NIWPI/js/bigtext.js

/*! BigText - v1.0.1 - 2017-06-01
 * https://github.com/zachleat/bigtext
 * Copyright (c) 2017 Zach Leatherman (@zachleat)
 * MIT License */

(function(window, $) {
  "use strict";

  var counter = 0,
    $headCache = $('head'),
    oldBigText = window.BigText,
    oldjQueryMethod = $.fn.bigtext,
    BigText = {
      DEBUG_MODE: false,
      DEFAULT_MIN_FONT_SIZE_PX: null,
      DEFAULT_MAX_FONT_SIZE_PX: 528,
      GLOBAL_STYLE_ID: 'bigtext-style',
      STYLE_ID: 'bigtext-id',
      LINE_CLASS_PREFIX: 'bigtext-line',
      EXEMPT_CLASS: 'bigtext-exempt',
      noConflict: function(restore)
      {
        if(restore) {
          $.fn.bigtext = oldjQueryMethod;
          window.BigText = oldBigText;
        }
        return BigText;
      },
      supports: {
        wholeNumberFontSizeOnly: (function() {
          if( !( 'getComputedStyle' in window ) ) {
            return true;
          }
          var test = $('<div/>').css({
              position: 'absolute',
              'font-size': '14.1px'
            }).insertBefore( $('script').eq(0) ),
            computedStyle = window.getComputedStyle( test[0], null );

          var ret = computedStyle && computedStyle.getPropertyValue( 'font-size' ) === '14px';
          test.remove();
          return ret;
        })()
      },
      init: function() {
        if(!$('#'+BigText.GLOBAL_STYLE_ID).length) {
          $headCache.append(BigText.generateStyleTag(BigText.GLOBAL_STYLE_ID, ['.bigtext * { white-space: nowrap; } .bigtext > * { display: block; }',
                                          '.bigtext .' + BigText.EXEMPT_CLASS + ', .bigtext .' + BigText.EXEMPT_CLASS + ' * { white-space: normal; }']));
        }
      },
      bindResize: function(eventName, resizeFunction) {
        var timeoutId;
        $(window).unbind(eventName).bind(eventName, function() {
          if( timeoutId ) {
            clearTimeout( timeoutId );
          }
          timeoutId = setTimeout( resizeFunction, 100 );
        });
      },
      getStyleId: function(id)
      {
        return BigText.STYLE_ID + '-' + id;
      },
      generateStyleTag: function(id, css)
      {
        return $('<style>' + css.join('\n') + '</style>').attr('id', id);
      },
      clearCss: function(id)
      {
        var styleId = BigText.getStyleId(id);
        $('#' + styleId).remove();
      },
      generateCss: function(id, linesFontSizes, lineWordSpacings, minFontSizes)
      {
        var css = [];

        BigText.clearCss(id);

        for(var j=0, k=linesFontSizes.length; j<k; j++) {
          css.push('#' + id + ' .' + BigText.LINE_CLASS_PREFIX + j + ' {' +
            (minFontSizes[j] ? ' white-space: normal;' : '') +
            (linesFontSizes[j] ? ' font-size: ' + linesFontSizes[j] + 'px;' : '') +
            (lineWordSpacings[j] ? ' word-spacing: ' + lineWordSpacings[j] + 'px;' : '') +
            '}');
        }

        return BigText.generateStyleTag(BigText.getStyleId(id), css);
      },
      jQueryMethod: function(options)
      {
        BigText.init();

        options = $.extend({
          minfontsize: BigText.DEFAULT_MIN_FONT_SIZE_PX,
          maxfontsize: BigText.DEFAULT_MAX_FONT_SIZE_PX,
          childSelector: '',
          resize: true
        }, options || {});

        this.each(function()
        {
          var $t = $(this).addClass('bigtext'),
            maxWidth = $t.width(),
            id = $t.attr('id'),
            $children = options.childSelector ? $t.find( options.childSelector ) : $t.children();

          if(!id) {
            id = 'bigtext-id' + (counter++);
            $t.attr('id', id);
          }

          if(options.resize) {
            BigText.bindResize('resize.bigtext-event-' + id, function()
            {
              // TODO only call this if the width has changed.
              BigText.jQueryMethod.call($('#' + id), options);
            });
          }

          BigText.clearCss(id);

          $children.addClass(function(lineNumber, className)
          {
            // remove existing line classes.
            return [className.replace(new RegExp('\\b' + BigText.LINE_CLASS_PREFIX + '\\d+\\b'), ''),
                BigText.LINE_CLASS_PREFIX + lineNumber].join(' ');
          });

          var sizes = BigText.calculateSizes($t, $children, maxWidth, options.maxfontsize, options.minfontsize);
          $headCache.append(BigText.generateCss(id, sizes.fontSizes, sizes.wordSpacings, sizes.minFontSizes));
        });

        return this.trigger('bigtext:complete');
      },
      testLineDimensions: function($line, maxWidth, property, size, interval, units, previousWidth)
      {
        var width;
        previousWidth = typeof previousWidth === 'number' ? previousWidth : 0;
        $line.css(property, size + units);

        width = $line.width();

        if(width >= maxWidth) {
    // console.log(width, ' previous: ' + previousWidth, property + ' at ' + interval, 'prior: ' + (parseFloat(size) - interval), 'new:' + parseFloat(size));
          $line.css(property, '');

          if(width === maxWidth) {
            return {
              match: 'exact',
              size: parseFloat((parseFloat(size) - 0.1).toFixed(3))
            };
          }

