Chart.js - 添加渐变而不是纯色 - 实现解决方案

2022-01-22 00:00:00 javascript chart.js

我正在使用 Chart.js，一切正常，但我想用渐变替换当前颜色背景 (fillColor : "rgba(250,174,50,0.5)").我有替换渐变的解决方案，但是用我糟糕的 JS 知识来实现​​它对我来说太难了.我想对于懂 JS 的人来说很容易.

I am using Chart.js and everything is ok, but I want to replace current color background (fillColor : "rgba(250,174,50,0.5)") with a gradient. I have solution for replacing gradient but it's too dificult for me to implement this with my poor JS knowledge. I guess pretty easy for someone who know JS.

所以我的 Chart.js 代码:

        <script>

        var data = {
            labels : ["02:00","04:00","06:00","08:00","10:00","12:00","14:00","16:00","18:00","20:00","22:00","00:00"],
            datasets: [
                {
                    fillColor : "rgba(250,174,50,0.5)",
                    strokeColor : "#ff6c23",
                    pointColor : "#fff",
                    pointStrokeColor : "#ff6c23",
                    pointHighlightFill: "#fff",
                    pointHighlightStroke: "#ff6c23",
                    data : [25.0,32.4,22.2,39.4,34.2,22.0,23.2,24.1,20.0,18.4,19.1,17.4]
                }
            ]
        };

        var options = {
            responsive: true,
            datasetStrokeWidth : 3,
            pointDotStrokeWidth : 4,
            tooltipFillColor: "rgba(0,0,0,0.8)",
            tooltipFontStyle: "bold",
            tooltipTemplate: "<%if (label){%><%=label + ' hod' %>: <%}%><%= value + '°C' %>",
            scaleLabel : "<%= Number(value).toFixed(0).replace('.', ',') + '°C'%>"
        };

        var ctx = document.getElementById("temp-chart").getContext("2d");
        var myLineChart = new Chart(ctx).Line(data, options);

    </script>

还有这里是渐变解决方案. 有人可以尝试实现这个渐变背景而不是我当前的纯色背景吗?感谢您的帮助.

And here is solution with gradient. Can someone try implement this gradient background instead of my current solid background? Thanks for help.

我尝试实现它，但其他功能不起作用(如 scaleLabels 等).

I tryed implement it, but then other functions don't work (like scaleLabels etc.).

推荐答案

您提供的链接非常清楚，您必须在数据集中的字段 fillColor 中放入一个线性渐变对象而不是纯色.你可以做复杂的渐变，但这里是一个简单的代码(改变同一个橙色的不透明度):

The link you provided was pretty clear, you have to put in the field fillColor in datasets a linearGradient object instead of a plain color. You can do complex gradients, but here is the code of a simple one (changing the opacity of the same orange) : 

var gradient = ctx.createLinearGradient(0, 0, 0, 400);
gradient.addColorStop(0, 'rgba(250,174,50,1)');   
gradient.addColorStop(1, 'rgba(250,174,50,0)');

还有你的完整数据集:

datasets: [
            {
                fillColor : gradient, // Put the gradient here as a fill color
                strokeColor : "#ff6c23",
                pointColor : "#fff",
                pointStrokeColor : "#ff6c23",
                pointHighlightFill: "#fff",
                pointHighlightStroke: "#ff6c23",
                data : [25.0,32.4,22.2,39.4,34.2,22.0,23.2,24.1,20.0,18.4,19.1,17.4]
            }
        ]

在这个 JSFiddle 中查看它的实际应用

See it in action in this JSFiddle

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