jquery圆形数字滑块插件

使用方法

$(document).ready(function(){
  var is_dragging = false;
  $(document).on("mousedown touchstart",".circle",function(e){
    is_dragging = true;
  });
  $(document).on("mouseup touchend",function(e){
    is_dragging = false;
  });
  $(document).on("mousemove touchmove",function(e){
    if(is_dragging){
      var circle = $(".circle")
      var touch = undefined;
      if (e.originalEvent.touches){
        var touch = e.originalEvent.touches[0];
      }
      var center_x = ($(circle).outerWidth() / 2) + $(circle).offset().left;
      var center_y = ($(circle).outerHeight() / 2) + $(circle).offset().top;
      var pos_x = (e.pageX || touch.pageX);
      var pos_y = (e.pageY || touch.pageY);
      var delta_y =  center_y - pos_y;
      var delta_x = center_x - pos_x;
      var angle = Math.atan2(delta_y, delta_x) * (180 / Math.PI);
      angle -= 90;
      if (angle < 0){
        angle = 360 + angle;
      }
      angle = Math.round(angle);
      $(".dot").css("transform", "rotate("+angle+"deg)");
      $(".debug input").val(Math.round(angle * 300000/360));
    }
  });
  $(".debug input").on('change',function(){
    angle = $(this).val()/300000*360;
    $(".dot").css("transform", "rotate("+angle+"deg)");
  })
});