Chart.js

สารบัญ

Chart.js เป็นไลบรารี JavaScript ฟรีสำหรับการสร้างแผนภูมิแบบ HTML มันเป็นหนึ่งในไลบรารีการแสดงภาพที่ง่ายที่สุดสำหรับ JavaScript และ มาพร้อมกับประเภทแผนภูมิในตัวมากมาย:

พล็อตกระจาย
แผนภูมิเส้น
แผนภูมิแท่ง
แผนภูมิวงกลม
แผนภูมิโดนัท
แผนภูมิฟอง
แผนภูมิพื้นที่
แผนภูมิเรดาร์
แผนภูมิผสม

วิธีใช้ Chart.js

1. เพิ่มลิงก์ไปยัง CDN ที่ให้บริการ (เครือข่ายการจัดส่งเนื้อหา):

<script
src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js">
</script>

2. เพิ่ม <canvas> ไปยังตำแหน่งใน HTML ที่คุณต้องการวาดแผนภูมิ:

<canvas id="myChart" style="width:100%;max-width:700px"></canvas>

องค์ประกอบ canvas ต้องมีรหัสเฉพาะ

ไวยากรณ์แผนภูมิแท่งทั่วไป:

const myChart = new Chart("myChart", {
  type: "bar",
  data: {},
  options: {}
});

ไวยากรณ์แผนภูมิเส้นทั่วไป:

const myChart = new Chart("myChart", {
  type: "line",
  data: {},
  options: {}
});

แผนภูมิแท่ง

รหัสแหล่งที่มา

const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = ["red", "green","blue","orange","brown"];

new Chart("myChart", {
  type: "bar",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {...}
});

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = ["red", "green","blue","orange","brown"];

new Chart("myChart", {
  type: "bar",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    legend: {display: false},
    title: {
      display: true,
      text: "World Wine Production 2018"
    }
  }
});
</script>

</body>
</html>

สีเพียงแถบเดียว:

const barColors = ["blue"];

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = ["blue"];

new Chart("myChart", {
  type: "bar",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    legend: {display: false},
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true
        }
      }],
    }
  }
});
</script>

</body>
</html>

สีเดียวกันทุกแท่ง:

const barColors ="red";

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
let barColors = "red";

new Chart("myChart", {
  type: "bar",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    xlegend: {display: false},
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true
        }
      }],
    }
  }
});
</script>

</body>
</html>

เฉดสี:

const barColors = [
  "rgba(0,0,255,1.0)",
  "rgba(0,0,255,0.8)",
  "rgba(0,0,255,0.6)",
  "rgba(0,0,255,0.4)",
  "rgba(0,0,255,0.2)",
];

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = [
  "rgba(255,0,0,1.0)",
  "rgba(255,0,0,0.8)",
  "rgba(255,0,0,0.6)",
  "rgba(255,0,0,0.4)",
  "rgba(255,0,0,0.2)"
];

new Chart("myChart", {
  type: "bar",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    legend: {display: false},
    scales: {
      yAxes: [{
        ticks: {
          beginAtZero: true
        }
      }],
    }
  }
});
</script>

</body>
</html>

แถบแนวนอน

เพียงเปลี่ยนประเภทจาก "bar" เป็น "horizontalBar":

type: "horizontalBar",

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
var xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
var yValues = [55, 49, 44, 24, 15];
var barColors = ["red", "green","blue","orange","brown"];

new Chart("myChart", {
  type: "horizontalBar",
  data: {
  labels: xValues,
  datasets: [{
    backgroundColor: barColors,
    data: yValues
  }]
},
  options: {
    legend: {display: false},
    title: {
      display: true,
      text: "World Wine Production 2018"
    },
    scales: {
      xAxes: [{ticks: {min: 10, max:60}}]
    }
  }
});
</script>

</body>
</html>

แผนภูมิวงกลม

ตัวอย่าง

new Chart("myChart", {
  type: "pie",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    title: {
      display: true,
      text: "World Wide Wine Production"
    }
  }
});

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = [
  "#b91d47",
  "#00aba9",
  "#2b5797",
  "#e8c3b9",
  "#1e7145"
];

new Chart("myChart", {
  type: "pie",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    title: {
      display: true,
      text: "World Wide Wine Production 2018"
    }
  }
});
</script>

</body>
</html>

แผนภูมิโดนัท

เพียงเปลี่ยนประเภทจาก "พาย" เป็น "โดนัท":

type: "doughnut";

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = ["Italy", "France", "Spain", "USA", "Argentina"];
const yValues = [55, 49, 44, 24, 15];
const barColors = [
  "#b91d47",
  "#00aba9",
  "#2b5797",
  "#e8c3b9",
  "#1e7145"
];

new Chart("myChart", {
  type: "doughnut",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor: barColors,
      data: yValues
    }]
  },
  options: {
    title: {
      display: true,
      text: "World Wide Wine Production 2018"
    }
  }
});
</script>

</body>
</html>

แปลงกระจาย

ราคาบ้านเทียบกับขนาด

รหัสแหล่งที่มา

const xyValues = [
  {x:50, y:7},
  {x:60, y:8},
  {x:70, y:8},
  {x:80, y:9},
  {x:90, y:9},
  {x:100, y:9},
  {x:110, y:10},
  {x:120, y:11},
  {x:130, y:14},
  {x:140, y:14},
  {x:150, y:15}
];

new Chart("myChart", {
  type: "scatter",
  data: {
    datasets: [{
      pointRadius: 4,
      pointBackgroundColor: "rgba(0,0,255,1)",
      data: xyValues
    }]
  },
  options:{...}
});

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>
<canvas id="myChart" style="width:100%;max-width:700px"></canvas>

