chart.js之 - 绘制水平线
我想绘制一条水平线使用Chart.js图表英寸但我无法做到。chart.js之 - 绘制水平线
我读过这个问题 - Chart.js — drawing an arbitrary vertical line - 但我不能变换代码绘制水平线不垂直。
我希望你能帮助我(尤其是potatopeelings :))。
这里是jquery的代码来绘制水平线。
var data = {
labels: ["JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"],
datasets: [{
data: [12, 3, 2, 1, 8, 8, 2, 2, 3, 5, 7, 1]
}]
};
var ctx = document.getElementById("LineWithLine").getContext("2d");
Chart.types.Line.extend({
name: "LineWithLine",
initialize: function() {
Chart.types.Line.prototype.initialize.apply(this, arguments);
},
draw: function() {
Chart.types.Line.prototype.draw.apply(this, arguments);
var point = this.datasets[0].points[this.options.lineAtIndex]
var scale = this.scale
console.log(this);
// draw line
this.chart.ctx.beginPath();
this.chart.ctx.moveTo(scale.startPoint+12, point.y);
this.chart.ctx.strokeStyle = '#ff0000';
this.chart.ctx.lineTo(this.chart.width, point.y);
this.chart.ctx.stroke();
// write TODAY
this.chart.ctx.textAlign = 'center';
this.chart.ctx.fillText("TODAY", scale.startPoint + 35, point.y+10);
}
});
new Chart(ctx).LineWithLine(data, {
datasetFill : false,
lineAtIndex: 2
});
http://jsfiddle.net/7a4hhzge/455/
这是基于关闭的the code used to draw an arbitrary vertical line,它可能不是完美的,但你应该能够对其进行调整,以满足您的需求。
如果你需要多行有一定的Y值,试试这个代码
var data = {
labels: ["JAN", "FEB", "MAR", "APR", "MAY", "JUN", "JUL", "AUG", "SEP", "OCT", "NOV", "DEC"],
datasets: [{
data: [12, 3, 2, 1, 8, 8, 2, 2, 3, 5, 7, 1]
}]
};
var ctx = document.getElementById("LineWithLine").getContext("2d");
Chart.types.Line.extend({
name: "LineWithLine",
draw: function() {
Chart.types.Line.prototype.draw.apply(this, arguments);
var lines = this.options.limitLines;
for (var i = lines.length; --i >= 0;) {
var xStart = Math.round(this.scale.xScalePaddingLeft);
var linePositionY = this.scale.calculateY(lines[i].value);
this.chart.ctx.fillStyle = lines[i].color ? lines[i].color : this.scale.textColor;
this.chart.ctx.font = this.scale.font;
this.chart.ctx.textAlign = "left";
this.chart.ctx.textBaseline = "top";
if (this.scale.showLabels && lines[i].label) {
this.chart.ctx.fillText(lines[i].label, xStart + 5, linePositionY);
}
this.chart.ctx.lineWidth = this.scale.gridLineWidth;
this.chart.ctx.strokeStyle = lines[i].color ? lines[i].color : this.scale.gridLineColor;
if (this.scale.showHorizontalLines) {
this.chart.ctx.beginPath();
this.chart.ctx.moveTo(xStart, linePositionY);
this.chart.ctx.lineTo(this.scale.width, linePositionY);
this.chart.ctx.stroke();
this.chart.ctx.closePath();
}
this.chart.ctx.lineWidth = this.lineWidth;
this.chart.ctx.strokeStyle = this.lineColor;
this.chart.ctx.beginPath();
this.chart.ctx.moveTo(xStart - 5, linePositionY);
this.chart.ctx.lineTo(xStart, linePositionY);
this.chart.ctx.stroke();
this.chart.ctx.closePath();
}
}
});
new Chart(ctx).LineWithLine(data, {
datasetFill : false,
limitLines: [
{
label: 'max',
value: 17,
color: 'rgba(255, 0, 0, .8)'
},
{
label: 'min',
value: 1
},
{
value: 7,
color: 'rgba(0, 255, 255, .8)'
}
],
});
无需任何额外的代码,我设法通过添加新条目与这些数据集画一条线选项:
只需用数据集的大小代替,并与该行代表的价值。
{
data: Array.apply(null, new Array(<length>)).map(Number.prototype.valueOf, <value>),
fill: false,
radius: 0,
backgroundColor: "rgba(0,0,0,0.1)"
}
0的半径会以某种方式隐藏点和填充:false将使其显示为一条线。
当我使用你的'Array.Apply'方法 – Zapnologica
作品非常感谢你,我得到了一个'Uncaught TypeError:Object.defineProperty在非对象上调用'! – Manuel
基于dFelinger消息我作出绘制线图上的平均线新的字符类型。这里的代码,只需复制并调用一个新的图表称为'lineWithAverage'工程仅适用于CHARTJS 2
Chart.controllers.lineWithAverage = Chart.controllers.line.extend({
initialize: function() {
Chart.controllers.line.prototype.initialize.apply(this, arguments);
},
draw: function() {
Chart.controllers.line.prototype.draw.apply(this, arguments);
var scale = this.scale
var sum = 0;
this.getDataset().data.forEach(function(value) {
sum = sum + value;
});
var average = sum/this.getDataset().data.length;
var averageCoord = this.calculatePointY(average);
// draw line
this.chart.chart.canvas.ctx = this.chart.chart.canvas.getContext('2d');
this.chart.chart.canvas.ctx.beginPath();
this.chart.chart.canvas.ctx.moveTo(0, averageCoord);
this.chart.chart.canvas.ctx.strokeStyle = '#979797';
this.chart.chart.canvas.ctx.lineTo(this.chart.chart.width, averageCoord);
this.chart.chart.canvas.ctx.stroke();
}
});
谢谢!一切正常。但是你知道如何改变代码来设置值,在哪里显示行,而不仅仅是点? – KRiSTiN