Question

是否有一种方法可以强制工具提示停留在画布中？

现在，如果窗口太小，则弹出窗口不可见。

那么，有没有办法迫使工具提示停留在画布中？

Answer 1

好吧，如果您使用的是自定义工具提示（例如this one），则可以创建一个偏移量，以便工具提示远离边框：

var offset = tooltip.caretX + 20;
if (offset < tooltip.width)
    offset = tooltip.width;
else if (tooltip.caretX > this._chart.width - tooltip.width)
    offset = this._chart.width - tooltip.width;

// Hidden Code
tooltipEl.style.left = positionX + offset + 'px';

一个有效的示例，此代码是从我在此post的另一个答案中复制来的：

var customTooltips = function(tooltip) {
  // Tooltip Element
  var tooltipEl = document.getElementById('tooltip');

  if (!tooltipEl) {
    tooltipEl = document.createElement('div');
    tooltipEl.id = 'tooltip';
    tooltipEl.innerHTML = '<table></table>';
    this._chart.canvas.parentNode.appendChild(tooltipEl);
  }

  // Hide if no tooltip
  if (tooltip.opacity === 0) {
    tooltipEl.style.opacity = 0;
    return;
  }

  // Set caret Position
  tooltipEl.classList.remove('above', 'below', 'no-transform');
  if (tooltip.yAlign) {
    tooltipEl.classList.add(tooltip.yAlign);
  } else {
    tooltipEl.classList.add('no-transform');
  }

  function getBody(bodyItem) {
    return bodyItem.lines;
  }

  // Set Text
  if (tooltip.body) {
    var titleLines = tooltip.title || [];
    var bodyLines = tooltip.body.map(getBody);

    var innerHtml = '<thead>';

    titleLines.forEach(function(title) {
      innerHtml += '<tr><th>' + title + '</th></tr>';
    });
    innerHtml += '</thead><tbody>';

    bodyLines.forEach(function(body, i) {
      var colors = tooltip.labelColors[i];
      var style = 'background:' + colors.backgroundColor;
      style += '; border-color:' + colors.borderColor;
      style += '; border-width: 2px';
      var span = '<span class="chartjs-tooltip-key" style="' + style + '"></span>';
      var innerContent = '<td>' + span + body + '</td>';
      // Every even/odd create a new tr
      if (i % 2 == 0)
        innerHtml += '<tr>' + innerContent;
      else
        innerHtml += innerContent + '</tr>';
    });
    // If is a odd number of itens close the last open tr
    if (bodyLines.count % 2 == 1)
      innerHtml += '</tr></tbody>';
    else
      innerHtml += '</tbody>';

    var tableRoot = tooltipEl.querySelector('table');
    tableRoot.innerHTML = innerHtml;
  }

  var positionY = this._chart.canvas.offsetTop;
  var positionX = this._chart.canvas.offsetLeft;
  
  var offset = tooltip.caretX + 20;
  if (offset < tooltip.width)
    offset = tooltip.width;
  else if (tooltip.caretX > this._chart.width - tooltip.width)
    offset = this._chart.width - tooltip.width;
  
  // Display, position, and set styles for font
  tooltipEl.style.opacity = 1;
  tooltipEl.style.left = positionX + offset + 'px';
  tooltipEl.style.top = positionY + tooltip.caretY + 'px';
  tooltipEl.style.fontFamily = tooltip._bodyFontFamily;
  tooltipEl.style.fontSize = tooltip.bodyFontSize + 'px';
  tooltipEl.style.fontStyle = tooltip._bodyFontStyle;
  tooltipEl.style.padding = tooltip.yPadding + 'px ' + tooltip.xPadding + 'px';
};

var myChart = new Chart($('#myChart'), {
  type: 'line',
  data: {
    labels: ['Day 1', 'Day 2', 'Day 3', 'Day 4'],
    datasets: [{
      label: 'Dats asd asda 1',
      data: [12, 19, 3, 5],
      pointRadius: 5,
      pointHoverRadius: 5,
      backgroundColor: 'rgba(255, 0, 0, 0.2)'
    }, {
      label: 'D 2',
      data: [13, 17, 4, 6],
      pointRadius: 5,
      pointHoverRadius: 5,
      backgroundColor: 'rgba(255, 255, 0, 0.2)'
    }, {
      label: 'D 3',
      data: [14, 19, 3, 9],
      pointRadius: 5,
      pointHoverRadius: 5,
      backgroundColor: 'rgba(0, 255, 0, 0.2)'
    }, {
      label: 'Data 4',
      data: [15, 20, 2, 8],
      pointRadius: 5,
      pointHoverRadius: 5,
      backgroundColor: 'rgba(0, 0, 255, 0.2)'
    }]
  },
  options: {
    responsive: false,
    scales: {
      yAxes: [{
        display: true,
        ticks: {
          suggestedMax: 50,
        }
      }]
    },
    tooltips: {
      enabled: false,
      mode: 'index',
      intersect: false,
      custom: customTooltips
    }
  }
});

