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arctext.js实现文字平滑弯曲弧形效果的插件

Posted in Javascript onMay 13, 2019

本文介绍了实现文字平滑弯曲弧形效果的插件-arctext.js，分享给大家，具体如下：

扇形的文字

有时候产品大佬就是很任性，说做一个宣传页，一个类似拱门的效果，每次文字不一样，但是文字得呈现拱形状，类似上图啦。

尝试自己使用canvas画和css3的rotate旋转div，两种方法都是计算旋转角度的时候很麻烦，因为可能5个字10个字，但是得均匀地呈拱形分布，要知道让每个文字都沿着弯曲路径排布相当的复杂，于是便发现了这个好用的插件---arctext.js

它能够自动计算每个文字正确的旋转角度，并且生成对应的CSS ，其实就是基于css3和jquery，使用起来也很方便。

1.创建一个容器装文字

<h3 id="title">文字弯曲效果类似扇形拱桥状</h3>

2.引入jquery和arctext.js

<script type="text/javascript" src="//code.jquery.com/jquery-1.8.2.min.js" ></script>
<script src="jquery.arctext.js"></script>

3.调用arctext的方法：

$(function(){
    $("#title").show().arctext({
      radius:180
    })
  })

arctext参数说明：

radius:弯曲度数，最小的值是文字长度，如果设置为-1，则显示直线。
rotate:默认true，为false则不旋转文字
dir:默认1 (1：向下弯曲非1（-1,0,2等）：向上弯曲 )
fitText:默认false,如果你想尝试使用fitText插件，设置为true，记住包装的标签需要fluid布局。

效果图完整demo：

<!DOCTYPE html>
<html>
<head lang="en">
  <meta charset="UTF-8">
  <title></title>
  <style>
   #title{
      font-size: 20px;
      color: #ffe400;
      text-align: center;
    }
  </style>
</head>
<body>
  <h3 id="title">文字弯曲效果类似扇形拱桥状</h3>
<script type="text/javascript" src="//code.jquery.com/jquery-1.8.2.min.js" ></script>
<script src="jquery.arctext.js"></script>
<script>
  $(function(){
    $("#title").arctext({
      radius:180
    })
  })
</script>
</body>
</html>

jquery.arctext.js

/**
 * Arctext.js
 * A jQuery plugin for curved text
 * http://www.codrops.com
 *
 * Copyright 2011, Pedro Botelho / Codrops
 * Free to use under the MIT license.
 *
 * Date: Mon Jan 23 2012
 */

(function( $, undefined ) {
  
  /*! 
  * FitText.js 1.0
  *
  * Copyright 2011, Dave Rupert http://daverupert.com
  * Released under the WTFPL license 
  * http://sam.zoy.org/wtfpl/
  *
  * Date: Thu May 05 14:23:00 2011 -0600
  */
  $.fn.fitText = function( kompressor, options ) {

    var settings = {
      'minFontSize' : Number.NEGATIVE_INFINITY,
      'maxFontSize' : Number.POSITIVE_INFINITY
    };

    return this.each(function() {
      var $this = $(this);       // store the object
      var compressor = kompressor || 1; // set the compressor
  
      if ( options ) { 
       $.extend( settings, options );
      }
  
      // Resizer() resizes items based on the object width divided by the compressor * 10
      var resizer = function () {
        $this.css('font-size', Math.max(Math.min($this.width() / (compressor*10), parseFloat(settings.maxFontSize)), parseFloat(settings.minFontSize)));
      };

      // Call once to set.
      resizer();

      // Call on resize. Opera debounces their resize by default. 
      $(window).resize(resizer);
    });

  };

  /*
   * Lettering plugin
   *
   * changed injector function:
   *  add   for empty chars.
   */
  function injector(t, splitter, klass, after) {
    var a = t.text().split(splitter), inject = '', emptyclass;
    if (a.length) {
      $(a).each(function(i, item) {
        emptyclass = '';
        if(item === ' ') {
          emptyclass = ' empty';
          item=' ';
        }  
        inject += '<span class="'+klass+(i+1)+emptyclass+'">'+item+'</span>'+after;
      }); 
      t.empty().append(inject);
    }
  }
  
  var methods       = {
    init : function() {

      return this.each(function() {
        injector($(this), '', 'char', '');
      });

    },

    words : function() {

      return this.each(function() {
        injector($(this), ' ', 'word', ' ');
      });

    },
    
    lines : function() {

      return this.each(function() {
        var r = "eefec303079ad17405c889e092e105b0";
        // Because it's hard to split a <br/> tag consistently across browsers,
        // (*ahem* IE *ahem*), we replaces all <br/> instances with an md5 hash 
        // (of the word "split"). If you're trying to use this plugin on that 
        // md5 hash string, it will fail because you're being ridiculous.
        injector($(this).children("br").replaceWith(r).end(), r, 'line', '');
      });

    }
  };

  $.fn.lettering     = function( method ) {
    // Method calling logic
    if ( method && methods[method] ) {
      return methods[ method ].apply( this, [].slice.call( arguments, 1 ));
    } else if ( method === 'letters' || ! method ) {
      return methods.init.apply( this, [].slice.call( arguments, 0 ) ); // always pass an array
    }
    $.error( 'Method ' + method + ' does not exist on jQuery.lettering' );
    return this;
  };
  
  /*
   * Arctext object.
   */
  $.Arctext        = function( options, element ) {
  
    this.$el  = $( element );
    this._init( options );
    
  };
  
  $.Arctext.defaults   = {
    radius : 0,  // the minimum value allowed is half of the word length. if set to -1, the word will be straight.
    dir   : 1,  // 1: curve is down, -1: curve is up.
    rotate : true, // if true each letter will be rotated.
    fitText : false // if you wanna try out the fitText plugin (http://fittextjs.com/) set this to true. Don't forget the wrapper should be fluid.
  };
  
  $.Arctext.prototype   = {
    _init        : function( options ) {
      
      this.options    = $.extend( true, {}, $.Arctext.defaults, options );
      
      // apply the lettering plugin.
      this._applyLettering();
      
      this.$el.data( 'arctext', true );
      
      // calculate values
      this._calc();
      
      // apply transformation.
      this._rotateWord();
      
      // load the events
      this._loadEvents();
      
    },
    _applyLettering   : function() {
    
      this.$el.lettering();
      
      if( this.options.fitText )
        this.$el.fitText();
      
      this.$letters  = this.$el.find('span').css('display', 'inline-block');
    
    },
    _calc        : function() {
      
      if( this.options.radius === -1 )
        return false;
      
      // calculate word / arc sizes & distances.
      this._calcBase();
      
      // get final values for each letter.
      this._calcLetters();
    
    },
    _calcBase      : function() {
      
      // total word width (sum of letters widths)
      this.dtWord   = 0;
      
      var _self    = this;
      
      this.$letters.each( function(i) {
                
        var $letter     = $(this),
          letterWidth   = $letter.outerWidth( true );
        
        _self.dtWord += letterWidth;
        
        // save the center point of each letter:
        $letter.data( 'center', _self.dtWord - letterWidth / 2 );
        
      });
      
      // the middle point of the word.
      var centerWord = this.dtWord / 2;
      
      // check radius : the minimum value allowed is half of the word length.
      if( this.options.radius < centerWord )
        this.options.radius = centerWord;
      
      // total arc segment length, where the letters will be placed.
      this.dtArcBase = this.dtWord;
      
      // calculate the arc (length) that goes from the beginning of the first letter (x=0) to the end of the last letter (x=this.dtWord).
      // first lets calculate the angle for the triangle with base = this.dtArcBase and the other two sides = radius.
      var angle    = 2 * Math.asin( this.dtArcBase / ( 2 * this.options.radius ) );
      
      // given the formula: L(ength) = R(adius) x A(ngle), we calculate our arc length.
      this.dtArc   = this.options.radius * angle;
      
    },
    _calcLetters    : function() {
      
      var _self    = this,
        iteratorX  = 0;
        
