chartjs-plugin-annotation.cjs

/*!
* chartjs-plugin-annotation v3.1.0
* https://www.chartjs.org/chartjs-plugin-annotation/index
 * (c) 2024 chartjs-plugin-annotation Contributors
 * Released under the MIT License
 */
(function (global, factory) {
typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory(require('chart.js'), require('chart.js/helpers')) :
typeof define === 'function' && define.amd ? define(['chart.js', 'chart.js/helpers'], factory) :
(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global["chartjs-plugin-annotation"] = factory(global.Chart, global.Chart.helpers));
})(this, (function (chart_js, helpers) { 'use strict';

/**
 * @typedef { import("chart.js").ChartEvent } ChartEvent
 * @typedef { import('../../types/element').AnnotationElement } AnnotationElement
 */

const interaction = {
  modes: {
    /**
     * Point mode returns all elements that hit test based on the event position
     * @param {AnnotationElement[]} visibleElements - annotation elements which are visible
     * @param {ChartEvent} event - the event we are find things at
     * @return {AnnotationElement[]} - elements that are found
     */
    point(visibleElements, event) {
      return filterElements(visibleElements, event, {intersect: true});
    },

    /**
     * Nearest mode returns the element closest to the event position
     * @param {AnnotationElement[]} visibleElements - annotation elements which are visible
     * @param {ChartEvent} event - the event we are find things at
     * @param {Object} options - interaction options to use
     * @return {AnnotationElement[]} - elements that are found (only 1 element)
     */
    nearest(visibleElements, event, options) {
      return getNearestItem(visibleElements, event, options);
    },
    /**
     * x mode returns the elements that hit-test at the current x coordinate
     * @param {AnnotationElement[]} visibleElements - annotation elements which are visible
     * @param {ChartEvent} event - the event we are find things at
     * @param {Object} options - interaction options to use
     * @return {AnnotationElement[]} - elements that are found
     */
    x(visibleElements, event, options) {
      return filterElements(visibleElements, event, {intersect: options.intersect, axis: 'x'});
    },

    /**
     * y mode returns the elements that hit-test at the current y coordinate
     * @param {AnnotationElement[]} visibleElements - annotation elements which are visible
     * @param {ChartEvent} event - the event we are find things at
     * @param {Object} options - interaction options to use
     * @return {AnnotationElement[]} - elements that are found
     */
    y(visibleElements, event, options) {
      return filterElements(visibleElements, event, {intersect: options.intersect, axis: 'y'});
    }
  }
};

/**
 * Returns all elements that hit test based on the event position
 * @param {AnnotationElement[]} visibleElements - annotation elements which are visible
 * @param {ChartEvent} event - the event we are find things at
 * @param {Object} options - interaction options to use
 * @return {AnnotationElement[]} - elements that are found
 */
function getElements(visibleElements, event, options) {
  const mode = interaction.modes[options.mode] || interaction.modes.nearest;
  return mode(visibleElements, event, options);
}

function inRangeByAxis(element, event, axis) {
  if (axis !== 'x' && axis !== 'y') {
    return element.inRange(event.x, event.y, 'x', true) || element.inRange(event.x, event.y, 'y', true);
  }
  return element.inRange(event.x, event.y, axis, true);
}

function getPointByAxis(event, center, axis) {
  if (axis === 'x') {
    return {x: event.x, y: center.y};
  } else if (axis === 'y') {
    return {x: center.x, y: event.y};
  }
  return center;
}

function filterElements(visibleElements, event, options) {
  return visibleElements.filter((element) => options.intersect ? element.inRange(event.x, event.y) : inRangeByAxis(element, event, options.axis));
}

function getNearestItem(visibleElements, event, options) {
  let minDistance = Number.POSITIVE_INFINITY;

  return filterElements(visibleElements, event, options)
    .reduce((nearestItems, element) => {
      const center = element.getCenterPoint();
      const evenPoint = getPointByAxis(event, center, options.axis);
      const distance = helpers.distanceBetweenPoints(event, evenPoint);
      if (distance < minDistance) {
        nearestItems = [element];
        minDistance = distance;
      } else if (distance === minDistance) {
        // Can have multiple items at the same distance in which case we sort by size
        nearestItems.push(element);
      }

      return nearestItems;
    }, [])
    .sort((a, b) => a._index - b._index)
    .slice(0, 1); // return only the top item;
}

/**
 * @typedef {import('chart.js').Point} Point
 */

/**
 * Rotate a `point` relative to `center` point by `angle`
 * @param {Point} point - the point to rotate
 * @param {Point} center - center point for rotation
 * @param {number} angle - angle for rotation, in radians
 * @returns {Point} rotated point
 */
function rotated(point, center, angle) {
  const cos = Math.cos(angle);
  const sin = Math.sin(angle);
  const cx = center.x;
  const cy = center.y;

  return {
    x: cx + cos * (point.x - cx) - sin * (point.y - cy),
    y: cy + sin * (point.x - cx) + cos * (point.y - cy)
  };
}

const isOlderPart = (act, req) => req > act || (act.length > req.length && act.slice(0, req.length) === req);

/**
 * @typedef { import('chart.js').Point } Point
 * @typedef { import('chart.js').InteractionAxis } InteractionAxis
 * @typedef { import('../../types/element').AnnotationElement } AnnotationElement
 */

const EPSILON = 0.001;
const clamp = (x, from, to) => Math.min(to, Math.max(from, x));

/**
 * @param {{value: number, start: number, end: number}} limit
 * @param {number} hitSize
 * @returns {boolean}
 */
const inLimit = (limit, hitSize) => limit.value >= limit.start - hitSize && limit.value <= limit.end + hitSize;

/**
 * @param {Object} obj
 * @param {number} from
 * @param {number} to
 * @returns {Object}
 */
function clampAll(obj, from, to) {
  for (const key of Object.keys(obj)) {
    obj[key] = clamp(obj[key], from, to);
  }
  return obj;
}

/**
 * @param {Point} point
 * @param {Point} center
 * @param {number} radius
 * @param {number} hitSize
 * @returns {boolean}
 */
function inPointRange(point, center, radius, hitSize) {
  if (!point || !center || radius <= 0) {
    return false;
  }
  return (Math.pow(point.x - center.x, 2) + Math.pow(point.y - center.y, 2)) <= Math.pow(radius + hitSize, 2);
}

/**
 * @param {Point} point
 * @param {{x: number, y: number, x2: number, y2: number}} rect
 * @param {InteractionAxis} axis
 * @param {{borderWidth: number, hitTolerance: number}} hitsize
 * @returns {boolean}
 */
function inBoxRange(point, {x, y, x2, y2}, axis, {borderWidth, hitTolerance}) {
  const hitSize = (borderWidth + hitTolerance) / 2;
  const inRangeX = point.x >= x - hitSize - EPSILON && point.x <= x2 + hitSize + EPSILON;
  const inRangeY = point.y >= y - hitSize - EPSILON && point.y <= y2 + hitSize + EPSILON;
  if (axis === 'x') {
    return inRangeX;
  } else if (axis === 'y') {
    return inRangeY;
  }
  return inRangeX && inRangeY;
}

/**
 * @param {Point} point
 * @param {rect: {x: number, y: number, x2: number, y2: number}, center: {x: number, y: number}} element
 * @param {InteractionAxis} axis
 * @param {{rotation: number, borderWidth: number, hitTolerance: number}}
 * @returns {boolean}
 */
function inLabelRange(point, {rect, center}, axis, {rotation, borderWidth, hitTolerance}) {
  const rotPoint = rotated(point, center, helpers.toRadians(-rotation));
  return inBoxRange(rotPoint, rect, axis, {borderWidth, hitTolerance});
}

/**
 * @param {AnnotationElement} element
 * @param {boolean} useFinalPosition
 * @returns {Point}
 */
function getElementCenterPoint(element, useFinalPosition) {
  const {centerX, centerY} = element.getProps(['centerX', 'centerY'], useFinalPosition);
  return {x: centerX, y: centerY};
}

/**
 * @param {string} pkg
 * @param {string} min
 * @param {string} ver
 * @param {boolean} [strict=true]
 * @returns {boolean}
 */
function requireVersion(pkg, min, ver, strict = true) {
  const parts = ver.split('.');
  let i = 0;
  for (const req of min.split('.')) {
    const act = parts[i++];
    if (parseInt(req, 10) < parseInt(act, 10)) {
      break;
    }
    if (isOlderPart(act, req)) {
      if (strict) {
        throw new Error(`${pkg} v${ver} is not supported. v${min} or newer is required.`);
      } else {
        return false;
      }
    }
  }
  return true;
}

const isPercentString = (s) => typeof s === 'string' && s.endsWith('%');
const toPercent = (s) => parseFloat(s) / 100;
const toPositivePercent = (s) => clamp(toPercent(s), 0, 1);

const boxAppering = (x, y) => ({x, y, x2: x, y2: y, width: 0, height: 0});
const defaultInitAnimation = {
  box: (properties) => boxAppering(properties.centerX, properties.centerY),
  doughnutLabel: (properties) => boxAppering(properties.centerX, properties.centerY),
  ellipse: (properties) => ({centerX: properties.centerX, centerY: properties.centerX, radius: 0, width: 0, height: 0}),
  label: (properties) => boxAppering(properties.centerX, properties.centerY),
  line: (properties) => boxAppering(properties.x, properties.y),
  point: (properties) => ({centerX: properties.centerX, centerY: properties.centerY, radius: 0, width: 0, height: 0}),
  polygon: (properties) => boxAppering(properties.centerX, properties.centerY)
};

/**
 * @typedef { import('chart.js').FontSpec } FontSpec
 * @typedef { import('chart.js').Point } Point
 * @typedef { import('chart.js').Padding } Padding
 * @typedef { import('../../types/element').AnnotationBoxModel } AnnotationBoxModel
 * @typedef { import('../../types/element').AnnotationElement } AnnotationElement
 * @typedef { import('../../types/options').AnnotationPointCoordinates } AnnotationPointCoordinates
 * @typedef { import('../../types/label').CoreLabelOptions } CoreLabelOptions
 * @typedef { import('../../types/label').LabelPositionObject } LabelPositionObject
 */

/**
 * @param {number} size
 * @param {number|string} position
 * @returns {number}
 */
function getRelativePosition(size, position) {
  if (position === 'start') {
    return 0;
  }
  if (position === 'end') {
    return size;
  }
  if (isPercentString(position)) {
    return toPositivePercent(position) * size;
  }
  return size / 2;
}

/**
 * @param {number} size
 * @param {number|string} value
 * @param {boolean} [positivePercent=true]
 * @returns {number}
 */
function getSize(size, value, positivePercent = true) {
  if (typeof value === 'number') {
    return value;
  } else if (isPercentString(value)) {
    return (positivePercent ? toPositivePercent(value) : toPercent(value)) * size;
  }
  return size;
}

/**
 * @param {{x: number, width: number}} size
 * @param {CoreLabelOptions} options
 * @returns {number}
 */
function calculateTextAlignment(size, options) {
  const {x, width} = size;
  const textAlign = options.textAlign;
  if (textAlign === 'center') {
    return x + width / 2;
  } else if (textAlign === 'end' || textAlign === 'right') {
    return x + width;
  }
  return x;
}

/**
 * @param {Point} point
 * @param {{height: number, width: number}} labelSize
 * @param {{borderWidth: number, position: {LabelPositionObject|string}, xAdjust: number, yAdjust: number}} options
 * @param {Padding|undefined} padding
 * @returns {{x: number, y: number, x2: number, y2: number, height: number, width: number, centerX: number, centerY: number}}
 */
function measureLabelRectangle(point, labelSize, {borderWidth, position, xAdjust, yAdjust}, padding) {
  const hasPadding = helpers.isObject(padding);
  const width = labelSize.width + (hasPadding ? padding.width : 0) + borderWidth;
  const height = labelSize.height + (hasPadding ? padding.height : 0) + borderWidth;
  const positionObj = toPosition(position);
  const x = calculateLabelPosition$1(point.x, width, xAdjust, positionObj.x);
  const y = calculateLabelPosition$1(point.y, height, yAdjust, positionObj.y);

  return {
    x,
    y,
    x2: x + width,
    y2: y + height,
    width,
    height,
    centerX: x + width / 2,
    centerY: y + height / 2
  };
}