#tooltip {
  opacity: 1;
  position: absolute;
  background: rgba(0, 0, 0, .7);
  color: white;
  border-radius: 3px;
  -webkit-transition: all .1s ease;
  transition: all .1s ease;
  pointer-events: none;
  -webkit-transform: translate(-50%, 0);
  transform: translate(-50%, 0);
  padding: 4px;
}

#tooltip td {
  text-align: left;
}

.chartjs-tooltip-key {
  display: inline-block;
  width: 10px;
  height: 10px;
  margin-right: 10px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.css" integrity="sha256-aa0xaJgmK/X74WM224KMQeNQC2xYKwlAt08oZqjeF0E=" crossorigin="anonymous" />
<script src="https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.8.0/Chart.min.js" integrity="sha256-Uv9BNBucvCPipKQ2NS9wYpJmi8DTOEfTA/nH2aoJALw=" crossorigin="anonymous"></script>

<canvas id="myChart" width="400" height="200"></canvas>

Answer 2

看看这个：https://stackoverflow.com/a/64887282/8411093

演示：https://codepen.io/themustafaomar/pen/wvWZrod

function customTooltips(tooltipModel) {
  // Tooltip Element
  var tooltipEl = document.getElementById("chartjs-tooltip");

  const yAlign = tooltipModel.yAlign;
  const xAlign = tooltipModel.xAlign;

  // Create element on first render
  if (!tooltipEl) {
    tooltipEl = document.createElement("div");
    tooltipEl.id = "chartjs-tooltip";
    tooltipEl.innerHTML = "<table></table>";
    document.body.appendChild(tooltipEl);
  }

  // Hide if no tooltip
  if (tooltipModel.opacity === 0) {
    tooltipEl.style.opacity = 0;
    return;
  }

  // Set caret Position
  tooltipEl.classList.remove("top", "bottom", "center", "left", "right");
  if (tooltipModel.yAlign || tooltipModel.xAlign) {
    tooltipEl.classList.add(tooltipModel.yAlign);
    tooltipEl.classList.add(tooltipModel.xAlign);
  }

  // Set Text
  if (tooltipModel.body) {
    var titleLines = tooltipModel.title || [];
    var bodyLines = tooltipModel.body.map((bodyItem) => {
      return bodyItem.lines;
    });

    var innerHtml = "<thead>";

    titleLines.forEach(function (title) {
      innerHtml += '<tr><th><div class="mb-1">' + title + "</div></th></tr>";
    });
    innerHtml += "</thead><tbody>";

    bodyLines.forEach((body, i) => {
      var colors = tooltipModel.labelColors[i];
      // var style = 'background-color:' + colors.borderColor
      var style =
        "background-color:" + this._chart.data.datasets[i].borderColor;
      var value = tooltipModel.dataPoints[i].value;
      var label = this._chart.data.datasets[i].label;

      style += "; border-color:" + colors.borderColor;
      style += "; border-color:" + this._chart.data.datasets[i].borderColor;
      style += "; border-width: 2px";

      var span =
        '<span class="chartjs-tooltip-key" style="' + style + '"></span>';

      innerHtml += `<tr><td> ${span} $${value}K </td></tr>`;
    });
    innerHtml += "</tbody>";

    var tableRoot = tooltipEl.querySelector("table");
    tableRoot.innerHTML = innerHtml;
  }

  // Tooltip height and width
  const { height, width } = tooltipEl.getBoundingClientRect();

  // Chart canvas positions
  const positionY = this._chart.canvas.offsetTop;
  const positionX = this._chart.canvas.offsetLeft;

  // Carets
  const caretY = tooltipModel.caretY;
  const caretX = tooltipModel.caretX;

  // Final coordinates
  let top = positionY + caretY - height;
  let left = positionX + caretX - width / 2;
  let space = 8; // This for making space between the caret and the element.

  // yAlign could be: `top`, `bottom`, `center`
  if (yAlign === "top") {
    top += height + space;
  } else if (yAlign === "center") {
    top += height / 2;
  } else if (yAlign === "bottom") {
    top -= space;
  }
  // xAlign could be: `left`, `center`, `right`
  if (xAlign === "left") {
    left = left + width / 2 - tooltipModel.xPadding - space / 2;
    if (yAlign === "center") {
      left = left + space * 2;
    }
  } else if (xAlign === "right") {
    left -= width / 2;
    if (yAlign === "center") {
      left = left - space;
    } else {
      left += space;
    }
  }

  // Display, position, and set styles for font
  tooltipEl.style.opacity = 1;

  // Left and right
  tooltipEl.style.top = `${top}px`;
  tooltipEl.style.left = `${left}px`;

  // Font
  tooltipEl.style.fontFamily = tooltipModel._bodyFontFamily;
  tooltipEl.style.fontSize = tooltipModel.bodyFontSize + "px";
  tooltipEl.style.fontStyle = tooltipModel._bodyFontStyle;

  // Paddings
  tooltipEl.style.padding =
    tooltipModel.yPadding + "px " + tooltipModel.xPadding + "px";
}

Chart.js工具提示页面外

2 个答案: