@alicloud/cloud-charts/es/common/ellipsisLabel.js


/**
 * 计算省略后的文本
 * @param text 原文本
 * @param maxWidth 最大宽度
 * @param font 字体样式
 * @param ellipsisText 省略文本
 * @param ellipsisType 省略方式，头/中间/尾
 */
export default function ellipsisLabel(text, maxWidth, font, ellipsisText, ellipsisType) {
  if (ellipsisText === void 0) {
    ellipsisText = '...';
  }

  if (ellipsisType === void 0) {
    ellipsisType = 'tail';
  }

  var str = typeof text !== 'string' ? text.toString() : text;
  var PLACEHOLDER_WIDTH = calcTextWidth(ellipsisText, font);

  if (PLACEHOLDER_WIDTH >= maxWidth) {
    return ellipsisText;
  }

  if (calcTextWidth(str, font) <= maxWidth) {
    return text;
  }

  var leftWidth = maxWidth - PLACEHOLDER_WIDTH;
  var length = str.length;

  if (ellipsisType === 'tail') {
    var leftStr = '';

    for (var index = 1; index <= length; index++) {
      var currentStr = str.slice(0, index);

      if (calcTextWidth(currentStr, font) >= leftWidth) {
        break;
      }

      leftStr = currentStr;
    }

    return "" + leftStr + ellipsisText;
  } else if (ellipsisType === 'head') {
    var _leftStr = '';

    for (var _index = length - 1; _index >= 0; _index--) {
      var _currentStr = str.slice(_index, length);

      if (calcTextWidth(_currentStr, font) >= leftWidth) {
        break;
      }

      _leftStr = _currentStr;
    }

    return "" + ellipsisText + _leftStr;
  } else {
    var left = '';
    var right = '';

    for (var _index2 = 1; _index2 < Math.floor(length / 2); _index2++) {
      var currentLeft = str.slice(0, _index2);
      var currentRight = str.slice(length - _index2, length);

      if (calcTextWidth("" + currentLeft + currentRight, font) >= leftWidth) {
        break;
      }

      left = currentLeft;
      right = currentRight;
    }

    return "" + left + ellipsisText + right;
  }
}
var ctx = null;
export function calcTextWidth(text, font) {
  var fontSize = font.fontSize,
      fontFamily = font.fontFamily,
      fontWeight = font.fontWeight,
      fontStyle = font.fontStyle,
      fontVariant = font.fontVariant;

  if (!ctx) {
    ctx = document.createElement('canvas').getContext('2d');
  }

  ctx.font = [fontStyle, fontVariant, fontWeight, fontSize + "px", fontFamily].join(' ');
  return ctx.measureText(text).width;
}