jsos

college code for operating system fundamentals in js

git clone https://9o.is/git/jsos.git

canvastext.js

(14510B)


      1 /* ----------------- *
      2  *   CanvasText.js   *
      3  *
      4  * Downlaoded from http://www.federated.com/~jim/canvastext.
      5  *
      6  * This code is released to the public domain by Jim Studt, 2007.
      7  * He may keep some sort of up to date copy at http://www.federated.com/~jim/canvastext/
      8  *
      9  * Modifications by Alan G. Labouseur.
     10  *  - fixed comma
     11  *  - added semi-colon.
     12  *
     13  * ----------------- */
     14 
     15 var CanvasTextFunctions = { };
     16 
     17 CanvasTextFunctions.letters = {
     18     ' ': { width: 16, points: [] },
     19     '!': { width: 10, points: [[5,21],[5,7],[-1,-1],[5,2],[4,1],[5,0],[6,1],[5,2]] },
     20     '"': { width: 16, points: [[4,21],[4,14],[-1,-1],[12,21],[12,14]] },
     21     '#': { width: 21, points: [[11,25],[4,-7],[-1,-1],[17,25],[10,-7],[-1,-1],[4,12],[18,12],[-1,-1],[3,6],[17,6]] },
     22     '$': { width: 20, points: [[8,25],[8,-4],[-1,-1],[12,25],[12,-4],[-1,-1],[17,18],[15,20],[12,21],[8,21],[5,20],[3,18],[3,16],[4,14],[5,13],[7,12],[13,10],[15,9],[16,8],[17,6],[17,3],[15,1],[12,0],[8,0],[5,1],[3,3]] },
     23     '%': { width: 24, points: [[21,21],[3,0],[-1,-1],[8,21],[10,19],[10,17],[9,15],[7,14],[5,14],[3,16],[3,18],[4,20],[6,21],[8,21],[10,20],[13,19],[16,19],[19,20],[21,21],[-1,-1],[17,7],[15,6],[14,4],[14,2],[16,0],[18,0],[20,1],[21,3],[21,5],[19,7],[17,7]] },
     24     '&': { width: 26, points: [[23,12],[23,13],[22,14],[21,14],[20,13],[19,11],[17,6],[15,3],[13,1],[11,0],[7,0],[5,1],[4,2],[3,4],[3,6],[4,8],[5,9],[12,13],[13,14],[14,16],[14,18],[13,20],[11,21],[9,20],[8,18],[8,16],[9,13],[11,10],[16,3],[18,1],[20,0],[22,0],[23,1],[23,2]] },
     25     '\'': { width: 10, points: [[5,19],[4,20],[5,21],[6,20],[6,18],[5,16],[4,15]] },
     26     '(': { width: 14, points: [[11,25],[9,23],[7,20],[5,16],[4,11],[4,7],[5,2],[7,-2],[9,-5],[11,-7]] },
     27     ')': { width: 14, points: [[3,25],[5,23],[7,20],[9,16],[10,11],[10,7],[9,2],[7,-2],[5,-5],[3,-7]] },
     28     '*': { width: 16, points: [[8,21],[8,9],[-1,-1],[3,18],[13,12],[-1,-1],[13,18],[3,12]] },
     29     '+': { width: 26, points: [[13,18],[13,0],[-1,-1],[4,9],[22,9]] },
     30     ',': { width: 10, points: [[6,1],[5,0],[4,1],[5,2],[6,1],[6,-1],[5,-3],[4,-4]] },
     31     '-': { width: 26, points: [[4,9],[22,9]] },
     32     '.': { width: 10, points: [[5,2],[4,1],[5,0],[6,1],[5,2]] },
     33     '/': { width: 22, points: [[20,25],[2,-7]] },
     34     '0': { width: 20, points: [[9,21],[6,20],[4,17],[3,12],[3,9],[4,4],[6,1],[9,0],[11,0],[14,1],[16,4],[17,9],[17,12],[16,17],[14,20],[11,21],[9,21]] },
     35     '1': { width: 20, points: [[6,17],[8,18],[11,21],[11,0]] },
     36     '2': { width: 20, points: [[4,16],[4,17],[5,19],[6,20],[8,21],[12,21],[14,20],[15,19],[16,17],[16,15],[15,13],[13,10],[3,0],[17,0]] },
     37     '3': { width: 20, points: [[5,21],[16,21],[10,13],[13,13],[15,12],[16,11],[17,8],[17,6],[16,3],[14,1],[11,0],[8,0],[5,1],[4,2],[3,4]] },
     38     '4': { width: 20, points: [[13,21],[3,7],[18,7],[-1,-1],[13,21],[13,0]] },
     39     '5': { width: 20, points: [[15,21],[5,21],[4,12],[5,13],[8,14],[11,14],[14,13],[16,11],[17,8],[17,6],[16,3],[14,1],[11,0],[8,0],[5,1],[4,2],[3,4]] },
     40     '6': { width: 20, points: [[16,18],[15,20],[12,21],[10,21],[7,20],[5,17],[4,12],[4,7],[5,3],[7,1],[10,0],[11,0],[14,1],[16,3],[17,6],[17,7],[16,10],[14,12],[11,13],[10,13],[7,12],[5,10],[4,7]] },
     41     '7': { width: 20, points: [[17,21],[7,0],[-1,-1],[3,21],[17,21]] },
     42     '8': { width: 20, points: [[8,21],[5,20],[4,18],[4,16],[5,14],[7,13],[11,12],[14,11],[16,9],[17,7],[17,4],[16,2],[15,1],[12,0],[8,0],[5,1],[4,2],[3,4],[3,7],[4,9],[6,11],[9,12],[13,13],[15,14],[16,16],[16,18],[15,20],[12,21],[8,21]] },
     43     '9': { width: 20, points: [[16,14],[15,11],[13,9],[10,8],[9,8],[6,9],[4,11],[3,14],[3,15],[4,18],[6,20],[9,21],[10,21],[13,20],[15,18],[16,14],[16,9],[15,4],[13,1],[10,0],[8,0],[5,1],[4,3]] },
     44     ':': { width: 10, points: [[5,14],[4,13],[5,12],[6,13],[5,14],[-1,-1],[5,2],[4,1],[5,0],[6,1],[5,2]] },
     45     ',': { width: 10, points: [[6,1],[5,0],[4,1],[5,2],[6,1],[6,-1],[5,-3],[4,-4]] },
     46     ';': { width: 10, points: [[5,14],[4,13],[5,12],[6,13],[5,14],[-1,-1],[6,1],[5,0],[4,1],[5,2],[6,1],[6,-1],[5,-3],[4,-4]] },
     47     '<': { width: 24, points: [[20,18],[4,9],[20,0]] },
     48     '=': { width: 26, points: [[4,12],[22,12],[-1,-1],[4,6],[22,6]] },
     49     '>': { width: 24, points: [[4,18],[20,9],[4,0]] },
     50     '?': { width: 18, points: [[3,16],[3,17],[4,19],[5,20],[7,21],[11,21],[13,20],[14,19],[15,17],[15,15],[14,13],[13,12],[9,10],[9,7],[-1,-1],[9,2],[8,1],[9,0],[10,1],[9,2]] },
     51     '@': { width: 27, points: [[18,13],[17,15],[15,16],[12,16],[10,15],[9,14],[8,11],[8,8],[9,6],[11,5],[14,5],[16,6],[17,8],[-1,-1],[12,16],[10,14],[9,11],[9,8],[10,6],[11,5],[-1,-1],[18,16],[17,8],[17,6],[19,5],[21,5],[23,7],[24,10],[24,12],[23,15],[22,17],[20,19],[18,20],[15,21],[12,21],[9,20],[7,19],[5,17],[4,15],[3,12],[3,9],[4,6],[5,4],[7,2],[9,1],[12,0],[15,0],[18,1],[20,2],[21,3],[-1,-1],[19,16],[18,8],[18,6],[19,5]] },
