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Chart.js show line with green above target and red below
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| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <title>Line Chart Example</title> | |
| <script src="https://cdn.jsdelivr.net/npm/chart.js"></script> | |
| </head> | |
| <body> | |
| <div style="width: 80%; margin: auto;"> | |
| <canvas id="myLineChart"></canvas> | |
| </div> | |
| <script> | |
| // Sample data for the line chart | |
| var data = { | |
| labels: ["January", "February", "March", "April", "May"], | |
| datasets: [ | |
| { | |
| "label": "Target", | |
| "data": [100, 100, 100, 100, 100], | |
| // no dots | |
| "pointRadius": 0, | |
| }, | |
| { | |
| label: "Our performance", | |
| data: [130, 75, 180, 80, 70], | |
| fill: false, | |
| pointBackgroundColor: function(context) { | |
| var value = context.parsed.y; | |
| return value >= 100 ? 'green' : 'red'; | |
| }, | |
| pointBorderColor: function(context) { | |
| var value = context.parsed.y; | |
| return value >= 100 ? 'green' : 'red'; | |
| }, | |
| borderColor: "green", // for legend | |
| segment: { | |
| borderColor: function(context) { | |
| const p0Value = context.p0.raw; | |
| const p1Value = context.p1.raw; | |
| var stopOffset = 0.5; | |
| if (p0Value > 100 && p1Value < 100) { | |
| // linearly interpolate the stop offset | |
| stopOffset = (100 - p0Value) / (p1Value - p0Value); | |
| } else if (p0Value < 100 && p1Value > 100) { | |
| stopOffset = 1 - (100 - p1Value) / (p0Value - p1Value); | |
| } | |
| var gradient = context.chart.ctx.createLinearGradient(context.p0.x, context.p0.y, context.p1.x, context.p1.y); | |
| gradient.addColorStop(stopOffset, p0Value >= 100 ? 'green' : 'red'); | |
| gradient.addColorStop(stopOffset, p1Value >= 100 ? 'green' : 'red'); | |
| return gradient; | |
| }, | |
| } | |
| }] | |
| }; | |
| // Chart configuration | |
| var options = { | |
| responsive: true, | |
| maintainAspectRatio: false, | |
| scales: { | |
| y: { | |
| beginAtZero: false, | |
| } | |
| } | |
| }; | |
| // Create the line chart | |
| var ctx = document.getElementById("myLineChart").getContext("2d"); | |
| var myLineChart = new Chart(ctx, { | |
| type: 'line', | |
| data: data, | |
| options: options | |
| }); | |
| </script> | |
| </body> | |
| </html> |
Author
fulldecent
commented
Aug 18, 2023
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