chartjs-plugin-annotation

# Point Annotations

Point annotations are used to mark points on the chart area. This can be useful for highlighting values that are of interest.

const options = {
  plugins: {
    annotation: {
      annotations: {
        point1: {
          type: 'point',
          xValue: 1,
          yValue: 60,
          backgroundColor: 'rgba(255, 99, 132, 0.25)'
        }
      }
    }
  }
};

# Configuration

# Point annotation specific options

The following options are available for point annotations.

Name Type Scriptable Default
backgroundShadowColor Color Yes 'transparent'
borderWidth number Yes 1
pointStyle PointStyle Yes 'circle'
radius number Yes 10
rotation number Yes 0
xAdjust number Yes 0
xValue number | string Yes undefined
yAdjust number Yes 0
yValue number | string Yes undefined

# Common options to all annotations

The following options are available for all annotations.

Name Type Scriptable Default
adjustScaleRange boolean Yes true
backgroundColor Color Yes options.color
borderColor Color Yes options.color
borderDash number[] Yes []
borderDashOffset number Yes 0
borderShadowColor Color Yes 'transparent'
display boolean Yes true
drawTime string|number Yes 'afterDatasetsDraw'
hitTolerance number Yes 0
init boolean See initial animation undefined
id string No undefined
shadowBlur number Yes 0
shadowOffsetX number Yes 0
shadowOffsetY number Yes 0
xMax number | string Yes undefined
xMin number | string Yes undefined
xScaleID string Yes undefined
yMin number | string Yes undefined
yMax number | string Yes undefined
yScaleID string Yes undefined
z number Yes 0

# General

If one of the axes does not match an axis in the chart, the point annotation will take the center of the chart as point. The 2 coordinates, xValue, yValue are optional. If not specified, the point annotation will take the center of the scale dimension as point.

The 4 coordinates, xMin, xMax, yMin, yMax are optional. If not specified, the box is expanded out to the edges in the respective direction and the box size is used to calculated the center of the point. To enable to use the box positioning, the radius must be set to 0 or NaN.

Name Description
adjustScaleRange Should the scale range be adjusted if this annotation is out of range.
display Whether or not this annotation is visible.
drawTime See drawTime.
hitTolerance Amount of pixels to interact with annotations within some distance of the mouse point.
id Identifies a unique id for the annotation and it will be stored in the element context. When the annotations are defined by an object, the id is automatically set using the key used to store the annotations in the object. When the annotations are configured by an array, the id, passed by this option in the annotation, will be used.
radius Size of the point in pixels.
rotation Rotation of point, in degrees.
xAdjust Adjustment along x-axis (left-right) of point relative to computed position. Negative values move the point left, positive right.
xMax Right edge of the box in units along the x axis.
xMin Left edge of the box in units along the x axis.
xScaleID ID of the X scale to bind onto. If missing, the plugin will try to use the scale of the chart, configured as 'x' axis. If more than one scale has been defined in the chart as 'x' axis, the option is mandatory to select the right scale.
xValue X coordinate of the point in units along the x axis.
yAdjust Adjustment along y-axis (top-bottom) of point relative to computed position. Negative values move the point up, positive down.
yMax Bottom edge of the box in units along the y axis.
yMin Top edge of the box in units along the y axis.
yScaleID ID of the Y scale to bind onto. If missing, the plugin will try to use the scale of the chart, configured as 'y' axis. If more than one scale has been defined in the chart as 'y' axis, the option is mandatory to select the right scale.
yValue Y coordinate of the point in units along the y axis.
z The z property determines the drawing stack level of the point annotation element. All visible elements will be drawn in ascending order of z option, with the same drawTime option.

# Styling

Name Description
backgroundColor Fill color.
backgroundShadowColor The color of shadow. See MDN (opens new window).
borderColor Stroke color.
borderDash Length and spacing of dashes. See MDN (opens new window).
borderDashOffset Offset for line dashes. See MDN (opens new window).
borderShadowColor The color of border shadow. See MDN (opens new window).
borderWidth Stroke width.
pointStyle Style of the point.
shadowBlur The amount of blur applied to shadow. See MDN (opens new window).
shadowOffsetX The distance that shadow will be offset horizontally. See MDN (opens new window).
shadowOffsetY The distance that shadow will be offset vertically. See MDN (opens new window).

# Element

The following diagram is showing the element properties about a 'point' annotation:

point

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