     52     'A': { width: 18, points: [[9,21],[1,0],[-1,-1],[9,21],[17,0],[-1,-1],[4,7],[14,7]] },
     53     'B': { width: 21, points: [[4,21],[4,0],[-1,-1],[4,21],[13,21],[16,20],[17,19],[18,17],[18,15],[17,13],[16,12],[13,11],[-1,-1],[4,11],[13,11],[16,10],[17,9],[18,7],[18,4],[17,2],[16,1],[13,0],[4,0]] },
     54     'C': { width: 21, points: [[18,16],[17,18],[15,20],[13,21],[9,21],[7,20],[5,18],[4,16],[3,13],[3,8],[4,5],[5,3],[7,1],[9,0],[13,0],[15,1],[17,3],[18,5]] },
     55     'D': { width: 21, points: [[4,21],[4,0],[-1,-1],[4,21],[11,21],[14,20],[16,18],[17,16],[18,13],[18,8],[17,5],[16,3],[14,1],[11,0],[4,0]] },
     56     'E': { width: 19, points: [[4,21],[4,0],[-1,-1],[4,21],[17,21],[-1,-1],[4,11],[12,11],[-1,-1],[4,0],[17,0]] },
     57     'F': { width: 18, points: [[4,21],[4,0],[-1,-1],[4,21],[17,21],[-1,-1],[4,11],[12,11]] },
     58     'G': { width: 21, points: [[18,16],[17,18],[15,20],[13,21],[9,21],[7,20],[5,18],[4,16],[3,13],[3,8],[4,5],[5,3],[7,1],[9,0],[13,0],[15,1],[17,3],[18,5],[18,8],[-1,-1],[13,8],[18,8]] },
     59     'H': { width: 22, points: [[4,21],[4,0],[-1,-1],[18,21],[18,0],[-1,-1],[4,11],[18,11]] },
     60     'I': { width: 8, points: [[4,21],[4,0]] },
     61     'J': { width: 16, points: [[12,21],[12,5],[11,2],[10,1],[8,0],[6,0],[4,1],[3,2],[2,5],[2,7]] },
     62     'K': { width: 21, points: [[4,21],[4,0],[-1,-1],[18,21],[4,7],[-1,-1],[9,12],[18,0]] },
     63     'L': { width: 17, points: [[4,21],[4,0],[-1,-1],[4,0],[16,0]] },
     64     'M': { width: 24, points: [[4,21],[4,0],[-1,-1],[4,21],[12,0],[-1,-1],[20,21],[12,0],[-1,-1],[20,21],[20,0]] },
     65     'N': { width: 22, points: [[4,21],[4,0],[-1,-1],[4,21],[18,0],[-1,-1],[18,21],[18,0]] },
     66     'O': { width: 22, points: [[9,21],[7,20],[5,18],[4,16],[3,13],[3,8],[4,5],[5,3],[7,1],[9,0],[13,0],[15,1],[17,3],[18,5],[19,8],[19,13],[18,16],[17,18],[15,20],[13,21],[9,21]] },
     67     'P': { width: 21, points: [[4,21],[4,0],[-1,-1],[4,21],[13,21],[16,20],[17,19],[18,17],[18,14],[17,12],[16,11],[13,10],[4,10]] },
     68     'Q': { width: 22, points: [[9,21],[7,20],[5,18],[4,16],[3,13],[3,8],[4,5],[5,3],[7,1],[9,0],[13,0],[15,1],[17,3],[18,5],[19,8],[19,13],[18,16],[17,18],[15,20],[13,21],[9,21],[-1,-1],[12,4],[18,-2]] },
     69     'R': { width: 21, points: [[4,21],[4,0],[-1,-1],[4,21],[13,21],[16,20],[17,19],[18,17],[18,15],[17,13],[16,12],[13,11],[4,11],[-1,-1],[11,11],[18,0]] },
     70     'S': { width: 20, points: [[17,18],[15,20],[12,21],[8,21],[5,20],[3,18],[3,16],[4,14],[5,13],[7,12],[13,10],[15,9],[16,8],[17,6],[17,3],[15,1],[12,0],[8,0],[5,1],[3,3]] },
     71     'T': { width: 16, points: [[8,21],[8,0],[-1,-1],[1,21],[15,21]] },
