D3 Examples - SVG Rotation Example

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<!DOCTYPE html>
<head>
  <meta charset="utf-8"> 
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    #container{
      position:relative;
    }
    svg{
      position:absolute;      
    }
    
  </style>
</head>
​
<p>Rotation: <span id="currotation">50</span></p>
<input id="slider" type="range" min="1" max="100" value="50">
<div id="container">
</div>
<body>
  <script>
    
    d3.selectAll("#slider")
        .on("change",function(){
                var selected = d3.select(this).property("value")      
        d3.select("#currotation").text(selected)
        
        rotation = selected;
        rotated_width = width/(Math.cos(rotation/360 * Math.PI*2)+Math.sin(rotation/360 * Math.PI*2))
    
        updateSVG()
        
    })
    
    var rotation = 45;
    
    var margin = {top: 100, right: 30, bottom: 20, left: 30};
    
    var width = 500;
    var height = 500;
    
    //calculates the width of an enclosed square for any rotation. 
    var rotated_width = width/(Math.cos(rotation/360 * Math.PI*2)+Math.sin(rotation/360 * Math.PI*2))
    
    var circleArray = [0,.2,.4,.6,.8,1]
​
    var xScale = d3.scalePoint()
        .range([0,rotated_width])
        .domain(circleArray)
​
    var xScale_norotation = d3.scalePoint()
        .range([0,width])
        .domain(circleArray)
​
    var svg = d3.select("#container").append("svg")
      .attr("width", width + margin.left + margin.right)
      .attr("height", height + margin.top + margin.bottom)
        .style("border","1px solid teal")
        .style("overflow","visible")
    
    var margin_g = svg.append("g")
        .attr("transform","translate(" + margin.left + "," + margin.top + ")")
        
    margin_g.append("rect")
        .attr("width",width)
    .attr("height",height)
    .style("fill","rgba(0,0,0,.2)")
    
    var container_g = margin_g.append("g")
        .attr("transform","translate(0," + (-height/2) + ")")
    
    var rotate_g =  container_g.append("g");
    
    rotate_g.append("rect")
        .attr("width",rotated_width)
        .attr("height",rotated_width)
        .attr("fill","red")
        .style("opacity",.2)
​
    rotate_g.append("text")
      .text("(x = 0, y = 0)")
      .attr("y", -5)
      .attr("x", 0)
      .attr("font-size", 16)
      .attr("font-family", "Helvetica")
​
    rotate_g.append("g").call(d3.axisBottom(xScale))
   
    var circles = container_g.selectAll("circle").data(circleArray)
    
    circles.enter().append("circle")
        .attr("cx",function(d){return xScale_norotation(d)})
        .attr("cy",height/2)
      .attr("r",5)
        .attr("fill","black")
     
    updateSVG()
   
    function updateSVG(){
        
      //figure out the distance between (0,height) and (width,0) in original x coordinates.  
        
      rotate_g.attr("transform","translate(" + width/2 + "," + 0 + ")" + " rotate(" + rotation +")")
      
      rotate_g.select("rect")
            .attr("width",rotated_width)
            .attr("height",rotated_width)
      
      //fix translation for new width. 
      var elem_width = rotate_g.select("rect").node().getBoundingClientRect().left;
​
        rotate_g.attr("transform","translate(" + (width/2 - elem_width + margin.left) + "," + 0 + ")" + " rotate(" + rotation +")")
      
      d3.selectAll("circle")
        .attr("cx",function(d){return xScale_norotation(d)})
            .attr("cy",height/2)
        .attr("r",5)
            .attr("fill","black")
      
      
      
    }
      
      
    
    
        
    
    
    
    
  </script>
</body>
​
    