/**
 * @param {LabelPositionObject|string} value
 * @param {string|number} defaultValue
 * @returns {LabelPositionObject}
 */
function toPosition(value, defaultValue = 'center') {
  if (helpers.isObject(value)) {
    return {
      x: helpers.valueOrDefault(value.x, defaultValue),
      y: helpers.valueOrDefault(value.y, defaultValue),
    };
  }
  value = helpers.valueOrDefault(value, defaultValue);
  return {
    x: value,
    y: value
  };
}

/**
 * @param {CoreLabelOptions} options
 * @param {number} fitRatio
 * @returns {boolean}
 */
const shouldFit = (options, fitRatio) => options && options.autoFit && fitRatio < 1;

/**
 * @param {CoreLabelOptions} options
 * @param {number} fitRatio
 * @returns {FontSpec[]}
 */
function toFonts(options, fitRatio) {
  const optFont = options.font;
  const fonts = helpers.isArray(optFont) ? optFont : [optFont];
  if (shouldFit(options, fitRatio)) {
    return fonts.map(function(f) {
      const font = helpers.toFont(f);
      font.size = Math.floor(f.size * fitRatio);
      font.lineHeight = f.lineHeight;
      return helpers.toFont(font);
    });
  }
  return fonts.map(f => helpers.toFont(f));
}

/**
 * @param {AnnotationPointCoordinates} options
 * @returns {boolean}
 */
function isBoundToPoint(options) {
  return options && (helpers.defined(options.xValue) || helpers.defined(options.yValue));
}

function calculateLabelPosition$1(start, size, adjust = 0, position) {
  return start - getRelativePosition(size, position) + adjust;
}

/**
 * @param {Chart} chart
 * @param {AnnotationBoxModel} properties
 * @param {CoreAnnotationOptions} options
 * @returns {AnnotationElement}
 */
function initAnimationProperties(chart, properties, options) {
  const initAnim = options.init;
  if (!initAnim) {
    return;
  } else if (initAnim === true) {
    return applyDefault(properties, options);
  }
  return execCallback(chart, properties, options);
}

/**
 * @param {Object} options
 * @param {Array} hooks
 * @param {Object} hooksContainer
 * @returns {boolean}
 */
function loadHooks(options, hooks, hooksContainer) {
  let activated = false;
  hooks.forEach(hook => {
    if (helpers.isFunction(options[hook])) {
      activated = true;
      hooksContainer[hook] = options[hook];
    } else if (helpers.defined(hooksContainer[hook])) {
      delete hooksContainer[hook];
    }
  });
  return activated;
}

function applyDefault(properties, options) {
  const type = options.type || 'line';
  return defaultInitAnimation[type](properties);
}

function execCallback(chart, properties, options) {
  const result = helpers.callback(options.init, [{chart, properties, options}]);
  if (result === true) {
    return applyDefault(properties, options);
  } else if (helpers.isObject(result)) {
    return result;
  }
}

const widthCache = new Map();
const notRadius = (radius) => isNaN(radius) || radius <= 0;
const fontsKey = (fonts) => fonts.reduce(function(prev, item) {
  prev += item.string;
  return prev;
}, '');

/**
 * @typedef { import('chart.js').Point } Point
 * @typedef { import('../../types/label').CoreLabelOptions } CoreLabelOptions
 * @typedef { import('../../types/options').PointAnnotationOptions } PointAnnotationOptions
 */

/**
 * Determine if content is an image or a canvas.
 * @param {*} content
 * @returns boolean|undefined
 * @todo move this function to chart.js helpers
 */
function isImageOrCanvas(content) {
  if (content && typeof content === 'object') {
    const type = content.toString();
    return (type === '[object HTMLImageElement]' || type === '[object HTMLCanvasElement]');
  }
}

/**
 * Set the translation on the canvas if the rotation must be applied.
 * @param {CanvasRenderingContext2D} ctx - chart canvas context
 * @param {Point} point - the point of translation
 * @param {number} rotation - rotation (in degrees) to apply
 */
function translate(ctx, {x, y}, rotation) {
  if (rotation) {
    ctx.translate(x, y);
    ctx.rotate(helpers.toRadians(rotation));
    ctx.translate(-x, -y);
  }
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {Object} options
 * @returns {boolean|undefined}
 */
function setBorderStyle(ctx, options) {
  if (options && options.borderWidth) {
    ctx.lineCap = options.borderCapStyle || 'butt';
    ctx.setLineDash(options.borderDash);
    ctx.lineDashOffset = options.borderDashOffset;
    ctx.lineJoin = options.borderJoinStyle || 'miter';
    ctx.lineWidth = options.borderWidth;
    ctx.strokeStyle = options.borderColor;
    return true;
  }
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {Object} options
 */
function setShadowStyle(ctx, options) {
  ctx.shadowColor = options.backgroundShadowColor;
  ctx.shadowBlur = options.shadowBlur;
  ctx.shadowOffsetX = options.shadowOffsetX;
  ctx.shadowOffsetY = options.shadowOffsetY;
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {CoreLabelOptions} options
 * @returns {{width: number, height: number}}
 */
function measureLabelSize(ctx, options) {
  const content = options.content;
  if (isImageOrCanvas(content)) {
    const size = {
      width: getSize(content.width, options.width),
      height: getSize(content.height, options.height)
    };
    return size;
  }
  const fonts = toFonts(options);
  const strokeWidth = options.textStrokeWidth;
  const lines = helpers.isArray(content) ? content : [content];
  const mapKey = lines.join() + fontsKey(fonts) + strokeWidth + (ctx._measureText ? '-spriting' : '');
  if (!widthCache.has(mapKey)) {
    widthCache.set(mapKey, calculateLabelSize(ctx, lines, fonts, strokeWidth));
  }
  return widthCache.get(mapKey);
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {{x: number, y: number, width: number, height: number}} rect
 * @param {Object} options
 */
function drawBox(ctx, rect, options) {
  const {x, y, width, height} = rect;
  ctx.save();
  setShadowStyle(ctx, options);
  const stroke = setBorderStyle(ctx, options);
  ctx.fillStyle = options.backgroundColor;
  ctx.beginPath();
  helpers.addRoundedRectPath(ctx, {
    x, y, w: width, h: height,
    radius: clampAll(helpers.toTRBLCorners(options.borderRadius), 0, Math.min(width, height) / 2)
  });
  ctx.closePath();
  ctx.fill();
  if (stroke) {
    ctx.shadowColor = options.borderShadowColor;
    ctx.stroke();
  }
  ctx.restore();
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {{x: number, y: number, width: number, height: number}} rect
 * @param {CoreLabelOptions} options
 * @param {number} fitRatio
 */
function drawLabel(ctx, rect, options, fitRatio) {
  const content = options.content;
  if (isImageOrCanvas(content)) {
    ctx.save();
    ctx.globalAlpha = getOpacity(options.opacity, content.style.opacity);
    ctx.drawImage(content, rect.x, rect.y, rect.width, rect.height);
    ctx.restore();
    return;
  }
  const labels = helpers.isArray(content) ? content : [content];
  const fonts = toFonts(options, fitRatio);
  const optColor = options.color;
  const colors = helpers.isArray(optColor) ? optColor : [optColor];
  const x = calculateTextAlignment(rect, options);
  const y = rect.y + options.textStrokeWidth / 2;
  ctx.save();
  ctx.textBaseline = 'middle';
  ctx.textAlign = options.textAlign;
  if (setTextStrokeStyle(ctx, options)) {
    applyLabelDecoration(ctx, {x, y}, labels, fonts);
  }
  applyLabelContent(ctx, {x, y}, labels, {fonts, colors});
  ctx.restore();
}

function setTextStrokeStyle(ctx, options) {
  if (options.textStrokeWidth > 0) {
    // https://stackoverflow.com/questions/13627111/drawing-text-with-an-outer-stroke-with-html5s-canvas
    ctx.lineJoin = 'round';
    ctx.miterLimit = 2;
    ctx.lineWidth = options.textStrokeWidth;
    ctx.strokeStyle = options.textStrokeColor;
    return true;
  }
}

/**
 * @param {CanvasRenderingContext2D} ctx
 * @param {{radius: number, options: PointAnnotationOptions}} element
 * @param {number} x
 * @param {number} y
 */
function drawPoint(ctx, element, x, y) {
  const {radius, options} = element;
  const style = options.pointStyle;
  const rotation = options.rotation;
  let rad = (rotation || 0) * helpers.RAD_PER_DEG;

  if (isImageOrCanvas(style)) {
    ctx.save();
    ctx.translate(x, y);
    ctx.rotate(rad);
    ctx.drawImage(style, -style.width / 2, -style.height / 2, style.width, style.height);
    ctx.restore();
    return;
  }
  if (notRadius(radius)) {
    return;
  }
  drawPointStyle(ctx, {x, y, radius, rotation, style, rad});
}

function drawPointStyle(ctx, {x, y, radius, rotation, style, rad}) {
  let xOffset, yOffset, size, cornerRadius;
  ctx.beginPath();

  switch (style) {
  // Default includes circle
  default:
    ctx.arc(x, y, radius, 0, helpers.TAU);
    ctx.closePath();
    break;
  case 'triangle':
    ctx.moveTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    rad += helpers.TWO_THIRDS_PI;
    ctx.lineTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    rad += helpers.TWO_THIRDS_PI;
    ctx.lineTo(x + Math.sin(rad) * radius, y - Math.cos(rad) * radius);
    ctx.closePath();
    break;
  case 'rectRounded':
    // NOTE: the rounded rect implementation changed to use `arc` instead of
    // `quadraticCurveTo` since it generates better results when rect is
    // almost a circle. 0.516 (instead of 0.5) produces results with visually
    // closer proportion to the previous impl and it is inscribed in the
    // circle with `radius`. For more details, see the following PRs:
    // https://github.com/chartjs/Chart.js/issues/5597
    // https://github.com/chartjs/Chart.js/issues/5858
    cornerRadius = radius * 0.516;
    size = radius - cornerRadius;
    xOffset = Math.cos(rad + helpers.QUARTER_PI) * size;
    yOffset = Math.sin(rad + helpers.QUARTER_PI) * size;
    ctx.arc(x - xOffset, y - yOffset, cornerRadius, rad - helpers.PI, rad - helpers.HALF_PI);
    ctx.arc(x + yOffset, y - xOffset, cornerRadius, rad - helpers.HALF_PI, rad);
    ctx.arc(x + xOffset, y + yOffset, cornerRadius, rad, rad + helpers.HALF_PI);
    ctx.arc(x - yOffset, y + xOffset, cornerRadius, rad + helpers.HALF_PI, rad + helpers.PI);
    ctx.closePath();
    break;
  case 'rect':
    if (!rotation) {
      size = Math.SQRT1_2 * radius;
      ctx.rect(x - size, y - size, 2 * size, 2 * size);
      break;
    }
    rad += helpers.QUARTER_PI;
    /* falls through */
  case 'rectRot':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + yOffset, y - xOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    ctx.closePath();
    break;
  case 'crossRot':
    rad += helpers.QUARTER_PI;
    /* falls through */
  case 'cross':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    break;
  case 'star':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    rad += helpers.QUARTER_PI;
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    ctx.moveTo(x + yOffset, y - xOffset);
    ctx.lineTo(x - yOffset, y + xOffset);
    break;
  case 'line':
    xOffset = Math.cos(rad) * radius;
    yOffset = Math.sin(rad) * radius;
    ctx.moveTo(x - xOffset, y - yOffset);
    ctx.lineTo(x + xOffset, y + yOffset);
    break;
  case 'dash':
    ctx.moveTo(x, y);
    ctx.lineTo(x + Math.cos(rad) * radius, y + Math.sin(rad) * radius);
    break;
  }

  ctx.fill();
}

function calculateLabelSize(ctx, lines, fonts, strokeWidth) {
  ctx.save();
  const count = lines.length;
  let width = 0;
  let height = strokeWidth;
  for (let i = 0; i < count; i++) {
    const font = fonts[Math.min(i, fonts.length - 1)];
    ctx.font = font.string;
    const text = lines[i];
    width = Math.max(width, ctx.measureText(text).width + strokeWidth);
    height += font.lineHeight;
  }
  ctx.restore();
  return {width, height};
}

function applyLabelDecoration(ctx, {x, y}, labels, fonts) {
  ctx.beginPath();
  let lhs = 0;
  labels.forEach(function(l, i) {
    const f = fonts[Math.min(i, fonts.length - 1)];
    const lh = f.lineHeight;
    ctx.font = f.string;
    ctx.strokeText(l, x, y + lh / 2 + lhs);
    lhs += lh;
  });
  ctx.stroke();
}

function applyLabelContent(ctx, {x, y}, labels, {fonts, colors}) {
  let lhs = 0;
  labels.forEach(function(l, i) {
    const c = colors[Math.min(i, colors.length - 1)];
    const f = fonts[Math.min(i, fonts.length - 1)];
    const lh = f.lineHeight;
    ctx.beginPath();
    ctx.font = f.string;
    ctx.fillStyle = c;
    ctx.fillText(l, x, y + lh / 2 + lhs);
    lhs += lh;
    ctx.fill();
  });
}

function getOpacity(value, elementValue) {
  const opacity = helpers.isNumber(value) ? value : elementValue;
  return helpers.isNumber(opacity) ? clamp(opacity, 0, 1) : 1;
}

const positions = ['left', 'bottom', 'top', 'right'];

/**
 * @typedef { import('../../types/element').AnnotationElement } AnnotationElement
 */

/**
 * Drawa the callout component for labels.
 * @param {CanvasRenderingContext2D} ctx - chart canvas context
 * @param {AnnotationElement} element - the label element
 */
function drawCallout(ctx, element) {
  const {pointX, pointY, options} = element;
  const callout = options.callout;
  const calloutPosition = callout && callout.display && resolveCalloutPosition(element, callout);
  if (!calloutPosition || isPointInRange(element, callout, calloutPosition)) {
    return;
  }

  ctx.save();
  ctx.beginPath();
  const stroke = setBorderStyle(ctx, callout);
  if (!stroke) {
    return ctx.restore();
  }
  const {separatorStart, separatorEnd} = getCalloutSeparatorCoord(element, calloutPosition);
  const {sideStart, sideEnd} = getCalloutSideCoord(element, calloutPosition, separatorStart);
  if (callout.margin > 0 || options.borderWidth === 0) {
    ctx.moveTo(separatorStart.x, separatorStart.y);
    ctx.lineTo(separatorEnd.x, separatorEnd.y);
  }
  ctx.moveTo(sideStart.x, sideStart.y);
  ctx.lineTo(sideEnd.x, sideEnd.y);
  const rotatedPoint = rotated({x: pointX, y: pointY}, element.getCenterPoint(), helpers.toRadians(-element.rotation));
  ctx.lineTo(rotatedPoint.x, rotatedPoint.y);
  ctx.stroke();
  ctx.restore();
}

function getCalloutSeparatorCoord(element, position) {
  const {x, y, x2, y2} = element;
  const adjust = getCalloutSeparatorAdjust(element, position);
  let separatorStart, separatorEnd;
  if (position === 'left' || position === 'right') {
    separatorStart = {x: x + adjust, y};
    separatorEnd = {x: separatorStart.x, y: y2};
  } else {
    //  position 'top' or 'bottom'
    separatorStart = {x, y: y + adjust};
    separatorEnd = {x: x2, y: separatorStart.y};
  }
  return {separatorStart, separatorEnd};
}

function getCalloutSeparatorAdjust(element, position) {
  const {width, height, options} = element;
  const adjust = options.callout.margin + options.borderWidth / 2;
  if (position === 'right') {
    return width + adjust;
  } else if (position === 'bottom') {
    return height + adjust;
  }
  return -adjust;
}

function getCalloutSideCoord(element, position, separatorStart) {
  const {y, width, height, options} = element;
  const start = options.callout.start;
  const side = getCalloutSideAdjust(position, options.callout);
  let sideStart, sideEnd;
  if (position === 'left' || position === 'right') {
    sideStart = {x: separatorStart.x, y: y + getSize(height, start)};
    sideEnd = {x: sideStart.x + side, y: sideStart.y};
  } else {
    //  position 'top' or 'bottom'
    sideStart = {x: separatorStart.x + getSize(width, start), y: separatorStart.y};
    sideEnd = {x: sideStart.x, y: sideStart.y + side};
  }
  return {sideStart, sideEnd};
}

function getCalloutSideAdjust(position, options) {
  const side = options.side;
  if (position === 'left' || position === 'top') {
    return -side;
  }
  return side;
}

function resolveCalloutPosition(element, options) {
  const position = options.position;
  if (positions.includes(position)) {
    return position;
  }
  return resolveCalloutAutoPosition(element, options);
}

function resolveCalloutAutoPosition(element, options) {
  const {x, y, x2, y2, width, height, pointX, pointY, centerX, centerY, rotation} = element;
  const center = {x: centerX, y: centerY};
  const start = options.start;
  const xAdjust = getSize(width, start);
  const yAdjust = getSize(height, start);
  const xPoints = [x, x + xAdjust, x + xAdjust, x2];
  const yPoints = [y + yAdjust, y2, y, y2];
  const result = [];
  for (let index = 0; index < 4; index++) {
    const rotatedPoint = rotated({x: xPoints[index], y: yPoints[index]}, center, helpers.toRadians(rotation));
    result.push({
      position: positions[index],
      distance: helpers.distanceBetweenPoints(rotatedPoint, {x: pointX, y: pointY})
    });
  }
  return result.sort((a, b) => a.distance - b.distance)[0].position;
}

function isPointInRange(element, callout, position) {
  const {pointX, pointY} = element;
  const margin = callout.margin;
  let x = pointX;
  let y = pointY;
  if (position === 'left') {
    x += margin;
  } else if (position === 'right') {
    x -= margin;
  } else if (position === 'top') {
    y += margin;
  } else if (position === 'bottom') {
    y -= margin;
  }
  return element.inRange(x, y);
}

const limitedLineScale = {
  xScaleID: {min: 'xMin', max: 'xMax', start: 'left', end: 'right', startProp: 'x', endProp: 'x2'},
  yScaleID: {min: 'yMin', max: 'yMax', start: 'bottom', end: 'top', startProp: 'y', endProp: 'y2'}
};

/**
 * @typedef { import("chart.js").Chart } Chart
 * @typedef { import("chart.js").Scale } Scale
 * @typedef { import("chart.js").Point } Point
 * @typedef { import('../../types/element').AnnotationBoxModel } AnnotationBoxModel
 * @typedef { import('../../types/options').CoreAnnotationOptions } CoreAnnotationOptions
 * @typedef { import('../../types/options').LineAnnotationOptions } LineAnnotationOptions
 * @typedef { import('../../types/options').PointAnnotationOptions } PointAnnotationOptions
 * @typedef { import('../../types/options').PolygonAnnotationOptions } PolygonAnnotationOptions
 */

/**
 * @param {Scale} scale
 * @param {number|string} value
 * @param {number} fallback
 * @returns {number}
 */
function scaleValue(scale, value, fallback) {
  value = typeof value === 'number' ? value : scale.parse(value);
  return helpers.isFinite(value) ? scale.getPixelForValue(value) : fallback;
}

/**
 * Search the scale defined in chartjs by the axis related to the annotation options key.
 * @param {{ [key: string]: Scale }} scales
 * @param {CoreAnnotationOptions} options
 * @param {string} key
 * @returns {string}
 */
function retrieveScaleID(scales, options, key) {
  const scaleID = options[key];
  if (scaleID || key === 'scaleID') {
    return scaleID;
  }
  const axis = key.charAt(0);
  const axes = Object.values(scales).filter((scale) => scale.axis && scale.axis === axis);
  if (axes.length) {
    return axes[0].id;
  }
  return axis;
}

/**
 * @param {Scale} scale
 * @param {{min: number, max: number, start: number, end: number}} options
 * @returns {{start: number, end: number}|undefined}
 */
function getDimensionByScale(scale, options) {
  if (scale) {
    const reverse = scale.options.reverse;
    const start = scaleValue(scale, options.min, reverse ? options.end : options.start);
    const end = scaleValue(scale, options.max, reverse ? options.start : options.end);
    return {
      start,
      end
    };
  }
}

/**
 * @param {Chart} chart
 * @param {CoreAnnotationOptions} options
 * @returns {Point}
 */
function getChartPoint(chart, options) {
  const {chartArea, scales} = chart;
  const xScale = scales[retrieveScaleID(scales, options, 'xScaleID')];
  const yScale = scales[retrieveScaleID(scales, options, 'yScaleID')];
  let x = chartArea.width / 2;
  let y = chartArea.height / 2;

  if (xScale) {
    x = scaleValue(xScale, options.xValue, xScale.left + xScale.width / 2);
  }

  if (yScale) {
    y = scaleValue(yScale, options.yValue, yScale.top + yScale.height / 2);
  }
  return {x, y};
}

/**
 * @param {Chart} chart
 * @param {CoreAnnotationOptions} options
 * @returns {AnnotationBoxModel}
 */
function resolveBoxProperties(chart, options) {
  const scales = chart.scales;
  const xScale = scales[retrieveScaleID(scales, options, 'xScaleID')];
  const yScale = scales[retrieveScaleID(scales, options, 'yScaleID')];

  if (!xScale && !yScale) {
    return {};
  }

  let {left: x, right: x2} = xScale || chart.chartArea;
  let {top: y, bottom: y2} = yScale || chart.chartArea;
  const xDim = getChartDimensionByScale(xScale, {min: options.xMin, max: options.xMax, start: x, end: x2});
  x = xDim.start;
  x2 = xDim.end;
  const yDim = getChartDimensionByScale(yScale, {min: options.yMin, max: options.yMax, start: y2, end: y});
  y = yDim.start;
  y2 = yDim.end;

  return {
    x,
    y,
    x2,
    y2,
    width: x2 - x,
    height: y2 - y,
    centerX: x + (x2 - x) / 2,
    centerY: y + (y2 - y) / 2
  };
}

/**
 * @param {Chart} chart
 * @param {PointAnnotationOptions|PolygonAnnotationOptions} options
 * @returns {AnnotationBoxModel}
 */
function resolvePointProperties(chart, options) {
  if (!isBoundToPoint(options)) {
    const box = resolveBoxProperties(chart, options);
    let radius = options.radius;
    if (!radius || isNaN(radius)) {
      radius = Math.min(box.width, box.height) / 2;
      options.radius = radius;
    }
    const size = radius * 2;
    const adjustCenterX = box.centerX + options.xAdjust;
    const adjustCenterY = box.centerY + options.yAdjust;
    return {
      x: adjustCenterX - radius,
      y: adjustCenterY - radius,
      x2: adjustCenterX + radius,
      y2: adjustCenterY + radius,
      centerX: adjustCenterX,
      centerY: adjustCenterY,
      width: size,
      height: size,
      radius
    };
  }
  return getChartCircle(chart, options);
}
/**
 * @param {Chart} chart
 * @param {LineAnnotationOptions} options
 * @returns {AnnotationBoxModel}
 */
function resolveLineProperties(chart, options) {
  const {scales, chartArea} = chart;
  const scale = scales[options.scaleID];
  const area = {x: chartArea.left, y: chartArea.top, x2: chartArea.right, y2: chartArea.bottom};

  if (scale) {
    resolveFullLineProperties(scale, area, options);
  } else {
    resolveLimitedLineProperties(scales, area, options);
  }
  return area;
}