     72     'U': { width: 22, points: [[4,21],[4,6],[5,3],[7,1],[10,0],[12,0],[15,1],[17,3],[18,6],[18,21]] },
     73     'V': { width: 18, points: [[1,21],[9,0],[-1,-1],[17,21],[9,0]] },
     74     'W': { width: 24, points: [[2,21],[7,0],[-1,-1],[12,21],[7,0],[-1,-1],[12,21],[17,0],[-1,-1],[22,21],[17,0]] },
     75     'X': { width: 20, points: [[3,21],[17,0],[-1,-1],[17,21],[3,0]] },
     76     'Y': { width: 18, points: [[1,21],[9,11],[9,0],[-1,-1],[17,21],[9,11]] },
     77     'Z': { width: 20, points: [[17,21],[3,0],[-1,-1],[3,21],[17,21],[-1,-1],[3,0],[17,0]] },
     78     '[': { width: 14, points: [[4,25],[4,-7],[-1,-1],[5,25],[5,-7],[-1,-1],[4,25],[11,25],[-1,-1],[4,-7],[11,-7]] },
     79     '\\': { width: 14, points: [[0,21],[14,-3]] },
     80     ']': { width: 14, points: [[9,25],[9,-7],[-1,-1],[10,25],[10,-7],[-1,-1],[3,25],[10,25],[-1,-1],[3,-7],[10,-7]] },
     81     '^': { width: 16, points: [[6,15],[8,18],[10,15],[-1,-1],[3,12],[8,17],[13,12],[-1,-1],[8,17],[8,0]] },
     82     '_': { width: 16, points: [[0,-2],[16,-2]] },
     83     '`': { width: 10, points: [[6,21],[5,20],[4,18],[4,16],[5,15],[6,16],[5,17]] },
     84     'a': { width: 19, points: [[15,14],[15,0],[-1,-1],[15,11],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
     85     'b': { width: 19, points: [[4,21],[4,0],[-1,-1],[4,11],[6,13],[8,14],[11,14],[13,13],[15,11],[16,8],[16,6],[15,3],[13,1],[11,0],[8,0],[6,1],[4,3]] },
     86     'c': { width: 18, points: [[15,11],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
     87     'd': { width: 19, points: [[15,21],[15,0],[-1,-1],[15,11],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
     88     'e': { width: 18, points: [[3,8],[15,8],[15,10],[14,12],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
     89     'f': { width: 12, points: [[10,21],[8,21],[6,20],[5,17],[5,0],[-1,-1],[2,14],[9,14]] },
     90     'g': { width: 19, points: [[15,14],[15,-2],[14,-5],[13,-6],[11,-7],[8,-7],[6,-6],[-1,-1],[15,11],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
     91     'h': { width: 19, points: [[4,21],[4,0],[-1,-1],[4,10],[7,13],[9,14],[12,14],[14,13],[15,10],[15,0]] },
     92     'i': { width: 8, points: [[3,21],[4,20],[5,21],[4,22],[3,21],[-1,-1],[4,14],[4,0]] },
     93     'j': { width: 10, points: [[5,21],[6,20],[7,21],[6,22],[5,21],[-1,-1],[6,14],[6,-3],[5,-6],[3,-7],[1,-7]] },
     94     'k': { width: 17, points: [[4,21],[4,0],[-1,-1],[14,14],[4,4],[-1,-1],[8,8],[15,0]] },
     95     'l': { width: 8, points: [[4,21],[4,0]] },
     96     'm': { width: 30, points: [[4,14],[4,0],[-1,-1],[4,10],[7,13],[9,14],[12,14],[14,13],[15,10],[15,0],[-1,-1],[15,10],[18,13],[20,14],[23,14],[25,13],[26,10],[26,0]] },
