html2canvas/src/Generate.js

/*
  html2canvas @VERSION@ <http://html2canvas.hertzen.com>
  Copyright (c) 2011 Niklas von Hertzen. All rights reserved.
  http://www.twitter.com/niklasvh

  Released under MIT License
 */

(function(){
    
_html2canvas.Generate = {};


// -webkit-linear-gradient(left top, rgb(255, 0, 0), rgb(0, 0, 255), rgb(186, 218, 85), rgba(0, 0, 255, 0.496094))
// -webkit-linear-gradient(left, rgb(206, 219, 233) 0%, rgb(170, 197, 222) 17%, rgb(97, 153, 199) 50%, rgb(58, 132, 195) 51%, rgb(65, 154, 214) 59%, rgb(75, 184, 240) 71%, rgb(58, 139, 194) 84%, rgb(38, 85, 139) 100%)
// -webkit-gradient(linear, 0% 0, 0% 100%, from(rgb(252, 252, 252)), to(rgb(232, 232, 232)))
// -moz-linear-gradient(100% 0%, rgb(255, 0, 0), rgb(0, 0, 255), rgb(186, 218, 85), rgba(0, 0, 255, 0.5))

var reGradients = [
    /^(-webkit-linear-gradient)\(([a-z\s]+)((?:,\s(?:rgb|rgba)\(\d{1,3},\s\d{1,3},\s\d{1,3}(?:,\s[0-9\.]+)?\)(?:\s\d{1,3}%)?)+)\)$/,
    /^(-webkit-gradient)\((linear|radial),\s((?:[a-z]+|\d{1,3}%?)\s(?:[a-z]+|\d{1,3}%?)),\s((?:[a-z]+|\d{1,3}%?)\s(?:[a-z]+|\d{1,3}%?))((?:,\s(?:from|to|color-stop)\((?:[0-9\.]+,\s)?(?:rgb|rgba)\(\d{1,3},\s\d{1,3},\s\d{1,3}(?:,\s[0-9\.]+)?\)\))+)\)$/
];

// ["-webkit-linear-gradient(left top, rgb(255, 0, 0), rgb(0, 0, 255), rgb(186, 218, 85), rgba(0, 0, 255, 0.496094))", "-webkit-linear-gradient", "left top", ", rgb(255, 0, 0), rgb(0, 0, 255), rgb(186, 218, 85), rgba(0, 0, 255, 0.496094)"]
// ["-webkit-linear-gradient(left, rgb(206, 219, 233) 0%, rgb(170, 197, 222) 17%, rgb(97, 153, 199) 50%, rgb(58, 132, 195) 51%, rgb(65, 154, 214) 59%, rgb(75, 184, 240) 71%, rgb(58, 139, 194) 84%, rgb(38, 85, 139) 100%)", "-webkit-linear-gradient", "left", ", rgb(206, 219, 233) 0%, rgb(170, 197, 222) 17%, rgb(97, 153, 199) 50%, rgb(58, 132, 195) 51%, rgb(65, 154, 214) 59%, rgb(75, 184, 240) 71%, rgb(58, 139, 194) 84%, rgb(38, 85, 139) 100%"]
// ["-webkit-gradient(linear, 0% 0, 0% 100%, from(rgb(252, 252, 252)), to(rgb(232, 232, 232)))", "-webkit-gradient", "linear", "0% 0", "0% 100%", ", from(rgb(252, 252, 252)), to(rgb(232, 232, 232))"]

_html2canvas.Generate.getColorStopsFromGradient = function(css, bounds) {  
    var gradient, i, len = reGradients.length, m1, stop, m2, m2Len, step, m3;
    
    for(i = 0; i < len; i+=1){
        m1 = css.match(reGradients[i]);
        if(m1) break;
    }
    
    if(m1) {
        switch(m1[1]) {
            case '-webkit-linear-gradient':
                
                gradient = {
                        type: 'linear',
                        x0: 0,
                        y0: 0,
                        x1: 0,
                        y1: 0,
                        colorStops: []
                };
                
                // get coordinates
                m2 = m1[2].match(/\w+/g);
                if(m2){
                    m2Len = m2.length;
                    for(i = 0; i < m2Len; i+=1){
                        switch(m2[i]) {
                            case 'top':
                                gradient.y1 = bounds.height;
                                break;
                                
                            case 'right':
                                gradient.x0 = bounds.width;
                                break;
                                
                            case 'bottom':
                                gradient.y0 = bounds.height;
                                break;
                                
                            case 'left':
                                gradient.x1 = bounds.width;
                                break;
                        }
                    }
                }
                
                // get colors and stops
                m2 = m1[3].match(/((?:rgb|rgba)\(\d{1,3},\s\d{1,3},\s\d{1,3}(?:,\s[0-9\.]+)?\)(?:\s\d{1,3}%)?)+/g);
                if(m2){
                    m2Len = m2.length;
                    step = 1 / Math.max(m2Len - 1, 1);
                    for(i = 0; i < m2Len; i+=1){
                        m3 = m2[i].match(/((?:rgb|rgba)\(\d{1,3},\s\d{1,3},\s\d{1,3}(?:,\s[0-9\.]+)?\))\s*(\d{1,3})?(%)?/);
                        if(m3[2]){
                            stop = parseFloat(m3[2]);
                            if(m3[3]){ //percentage
                                stop /= 100;
                            }
                        } else {
                            stop = i * step;
                        }
                        gradient.colorStops.push({
                            color: m3[1],
                            stop: stop
                        });
                    }
                }
                break;
                
            case '-webkit-gradient':
                // stop = m2[1] == 'from' ? 0.0 : 1.0;
                break;
        }
    }
    
    return gradient;
};

_html2canvas.Generate.Gradient = function(src, bounds) {
    var canvas = document.createElement('canvas'),
    ctx = canvas.getContext('2d'),
    gradient, lingrad, i, len, img;
    
    canvas.width = bounds.width;
    canvas.height = bounds.height;
    
    gradient = _html2canvas.Generate.getColorStopsFromGradient(src, bounds);
    
    img = new Image();
    
    if(gradient){
        lingrad = ctx.createLinearGradient(gradient.x0, gradient.y0, gradient.x1, gradient.y1);
        
        for (i = 0, len = gradient.colorStops.length; i < len; i+=1) {
            try {
                lingrad.addColorStop(gradient.colorStops[i].stop, gradient.colorStops[i].color);
            }
            catch(e) {
                h2clog(['failed to add color stop: ', e, '; tried to add: ', gradient.colorStops[i], '; stop: ', i, '; in: ', src]);
            }
        }
        
        ctx.fillStyle = lingrad;
        ctx.fillRect(0, 0, bounds.width, bounds.height);
    
        img.src = canvas.toDataURL();
    }
    
    return img;
};

_html2canvas.Generate.ListAlpha = function(number) {
    var tmp = "",
    modulus;
    
    do {
        modulus = number % 26; 
        tmp = String.fromCharCode((modulus) + 64) + tmp;
        number = number / 26;
    }while((number*26) > 26);
   
    return tmp;  
};

_html2canvas.Generate.ListRoman = function(number) {
    var romanArray = ["M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"],
    decimal = [1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1],
    roman = "",
    v,
    len = romanArray.length;

    if (number <= 0 || number >= 4000) { 
        return number;
    }
    
    for (v=0; v < len; v+=1) {
        while (number >= decimal[v]) { 
            number -= decimal[v];
            roman += romanArray[v];
        }
    }
        
    return roman;
   
};

})();