      this.$letters.each( function(i) {
          
        var $letter     = $(this),
          // calculate each letter's semi arc given the percentage of each letter on the original word.
          dtArcLetter   = ( $letter.outerWidth( true ) / _self.dtWord ) * _self.dtArc,
          // angle for the dtArcLetter given our radius.
          beta      = dtArcLetter / _self.options.radius,
          // distance from the middle point of the semi arc's chord to the center of the circle.
          // this is going to be the place where the letter will be positioned.
          h        = _self.options.radius * ( Math.cos( beta / 2 ) ),
          // angle formed by the x-axis and the left most point of the chord.
          alpha      = Math.acos( ( _self.dtWord / 2 - iteratorX ) / _self.options.radius ),
          // angle formed by the x-axis and the right most point of the chord.
          theta      = alpha + beta / 2,
          // distances of the sides of the triangle formed by h and the orthogonal to the x-axis.
          x        = Math.cos( theta ) * h,
          y        = Math.sin( theta ) * h,
          // the value for the coordinate x of the middle point of the chord.
          xpos      = iteratorX + Math.abs( _self.dtWord / 2 - x - iteratorX ),
          // finally, calculate how much to translate each letter, given its center point.
          // also calculate the angle to rotate the letter accordingly.
          xval  = 0| xpos - $letter.data( 'center' ),
          yval  = 0| _self.options.radius - y,
          angle  = ( _self.options.rotate ) ? 0| -Math.asin( x / _self.options.radius ) * ( 180 / Math.PI ) : 0;
        
        // the iteratorX will be positioned on the second point of each semi arc
        iteratorX = 2 * xpos - iteratorX;
        
        // save these values
        $letter.data({
          x  : xval,
          y  : ( _self.options.dir === 1 ) ? yval : -yval,
          a  : ( _self.options.dir === 1 ) ? angle : -angle
        });
          
      });
    
    },
    _rotateWord     : function( animation ) {
      
      if( !this.$el.data('arctext') ) return false;
      
      var _self = this;
      
      this.$letters.each( function(i) {
        
        var $letter     = $(this),
          transformation = ( _self.options.radius === -1 ) ? 'none' : 'translateX(' + $letter.data('x') + 'px) translateY(' + $letter.data('y') + 'px) rotate(' + $letter.data('a') + 'deg)',
          transition   = ( animation ) ? 'all ' + ( animation.speed || 0 ) + 'ms ' + ( animation.easing || 'linear' ) : 'none';
        
        $letter.css({
          '-webkit-transition' : transition,
          '-moz-transition' : transition,
          '-o-transition' : transition,
          '-ms-transition' : transition,
          'transition' : transition
        })
        .css({
          '-webkit-transform' : transformation,
          '-moz-transform' : transformation,
          '-o-transform' : transformation,
          '-ms-transform' : transformation,
          'transform' : transformation
        });
      
      });
      
    },
    _loadEvents     : function() {
      
      if( this.options.fitText ) {
      
        var _self = this;
        
        $(window).on( 'resize.arctext', function() {
          
          _self._calc();
          
          // apply transformation.
          _self._rotateWord();
          
        });
      
      }
    
    },
    set         : function( opts ) {
      
      if( !opts.radius && 
        !opts.dir &&
        opts.rotate === 'undefined' ) {
          return false;
      }
      
      this.options.radius = opts.radius || this.options.radius;
      this.options.dir  = opts.dir || this.options.dir;
      
      if( opts.rotate !== undefined ) {
        this.options.rotate = opts.rotate;
      }  
      
      this._calc();
      
      this._rotateWord( opts.animation );
      
    },
    destroy       : function() {
      
      this.options.radius = -1;
      this._rotateWord();
      this.$letters.removeData('x y a center');
      this.$el.removeData('arctext');
      $(window).off('.arctext');
      
    }
  };
  
  var logError      = function( message ) {
    if ( this.console ) {
      console.error( message );
    }
  };
  
  $.fn.arctext      = function( options ) {
  
    if ( typeof options === 'string' ) {
      
      var args = Array.prototype.slice.call( arguments, 1 );
      
      this.each(function() {
      
        var instance = $.data( this, 'arctext' );
        
        if ( !instance ) {
          logError( "cannot call methods on arctext prior to initialization; " +
          "attempted to call method '" + options + "'" );
          return;
        }
        
        if ( !$.isFunction( instance[options] ) || options.charAt(0) === "_" ) {
          logError( "no such method '" + options + "' for arctext instance" );
          return;
        }
        
        instance[ options ].apply( instance, args );
      
      });
    
    } 
    else {
    
      this.each(function() {
      
        var instance = $.data( this, 'arctext' );
        if ( !instance ) {
          $.data( this, 'arctext', new $.Arctext( options, this ) );
        }
      });
    
    }
    
    return this;
    
  };
  
})( jQuery );

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持三水点靠木。

arctext.js实现文字平滑弯曲弧形效果的插件

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