frappe/js/jquery/jqplot-plugins/jqplot.canvasAxisLabelRenderer.js

/**
 * jqPlot
 * Pure JavaScript plotting plugin using jQuery
 *
 * Version: 1.0.0b2_r792
 *
 * Copyright (c) 2009-2011 Chris Leonello
 * jqPlot is currently available for use in all personal or commercial projects 
 * under both the MIT (http://www.opensource.org/licenses/mit-license.php) and GPL 
 * version 2.0 (http://www.gnu.org/licenses/gpl-2.0.html) licenses. This means that you can 
 * choose the license that best suits your project and use it accordingly. 
 *
 * Although not required, the author would appreciate an email letting him 
 * know of any substantial use of jqPlot.  You can reach the author at: 
 * chris at jqplot dot com or see http://www.jqplot.com/info.php .
 *
 * If you are feeling kind and generous, consider supporting the project by
 * making a donation at: http://www.jqplot.com/donate.php .
 *
 * sprintf functions contained in jqplot.sprintf.js by Ash Searle:
 *
 *     version 2007.04.27
 *     author Ash Searle
 *     http://hexmen.com/blog/2007/03/printf-sprintf/
 *     http://hexmen.com/js/sprintf.js
 *     The author (Ash Searle) has placed this code in the public domain:
 *     "This code is unrestricted: you are free to use it however you like."
 * 
 */
(function($) {
    /**
    * Class: $.jqplot.CanvasAxisLabelRenderer
    * Renderer to draw axis labels with a canvas element to support advanced
    * featrues such as rotated text.  This renderer uses a separate rendering engine
    * to draw the text on the canvas.  Two modes of rendering the text are available.
    * If the browser has native font support for canvas fonts (currently Mozila 3.5
    * and Safari 4), you can enable text rendering with the canvas fillText method.
    * You do so by setting the "enableFontSupport" option to true. 
    * 
    * Browsers lacking native font support will have the text drawn on the canvas
    * using the Hershey font metrics.  Even if the "enableFontSupport" option is true
    * non-supporting browsers will still render with the Hershey font.
    * 
    */
    $.jqplot.CanvasAxisLabelRenderer = function(options) {
        // Group: Properties
        
        // prop: angle
        // angle of text, measured clockwise from x axis.
        this.angle = 0;
        // name of the axis associated with this tick
        this.axis;
        // prop: show
        // wether or not to show the tick (mark and label).
        this.show = true;
        // prop: showLabel
        // wether or not to show the label.
        this.showLabel = true;
        // prop: label
        // label for the axis.
        this.label = '';
        // prop: fontFamily
        // CSS spec for the font-family css attribute.
        // Applies only to browsers supporting native font rendering in the
        // canvas tag.  Currently Mozilla 3.5 and Safari 4.
        this.fontFamily = '"Trebuchet MS", Arial, Helvetica, sans-serif';
        // prop: fontSize
        // CSS spec for font size.
        this.fontSize = '11pt';
        // prop: fontWeight
        // CSS spec for fontWeight:  normal, bold, bolder, lighter or a number 100 - 900
        this.fontWeight = 'normal';
        // prop: fontStretch
        // Multiplier to condense or expand font width.  
        // Applies only to browsers which don't support canvas native font rendering.
        this.fontStretch = 1.0;
        // prop: textColor
        // css spec for the color attribute.
        this.textColor = '#666666';
        // prop: enableFontSupport
        // true to turn on native canvas font support in Mozilla 3.5+ and Safari 4+.
        // If true, label will be drawn with canvas tag native support for fonts.
        // If false, label will be drawn with Hershey font metrics.
        this.enableFontSupport = true;
        // prop: pt2px
        // Point to pixel scaling factor, used for computing height of bounding box
        // around a label.  The labels text renderer has a default setting of 1.4, which 
        // should be suitable for most fonts.  Leave as null to use default.  If tops of
        // letters appear clipped, increase this.  If bounding box seems too big, decrease.
        // This is an issue only with the native font renderering capabilities of Mozilla
        // 3.5 and Safari 4 since they do not provide a method to determine the font height.
        this.pt2px = null;
        
        this._elem;
        this._ctx;
        this._plotWidth;
        this._plotHeight;
        this._plotDimensions = {height:null, width:null};
        
