本文介紹了d3 v4 帶 x 和 y 軸的拖動折線圖的處理方法，對大家解決問題具有一定的參考價值，需要的朋友們下面隨著小編來一起學習吧！
問題描述
限時送ChatGPT賬號..
我是 d3.js 的新手.我想用它的點來拖動一個折線圖.沒有 x 和 y 軸它工作正常.我已將此示例用作參考:https://bl.ocks.org/mbostock/4342190
I'm new to d3.js. I wanted to drag a line chart using its points. It is working fine without the x and y axes. I have used this example as reference: https://bl.ocks.org/mbostock/4342190
對于折線圖的軸，該線未正確繪制.請查看下面的代碼段.
With the axes to the line chart the line is not plotting correcly. Please have a look into the snippet below.
提前致謝.
<!DOCTYPE html>
<svg width="500" height="350"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var svg = d3.select("svg"),
margin = {top: 20, right: 20, bottom: 30, left: 50},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom;
let points = d3.range(1, 10).map(function(i) {
return [i * width / 10, 50 + Math.random() * (height - 100)];
});
var x = d3.scaleLinear()
.rangeRound([0, width]);
var y = d3.scaleLinear()
.rangeRound([height, 0]);
var xAxis = d3.axisBottom(x),
yAxis = d3.axisLeft(y);
var line = d3.line()
.x(function(d) { return x(d[0]); })
.y(function(d) { return y(d[1]); });
let drag = d3.drag()
.on('start', dragstarted)
.on('drag', dragged)
.on('end', dragended);
svg.append('rect')
.attr('class', 'zoom')
.attr('cursor', 'move')
.attr('fill', 'none')
.attr('pointer-events', 'all')
.attr('width', width)
.attr('height', height)
.attr('transform', 'translate(' + margin.left + ',' + margin.top + ')')
var focus = svg.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
x.domain(d3.extent(points, function(d) { return d[0]; }));
y.domain(d3.extent(points, function(d) { return d[1]; }));
focus.append("path")
.datum(points)
.attr("fill", "none")
.attr("stroke", "steelblue")
.attr("stroke-linejoin", "round")
.attr("stroke-linecap", "round")
.attr("stroke-width", 1.5)
.attr("d", line);
focus.selectAll('circle')
.data(points)
.enter()
.append('circle')
.attr('r', 5.0)
.attr('cx', function(d) { return x(d[0]); })
.attr('cy', function(d) { return y(d[1]); })
.style('cursor', 'pointer')
.style('fill', 'steelblue');
focus.selectAll('circle')
.call(drag);
focus.append('g')
.attr('class', 'axis axis--x')
.attr('transform', 'translate(0,' + height + ')')
.call(xAxis);
focus.append('g')
.attr('class', 'axis axis--y')
.call(yAxis);
function dragstarted(d) {
d3.select(this).raise().classed('active', true);
}
function dragged(d) {
d3.select(this)
.attr('cx', d[0] = d3.event.x)
.attr('cy', d[1] = d3.event.y)
focus.select('path').attr('d', line);
}
function dragended(d) {
d3.select(this).classed('active', false);
}
</script>推薦答案
d3.event 保存像素位置，但您的繪圖是由用戶空間坐標驅動的.因此，您需要將這些像素位置轉換為用戶空間.您可以使用您的秤 invert 方法來做到這一點.
d3.event is holding pixel positions, but your plot is driven by user-space coordinates. So, you need to convert those pixel positions to user-space. You can use your scales invert method to do so.
function dragged(d) {
d[0] = x.invert(d3.event.x); // convert to user-space
d[1] = y.invert(d3.event.y);
d3.select(this)
.attr('cx', x(d[0])) // back to pixels
.attr('cy', y(d[1]))
focus.select('path').attr('d', line); //line does pixel conversion too
}
運行代碼:
<!DOCTYPE html>
<svg width="500" height="350"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
var svg = d3.select("svg"),
margin = {top: 20, right: 20, bottom: 30, left: 50},
width = +svg.attr("width") - margin.left - margin.right,
height = +svg.attr("height") - margin.top - margin.bottom;
let points = d3.range(1, 10).map(function(i) {
return [i * width / 10, 50 + Math.random() * (height - 100)];
});
var x = d3.scaleLinear()
.rangeRound([0, width]);
var y = d3.scaleLinear()
.rangeRound([height, 0]);
var xAxis = d3.axisBottom(x),
yAxis = d3.axisLeft(y);
var line = d3.line()
.x(function(d) { return x(d[0]); })
.y(function(d) { return y(d[1]); });
let drag = d3.drag()
.on('start', dragstarted)
.on('drag', dragged)
.on('end', dragended);
svg.append('rect')
.attr('class', 'zoom')
.attr('cursor', 'move')
.attr('fill', 'none')
.attr('pointer-events', 'all')
.attr('width', width)
.attr('height', height)
.attr('transform', 'translate(' + margin.left + ',' + margin.top + ')')
var focus = svg.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
x.domain(d3.extent(points, function(d) { return d[0]; }));
y.domain(d3.extent(points, function(d) { return d[1]; }));
focus.append("path")
.datum(points)
.attr("fill", "none")
.attr("stroke", "steelblue")
.attr("stroke-linejoin", "round")
.attr("stroke-linecap", "round")
.attr("stroke-width", 1.5)
.attr("d", line);
focus.selectAll('circle')
.data(points)
.enter()
.append('circle')
.attr('r', 5.0)
.attr('cx', function(d) { return x(d[0]); })
.attr('cy', function(d) { return y(d[1]); })
.style('cursor', 'pointer')
.style('fill', 'steelblue');
focus.selectAll('circle')
.call(drag);
focus.append('g')
.attr('class', 'axis axis--x')
.attr('transform', 'translate(0,' + height + ')')
.call(xAxis);
focus.append('g')
.attr('class', 'axis axis--y')
.call(yAxis);
function dragstarted(d) {
d3.select(this).raise().classed('active', true);
}
function dragged(d) {
d[0] = x.invert(d3.event.x);
d[1] = y.invert(d3.event.y);
d3.select(this)
.attr('cx', x(d[0]))
.attr('cy', y(d[1]))
focus.select('path').attr('d', line);
}
function dragended(d) {
d3.select(this).classed('active', false);
}
</script>這篇關于d3 v4 帶 x 和 y 軸的拖動折線圖的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！
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