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我是使用D3和JavaScript的新手，所以希望這是一個簡單的點，有人可以爲我清理。使用數組和數組對數組的拖拽時的不同行爲
我正在製作一個可拖動點的散點圖，使用與this堆棧溢出問題非常相似的代碼。當我將數據集作爲[x, y]對的數組並將它們稱爲d[0]和d[1]時，代碼將按預期工作。然而，當我就與屬性x和y對象的數組，提到他們作爲d.x和d.y，劇情出現過，但工作 - 被點擊的點擊落低於x軸拖動行爲不 。
所以此代碼的工作：
<!DOCTYPE html>
<svg width="500" height="350"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
let 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;
//Make the fake data as an array of [x, y] pairs
let m=3.0, c=15.0;
let points = d3.range(1, 10).map(function(i) {
let x=i * width/10;
let noise=Math.random()*500;
let y=m*x+c + noise;
return [x, y];
});
let x = d3.scaleLinear()
.rangeRound([0, width]);
let y = d3.scaleLinear()
.rangeRound([height, 0]);
let xAxis = d3.axisBottom(x),
yAxis = d3.axisLeft(y);
let 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 + ')')
let 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>但拖動點時，該代碼給出了怪異的行爲：
<!DOCTYPE html>
<svg width="500" height="350"></svg>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
let 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;
//Make the fake data as an array of objects, with attributes x and y
let m=3.0, c=15.0;
let points = d3.range(1, 10).map(function(i) {
let x_val=i * width/10;
let noise=Math.random()*500;
let y_val=m*x_val+c + noise;
return {
x:x_val,
y:y_val
};
});
let x = d3.scaleLinear()
.rangeRound([0, width]);
let y = d3.scaleLinear()
.rangeRound([height, 0]);
let xAxis = d3.axisBottom(x),
yAxis = d3.axisLeft(y);
let line = d3.line()
.x(function(d) { return x(d.x); })
.y(function(d) { return y(d.y); });
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 + ')');
let focus = svg.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
x.domain(d3.extent(points, function(d) { return d.x; }));
y.domain(d3.extent(points, function(d) { return d.y; }));
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.x); })
.attr('cy', function(d) { return y(d.y); })
.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.x = x.invert(d3.event.x);
d.y = y.invert(d3.event.y);
d3.select(this)
.attr('cx', x(d.x))
.attr('cy', y(d.y));
focus.select('path').attr('d', line);
}
function dragended(d) {
d3.select(this).classed('active', false);
}
</script>任何人都可以解釋爲什麼他們給不同結果，當我改變了所有結構數據的重新？謝謝！