        $.extend(true, this, options);
        
        if (options.angle == null && this.axis != 'xaxis' && this.axis != 'x2axis') {
            this.angle = -90;
        }
        
        var ropts = {fontSize:this.fontSize, fontWeight:this.fontWeight, fontStretch:this.fontStretch, fillStyle:this.textColor, angle:this.getAngleRad(), fontFamily:this.fontFamily};
        if (this.pt2px) {
            ropts.pt2px = this.pt2px;
        }
        
        if (this.enableFontSupport) {
            
            function support_canvas_text() {
                return !!(document.createElement('canvas').getContext && typeof document.createElement('canvas').getContext('2d').fillText == 'function');
            }
            
            if (support_canvas_text()) {
                this._textRenderer = new $.jqplot.CanvasFontRenderer(ropts);
            }
            
            else {
                this._textRenderer = new $.jqplot.CanvasTextRenderer(ropts); 
            }
        }
        else {
            this._textRenderer = new $.jqplot.CanvasTextRenderer(ropts); 
        }
    };
    
    $.jqplot.CanvasAxisLabelRenderer.prototype.init = function(options) {
        $.extend(true, this, options);
        this._textRenderer.init({fontSize:this.fontSize, fontWeight:this.fontWeight, fontStretch:this.fontStretch, fillStyle:this.textColor, angle:this.getAngleRad(), fontFamily:this.fontFamily});
    };
    
    // return width along the x axis
    // will check first to see if an element exists.
    // if not, will return the computed text box width.
    $.jqplot.CanvasAxisLabelRenderer.prototype.getWidth = function(ctx) {
        if (this._elem) {
         return this._elem.outerWidth(true);
        }
        else {
            var tr = this._textRenderer;
            var l = tr.getWidth(ctx);
            var h = tr.getHeight(ctx);
            var w = Math.abs(Math.sin(tr.angle)*h) + Math.abs(Math.cos(tr.angle)*l);
            return w;
        }
    };
    
    // return height along the y axis.
    $.jqplot.CanvasAxisLabelRenderer.prototype.getHeight = function(ctx) {
        if (this._elem) {
         return this._elem.outerHeight(true);
        }
        else {
            var tr = this._textRenderer;
            var l = tr.getWidth(ctx);
            var h = tr.getHeight(ctx);
            var w = Math.abs(Math.cos(tr.angle)*h) + Math.abs(Math.sin(tr.angle)*l);
            return w;
        }
    };
    
    $.jqplot.CanvasAxisLabelRenderer.prototype.getAngleRad = function() {
        var a = this.angle * Math.PI/180;
        return a;
    };
    
    $.jqplot.CanvasAxisLabelRenderer.prototype.draw = function(ctx, plot) {
          // Memory Leaks patch
          if (this._elem) {
              if ($.jqplot.use_excanvas) {
                  window.G_vmlCanvasManager.uninitElement(this._elem.get(0));
              }
            
              this._elem.emptyForce();
              this._elem = null;
          }

        // create a canvas here, but can't draw on it untill it is appended
        // to dom for IE compatability.
        var elem = plot.canvasManager.getCanvas();

        this._textRenderer.setText(this.label, ctx);
        var w = this.getWidth(ctx);
        var h = this.getHeight(ctx);
        elem.width = w;
        elem.height = h;
        elem.style.width = w;
        elem.style.height = h;
        
		elem = plot.canvasManager.initCanvas(elem);
		
        this._elem = $(elem);
        this._elem.css({ position: 'absolute'});
        this._elem.addClass('jqplot-'+this.axis+'-label');
        
        elem = null;
        return this._elem;
    };
    
    $.jqplot.CanvasAxisLabelRenderer.prototype.pack = function() {
        this._textRenderer.draw(this._elem.get(0).getContext("2d"), this.label);
    };
    
})(jQuery);