/**
 * @param {Chart} chart
 * @param {CoreAnnotationOptions} options
 * @param {boolean} [centerBased=false]
 * @returns {AnnotationBoxModel}
 */
function resolveBoxAndLabelProperties(chart, options) {
  const properties = resolveBoxProperties(chart, options);
  properties.initProperties = initAnimationProperties(chart, properties, options);
  properties.elements = [{
    type: 'label',
    optionScope: 'label',
    properties: resolveLabelElementProperties$1(chart, properties, options),
    initProperties: properties.initProperties
  }];
  return properties;
}

function getChartCircle(chart, options) {
  const point = getChartPoint(chart, options);
  const size = options.radius * 2;
  return {
    x: point.x - options.radius + options.xAdjust,
    y: point.y - options.radius + options.yAdjust,
    x2: point.x + options.radius + options.xAdjust,
    y2: point.y + options.radius + options.yAdjust,
    centerX: point.x + options.xAdjust,
    centerY: point.y + options.yAdjust,
    radius: options.radius,
    width: size,
    height: size
  };
}

function getChartDimensionByScale(scale, options) {
  const result = getDimensionByScale(scale, options) || options;
  return {
    start: Math.min(result.start, result.end),
    end: Math.max(result.start, result.end)
  };
}

function resolveFullLineProperties(scale, area, options) {
  const min = scaleValue(scale, options.value, NaN);
  const max = scaleValue(scale, options.endValue, min);
  if (scale.isHorizontal()) {
    area.x = min;
    area.x2 = max;
  } else {
    area.y = min;
    area.y2 = max;
  }
}

function resolveLimitedLineProperties(scales, area, options) {
  for (const scaleId of Object.keys(limitedLineScale)) {
    const scale = scales[retrieveScaleID(scales, options, scaleId)];
    if (scale) {
      const {min, max, start, end, startProp, endProp} = limitedLineScale[scaleId];
      const dim = getDimensionByScale(scale, {min: options[min], max: options[max], start: scale[start], end: scale[end]});
      area[startProp] = dim.start;
      area[endProp] = dim.end;
    }
  }
}

function calculateX({properties, options}, labelSize, position, padding) {
  const {x: start, x2: end, width: size} = properties;
  return calculatePosition({start, end, size, borderWidth: options.borderWidth}, {
    position: position.x,
    padding: {start: padding.left, end: padding.right},
    adjust: options.label.xAdjust,
    size: labelSize.width
  });
}

function calculateY({properties, options}, labelSize, position, padding) {
  const {y: start, y2: end, height: size} = properties;
  return calculatePosition({start, end, size, borderWidth: options.borderWidth}, {
    position: position.y,
    padding: {start: padding.top, end: padding.bottom},
    adjust: options.label.yAdjust,
    size: labelSize.height
  });
}

function calculatePosition(boxOpts, labelOpts) {
  const {start, end, borderWidth} = boxOpts;
  const {position, padding: {start: padStart, end: padEnd}, adjust} = labelOpts;
  const availableSize = end - borderWidth - start - padStart - padEnd - labelOpts.size;
  return start + borderWidth / 2 + adjust + getRelativePosition(availableSize, position);
}

function resolveLabelElementProperties$1(chart, properties, options) {
  const label = options.label;
  label.backgroundColor = 'transparent';
  label.callout.display = false;
  const position = toPosition(label.position);
  const padding = helpers.toPadding(label.padding);
  const labelSize = measureLabelSize(chart.ctx, label);
  const x = calculateX({properties, options}, labelSize, position, padding);
  const y = calculateY({properties, options}, labelSize, position, padding);
  const width = labelSize.width + padding.width;
  const height = labelSize.height + padding.height;
  return {
    x,
    y,
    x2: x + width,
    y2: y + height,
    width,
    height,
    centerX: x + width / 2,
    centerY: y + height / 2,
    rotation: label.rotation
  };

}

const moveHooks = ['enter', 'leave'];

/**
 * @typedef { import("chart.js").Chart } Chart
 * @typedef { import('../../types/options').AnnotationPluginOptions } AnnotationPluginOptions
 */

const eventHooks = moveHooks.concat('click');

/**
 * @param {Chart} chart
 * @param {Object} state
 * @param {AnnotationPluginOptions} options
 */
function updateListeners(chart, state, options) {
  state.listened = loadHooks(options, eventHooks, state.listeners);
  state.moveListened = false;

  moveHooks.forEach(hook => {
    if (helpers.isFunction(options[hook])) {
      state.moveListened = true;
    }
  });

  if (!state.listened || !state.moveListened) {
    state.annotations.forEach(scope => {
      if (!state.listened && helpers.isFunction(scope.click)) {
        state.listened = true;
      }
      if (!state.moveListened) {
        moveHooks.forEach(hook => {
          if (helpers.isFunction(scope[hook])) {
            state.listened = true;
            state.moveListened = true;
          }
        });
      }
    });
  }
}

/**
 * @param {Object} state
 * @param {ChartEvent} event
 * @param {AnnotationPluginOptions} options
 * @return {boolean|undefined}
 */
function handleEvent(state, event, options) {
  if (state.listened) {
    switch (event.type) {
    case 'mousemove':
    case 'mouseout':
      return handleMoveEvents(state, event, options);
    case 'click':
      return handleClickEvents(state, event, options);
    }
  }
}

function handleMoveEvents(state, event, options) {
  if (!state.moveListened) {
    return;
  }

  let elements;

  if (event.type === 'mousemove') {
    elements = getElements(state.visibleElements, event, options.interaction);
  } else {
    elements = [];
  }

  const previous = state.hovered;
  state.hovered = elements;

  const context = {state, event};
  let changed = dispatchMoveEvents(context, 'leave', previous, elements);
  return dispatchMoveEvents(context, 'enter', elements, previous) || changed;
}

function dispatchMoveEvents({state, event}, hook, elements, checkElements) {
  let changed;
  for (const element of elements) {
    if (checkElements.indexOf(element) < 0) {
      changed = dispatchEvent(element.options[hook] || state.listeners[hook], element, event) || changed;
    }
  }
  return changed;
}

function handleClickEvents(state, event, options) {
  const listeners = state.listeners;
  const elements = getElements(state.visibleElements, event, options.interaction);
  let changed;
  for (const element of elements) {
    changed = dispatchEvent(element.options.click || listeners.click, element, event) || changed;
  }
  return changed;
}

function dispatchEvent(handler, element, event) {
  return helpers.callback(handler, [element.$context, event]) === true;
}

/**
 * @typedef { import("chart.js").Chart } Chart
 * @typedef { import('../../types/options').AnnotationPluginOptions } AnnotationPluginOptions
 * @typedef { import('../../types/element').AnnotationElement } AnnotationElement
 */

const elementHooks = ['afterDraw', 'beforeDraw'];

/**
 * @param {Chart} chart
 * @param {Object} state
 * @param {AnnotationPluginOptions} options
 */
function updateHooks(chart, state, options) {
  const visibleElements = state.visibleElements;
  state.hooked = loadHooks(options, elementHooks, state.hooks);

  if (!state.hooked) {
    visibleElements.forEach(scope => {
      if (!state.hooked) {
        elementHooks.forEach(hook => {
          if (helpers.isFunction(scope.options[hook])) {
            state.hooked = true;
          }
        });
      }
    });
  }
}

/**
 * @param {Object} state
 * @param {AnnotationElement} element
 * @param {string} hook
 */
function invokeHook(state, element, hook) {
  if (state.hooked) {
    const callbackHook = element.options[hook] || state.hooks[hook];
    return helpers.callback(callbackHook, [element.$context]);
  }
}

/**
 * @typedef { import("chart.js").Chart } Chart
 * @typedef { import("chart.js").Scale } Scale
 * @typedef { import('../../types/options').CoreAnnotationOptions } CoreAnnotationOptions
 */

/**
 * @param {Chart} chart
 * @param {Scale} scale
 * @param {CoreAnnotationOptions[]} annotations
 */
function adjustScaleRange(chart, scale, annotations) {
  const range = getScaleLimits(chart.scales, scale, annotations);
  let changed = changeScaleLimit(scale, range, 'min', 'suggestedMin');
  changed = changeScaleLimit(scale, range, 'max', 'suggestedMax') || changed;
  if (changed && helpers.isFunction(scale.handleTickRangeOptions)) {
    scale.handleTickRangeOptions();
  }
}

/**
 * @param {CoreAnnotationOptions[]} annotations
 * @param {{ [key: string]: Scale }} scales
 */
function verifyScaleOptions(annotations, scales) {
  for (const annotation of annotations) {
    verifyScaleIDs(annotation, scales);
  }
}

function changeScaleLimit(scale, range, limit, suggestedLimit) {
  if (helpers.isFinite(range[limit]) && !scaleLimitDefined(scale.options, limit, suggestedLimit)) {
    const changed = scale[limit] !== range[limit];
    scale[limit] = range[limit];
    return changed;
  }
}

function scaleLimitDefined(scaleOptions, limit, suggestedLimit) {
  return helpers.defined(scaleOptions[limit]) || helpers.defined(scaleOptions[suggestedLimit]);
}

function verifyScaleIDs(annotation, scales) {
  for (const key of ['scaleID', 'xScaleID', 'yScaleID']) {
    const scaleID = retrieveScaleID(scales, annotation, key);
    if (scaleID && !scales[scaleID] && verifyProperties(annotation, key)) {
      console.warn(`No scale found with id '${scaleID}' for annotation '${annotation.id}'`);
    }
  }
}

function verifyProperties(annotation, key) {
  if (key === 'scaleID') {
    return true;
  }
  const axis = key.charAt(0);
  for (const prop of ['Min', 'Max', 'Value']) {
    if (helpers.defined(annotation[axis + prop])) {
      return true;
    }
  }
  return false;
}

function getScaleLimits(scales, scale, annotations) {
  const axis = scale.axis;
  const scaleID = scale.id;
  const scaleIDOption = axis + 'ScaleID';
  const limits = {
    min: helpers.valueOrDefault(scale.min, Number.NEGATIVE_INFINITY),
    max: helpers.valueOrDefault(scale.max, Number.POSITIVE_INFINITY)
  };
  for (const annotation of annotations) {
    if (annotation.scaleID === scaleID) {
      updateLimits(annotation, scale, ['value', 'endValue'], limits);
    } else if (retrieveScaleID(scales, annotation, scaleIDOption) === scaleID) {
      updateLimits(annotation, scale, [axis + 'Min', axis + 'Max', axis + 'Value'], limits);
    }
  }
  return limits;
}

function updateLimits(annotation, scale, props, limits) {
  for (const prop of props) {
    const raw = annotation[prop];
    if (helpers.defined(raw)) {
      const value = scale.parse(raw);
      limits.min = Math.min(limits.min, value);
      limits.max = Math.max(limits.max, value);
    }
  }
}

class BoxAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    const {x, y} = rotated({x: mouseX, y: mouseY}, this.getCenterPoint(useFinalPosition), helpers.toRadians(-this.options.rotation));
    return inBoxRange({x, y}, this.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition), axis, this.options);
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    ctx.save();
    translate(ctx, this.getCenterPoint(), this.options.rotation);
    drawBox(ctx, this, this.options);
    ctx.restore();
  }

  get label() {
    return this.elements && this.elements[0];
  }

  resolveElementProperties(chart, options) {
    return resolveBoxAndLabelProperties(chart, options);
  }
}

BoxAnnotation.id = 'boxAnnotation';

