D3 Examples - D3 Bounded Zoom

D3 Bounded Zoom
This D3 example demonstrates using the zoom event and limits the bounds of the zooming to a specified domain. It is largely based on /jasondavies/3689931, but with bounds. Most of this bounding is done in the refresh function. You need to zoom in before you can pan or zoom out.
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<!DOCTYPE html>
<meta charset="utf-8">
<title>Constrained Zoom by Rectangle</title>
<script src="https://d3js.org/d3.v4.min.js"></script>
<style>
​
body {
  font-family: sans-serif;
}
​
.noselect {
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
​
svg {
  font: 9pt sans-serif;
  shape-rendering: crispEdges;
}
​
rect {
  fill: #ddd;
}
​
rect.zoom {
  stroke: steelblue;
  fill: #bbb;
  fill-opacity: 0.5;
}
​
.axis path, .axis line {
  fill: none;
  stroke: #fff;
}
​
</style>
<p><label for="zoom-rect"><input type="checkbox" id="zoom-rect"> zoom by rectangle</label>
<script>
​
var margin = {top: 0, right: 12, bottom: 20, left: 60},
    width = 960 - margin.left - margin.right,
    height = 430 - margin.top - margin.bottom;
​
var xmin = 0,
    xmax = 500,
    ymin = 0,
    ymax = 1000;
​
var x = d3.scaleLinear()
    .domain([xmin+.5, xmax+.5])
    .range([0.5, width+.5]);
​
var y = d3.scaleLinear()
    .domain([ymin+.5, ymax+.5])
    .range([height+.5, 0.5]);
​
var xAxis = d3.axisBottom()
    .scale(x)
    .tickSize(-height);
​
var yAxis = d3.axisLeft()
    .scale(y)
    .ticks(5)
    .tickSize(-width); // tickLine == gridline
​
var refresh = function() {
  var reset_s = 0;
  //var zt = d3.event.transform;
  
  //console.log(zt);
​
  if ((x.domain()[1] - x.domain()[0]) >= (xmax - xmin)) {
    //zoom.x(x.domain([xmin, xmax]));
    
    reset_s = 1;
  }
  
  if ((y.domain()[1] - y.domain()[0]) >= (ymax - ymin)) {
    //zoom.y(y.domain([ymin, ymax]));
    reset_s += 1;
  }
  
  if (reset_s == 2) { // Both axes are full resolution. Reset.
    zoom.transform(d3.select("#main"), d3.zoomIdentity);
  }
  else {
    if (x.domain()[0] < xmin) {
      x.domain([xmin, x.domain()[1] - x.domain()[0] + xmin]);
    }
    if (x.domain()[1] > xmax) {
      var xdom0 = x.domain()[0] - x.domain()[1] + xmax;
      x.domain([xdom0, xmax]);
    }
    if (y.domain()[0] < ymin) {
      y.domain([ymin, y.domain()[1] - y.domain()[0] + ymin]);
    }
    if (y.domain()[1] > ymax) {
      var ydom0 = y.domain()[0] - y.domain()[1] + ymax;
      y.domain([ydom0, ymax]);
    }
  }
  svg.select(".x.axis").call(xAxis);
  svg.select(".y.axis").call(yAxis);
}
​
var zoom = d3.zoom()
        .scaleExtent([.001, Infinity]).on("zoom", refresh);
​
var zoomRect = false;
​
d3.select("#zoom-rect").on("change", function() {
      zoomRect = this.checked;
    });
​
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
        .attr("id", "main")
    .attr("transform", "translate(" + margin.left + "," + margin.top + ")")
    .call(zoom)
  .append("g")
    .on("mousedown", function() {
      if (!zoomRect) return;
      var e = this,
          origin = d3.mouse(e),
          rect = svg.append("rect").attr("class", "zoom");
      d3.select("body").classed("noselect", true);
      origin[0] = Math.max(0, Math.min(width, origin[0]));
      origin[1] = Math.max(0, Math.min(height, origin[1]));
      d3.select(window)
          .on("mousemove.zoomRect", function() {
            var m = d3.mouse(e);
            m[0] = Math.max(0, Math.min(width, m[0]));
            m[1] = Math.max(0, Math.min(height, m[1]));
            rect.attr("x", Math.min(origin[0], m[0]))
                .attr("y", Math.min(origin[1], m[1]))
                .attr("width", Math.abs(m[0] - origin[0]))
                .attr("height", Math.abs(m[1] - origin[1]));
          })
          .on("mouseup.zoomRect", function() {
            d3.select(window).on("mousemove.zoomRect", null).on("mouseup.zoomRect", null);
            d3.select("body").classed("noselect", false);
            var m = d3.mouse(e);
            m[0] = Math.max(0, Math.min(width, m[0]));
            m[1] = Math.max(0, Math.min(height, m[1]));
            if (m[0] !== origin[0] && m[1] !== origin[1]) {
              //zoom.x(x.domain([origin[0], m[0]].map(x.invert).sort(function(a,b) { return a - b;})))
                  //.y(y.domain([origin[1], m[1]].map(y.invert).sort(function(a,b) { return a - b;})));
              
                            x.domain([origin[0], m[0]].map(x.invert, x));
                    y.domain([origin[1], m[1]].map(y.invert, y));
​
              
                            //var dx = m[0] - origin[0];
                    //var dy = m[1] - origin[1];
                    //var x = (origin[0] + m[0]) / 2;
                    //var y = (origin[1] + m[1]) / 2;
              
              //var scale = Math.max(width / dx, height / dy);
                    //var translate = [width / 2 - scale * x, height / 2 - scale * y];
              
              //var zt = d3.zoomIdentity
                //      .scale(scale)
                //      .translate(-origin[0], translate[1]);
              
              //zoom.transform(d3.select("#main"), zt)
              
            }
            rect.remove();
            refresh();
          }, true);
      d3.event.stopPropagation();
    });
​
svg.append("rect")
    .attr("width", width)
    .attr("height", height);
​
svg.append("g")
    .attr("class", "x axis")
    .attr("transform", "translate(0," + height + ")")
    .call(xAxis);
​
svg.append("g")
    .attr("class", "y axis")
    .call(yAxis);
</script>
    