{
    annotation: {
        annotations: [{
            type: 'line',
            mode: 'horizontal',
            scaleID: 'y-axis-0',
            value: '25',
            borderColor: 'red',
            borderWidth: 2
        }],
        // Defines when the annotations are drawn.
        // This allows positioning of the annotation relative to the other
        // elements of the graph.
        // Should be one of: afterDraw, afterDatasetsDraw, beforeDatasetsDraw
        // See http://www.chartjs.org/docs/#advanced-usage-creating-plugins
        drawTime: "afterDraw" // (default)
    }
}

{
    type: 'line',
    // set to 'vertical' to draw a vertical line
    mode: 'horizontal',

    // ID of the scale to bind onto
    scaleID: 'y-axis-0',

    // Data value to draw the line at
    value: 25,

    // Optional value at which the line draw should end
    endValue: 26,

    // Line color
    borderColor: 'red',

    // Line width
    borderWidth: 2,

    // Line dash
    // https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/setLineDash
    borderDash: [2, 2],

    // Line Dash Offset
    // https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineDashOffset
    borderDashOffset: 5,

    label: {
        // Background color of label, default below
        backgroundColor: 'rgba(0,0,0,0.8)',

        // Font family of text, inherits from global
        fontFamily: "sans-serif",

        // Font size of text, inherits from global
        fontSize: 12,

        // Font style of text, default below
        fontStyle: "bold",

        // Font color of text, default below
        fontColor: "#fff",

        // Padding of label to add left/right, default below
        xPadding: 6,

        // Padding of label to add top/bottom, default below
        yPadding: 6,

        // Radius of label rectangle, default below
        cornerRadius: 6,

        // Anchor position of label on line, can be one of: top, bottom, left, right, center. Default below.
        position: "center",

        // Adjustment along x-axis (left-right) of label relative to above number (can be negative)
        // For horizontal lines positioned left or right, negative values move
        // the label toward the edge, and negative values toward the center.
        xAdjust: 0,

        // Adjustment along y-axis (top-bottom) of label relative to above number (can be negative)
        // For vertical lines positioned top or bottom, negative values move
        // the label toward the edge, and negative values toward the center.
        yAdjust: 0,

        // Whether the label is enabled and should be displayed
        enabled: false,

        // Text to display in label - default is null
        content: "Test label"
    }
}

{
    type: 'box',

    // ID of the X scale to bind onto
    xScaleID: 'x-axis-0',

    // ID of the Y scale to bind onto
    yScaleID: 'y-axis-0',

    // Left edge of the box. in units along the x axis
    xMin: 25,

    // Right edge of the box
    xMax: 40,

    // Top edge of the box in units along the y axis
    yMax: 20,

    // Bottom edge of the box
    yMin:  15,

    // Stroke color
    borderColor: 'red',

    // Stroke width
    borderWidth: 2,

    // Fill color
    backgroundColor: 'green'
}