p5.hershey.js

// p5.hershey.js
// hershey font renderer for p5.js

// (c) Lingdong Huang 2018

var P5 = window;
P5.hershey={
  parseFontString : function(txt){
    var lines = txt.split("\n")
    var result = {}
    for (var i = 0; i < lines.length; i++){
      if (!lines[i].length){
        continue;
      }
      var code = 1*lines[i].slice(0,5);
      var entry =lines[i].slice(5);
      result[code] = entry
    }
    return result
  },
  validateFont: function(font){
    var invalid_indices = []
    for (var k in font){
      var entry = font[k]
      var cksum = 1*entry.slice(0,3);
      var coords = entry.slice(3);
      if (cksum*2 != coords.length){
        invalid_indices.push(k)
      }
    }
    return invalid_indices;
  },
  parseBound : function(entry){
    var ordR = "R".charCodeAt(0);
    var bound = entry.slice(3,5);
    var xmin = 1*bound[0].charCodeAt(0)-ordR;
    var xmax = 1*bound[1].charCodeAt(0)-ordR;
    return [xmin,xmax]
  },
  putChar : function(c,args){
    if (args == undefined){args = {}}
    if (args.font == undefined){args.font = FONT_HERSHEY.DATA}
    if (args.cmap == undefined){args.cmap = FONT_HERSHEY.SIMPLEX};
    if (args.noise == undefined){args.noise = 0}
    var ordR = "R".charCodeAt(0);
    // console.log(args.cmap(c.charCodeAt(0)))
    var entry = args.font[args.cmap(c.charCodeAt(0))];
    if (entry == undefined){
      return 0;
    }
    var cksum = 1*entry.slice(0,3);
    var [xmin,xmax] = P5.hershey.parseBound(entry);
    var content = entry.slice(5);
    P5.push();
    P5.translate(-xmin,0);
    P5.beginShape();
    
    for (var i = 0; i < content.length; i+=2){
      var digit = content.slice(i,i+2);
      if (digit == " R"){
        P5.endShape();
        P5.beginShape();
      }else{
        var x = digit[0].charCodeAt(0)-ordR;
        var y = digit[1].charCodeAt(0)-ordR;
        if (typeof(args.noise) == typeof(0)){
          if (args.noise != 0){
            x+= Math.pow(P5.randomGaussian(0,args.noise),3);
          }
        }else{
          x += args.noise.x(x,y);
          y += args.noise.y(x,y);
        }
        P5.vertex(x,y);
      }
    }
    P5.endShape();
    P5.pop();
    return xmax-xmin;
  },
  putText : function (s, args){
    if (args == undefined){args = {}}
    if (args.align == undefined){args.align = "left"};
    P5.push();
    if (args.align == "left"){
    }else if (args.align == "center"){
      P5.translate(-P5.hershey.estimateTextWidth(s,args)/2,0);
    }else if (args.align == "right"){
      P5.translate(-P5.hershey.estimateTextWidth(s,args),0);
    }
    for (var i = 0; i < s.length; i++){
      var x = P5.hershey.putChar(s[i],args);
      P5.translate(x,0);
    }
    P5.pop();
  },
  estimateTextWidth : function (s, args){
    if (args == undefined){args = {}}
    if (args.font == undefined){args.font = FONT_HERSHEY.DATA}
    if (args.cmap == undefined){args.cmap = FONT_HERSHEY.SIMPLEX};
    var sum = 0;
    for (var i = 0; i < s.length; i++){
      var entry = args.font[args.cmap(s[i].charCodeAt(0))];
      if (entry == undefined){
        return 0;
      }
      var [xmin,xmax] = P5.hershey.parseBound(entry);
      sum += (xmax-xmin)
    }
    return sum;
  }
}