     97     'n': { width: 19, points: [[4,14],[4,0],[-1,-1],[4,10],[7,13],[9,14],[12,14],[14,13],[15,10],[15,0]] },
     98     'o': { width: 19, points: [[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3],[16,6],[16,8],[15,11],[13,13],[11,14],[8,14]] },
     99     'p': { width: 19, points: [[4,14],[4,-7],[-1,-1],[4,11],[6,13],[8,14],[11,14],[13,13],[15,11],[16,8],[16,6],[15,3],[13,1],[11,0],[8,0],[6,1],[4,3]] },
    100     'q': { width: 19, points: [[15,14],[15,-7],[-1,-1],[15,11],[13,13],[11,14],[8,14],[6,13],[4,11],[3,8],[3,6],[4,3],[6,1],[8,0],[11,0],[13,1],[15,3]] },
    101     'r': { width: 13, points: [[4,14],[4,0],[-1,-1],[4,8],[5,11],[7,13],[9,14],[12,14]] },
    102     's': { width: 17, points: [[14,11],[13,13],[10,14],[7,14],[4,13],[3,11],[4,9],[6,8],[11,7],[13,6],[14,4],[14,3],[13,1],[10,0],[7,0],[4,1],[3,3]] },
    103     't': { width: 12, points: [[5,21],[5,4],[6,1],[8,0],[10,0],[-1,-1],[2,14],[9,14]] },
    104     'u': { width: 19, points: [[4,14],[4,4],[5,1],[7,0],[10,0],[12,1],[15,4],[-1,-1],[15,14],[15,0]] },
    105     'v': { width: 16, points: [[2,14],[8,0],[-1,-1],[14,14],[8,0]] },
    106     'w': { width: 22, points: [[3,14],[7,0],[-1,-1],[11,14],[7,0],[-1,-1],[11,14],[15,0],[-1,-1],[19,14],[15,0]] },
    107     'x': { width: 17, points: [[3,14],[14,0],[-1,-1],[14,14],[3,0]] },
    108     'y': { width: 16, points: [[2,14],[8,0],[-1,-1],[14,14],[8,0],[6,-4],[4,-6],[2,-7],[1,-7]] },
    109     'z': { width: 17, points: [[14,14],[3,0],[-1,-1],[3,14],[14,14],[-1,-1],[3,0],[14,0]] },
    110     '{': { width: 14, points: [[9,25],[7,24],[6,23],[5,21],[5,19],[6,17],[7,16],[8,14],[8,12],[6,10],[-1,-1],[7,24],[6,22],[6,20],[7,18],[8,17],[9,15],[9,13],[8,11],[4,9],[8,7],[9,5],[9,3],[8,1],[7,0],[6,-2],[6,-4],[7,-6],[-1,-1],[6,8],[8,6],[8,4],[7,2],[6,1],[5,-1],[5,-3],[6,-5],[7,-6],[9,-7]] },
    111     '|': { width: 8, points: [[4,25],[4,-7]] },
    112     '}': { width: 14, points: [[5,25],[7,24],[8,23],[9,21],[9,19],[8,17],[7,16],[6,14],[6,12],[8,10],[-1,-1],[7,24],[8,22],[8,20],[7,18],[6,17],[5,15],[5,13],[6,11],[10,9],[6,7],[5,5],[5,3],[6,1],[7,0],[8,-2],[8,-4],[7,-6],[-1,-1],[8,8],[6,6],[6,4],[7,2],[8,1],[9,-1],[9,-3],[8,-5],[7,-6],[5,-7]] },
    113     '~': { width: 24, points: [[3,6],[3,8],[4,11],[6,12],[8,12],[10,11],[14,8],[16,7],[18,7],[20,8],[21,10],[-1,-1],[3,8],[4,10],[6,11],[8,11],[10,10],[14,7],[16,6],[18,6],[20,7],[21,10],[21,12]] }
    114 };
    115 
    116 CanvasTextFunctions.letter = function (ch) 
    117 {
    118     return CanvasTextFunctions.letters[ch];
    119 };
    120 
    121 CanvasTextFunctions.ascent = function(font, size) 
    122 {
    123     return size;
    124 };
    125 
    126 CanvasTextFunctions.descent = function(font, size) 
    127 {
    128     return 7.0*size/25.0;
    129 };
    130 
    131 CanvasTextFunctions.measure = function(font, size, str) 
    132 {
    133     var total = 0;
    134     var len = str.length;
    135 
    136     for (var i = 0; i < len; i++) 
    137 	{
    138 		var c = CanvasTextFunctions.letter(str.charAt(i));
    139 		if (c) 
    140 		{
    141 			total += c.width * size / 25.0;
    142 		}
    143     }
    144     return total;
    145 };
    146 
    147 CanvasTextFunctions.draw = function(ctx,font,size,x,y,str) 
    148 {
    149     var total = 0;
    150     var len = str.length;
    151     var mag = size / 25.0;
    152 
    153     ctx.save();
    154     ctx.lineCap = "round";
    155     ctx.lineWidth = 2.0 * mag;
    156 	ctx.strokeStyle = "black";
    157 
    158     for (var i = 0; i < len; i++) 
    159 	{
    160 		var c = CanvasTextFunctions.letter( str.charAt(i));
    161 		if (!c)
    162 		{
    163 			continue;	
    164 		} 
    165 		ctx.beginPath();
    166 		var penUp = 1;
    167 		var needStroke = 0;
    168 		for (var j = 0; j < c.points.length; j++) 
    169 		{
    170 		    var a = c.points[j];
    171 		    if ( a[0] === -1 && a[1] === -1) 
    172 			{
    173 				penUp = 1;
    174 				continue;
    175 		    }
    176 		    if ( penUp) 
    177 			{
    178 				ctx.moveTo( x + a[0]*mag, y - a[1]*mag);
    179 				penUp = false;
    180 		    } 
    181 			else 
    182 			{
    183 				ctx.lineTo( x + a[0]*mag, y - a[1]*mag);
    184 		    }
    185 		}
    186 		ctx.stroke();
    187 		x += c.width*mag;
    188     }
    189     ctx.restore();
    190     return total;
    191 };
    192 
    193 CanvasTextFunctions.enable = function(ctx) 
    194 {
    195     ctx.drawText = function(font,size,x,y,text) { return CanvasTextFunctions.draw( ctx, font,size,x,y,text); };
    196     ctx.measureText = function(font,size,text) { return CanvasTextFunctions.measure( font,size,text); };
    197     ctx.fontAscent = function(font,size) { return CanvasTextFunctions.ascent(font,size); };
    198     ctx.fontDescent = function(font,size) { return CanvasTextFunctions.descent(font,size); };
    199     ctx.drawTextRight = function(font,size,x,y,text) {  
    200 		var w = CanvasTextFunctions.measure(font,size,text);
    201 		return CanvasTextFunctions.draw( ctx, font,size,x-w,y,text); 
    202     };
    203     ctx.drawTextCenter = function(font,size,x,y,text) { 
    204 		var w = CanvasTextFunctions.measure(font,size,text);
    205 		return CanvasTextFunctions.draw( ctx, font,size,x-w/2,y,text); 
    206     };
    207 };