering));
                },
                
                _getFont: function(){
                        // summary:
                        //              Internal method.
                        // tags:
                        //              private
                        var font = this.font;
                        if(!font && this._gauge){
                                font = this._gauge.font;
                        }
                        if(!font){
                                font = gfx.defaultFont;
                        }
                        return font;
                },
                
                _textCreated: false,
                _textInstance: null,
                
                _createText: function(group, font, color, text, x, y, align){
                        // summary:
                        //              Internal method.
                        // tags:
                        //              private
                        var gfxText = group.createText({
                                x: x,
                                y: y,
                                text: text,
                                align: align
                        }).setFont(font).setFill(color);
                        return gfxText;
                },
                
                refreshRendering: function(){
                        if(this._gfxGroup == null){
                                return;
                        }
                        var text;
                        if(this.indicator){
                                text = this.indicator.value;
                        }else{
                                text = this.value;
                        }
                        if(this.labelFunc){
                                text = this.labelFunc(text);
                        }
                        var iOsVersion = has("iphone");
                        // Workaround for a bug on iOS version < 5.0: Recreate the text every times
                        if(!this._textCreated || (iOsVersion != undefined && iOsVersion < 5)){
                                this._gfxGroup.clear();
                                var font = this._getFont();
                                this._textInstance = this._createText(this._gfxGroup, font, font.color ? font.color : this.color, "", this.x, this.y, this.align);
                                this._textCreated = true;
                        }
                        this._textInstance.setShape({
                                text: text
                        });
                        
                        return this._textInstance;
                }
        })
});