BoxAnnotation.defaults = {
  adjustScaleRange: true,
  backgroundShadowColor: 'transparent',
  borderCapStyle: 'butt',
  borderDash: [],
  borderDashOffset: 0,
  borderJoinStyle: 'miter',
  borderRadius: 0,
  borderShadowColor: 'transparent',
  borderWidth: 1,
  display: true,
  init: undefined,
  hitTolerance: 0,
  label: {
    backgroundColor: 'transparent',
    borderWidth: 0,
    callout: {
      display: false
    },
    color: 'black',
    content: null,
    display: false,
    drawTime: undefined,
    font: {
      family: undefined,
      lineHeight: undefined,
      size: undefined,
      style: undefined,
      weight: 'bold'
    },
    height: undefined,
    hitTolerance: undefined,
    opacity: undefined,
    padding: 6,
    position: 'center',
    rotation: undefined,
    textAlign: 'start',
    textStrokeColor: undefined,
    textStrokeWidth: 0,
    width: undefined,
    xAdjust: 0,
    yAdjust: 0,
    z: undefined
  },
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  z: 0
};

BoxAnnotation.defaultRoutes = {
  borderColor: 'color',
  backgroundColor: 'color'
};

BoxAnnotation.descriptors = {
  label: {
    _fallback: true
  }
};

class DoughnutLabelAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    return inLabelRange(
      {x: mouseX, y: mouseY},
      {rect: this.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition), center: this.getCenterPoint(useFinalPosition)},
      axis,
      {rotation: this.rotation, borderWidth: 0, hitTolerance: this.options.hitTolerance}
    );
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const options = this.options;
    if (!options.display || !options.content) {
      return;
    }
    drawBackground(ctx, this);
    ctx.save();
    translate(ctx, this.getCenterPoint(), this.rotation);
    drawLabel(ctx, this, options, this._fitRatio);
    ctx.restore();
  }

  resolveElementProperties(chart, options) {
    const meta = getDatasetMeta(chart, options);
    if (!meta) {
      return {};
    }
    const {controllerMeta, point, radius} = getControllerMeta(chart, options, meta);
    let labelSize = measureLabelSize(chart.ctx, options);
    const _fitRatio = getFitRatio(labelSize, radius);
    if (shouldFit(options, _fitRatio)) {
      labelSize = {width: labelSize.width * _fitRatio, height: labelSize.height * _fitRatio};
    }
    const {position, xAdjust, yAdjust} = options;
    const boxSize = measureLabelRectangle(point, labelSize, {borderWidth: 0, position, xAdjust, yAdjust});
    return {
      initProperties: initAnimationProperties(chart, boxSize, options),
      ...boxSize,
      ...controllerMeta,
      rotation: options.rotation,
      _fitRatio
    };
  }
}

DoughnutLabelAnnotation.id = 'doughnutLabelAnnotation';

DoughnutLabelAnnotation.defaults = {
  autoFit: true,
  autoHide: true,
  backgroundColor: 'transparent',
  backgroundShadowColor: 'transparent',
  borderColor: 'transparent',
  borderDash: [],
  borderDashOffset: 0,
  borderJoinStyle: 'miter',
  borderShadowColor: 'transparent',
  borderWidth: 0,
  color: 'black',
  content: null,
  display: true,
  font: {
    family: undefined,
    lineHeight: undefined,
    size: undefined,
    style: undefined,
    weight: undefined
  },
  height: undefined,
  hitTolerance: 0,
  init: undefined,
  opacity: undefined,
  position: 'center',
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  spacing: 1,
  textAlign: 'center',
  textStrokeColor: undefined,
  textStrokeWidth: 0,
  width: undefined,
  xAdjust: 0,
  yAdjust: 0
};

DoughnutLabelAnnotation.defaultRoutes = {
};

function getDatasetMeta(chart, options) {
  return chart.getSortedVisibleDatasetMetas().reduce(function(result, value) {
    const controller = value.controller;
    if (controller instanceof chart_js.DoughnutController &&
      isControllerVisible(chart, options, value.data) &&
      (!result || controller.innerRadius < result.controller.innerRadius) &&
      controller.options.circumference >= 90) {
      return value;
    }
    return result;
  }, undefined);
}

function isControllerVisible(chart, options, elements) {
  if (!options.autoHide) {
    return true;
  }
  for (let i = 0; i < elements.length; i++) {
    if (!elements[i].hidden && chart.getDataVisibility(i)) {
      return true;
    }
  }
}

function getControllerMeta({chartArea}, options, meta) {
  const {left, top, right, bottom} = chartArea;
  const {innerRadius, offsetX, offsetY} = meta.controller;
  const x = (left + right) / 2 + offsetX;
  const y = (top + bottom) / 2 + offsetY;
  const square = {
    left: Math.max(x - innerRadius, left),
    right: Math.min(x + innerRadius, right),
    top: Math.max(y - innerRadius, top),
    bottom: Math.min(y + innerRadius, bottom)
  };
  const point = {
    x: (square.left + square.right) / 2,
    y: (square.top + square.bottom) / 2
  };
  const space = options.spacing + options.borderWidth / 2;
  const _radius = innerRadius - space;
  const _counterclockwise = point.y > y;
  const side = _counterclockwise ? top + space : bottom - space;
  const angles = getAngles(side, x, y, _radius);
  const controllerMeta = {
    _centerX: x,
    _centerY: y,
    _radius,
    _counterclockwise,
    ...angles
  };
  return {
    controllerMeta,
    point,
    radius: Math.min(innerRadius, Math.min(square.right - square.left, square.bottom - square.top) / 2)
  };
}

function getFitRatio({width, height}, radius) {
  const hypo = Math.sqrt(Math.pow(width, 2) + Math.pow(height, 2));
  return (radius * 2) / hypo;
}

function getAngles(y, centerX, centerY, radius) {
  const yk2 = Math.pow(centerY - y, 2);
  const r2 = Math.pow(radius, 2);
  const b = centerX * -2;
  const c = Math.pow(centerX, 2) + yk2 - r2;
  const delta = Math.pow(b, 2) - (4 * c);
  if (delta <= 0) {
    return {
      _startAngle: 0,
      _endAngle: helpers.TAU
    };
  }
  const start = (-b - Math.sqrt(delta)) / 2;
  const end = (-b + Math.sqrt(delta)) / 2;
  return {
    _startAngle: helpers.getAngleFromPoint({x: centerX, y: centerY}, {x: start, y}).angle,
    _endAngle: helpers.getAngleFromPoint({x: centerX, y: centerY}, {x: end, y}).angle
  };
}

function drawBackground(ctx, element) {
  const {_centerX, _centerY, _radius, _startAngle, _endAngle, _counterclockwise, options} = element;
  ctx.save();
  const stroke = setBorderStyle(ctx, options);
  ctx.fillStyle = options.backgroundColor;
  ctx.beginPath();
  ctx.arc(_centerX, _centerY, _radius, _startAngle, _endAngle, _counterclockwise);
  ctx.closePath();
  ctx.fill();
  if (stroke) {
    ctx.stroke();
  }
  ctx.restore();
}

class LabelAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    return inLabelRange(
      {x: mouseX, y: mouseY},
      {rect: this.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition), center: this.getCenterPoint(useFinalPosition)},
      axis,
      {rotation: this.rotation, borderWidth: this.options.borderWidth, hitTolerance: this.options.hitTolerance}
    );
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const options = this.options;
    const visible = !helpers.defined(this._visible) || this._visible;
    if (!options.display || !options.content || !visible) {
      return;
    }
    ctx.save();
    translate(ctx, this.getCenterPoint(), this.rotation);
    drawCallout(ctx, this);
    drawBox(ctx, this, options);
    drawLabel(ctx, getLabelSize(this), options);
    ctx.restore();
  }

  resolveElementProperties(chart, options) {
    let point;
    if (!isBoundToPoint(options)) {
      const {centerX, centerY} = resolveBoxProperties(chart, options);
      point = {x: centerX, y: centerY};
    } else {
      point = getChartPoint(chart, options);
    }
    const padding = helpers.toPadding(options.padding);
    const labelSize = measureLabelSize(chart.ctx, options);
    const boxSize = measureLabelRectangle(point, labelSize, options, padding);
    return {
      initProperties: initAnimationProperties(chart, boxSize, options),
      pointX: point.x,
      pointY: point.y,
      ...boxSize,
      rotation: options.rotation
    };
  }
}

LabelAnnotation.id = 'labelAnnotation';

LabelAnnotation.defaults = {
  adjustScaleRange: true,
  backgroundColor: 'transparent',
  backgroundShadowColor: 'transparent',
  borderCapStyle: 'butt',
  borderDash: [],
  borderDashOffset: 0,
  borderJoinStyle: 'miter',
  borderRadius: 0,
  borderShadowColor: 'transparent',
  borderWidth: 0,
  callout: {
    borderCapStyle: 'butt',
    borderColor: undefined,
    borderDash: [],
    borderDashOffset: 0,
    borderJoinStyle: 'miter',
    borderWidth: 1,
    display: false,
    margin: 5,
    position: 'auto',
    side: 5,
    start: '50%',
  },
  color: 'black',
  content: null,
  display: true,
  font: {
    family: undefined,
    lineHeight: undefined,
    size: undefined,
    style: undefined,
    weight: undefined
  },
  height: undefined,
  hitTolerance: 0,
  init: undefined,
  opacity: undefined,
  padding: 6,
  position: 'center',
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  textAlign: 'center',
  textStrokeColor: undefined,
  textStrokeWidth: 0,
  width: undefined,
  xAdjust: 0,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  xValue: undefined,
  yAdjust: 0,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  yValue: undefined,
  z: 0
};

LabelAnnotation.defaultRoutes = {
  borderColor: 'color'
};

function getLabelSize({x, y, width, height, options}) {
  const hBorderWidth = options.borderWidth / 2;
  const padding = helpers.toPadding(options.padding);
  return {
    x: x + padding.left + hBorderWidth,
    y: y + padding.top + hBorderWidth,
    width: width - padding.left - padding.right - options.borderWidth,
    height: height - padding.top - padding.bottom - options.borderWidth
  };
}

const pointInLine = (p1, p2, t) => ({x: p1.x + t * (p2.x - p1.x), y: p1.y + t * (p2.y - p1.y)});
const interpolateX = (y, p1, p2) => pointInLine(p1, p2, Math.abs((y - p1.y) / (p2.y - p1.y))).x;
const interpolateY = (x, p1, p2) => pointInLine(p1, p2, Math.abs((x - p1.x) / (p2.x - p1.x))).y;
const sqr = v => v * v;
const rangeLimit = (mouseX, mouseY, {x, y, x2, y2}, axis) => axis === 'y' ? {start: Math.min(y, y2), end: Math.max(y, y2), value: mouseY} : {start: Math.min(x, x2), end: Math.max(x, x2), value: mouseX};
// http://www.independent-software.com/determining-coordinates-on-a-html-canvas-bezier-curve.html
const coordInCurve = (start, cp, end, t) => (1 - t) * (1 - t) * start + 2 * (1 - t) * t * cp + t * t * end;
const pointInCurve = (start, cp, end, t) => ({x: coordInCurve(start.x, cp.x, end.x, t), y: coordInCurve(start.y, cp.y, end.y, t)});
const coordAngleInCurve = (start, cp, end, t) => 2 * (1 - t) * (cp - start) + 2 * t * (end - cp);
const angleInCurve = (start, cp, end, t) => -Math.atan2(coordAngleInCurve(start.x, cp.x, end.x, t), coordAngleInCurve(start.y, cp.y, end.y, t)) + 0.5 * helpers.PI;

class LineAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    const hitSize = (this.options.borderWidth + this.options.hitTolerance) / 2;
    if (axis !== 'x' && axis !== 'y') {
      const point = {mouseX, mouseY};
      const {path, ctx} = this;
      if (path) {
        setBorderStyle(ctx, this.options);
        ctx.lineWidth += this.options.hitTolerance;
        const {chart} = this.$context;
        const mx = mouseX * chart.currentDevicePixelRatio;
        const my = mouseY * chart.currentDevicePixelRatio;
        const result = ctx.isPointInStroke(path, mx, my) || isOnLabel(this, point, useFinalPosition);
        ctx.restore();
        return result;
      }
      const epsilon = sqr(hitSize);
      return intersects(this, point, epsilon, useFinalPosition) || isOnLabel(this, point, useFinalPosition);
    }
    return inAxisRange(this, {mouseX, mouseY}, axis, {hitSize, useFinalPosition});
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const {x, y, x2, y2, cp, options} = this;

