我在 Angular 2 中使用来自 ng2-charts ( http://valor-software.com/ng2-charts/ ) 的圆环图。 我一直在寻找将文本放在中间但没有成功的选项。 我已经在 chart.js(依赖项)中搜索了 ng-chart 选项。 你知道在 Angular 2 typescript 中实现这一目标的另一种方法吗?还是我缺少什么?
最佳答案
您可以将 LABEL 及其值都放在 Doughnut 的中心。
当您悬停它时,悬停值将在图表中心更新。
import { Component, OnInit } from '@angular/core';
import { ChartType } from 'chart.js';
import { SingleDataSet, Label, PluginServiceGlobalRegistrationAndOptions } from 'ng2-charts';
@Component({
selector: 'my-app',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
// Doughnut
public doughnutChartLabels = ['Download Sales', 'In-Store Sales'];
public doughnutChartData: SingleDataSet = [
[350, 450]
];
public doughnutChartType: ChartType = 'doughnut';
public doughnutChartPlugins: PluginServiceGlobalRegistrationAndOptions[] = [{
afterDraw(chart) {
const ctx = chart.ctx;
var txt1 = '';
var txt2 = '';
try{
var check = chart.active ? chart.tooltip._active[0]._datasetIndex : "None";
if(check !== "None"){
txt1 = chart.tooltip._data.labels[chart.tooltip._active[0]._index];
txt2 = chart.tooltip._data.datasets[0].data[chart.tooltip._active[0]._index];
}else{
txt1 = chart.tooltip._data.labels[0];
txt2 = chart.tooltip._data.datasets[0].data[0];
}
}
catch(err){
txt1 = chart.tooltip._data.labels[0]
txt2 = chart.tooltip._data.datasets[0].data[0];
}
//Get options from the center object in options
const sidePadding = 60;
const sidePaddingCalculated = (sidePadding / 100) * (chart.innerRadius * 2)
ctx.textAlign = 'center';
ctx.textBaseline = 'middle';
const centerX = ((chart.chartArea.left + chart.chartArea.right) / 2);
const centerY = ((chart.chartArea.top + chart.chartArea.bottom) / 2);
//Get the width of the string and also the width of the element minus 10 to give it 5px side padding
const stringWidth = ctx.measureText(txt1).width;
const elementWidth = (chart.innerRadius * 2) - sidePaddingCalculated;
// Find out how much the font can grow in width.
const widthRatio = elementWidth / stringWidth;
const newFontSize = Math.floor(30 * widthRatio);
const elementHeight = (chart.innerRadius * 2);
// Pick a new font size so it will not be larger than the height of label.
const fontSizeToUse = 30;
ctx.font = fontSizeToUse + 'px Arial';
ctx.fillStyle = 'black';
// Draw text in center
ctx.fillText(txt2, centerX, centerY - 10);
var fontSizeToUse1 = 15;
ctx.font = fontSizeToUse1 + 'px Arial';
ctx.fillText(txt1, centerX, centerY + 10);
}
}];
constructor() { }
ngOnInit() {
}
// events
public chartClicked({ event, active }: { event: MouseEvent, active: {}[] }): void {
//console.log(event, active);
}
public chartHovered({ event, active }: { event: MouseEvent, active: {}[] }): void {
//console.log(event, active);
}
}
HTML
<div>
<div>
<div style="display: block">
<canvas baseChart [data]="doughnutChartData" [labels]="doughnutChartLabels" [chartType]="doughnutChartType"
[plugins]="doughnutChartPlugins" (chartHover)="chartHovered($event)"
(chartClick)="chartClicked($event)"></canvas>
</div>
</div>
</div>
快乐编码:)
关于Angular 2 ng2-charts donut 文字在中间?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42662539/