| license: gpl-3.0 |
This example demonstrates how to compute a suitable translate and scale to zoom to the bounding box of a particular feature. Click on any state to zoom in; click on the focused state or the background to zoom out.
This variant uses transform transitions to change the viewport. A slightly better approach, and one that can also allow free panning and zooming with the mouse if desired, is to use zoom transitions.
forked from mbostock's block: Zoom to Bounding Box
| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .background { | |
| fill: none; | |
| pointer-events: all; | |
| } | |
| .feature { | |
| fill: #ccc; | |
| cursor: pointer; | |
| } | |
| .feature.active { | |
| fill: orange; | |
| } | |
| .mesh { | |
| fill: none; | |
| stroke: #fff; | |
| stroke-linecap: round; | |
| stroke-linejoin: round; | |
| } | |
| </style> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="//d3js.org/topojson.v1.min.js"></script> | |
| <script> | |
| var width = 960, | |
| height = 500, | |
| active = d3.select(null); | |
| var projection = d3.geo.albersUsa() | |
| .scale(1000) | |
| .translate([width / 2, height / 2]); | |
| var path = d3.geo.path() | |
| .projection(projection); | |
| var svg = d3.select("body").append("svg") | |
| .attr("width", width) | |
| .attr("height", height); | |
| svg.append("rect") | |
| .attr("class", "background") | |
| .attr("width", width) | |
| .attr("height", height) | |
| .on("click", reset); | |
| var g = svg.append("g") | |
| .style("stroke-width", "1.5px"); | |
| d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/us.json", function(error, us) { | |
| if (error) throw error; | |
| .on("click", clicked); | |
| g.append("path") | |
| .datum(topojson.mesh(us, us.objects.states, function(a, b) { return a !== b; })) | |
| .attr("class", "mesh") | |
| .attr("d", path) | |
| .on("click", clicked); | |
| }); | |
| function clicked(d) { | |
| if (active.node() === this) return reset(); | |
| active.classed("active", false); | |
| active = d3.select(this).classed("active", true); | |
| var bounds = path.bounds(d), | |
| dx = bounds[1][0] - bounds[0][0], | |
| dy = bounds[1][1] - bounds[0][1], | |
| x = (bounds[0][0] + bounds[1][0]) / 2, | |
| y = (bounds[0][1] + bounds[1][1]) / 2, | |
| scale = .9 / Math.max(dx / width, dy / height), | |
| translate = [width / 2 - scale * x, height / 2 - scale * y]; | |
| g.transition() | |
| .duration(750) | |
| .style("stroke-width", 1.5 / scale + "px") | |
| .attr("transform", "translate(" + translate + ")scale(" + scale + ")"); | |
| } | |
| function reset() { | |
| active.classed("active", false); | |
| active = d3.select(null); | |
| g.transition() | |
| .duration(750) | |
| .style("stroke-width", "1.5px") | |
| .attr("transform", ""); | |
| } | |
| </script> |