Example of how to use zoom.extent and zoom.translateExtent to limit panning/zooming in d3 v4. The initial state of the visualisation are centered on coordinates [500, 1500] using zoom.transform. The limits for panning/zooming are set to [0, 5000].
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December 5, 2023 13:48
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Limit panning/zooming in d3 v4
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| <!DOCTYPE html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <script src="https://d3js.org/d3.v4.js"></script> | |
| <style> | |
| svg text { | |
| font-family: sans-serif; | |
| font-size: 13px; | |
| } | |
| circle { | |
| fill: transparent; | |
| stroke: black; | |
| stroke-width: 1px; | |
| pointer-events:none; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <div id="block"></div> | |
| <script> | |
| // dimensions | |
| var dims = { | |
| width: 800, | |
| height: 300, | |
| svg_dx: 100, | |
| svg_dy: 100 | |
| }; | |
| // Data | |
| var dataPoints = [1, 1010, 1020, 5000]; | |
| // Zoom | |
| var zoom = d3.zoom() | |
| .extent([[dims.svg_dx, dims.svg_dy], [dims.width-(dims.svg_dx*2), dims.height-dims.svg_dy]]) | |
| .scaleExtent([1, 10]) | |
| .translateExtent([[dims.svg_dx, dims.svg_dy], [dims.width-(dims.svg_dx*2), dims.height-dims.svg_dy]]) | |
| .on('zoom', zoomed); | |
| // Scale | |
| var xScale = d3.scaleLinear() | |
| .domain([0, 5000]) | |
| .range([dims.svg_dx, dims.width-(dims.svg_dx*2)]); | |
| // Axis | |
| var xAxis = d3.axisTop(xScale) | |
| // Main svg | |
| var gMain = d3.select('#block') | |
| .append("svg") | |
| .attr("width", dims.width) | |
| .attr("height", dims.height) | |
| .append("g") | |
| .attr("transform", "translate(100, 100)"); | |
| var rect = gMain | |
| .append("rect") | |
| .attr("x", 0) | |
| .attr("y", -25) | |
| .attr("width", dims.width) | |
| .attr("height", 50) | |
| .style("fill", "transparent") | |
| .call(zoom); | |
| // circles | |
| var circles = gMain.selectAll('circle') | |
| .data(dataPoints) | |
| .enter() | |
| .append('circle') | |
| .attr('r', 7) | |
| .attr('cx', function (d) { | |
| return xScale(d); | |
| }); | |
| // axis | |
| var axis = gMain.append("g") | |
| // Jump to position (500, 1500) at start | |
| startTransition(); | |
| function zoomed() { | |
| var transform = d3.event.transform; | |
| // Zoom the circles | |
| var xNewScale = transform.rescaleX(xScale); | |
| circles | |
| .attr("cx", function (d) { | |
| return xNewScale(d); | |
| }); | |
| // Zoom the axis | |
| xAxis.scale(xNewScale); | |
| axis.call(xAxis); | |
| } | |
| function startTransition() { | |
| // Position to (500, 1500) at start | |
| // to jump to [500,1500] we need to calculate a new scale factor (k)... | |
| var k = (xScale(5000) - xScale(0)) / (xScale(1500) - xScale(500)); | |
| // ...and then a translate to [500, 0] | |
| var tx = dims.svg_dx - (k * xScale(500)); | |
| var t = d3.zoomIdentity.translate(tx, 0).scale(k); | |
| // Rescale the axis | |
| xAxis.scale(t.rescaleX(xScale)); | |
| axis | |
| .attr("transform", "translate(0,-20)") | |
| .call(xAxis); | |
| // Rescale the circles | |
| rect.call(zoom.transform, t); | |
| } | |
| </script> | |
| </body> |
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