    ctx.save();
    if (!setBorderStyle(ctx, options)) {
      // no border width, then line is not drawn
      return ctx.restore();
    }
    setShadowStyle(ctx, options);

    const length = Math.sqrt(Math.pow(x2 - x, 2) + Math.pow(y2 - y, 2));
    if (options.curve && cp) {
      drawCurve(ctx, this, cp, length);
      return ctx.restore();
    }
    const {startOpts, endOpts, startAdjust, endAdjust} = getArrowHeads(this);
    const angle = Math.atan2(y2 - y, x2 - x);
    ctx.translate(x, y);
    ctx.rotate(angle);
    ctx.beginPath();
    ctx.moveTo(0 + startAdjust, 0);
    ctx.lineTo(length - endAdjust, 0);
    ctx.shadowColor = options.borderShadowColor;
    ctx.stroke();
    drawArrowHead(ctx, 0, startAdjust, startOpts);
    drawArrowHead(ctx, length, -endAdjust, endOpts);
    ctx.restore();
  }

  get label() {
    return this.elements && this.elements[0];
  }

  resolveElementProperties(chart, options) {
    const area = resolveLineProperties(chart, options);
    const {x, y, x2, y2} = area;
    const inside = isLineInArea(area, chart.chartArea);
    const properties = inside
      ? limitLineToArea({x, y}, {x: x2, y: y2}, chart.chartArea)
      : {x, y, x2, y2, width: Math.abs(x2 - x), height: Math.abs(y2 - y)};
    properties.centerX = (x2 + x) / 2;
    properties.centerY = (y2 + y) / 2;
    properties.initProperties = initAnimationProperties(chart, properties, options);
    if (options.curve) {
      const p1 = {x: properties.x, y: properties.y};
      const p2 = {x: properties.x2, y: properties.y2};
      properties.cp = getControlPoint(properties, options, helpers.distanceBetweenPoints(p1, p2));
    }
    const labelProperties = resolveLabelElementProperties(chart, properties, options.label);
    // additonal prop to manage zoom/pan
    labelProperties._visible = inside;

    properties.elements = [{
      type: 'label',
      optionScope: 'label',
      properties: labelProperties,
      initProperties: properties.initProperties
    }];
    return properties;
  }
}

LineAnnotation.id = 'lineAnnotation';

const arrowHeadsDefaults = {
  backgroundColor: undefined,
  backgroundShadowColor: undefined,
  borderColor: undefined,
  borderDash: undefined,
  borderDashOffset: undefined,
  borderShadowColor: undefined,
  borderWidth: undefined,
  display: undefined,
  fill: undefined,
  length: undefined,
  shadowBlur: undefined,
  shadowOffsetX: undefined,
  shadowOffsetY: undefined,
  width: undefined
};

LineAnnotation.defaults = {
  adjustScaleRange: true,
  arrowHeads: {
    display: false,
    end: Object.assign({}, arrowHeadsDefaults),
    fill: false,
    length: 12,
    start: Object.assign({}, arrowHeadsDefaults),
    width: 6
  },
  borderDash: [],
  borderDashOffset: 0,
  borderShadowColor: 'transparent',
  borderWidth: 2,
  curve: false,
  controlPoint: {
    y: '-50%'
  },
  display: true,
  endValue: undefined,
  init: undefined,
  hitTolerance: 0,
  label: {
    backgroundColor: 'rgba(0,0,0,0.8)',
    backgroundShadowColor: 'transparent',
    borderCapStyle: 'butt',
    borderColor: 'black',
    borderDash: [],
    borderDashOffset: 0,
    borderJoinStyle: 'miter',
    borderRadius: 6,
    borderShadowColor: 'transparent',
    borderWidth: 0,
    callout: Object.assign({}, LabelAnnotation.defaults.callout),
    color: '#fff',
    content: null,
    display: false,
    drawTime: undefined,
    font: {
      family: undefined,
      lineHeight: undefined,
      size: undefined,
      style: undefined,
      weight: 'bold'
    },
    height: undefined,
    hitTolerance: undefined,
    opacity: undefined,
    padding: 6,
    position: 'center',
    rotation: 0,
    shadowBlur: 0,
    shadowOffsetX: 0,
    shadowOffsetY: 0,
    textAlign: 'center',
    textStrokeColor: undefined,
    textStrokeWidth: 0,
    width: undefined,
    xAdjust: 0,
    yAdjust: 0,
    z: undefined
  },
  scaleID: undefined,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  value: undefined,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  z: 0
};

LineAnnotation.descriptors = {
  arrowHeads: {
    start: {
      _fallback: true
    },
    end: {
      _fallback: true
    },
    _fallback: true
  }
};

LineAnnotation.defaultRoutes = {
  borderColor: 'color'
};

function inAxisRange(element, {mouseX, mouseY}, axis, {hitSize, useFinalPosition}) {
  const limit = rangeLimit(mouseX, mouseY, element.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition), axis);
  return inLimit(limit, hitSize) || isOnLabel(element, {mouseX, mouseY}, useFinalPosition, axis);
}

function isLineInArea({x, y, x2, y2}, {top, right, bottom, left}) {
  return !(
    (x < left && x2 < left) ||
    (x > right && x2 > right) ||
    (y < top && y2 < top) ||
    (y > bottom && y2 > bottom)
  );
}

function limitPointToArea({x, y}, p2, {top, right, bottom, left}) {
  if (x < left) {
    y = interpolateY(left, {x, y}, p2);
    x = left;
  }
  if (x > right) {
    y = interpolateY(right, {x, y}, p2);
    x = right;
  }
  if (y < top) {
    x = interpolateX(top, {x, y}, p2);
    y = top;
  }
  if (y > bottom) {
    x = interpolateX(bottom, {x, y}, p2);
    y = bottom;
  }
  return {x, y};
}

function limitLineToArea(p1, p2, area) {
  const {x, y} = limitPointToArea(p1, p2, area);
  const {x: x2, y: y2} = limitPointToArea(p2, p1, area);
  return {x, y, x2, y2, width: Math.abs(x2 - x), height: Math.abs(y2 - y)};
}

function intersects(element, {mouseX, mouseY}, epsilon = EPSILON, useFinalPosition) {
  // Adapted from https://stackoverflow.com/a/6853926/25507
  const {x: x1, y: y1, x2, y2} = element.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition);
  const dx = x2 - x1;
  const dy = y2 - y1;
  const lenSq = sqr(dx) + sqr(dy);
  const t = lenSq === 0 ? -1 : ((mouseX - x1) * dx + (mouseY - y1) * dy) / lenSq;

  let xx, yy;
  if (t < 0) {
    xx = x1;
    yy = y1;
  } else if (t > 1) {
    xx = x2;
    yy = y2;
  } else {
    xx = x1 + t * dx;
    yy = y1 + t * dy;
  }
  return (sqr(mouseX - xx) + sqr(mouseY - yy)) <= epsilon;
}

function isOnLabel(element, {mouseX, mouseY}, useFinalPosition, axis) {
  const label = element.label;
  return label.options.display && label.inRange(mouseX, mouseY, axis, useFinalPosition);
}

function resolveLabelElementProperties(chart, properties, options) {
  const borderWidth = options.borderWidth;
  const padding = helpers.toPadding(options.padding);
  const textSize = measureLabelSize(chart.ctx, options);
  const width = textSize.width + padding.width + borderWidth;
  const height = textSize.height + padding.height + borderWidth;
  return calculateLabelPosition(properties, options, {width, height, padding}, chart.chartArea);
}

function calculateAutoRotation(properties) {
  const {x, y, x2, y2} = properties;
  const rotation = Math.atan2(y2 - y, x2 - x);
  // Flip the rotation if it goes > PI/2 or < -PI/2, so label stays upright
  return rotation > helpers.PI / 2 ? rotation - helpers.PI : rotation < helpers.PI / -2 ? rotation + helpers.PI : rotation;
}

function calculateLabelPosition(properties, label, sizes, chartArea) {
  const {width, height, padding} = sizes;
  const {xAdjust, yAdjust} = label;
  const p1 = {x: properties.x, y: properties.y};
  const p2 = {x: properties.x2, y: properties.y2};
  const rotation = label.rotation === 'auto' ? calculateAutoRotation(properties) : helpers.toRadians(label.rotation);
  const size = rotatedSize(width, height, rotation);
  const t = calculateT(properties, label, {labelSize: size, padding}, chartArea);
  const pt = properties.cp ? pointInCurve(p1, properties.cp, p2, t) : pointInLine(p1, p2, t);
  const xCoordinateSizes = {size: size.w, min: chartArea.left, max: chartArea.right, padding: padding.left};
  const yCoordinateSizes = {size: size.h, min: chartArea.top, max: chartArea.bottom, padding: padding.top};
  const centerX = adjustLabelCoordinate(pt.x, xCoordinateSizes) + xAdjust;
  const centerY = adjustLabelCoordinate(pt.y, yCoordinateSizes) + yAdjust;
  return {
    x: centerX - (width / 2),
    y: centerY - (height / 2),
    x2: centerX + (width / 2),
    y2: centerY + (height / 2),
    centerX,
    centerY,
    pointX: pt.x,
    pointY: pt.y,
    width,
    height,
    rotation: helpers.toDegrees(rotation)
  };
}

function rotatedSize(width, height, rotation) {
  const cos = Math.cos(rotation);
  const sin = Math.sin(rotation);
  return {
    w: Math.abs(width * cos) + Math.abs(height * sin),
    h: Math.abs(width * sin) + Math.abs(height * cos)
  };
}

function calculateT(properties, label, sizes, chartArea) {
  let t;
  const space = spaceAround(properties, chartArea);
  if (label.position === 'start') {
    t = calculateTAdjust({w: properties.x2 - properties.x, h: properties.y2 - properties.y}, sizes, label, space);
  } else if (label.position === 'end') {
    t = 1 - calculateTAdjust({w: properties.x - properties.x2, h: properties.y - properties.y2}, sizes, label, space);
  } else {
    t = getRelativePosition(1, label.position);
  }
  return t;
}

function calculateTAdjust(lineSize, sizes, label, space) {
  const {labelSize, padding} = sizes;
  const lineW = lineSize.w * space.dx;
  const lineH = lineSize.h * space.dy;
  const x = (lineW > 0) && ((labelSize.w / 2 + padding.left - space.x) / lineW);
  const y = (lineH > 0) && ((labelSize.h / 2 + padding.top - space.y) / lineH);
  return clamp(Math.max(x, y), 0, 0.25);
}

function spaceAround(properties, chartArea) {
  const {x, x2, y, y2} = properties;
  const t = Math.min(y, y2) - chartArea.top;
  const l = Math.min(x, x2) - chartArea.left;
  const b = chartArea.bottom - Math.max(y, y2);
  const r = chartArea.right - Math.max(x, x2);
  return {
    x: Math.min(l, r),
    y: Math.min(t, b),
    dx: l <= r ? 1 : -1,
    dy: t <= b ? 1 : -1
  };
}

function adjustLabelCoordinate(coordinate, labelSizes) {
  const {size, min, max, padding} = labelSizes;
  const halfSize = size / 2;
  if (size > max - min) {
    // if it does not fit, display as much as possible
    return (max + min) / 2;
  }
  if (min >= (coordinate - padding - halfSize)) {
    coordinate = min + padding + halfSize;
  }
  if (max <= (coordinate + padding + halfSize)) {
    coordinate = max - padding - halfSize;
  }
  return coordinate;
}