<script>
const xyValues = [
  {x:50, y:7},
  {x:60, y:8},
  {x:70, y:8},
  {x:80, y:9},
  {x:90, y:9},
  {x:100, y:9},
  {x:110, y:10},
  {x:120, y:11},
  {x:130, y:14},
  {x:140, y:14},
  {x:150, y:15}
];

new Chart("myChart", {
  type: "scatter",
  data: {
    datasets: [{
      pointRadius: 4,
      pointBackgroundColor: "rgb(0,0,255)",
      data: xyValues
    }]
  },
  options: {
    legend: {display: false},
    scales: {
      xAxes: [{ticks: {min: 40, max:160}}],
      yAxes: [{ticks: {min: 6, max:16}}],
    }
  }
});
</script>

</body>
</html>

กราฟเส้น

ราคาบ้านเทียบกับขนาด

รหัสแหล่งที่มา

const xValues = [50,60,70,80,90,100,110,120,130,140,150];
const yValues = [7,8,8,9,9,9,10,11,14,14,15];

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      backgroundColor:"rgba(0,0,255,1.0)",
      borderColor: "rgba(0,0,255,0.1)",
      data: yValues
    }]
  },
  options:{...}
});

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>
<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = [50,60,70,80,90,100,110,120,130,140,150];
const yValues = [7,8,8,9,9,9,10,11,14,14,15];

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      fill: false,
      lineTension: 0,
      backgroundColor: "rgba(0,0,255,1.0)",
      borderColor: "rgba(0,0,255,0.1)",
      data: yValues
    }]
  },
  options: {
    legend: {display: false},
    scales: {
      yAxes: [{ticks: {min: 6, max:16}}],
    }
  }
});
</script>

</body>
</html>

หากคุณตั้งค่า borderColor เป็นศูนย์ คุณสามารถ กระจายจุด กราฟเส้นได้:

borderColor: "rgba(0,0,0,0)",

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>
<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = [50,60,70,80,90,100,110,120,130,140,150];
const yValues = [7,8,8,9,9,9,10,11,14,14,15];

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      fill: false,
      lineTension: 0,
      backgroundColor: "rgba(0,0,255,1)",
      borderColor: "rgba(0,0,0,0)",
      data: yValues
    }]
  },
  options: {
    legend: {display: false},
    scales: {
      yAxes: [{ticks: {min: 6, max:16}}],
    }
  }
});
</script>

</body>
</html>

หลายบรรทัด

รหัสแหล่งที่มา

const xValues = [100,200,300,400,500,600,700,800,900,1000];

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      data: [860,1140,1060,1060,1070,1110,1330,2210,7830,2478],
      borderColor: "red",
      fill: false
    },{
      data: [1600,1700,1700,1900,2000,2700,4000,5000,6000,7000],
      borderColor: "green",
      fill: false
    },{
      data: [300,700,2000,5000,6000,4000,2000,1000,200,100],
      borderColor: "blue",
      fill: false
    }]
  },
  options: {
    legend: {display: false}
  }
});

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>
<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = [100,200,300,400,500,600,700,800,900,1000];

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{ 
      data: [860,1140,1060,1060,1070,1110,1330,2210,7830,2478],
      borderColor: "red",
      fill: false
    }, { 
      data: [1600,1700,1700,1900,2000,2700,4000,5000,6000,7000],
      borderColor: "green",
      fill: false
    }, { 
      data: [300,700,2000,5000,6000,4000,2000,1000,200,100],
      borderColor: "blue",
      fill: false
    }]
  },
  options: {
    legend: {display: false}
  }
});
</script>

กราฟเชิงเส้น

รหัสแหล่งที่มา

const xValues = [];
const yValues = [];
generateData("x * 2 + 7", 0, 10, 0.5);

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      fill: false,
      pointRadius: 1,
      borderColor: "rgba(255,0,0,0.5)",
      data: yValues
    }]
  },
  options: {...}
});

function generateData(value, i1, i2, step = 1) {
  for (let x = i1; x <= i2; x += step) {
    yValues.push(eval(value));
    xValues.push(x);
  }
}

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = [];
const yValues = [];
generateData("x * 2 + 7", 0, 10, 0.5);

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      fill: false,
      pointRadius: 1,
      borderColor: "rgba(255,0,0,0.5)",
      data: yValues
    }]
  },    
  options: {
    legend: {display: false},
    title: {
      display: true,
      text: "y = x * 2 + 7",
      fontSize: 16
    }
  }
});
function generateData(value, i1, i2, step = 1) {
  for (let x = i1; x <= i2; x += step) {
    xValues.push(x);
    yValues.push(eval(value));
  }
}
</script>

</body>
</html>

กราฟฟังก์ชัน

เช่นเดียวกับกราฟเชิงเส้น เพียงเปลี่ยนพารามิเตอร์ GenerateData:

generateData("Math.sin(x)", 0, 10, 0.5);

ลองด้วยตัวคุณเอง →

<!DOCTYPE html>
<html>
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.js"></script>
<body>

<canvas id="myChart" style="width:100%;max-width:600px"></canvas>

<script>
const xValues = [];
const yValues = [];
generateData("Math.sin(x)", 0, 10, 0.5);

new Chart("myChart", {
  type: "line",
  data: {
    labels: xValues,
    datasets: [{
      fill: false,
      pointRadius: 2,
      borderColor: "rgba(0,0,255,0.5)",
      data: yValues
    }]
  },    
  options: {
    legend: {display: false},
    title: {
      display: true,
      text: "y = sin(x)",
      fontSize: 16
    }
  }
});
function generateData(value, i1, i2, step = 1) {
  for (let x = i1; x <= i2; x += step) {
    yValues.push(eval(value));
    xValues.push(x);
  }
}
</script>

</body>
</html>