          // Since this is an estimate, we calculate how far over the width we went with the new value.
          // If this is word-spacing (our last resort guess) and the over is less than the under, we keep the higher value.
          // Otherwise, we revert to the underestimate.
          var under = maxWidth - previousWidth,
            over = width - maxWidth;

          return {
            match: 'estimate',
            size: parseFloat((parseFloat(size) - (property === 'word-spacing' && previousWidth && ( over < under ) ? 0 : interval)).toFixed(3))
          };
        }

        return width;
      },
      calculateSizes: function($t, $children, maxWidth, maxFontSize, minFontSize)
      {
        var $c = $t.clone(true)
          .addClass('bigtext-cloned')
          .css({
            fontFamily: $t.css('font-family'),
            textTransform: $t.css('text-transform'),
            wordSpacing: $t.css('word-spacing'),
            letterSpacing: $t.css('letter-spacing'),
            position: 'absolute',
            left: BigText.DEBUG_MODE ? 0 : -9999,
            top: BigText.DEBUG_MODE ? 0 : -9999
          })
          .appendTo(document.body);

        // font-size isn't the only thing we can modify, we can also mess with:
        // word-spacing and letter-spacing. WebKit does not respect subpixel
        // letter-spacing, word-spacing, or font-size.
        // TODO try -webkit-transform: scale() as a workaround.
        var fontSizes = [],
          wordSpacings = [],
          minFontSizes = [],
          ratios = [];

        $children.css('float', 'left').each(function() {
          var $line = $(this),
            // TODO replace 8, 4 with a proportional size to the calculated font-size.
            intervals = BigText.supports.wholeNumberFontSizeOnly ? [8, 4, 1] : [8, 4, 1, 0.1],
            lineMax,
            newFontSize;

          if($line.hasClass(BigText.EXEMPT_CLASS)) {
            fontSizes.push(null);
            ratios.push(null);
            minFontSizes.push(false);
            return;
          }

          // TODO we can cache this ratio?
          var autoGuessSubtraction = 32, // font size in px
            currentFontSize = parseFloat($line.css('font-size')),
            ratio = ( $line.width() / currentFontSize ).toFixed(6);

          newFontSize = parseInt( maxWidth / ratio, 10 ) - autoGuessSubtraction;

          outer: for(var m=0, n=intervals.length; m<n; m++) {
            inner: for(var j=1, k=10; j<=k; j++) {
              if(newFontSize + j*intervals[m] > maxFontSize) {
                newFontSize = maxFontSize;
                break outer;
              }

              lineMax = BigText.testLineDimensions($line, maxWidth, 'font-size', newFontSize + j*intervals[m], intervals[m], 'px', lineMax);
              if(typeof lineMax !== 'number') {
                newFontSize = lineMax.size;

                if(lineMax.match === 'exact') {
                  break outer;
                }
                break inner;
              }
            }
          }

          ratios.push(maxWidth / newFontSize);

          if(newFontSize > maxFontSize) {
            fontSizes.push(maxFontSize);
            minFontSizes.push(false);
          } else if(!!minFontSize && newFontSize < minFontSize) {
            fontSizes.push(minFontSize);
            minFontSizes.push(true);
          } else {
            fontSizes.push(newFontSize);
            minFontSizes.push(false);
          }
        }).each(function(lineNumber) {
          var $line = $(this),
            wordSpacing = 0,
            interval = 1,
            maxWordSpacing;

          if($line.hasClass(BigText.EXEMPT_CLASS)) {
            wordSpacings.push(null);
            return;
          }

          // must re-use font-size, even though it was removed above.
          $line.css('font-size', fontSizes[lineNumber] + 'px');

          for(var m=1, n=3; m<n; m+=interval) {
            maxWordSpacing = BigText.testLineDimensions($line, maxWidth, 'word-spacing', m, interval, 'px', maxWordSpacing);
            if(typeof maxWordSpacing !== 'number') {
              wordSpacing = maxWordSpacing.size;
              break;
            }
          }

          $line.css('font-size', '');
          wordSpacings.push(wordSpacing);
        }).removeAttr('style');

        if( !BigText.DEBUG_MODE ) {
          $c.remove();
        } else {
          $c.css({
            'background-color': 'rgba(255,255,255,.4)'
          });
        }

        return {
          fontSizes: fontSizes,
          wordSpacings: wordSpacings,
          ratios: ratios,
          minFontSizes: minFontSizes
        };
      }
    };

  $.fn.bigtext = BigText.jQueryMethod;
  window.BigText = BigText;

})(this, jQuery);