replay;

// Declare the chart dimensions and margins.

const width = 3000;

const height = 600;

const marginTop = 20;

const marginRight = 30;

const marginBottom = 30;

const marginLeft = 40;

// Declare the positional encodings.

const x = d3.scaleLinear()

.domain([7900,90000]).nice()

.range([marginLeft, width - marginRight]);

const y = d3.scaleLinear()

.domain([0,250]).nice()

.range([height - marginBottom, marginTop]);

const line = d3.line()

.curve(d3.curveCatmullRom)

.x(d => x(d.miles))

.y(d => y(d.gas));

const svg = d3.create("svg")

.attr("width", width)

.attr("height", height)

.attr("viewBox", [0, 0, width, height])

.attr("style", "max-width: 100%; height: auto;");

const l = length(line(driving));

// 画x轴的，用.call(d3.axisBottom(x))设定自己需要的坐标

svg.append("g")

.attr("transform", `translate(0,${height - marginBottom})`)

.call(d3.axisBottom(x)

.tickValues([7927.39079512154, 17452.6259671028, 28949.9240890961, 31372.4674383127, 58193.0031719582, 62412.7297059271, 78066.1020967475, 84942.2615386223]).tickFormat((d, i) => ['Jomsom', 'Kāgbeni', 'Chhusang', 'Chele', 'Ghami', 'Dhakmar', 'Lo Manthang', 'Chhoser'][i]))

//.call(g => g.select(".domain").remove())// 移除x轴的轴线

.call(g => g.selectAll(".tick line").clone()

.attr("y2", -height)

.attr("stroke-opacity", 0.1))

.call(g => g.append("text")

.attr("x", width - 4)

.attr("y", -4)

.attr("font-weight", "bold")

.attr("text-anchor", "end")

.attr("fill", "currentColor")

.text("Jomsom to LoManthang"));

// 画y轴的

svg.append("g")

.attr("transform", `translate(${marginLeft},0)`)

.call(d3.axisLeft(y).ticks(3).tickValues([80, 179, 236]))

//.call(g => g.select(".domain").remove()) // 移除y轴的轴线

.call(g => g.selectAll(".tick line").clone()

.attr("x2", width)

.attr("stroke-opacity", 0.1))

.call(g => g.select(".tick:last-of-type text").clone()

.attr("x", 4)

.attr("text-anchor", "start")

.attr("font-weight", "bold")

.text());

svg.append("path")

.datum(driving)

.attr("fill", "none")

.attr("stroke", "black")

.attr("stroke-width", 2.5)

.attr("stroke-linejoin", "round")

.attr("stroke-linecap", "round")

.attr("stroke-dasharray", `0,${l}`)

.attr("d", line)

.transition()

.duration(5000)

.ease(d3.easeLinear)

.attr("stroke-dasharray", `${l},${l}`);

svg.append("g")

.attr("fill", "black")

//.attr("stroke", "black")设置圆是黑色描边

//.attr("stroke-width", 2)

.selectAll("circle")

.data(driving)

.join("circle")

.attr("cx", d => x(d.miles))

.attr("cy", d => y(d.gas))

.attr("r", 3);　//圆圈半径设置三像素

// 设置点标签的

/* // 开始注释

const label = svg.append("g")

.attr("font-family", "sans-serif")

.attr("font-size", 10)

.selectAll()

.data(driving)

.join("text")

.attr("transform", d => `translate(${x(d.miles)},${y(d.gas)})`)

.attr("fill-opacity", 0)

.text(d => d.year)

.attr("stroke", "white")

.attr("paint-order", "stroke")

.attr("fill", "currentColor")

.each(function(d) {

const t = d3.select(this);

switch (d.side) {

case "top": t.attr("text-anchor", "middle").attr("dy", "-0.7em"); break;

case "right": t.attr("dx", "0.5em").attr("dy", "0.32em").attr("text-anchor", "start"); break;

case "bottom": t.attr("text-anchor", "middle").attr("dy", "1.4em"); break;

case "left": t.attr("dx", "-0.5em").attr("dy", "0.32em").attr("text-anchor", "end"); break;

}

});

label.transition()

.delay((d, i) => length(line(driving.slice(0, i + 1))) / l * (5000 - 125))

.attr("fill-opacity", 1);

*/ // 结束注释

return svg.node();

}