function getArrowHeads(line) {
  const options = line.options;
  const arrowStartOpts = options.arrowHeads && options.arrowHeads.start;
  const arrowEndOpts = options.arrowHeads && options.arrowHeads.end;
  return {
    startOpts: arrowStartOpts,
    endOpts: arrowEndOpts,
    startAdjust: getLineAdjust(line, arrowStartOpts),
    endAdjust: getLineAdjust(line, arrowEndOpts)
  };
}

function getLineAdjust(line, arrowOpts) {
  if (!arrowOpts || !arrowOpts.display) {
    return 0;
  }
  const {length, width} = arrowOpts;
  const adjust = line.options.borderWidth / 2;
  const p1 = {x: length, y: width + adjust};
  const p2 = {x: 0, y: adjust};
  return Math.abs(interpolateX(0, p1, p2));
}

function drawArrowHead(ctx, offset, adjust, arrowOpts) {
  if (!arrowOpts || !arrowOpts.display) {
    return;
  }
  const {length, width, fill, backgroundColor, borderColor} = arrowOpts;
  const arrowOffsetX = Math.abs(offset - length) + adjust;
  ctx.beginPath();
  setShadowStyle(ctx, arrowOpts);
  setBorderStyle(ctx, arrowOpts);
  ctx.moveTo(arrowOffsetX, -width);
  ctx.lineTo(offset + adjust, 0);
  ctx.lineTo(arrowOffsetX, width);
  if (fill === true) {
    ctx.fillStyle = backgroundColor || borderColor;
    ctx.closePath();
    ctx.fill();
    ctx.shadowColor = 'transparent';
  } else {
    ctx.shadowColor = arrowOpts.borderShadowColor;
  }
  ctx.stroke();
}

function getControlPoint(properties, options, distance) {
  const {x, y, x2, y2, centerX, centerY} = properties;
  const angle = Math.atan2(y2 - y, x2 - x);
  const cp = toPosition(options.controlPoint, 0);
  const point = {
    x: centerX + getSize(distance, cp.x, false),
    y: centerY + getSize(distance, cp.y, false)
  };
  return rotated(point, {x: centerX, y: centerY}, angle);
}

function drawArrowHeadOnCurve(ctx, {x, y}, {angle, adjust}, arrowOpts) {
  if (!arrowOpts || !arrowOpts.display) {
    return;
  }
  ctx.save();
  ctx.translate(x, y);
  ctx.rotate(angle);
  drawArrowHead(ctx, 0, -adjust, arrowOpts);
  ctx.restore();
}

function drawCurve(ctx, element, cp, length) {
  const {x, y, x2, y2, options} = element;
  const {startOpts, endOpts, startAdjust, endAdjust} = getArrowHeads(element);
  const p1 = {x, y};
  const p2 = {x: x2, y: y2};
  const startAngle = angleInCurve(p1, cp, p2, 0);
  const endAngle = angleInCurve(p1, cp, p2, 1) - helpers.PI;
  const ps = pointInCurve(p1, cp, p2, startAdjust / length);
  const pe = pointInCurve(p1, cp, p2, 1 - endAdjust / length);

  const path = new Path2D();
  ctx.beginPath();
  path.moveTo(ps.x, ps.y);
  path.quadraticCurveTo(cp.x, cp.y, pe.x, pe.y);
  ctx.shadowColor = options.borderShadowColor;
  ctx.stroke(path);
  element.path = path;
  element.ctx = ctx;
  drawArrowHeadOnCurve(ctx, ps, {angle: startAngle, adjust: startAdjust}, startOpts);
  drawArrowHeadOnCurve(ctx, pe, {angle: endAngle, adjust: endAdjust}, endOpts);
}

class EllipseAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    const rotation = this.options.rotation;
    const hitSize = (this.options.borderWidth + this.options.hitTolerance) / 2;
    if (axis !== 'x' && axis !== 'y') {
      return pointInEllipse({x: mouseX, y: mouseY}, this.getProps(['width', 'height', 'centerX', 'centerY'], useFinalPosition), rotation, hitSize);
    }
    const {x, y, x2, y2} = this.getProps(['x', 'y', 'x2', 'y2'], useFinalPosition);
    const limit = axis === 'y' ? {start: y, end: y2} : {start: x, end: x2};
    const rotatedPoint = rotated({x: mouseX, y: mouseY}, this.getCenterPoint(useFinalPosition), helpers.toRadians(-rotation));
    return rotatedPoint[axis] >= limit.start - hitSize - EPSILON && rotatedPoint[axis] <= limit.end + hitSize + EPSILON;
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const {width, height, centerX, centerY, options} = this;
    ctx.save();
    translate(ctx, this.getCenterPoint(), options.rotation);
    setShadowStyle(ctx, this.options);
    ctx.beginPath();
    ctx.fillStyle = options.backgroundColor;
    const stroke = setBorderStyle(ctx, options);
    ctx.ellipse(centerX, centerY, height / 2, width / 2, helpers.PI / 2, 0, 2 * helpers.PI);
    ctx.fill();
    if (stroke) {
      ctx.shadowColor = options.borderShadowColor;
      ctx.stroke();
    }
    ctx.restore();
  }

  get label() {
    return this.elements && this.elements[0];
  }

  resolveElementProperties(chart, options) {
    return resolveBoxAndLabelProperties(chart, options);
  }

}

EllipseAnnotation.id = 'ellipseAnnotation';

EllipseAnnotation.defaults = {
  adjustScaleRange: true,
  backgroundShadowColor: 'transparent',
  borderDash: [],
  borderDashOffset: 0,
  borderShadowColor: 'transparent',
  borderWidth: 1,
  display: true,
  hitTolerance: 0,
  init: undefined,
  label: Object.assign({}, BoxAnnotation.defaults.label),
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  z: 0
};

EllipseAnnotation.defaultRoutes = {
  borderColor: 'color',
  backgroundColor: 'color'
};

EllipseAnnotation.descriptors = {
  label: {
    _fallback: true
  }
};

function pointInEllipse(p, ellipse, rotation, hitSize) {
  const {width, height, centerX, centerY} = ellipse;
  const xRadius = width / 2;
  const yRadius = height / 2;

  if (xRadius <= 0 || yRadius <= 0) {
    return false;
  }
  // https://stackoverflow.com/questions/7946187/point-and-ellipse-rotated-position-test-algorithm
  const angle = helpers.toRadians(rotation || 0);
  const cosAngle = Math.cos(angle);
  const sinAngle = Math.sin(angle);
  const a = Math.pow(cosAngle * (p.x - centerX) + sinAngle * (p.y - centerY), 2);
  const b = Math.pow(sinAngle * (p.x - centerX) - cosAngle * (p.y - centerY), 2);
  return (a / Math.pow(xRadius + hitSize, 2)) + (b / Math.pow(yRadius + hitSize, 2)) <= 1.0001;
}

class PointAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    const {x, y, x2, y2, width} = this.getProps(['x', 'y', 'x2', 'y2', 'width'], useFinalPosition);
    const hitSize = (this.options.borderWidth + this.options.hitTolerance) / 2;
    if (axis !== 'x' && axis !== 'y') {
      return inPointRange({x: mouseX, y: mouseY}, this.getCenterPoint(useFinalPosition), width / 2, hitSize);
    }
    const limit = axis === 'y' ? {start: y, end: y2, value: mouseY} : {start: x, end: x2, value: mouseX};
    return inLimit(limit, hitSize);
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const options = this.options;
    const borderWidth = options.borderWidth;
    if (options.radius < 0.1) {
      return;
    }
    ctx.save();
    ctx.fillStyle = options.backgroundColor;
    setShadowStyle(ctx, options);
    const stroke = setBorderStyle(ctx, options);
    drawPoint(ctx, this, this.centerX, this.centerY);
    if (stroke && !isImageOrCanvas(options.pointStyle)) {
      ctx.shadowColor = options.borderShadowColor;
      ctx.stroke();
    }
    ctx.restore();
    options.borderWidth = borderWidth;
  }

  resolveElementProperties(chart, options) {
    const properties = resolvePointProperties(chart, options);
    properties.initProperties = initAnimationProperties(chart, properties, options);
    return properties;
  }
}

PointAnnotation.id = 'pointAnnotation';

PointAnnotation.defaults = {
  adjustScaleRange: true,
  backgroundShadowColor: 'transparent',
  borderDash: [],
  borderDashOffset: 0,
  borderShadowColor: 'transparent',
  borderWidth: 1,
  display: true,
  hitTolerance: 0,
  init: undefined,
  pointStyle: 'circle',
  radius: 10,
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  xAdjust: 0,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  xValue: undefined,
  yAdjust: 0,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  yValue: undefined,
  z: 0
};

PointAnnotation.defaultRoutes = {
  borderColor: 'color',
  backgroundColor: 'color'
};

class PolygonAnnotation extends chart_js.Element {

  inRange(mouseX, mouseY, axis, useFinalPosition) {
    if (axis !== 'x' && axis !== 'y') {
      return this.options.radius >= 0.1 && this.elements.length > 1 && pointIsInPolygon(this.elements, mouseX, mouseY, useFinalPosition);
    }
    const rotatedPoint = rotated({x: mouseX, y: mouseY}, this.getCenterPoint(useFinalPosition), helpers.toRadians(-this.options.rotation));
    const axisPoints = this.elements.map((point) => axis === 'y' ? point.bY : point.bX);
    const start = Math.min(...axisPoints);
    const end = Math.max(...axisPoints);
    return rotatedPoint[axis] >= start && rotatedPoint[axis] <= end;
  }

  getCenterPoint(useFinalPosition) {
    return getElementCenterPoint(this, useFinalPosition);
  }

  draw(ctx) {
    const {elements, options} = this;
    ctx.save();
    ctx.beginPath();
    ctx.fillStyle = options.backgroundColor;
    setShadowStyle(ctx, options);
    const stroke = setBorderStyle(ctx, options);
    let first = true;
    for (const el of elements) {
      if (first) {
        ctx.moveTo(el.x, el.y);
        first = false;
      } else {
        ctx.lineTo(el.x, el.y);
      }
    }
    ctx.closePath();
    ctx.fill();
    // If no border, don't draw it
    if (stroke) {
      ctx.shadowColor = options.borderShadowColor;
      ctx.stroke();
    }
    ctx.restore();
  }

  resolveElementProperties(chart, options) {
    const properties = resolvePointProperties(chart, options);
    const {sides, rotation} = options;
    const elements = [];
    const angle = (2 * helpers.PI) / sides;
    let rad = rotation * helpers.RAD_PER_DEG;
    for (let i = 0; i < sides; i++, rad += angle) {
      const elProps = buildPointElement(properties, options, rad);
      elProps.initProperties = initAnimationProperties(chart, properties, options);
      elements.push(elProps);
    }
    properties.elements = elements;
    return properties;
  }
}

PolygonAnnotation.id = 'polygonAnnotation';

PolygonAnnotation.defaults = {
  adjustScaleRange: true,
  backgroundShadowColor: 'transparent',
  borderCapStyle: 'butt',
  borderDash: [],
  borderDashOffset: 0,
  borderJoinStyle: 'miter',
  borderShadowColor: 'transparent',
  borderWidth: 1,
  display: true,
  hitTolerance: 0,
  init: undefined,
  point: {
    radius: 0
  },
  radius: 10,
  rotation: 0,
  shadowBlur: 0,
  shadowOffsetX: 0,
  shadowOffsetY: 0,
  sides: 3,
  xAdjust: 0,
  xMax: undefined,
  xMin: undefined,
  xScaleID: undefined,
  xValue: undefined,
  yAdjust: 0,
  yMax: undefined,
  yMin: undefined,
  yScaleID: undefined,
  yValue: undefined,
  z: 0
};

PolygonAnnotation.defaultRoutes = {
  borderColor: 'color',
  backgroundColor: 'color'
};

function buildPointElement({centerX, centerY}, {radius, borderWidth, hitTolerance}, rad) {
  const hitSize = (borderWidth + hitTolerance) / 2;
  const sin = Math.sin(rad);
  const cos = Math.cos(rad);
  const point = {x: centerX + sin * radius, y: centerY - cos * radius};
  return {
    type: 'point',
    optionScope: 'point',
    properties: {
      x: point.x,
      y: point.y,
      centerX: point.x,
      centerY: point.y,
      bX: centerX + sin * (radius + hitSize),
      bY: centerY - cos * (radius + hitSize)
    }
  };
}

function pointIsInPolygon(points, x, y, useFinalPosition) {
  let isInside = false;
  let A = points[points.length - 1].getProps(['bX', 'bY'], useFinalPosition);
  for (const point of points) {
    const B = point.getProps(['bX', 'bY'], useFinalPosition);
    if ((B.bY > y) !== (A.bY > y) && x < (A.bX - B.bX) * (y - B.bY) / (A.bY - B.bY) + B.bX) {
      isInside = !isInside;
    }
    A = B;
  }
  return isInside;
}

const annotationTypes = {
  box: BoxAnnotation,
  doughnutLabel: DoughnutLabelAnnotation,
  ellipse: EllipseAnnotation,
  label: LabelAnnotation,
  line: LineAnnotation,
  point: PointAnnotation,
  polygon: PolygonAnnotation
};

/**
 * Register fallback for annotation elements
 * For example lineAnnotation options would be looked through:
 * - the annotation object (options.plugins.annotation.annotations[id])
 * - element options (options.elements.lineAnnotation)
 * - element defaults (defaults.elements.lineAnnotation)
 * - annotation plugin defaults (defaults.plugins.annotation, this is what we are registering here)
 */
Object.keys(annotationTypes).forEach(key => {
  chart_js.defaults.describe(`elements.${annotationTypes[key].id}`, {
    _fallback: 'plugins.annotation.common'
  });
});

const directUpdater = {
  update: Object.assign
};

const hooks$1 = eventHooks.concat(elementHooks);
const resolve = (value, optDefs) => helpers.isObject(optDefs) ? resolveObj(value, optDefs) : value;


/**
 * @typedef { import("chart.js").Chart } Chart
 * @typedef { import("chart.js").UpdateMode } UpdateMode
 * @typedef { import('../../types/options').AnnotationPluginOptions } AnnotationPluginOptions
 */

/**
 * @param {string} prop
 * @returns {boolean}
 */
const isIndexable = (prop) => prop === 'color' || prop === 'font';

/**
 * Resolve the annotation type, checking if is supported.
 * @param {string} [type=line] - annotation type
 * @returns {string} resolved annotation type
 */
function resolveType(type = 'line') {
  if (annotationTypes[type]) {
    return type;
  }
  console.warn(`Unknown annotation type: '${type}', defaulting to 'line'`);
  return 'line';
}

/**
 * @param {Chart} chart
 * @param {Object} state
 * @param {AnnotationPluginOptions} options
 * @param {UpdateMode} mode
 */
function updateElements(chart, state, options, mode) {
  const animations = resolveAnimations(chart, options.animations, mode);

  const annotations = state.annotations;
  const elements = resyncElements(state.elements, annotations);

  for (let i = 0; i < annotations.length; i++) {
    const annotationOptions = annotations[i];
    const element = getOrCreateElement(elements, i, annotationOptions.type);
    const resolver = annotationOptions.setContext(getContext(chart, element, elements, annotationOptions));
    const properties = element.resolveElementProperties(chart, resolver);

    properties.skip = toSkip(properties);

    if ('elements' in properties) {
      updateSubElements(element, properties.elements, resolver, animations);
      // Remove the sub-element definitions from properties, so the actual elements
      // are not overwritten by their definitions
      delete properties.elements;
    }

    if (!helpers.defined(element.x)) {
      // If the element is newly created, assing the properties directly - to
      // make them readily awailable to any scriptable options. If we do not do this,
      // the properties retruned by `resolveElementProperties` are available only
      // after options resolution.
      Object.assign(element, properties);
    }

    Object.assign(element, properties.initProperties);
    properties.options = resolveAnnotationOptions(resolver);

    animations.update(element, properties);
  }
}

function toSkip(properties) {
  return isNaN(properties.x) || isNaN(properties.y);
}

function resolveAnimations(chart, animOpts, mode) {
  if (mode === 'reset' || mode === 'none' || mode === 'resize') {
    return directUpdater;
  }
  return new chart_js.Animations(chart, animOpts);
}

function updateSubElements(mainElement, elements, resolver, animations) {
  const subElements = mainElement.elements || (mainElement.elements = []);
  subElements.length = elements.length;
  for (let i = 0; i < elements.length; i++) {
    const definition = elements[i];
    const properties = definition.properties;
    const subElement = getOrCreateElement(subElements, i, definition.type, definition.initProperties);
    const subResolver = resolver[definition.optionScope].override(definition);
    properties.options = resolveAnnotationOptions(subResolver);
    animations.update(subElement, properties);
  }
}

function getOrCreateElement(elements, index, type, initProperties) {
  const elementClass = annotationTypes[resolveType(type)];
  let element = elements[index];
  if (!element || !(element instanceof elementClass)) {
    element = elements[index] = new elementClass();
    Object.assign(element, initProperties);
  }
  return element;
}

function resolveAnnotationOptions(resolver) {
  const elementClass = annotationTypes[resolveType(resolver.type)];
  const result = {};
  result.id = resolver.id;
  result.type = resolver.type;
  result.drawTime = resolver.drawTime;
  Object.assign(result,
    resolveObj(resolver, elementClass.defaults),
    resolveObj(resolver, elementClass.defaultRoutes));
  for (const hook of hooks$1) {
    result[hook] = resolver[hook];
  }
  return result;
}

function resolveObj(resolver, defs) {
  const result = {};
  for (const prop of Object.keys(defs)) {
    const optDefs = defs[prop];
    const value = resolver[prop];
    if (isIndexable(prop) && helpers.isArray(value)) {
      result[prop] = value.map((item) => resolve(item, optDefs));
    } else {
      result[prop] = resolve(value, optDefs);
    }
  }
  return result;
}

function getContext(chart, element, elements, annotation) {
  return element.$context || (element.$context = Object.assign(Object.create(chart.getContext()), {
    element,
    get elements() {
      return elements.filter((el) => el && el.options);
    },
    id: annotation.id,
    type: 'annotation'
  }));
}

function resyncElements(elements, annotations) {
  const count = annotations.length;
  const start = elements.length;

  if (start < count) {
    const add = count - start;
    elements.splice(start, 0, ...new Array(add));
  } else if (start > count) {
    elements.splice(count, start - count);
  }
  return elements;
}

var version = "3.1.0";

const chartStates = new Map();
const isNotDoughnutLabel = annotation => annotation.type !== 'doughnutLabel';
const hooks = eventHooks.concat(elementHooks);

var Annotation = {
  id: 'annotation',

  version,

  beforeRegister() {
    requireVersion('chart.js', '4.0', chart_js.Chart.version);
  },

  afterRegister() {
    chart_js.Chart.register(annotationTypes);
  },

  afterUnregister() {
    chart_js.Chart.unregister(annotationTypes);
  },

  beforeInit(chart) {
    chartStates.set(chart, {
      annotations: [],
      elements: [],
      visibleElements: [],
      listeners: {},
      listened: false,
      moveListened: false,
      hooks: {},
      hooked: false,
      hovered: []
    });
  },

  beforeUpdate(chart, args, options) {
    const state = chartStates.get(chart);
    const annotations = state.annotations = [];

    let annotationOptions = options.annotations;
    if (helpers.isObject(annotationOptions)) {
      Object.keys(annotationOptions).forEach(key => {
        const value = annotationOptions[key];
        if (helpers.isObject(value)) {
          value.id = key;
          annotations.push(value);
        }
      });
    } else if (helpers.isArray(annotationOptions)) {
      annotations.push(...annotationOptions);
    }
    verifyScaleOptions(annotations.filter(isNotDoughnutLabel), chart.scales);
  },

  afterDataLimits(chart, args) {
    const state = chartStates.get(chart);
    adjustScaleRange(chart, args.scale, state.annotations.filter(isNotDoughnutLabel).filter(a => a.display && a.adjustScaleRange));
  },

  afterUpdate(chart, args, options) {
    const state = chartStates.get(chart);
    updateListeners(chart, state, options);
    updateElements(chart, state, options, args.mode);
    state.visibleElements = state.elements.filter(el => !el.skip && el.options.display);
    updateHooks(chart, state, options);
  },

  beforeDatasetsDraw(chart, _args, options) {
    draw(chart, 'beforeDatasetsDraw', options.clip);
  },

  afterDatasetsDraw(chart, _args, options) {
    draw(chart, 'afterDatasetsDraw', options.clip);
  },

  beforeDatasetDraw(chart, _args, options) {
    draw(chart, _args.index, options.clip);
  },

  beforeDraw(chart, _args, options) {
    draw(chart, 'beforeDraw', options.clip);
  },

  afterDraw(chart, _args, options) {
    draw(chart, 'afterDraw', options.clip);
  },

  beforeEvent(chart, args, options) {
    const state = chartStates.get(chart);
    if (handleEvent(state, args.event, options)) {
      args.changed = true;
    }
  },

  afterDestroy(chart) {
    chartStates.delete(chart);
  },

  getAnnotations(chart) {
    const state = chartStates.get(chart);
    return state ? state.elements : [];
  },

  // only for testing
  _getAnnotationElementsAtEventForMode(visibleElements, event, options) {
    return getElements(visibleElements, event, options);
  },

  defaults: {
    animations: {
      numbers: {
        properties: ['x', 'y', 'x2', 'y2', 'width', 'height', 'centerX', 'centerY', 'pointX', 'pointY', 'radius'],
        type: 'number'
      },
      colors: {
        properties: ['backgroundColor', 'borderColor'],
        type: 'color'
      }
    },
    clip: true,
    interaction: {
      mode: undefined,
      axis: undefined,
      intersect: undefined
    },
    common: {
      drawTime: 'afterDatasetsDraw',
      init: false,
      label: {
      }
    }
  },

  descriptors: {
    _indexable: false,
    _scriptable: (prop) => !hooks.includes(prop) && prop !== 'init',
    annotations: {
      _allKeys: false,
      _fallback: (prop, opts) => `elements.${annotationTypes[resolveType(opts.type)].id}`
    },
    interaction: {
      _fallback: true
    },
    common: {
      label: {
        _indexable: isIndexable,
        _fallback: true
      },
      _indexable: isIndexable
    }
  },

  additionalOptionScopes: ['']
};

function draw(chart, caller, clip) {
  const {ctx, chartArea} = chart;
  const state = chartStates.get(chart);

  if (clip) {
    helpers.clipArea(ctx, chartArea);
  }

  const drawableElements = getDrawableElements(state.visibleElements, caller).sort((a, b) => a.element.options.z - b.element.options.z);
  for (const item of drawableElements) {
    drawElement(ctx, chartArea, state, item);
  }

  if (clip) {
    helpers.unclipArea(ctx);
  }
}

function getDrawableElements(elements, caller) {
  const drawableElements = [];
  for (const el of elements) {
    if (el.options.drawTime === caller) {
      drawableElements.push({element: el, main: true});
    }
    if (el.elements && el.elements.length) {
      for (const sub of el.elements) {
        if (sub.options.display && sub.options.drawTime === caller) {
          drawableElements.push({element: sub});
        }
      }
    }
  }
  return drawableElements;
}

function drawElement(ctx, chartArea, state, item) {
  const el = item.element;
  if (item.main) {
    invokeHook(state, el, 'beforeDraw');
    el.draw(ctx, chartArea);
    invokeHook(state, el, 'afterDraw');
  } else {
    el.draw(ctx, chartArea);
  }
}

chart_js.Chart.register(Annotation);

return Annotation;

}));