This section explains how to create and customize an Arc annotation object. An arc annotation looks as under:

 

 
The XML to create the above arc is:
 
<chart>
   ...
   <annotations>
      <annotationGroup id='Grp1' >
         <annotation type='arc' color='639ACE' x='200' y='200' radius='50'/>
      </annotationGroup>
   </annotations>
   ...
</chart>
 
Defining inner radius
In an arc, you often need to customize the inner radius of the arc. You can do the same using the innerRadius attribute. Here we have set innerRadius='35'.
 
 
Setting start and end angle
Also, with arcs, the starting and ending angle needs to be customizable. The same is done using startAngle and endAngle attributes. Setting startAngle='0' and endAngle='180', we can create a semi-circular arc as under:
 
 
Adding a gradient fill to the arc
Now we will add a gradient fill to the arc. For that, all we have to do is add another color to the list in the color attribute.
 
 
The gradient pattern for an arc by default is radial. We can make it linear by setting fillPattern='linear':
 
 
We can also set the ratio in which the constituent colors of the gradient would be divided using fillRatio attribute. Since we have 2 colors in the gradient here, we would need 2 values in fillRatio, which should sum upto 100. fillRatio='80, 20' would give:
 
 
Adding a border to the arc and customizing it
Now lets add a border to the arc. For that, we need to set showBorder='1'.
 
 
The border color and thickness can be customized using the borderColor and borderThickness attributes. Setting borderColor='333333' and borderThickness='4' would give:
 
 
So the XML for the above arc would look as under:
<chart>
   ...
   <annotations>
      <annotationGroup id='Grp1' >
         <annotation type='arc' color='639ACE,FFFFFF' x='200' y='200' radius='50' innerRadius='35' startAngle='0' endAngle='180' fillRatio='80, 20' fillPattern='linear' showBorder='1' borderColor='333333' borderThickness='4'/>
      </annotationGroup>
   </annotations>
   ...
</chart>
 
The various attributes for the arc annotation using which it can be customized are:
 
Attribute Name Type / Range Description
type Rectangle, Circle, Polygon, Line, Arc, Text, Image Needs to be set to Arc to create an arc annotation type.
x Number The starting x co-ordinate for the annotation. This x co-ordinate is relative to the x co-ordinate of the annotation group in which the annotation is placed. For example, if you have set the x co-ordinate of the annotation group as 50 and the x co-ordinate of the annotation is 100, then th effective x co-ordinate of the annotation would be 150 w.r.t to the starting position of the chart.
y Number The starting y co-ordinate for the annotation. This again is relative to the starting y co-ordinate of the annotation group in which the annotation is placed.
radius Number The radius of the arc.
innerRadius Number The inner radius for an arc. By default it is 80% of outer radius.
yRadius Number The y-radius of the arc. Allows you to stretch or compress the annotation vertically.
color Hex Color (without the '#') A generic color for the annotation from which fill color and border color (whichever applies) will be derived automatically.
alpha Number(1-100) The alpha(transparency) of the annotation. By default, it would be set to 100.
startAngle Number (0-360) This attribute is used to set the starting angle for a circle, arc or polygon. For example, if you need to draw a semi-circle or a semi-circular arc, then set startAngle="0" and endAngle="180" for the respective annotation. Similarly for a polygon, if you need to draw a diamond shape, then set sides="4" and the startAngle="90".
endAngle Number (0-360) This attribute is used to set the ending angle for a circle or arc.
 
Fill and Border properties
fillColor Hex code (separated by commas if there are multiple codes for a gradient) This attribute sets the background fill color for the annotation. You can set any hex color code as the value of this attribute. To specify a gradient as background color, separate the hex color codes of each color in the gradient using comma.
Example: FF5904,FFFFFF. Remember to remove # and any spaces in between. See the gradient specification page for more details.
fillAlpha Number (0-100) Sets the alpha (transparency) for the background fill. If you've opted for gradient background, you need to set a list of alpha(s) separated by comma. If the number of alpha values you have specified is lesser than the number of colors in the gradient, then the remaining colors would by default have an alpha of 100.
fillRatio Number (0-100) If you've opted for a gradient background fill, this attribute lets you set the ratio of each color constituent. Tha ratio for the colors should be separated by commas and the same must sum upto 100. For example, if you have 2 colors in your gradient, then fillRatio could be 80,20. There should be no spaces in between the values.
fillAngle Number (0-360) Angle of the background fill color, in case of a gradient. Evey color in the gradient can have a fill angle (which have to be separated by commas without any spaces in between). If the number of angle values is less than the number of colors in the gradient, then a default value of 0 is taken for the remaining colors. For example, fillAngle='90, 270' for a gradient having 2 colors.
fillPattern Radial/Linear The pattern of the gradient. It takes a default value of radial for circle.
showBorder Boolean (0/1) Whether to show a border for the annotation.
borderColor Hex code (without the '#') The border color of the annotation if showBorder='1'.
borderThickness Hex code (without the '#') The border thickness of the annotation if showBorder='1'.
borderAlpha Number (0-100) The border alpha(transparency) of the annotation if showBorder='1'.
 
Application
 
 
The XML for the above is:

<chart ... >
   ...
   <annotations>
      <annotationGroup id='Grp1' showBelow='1'>
         <annotation type='arc' x='165' y='130' radius='106' innerRadius='55' startAngle='0' endAngle='180' fillAngle='90' fillRatio='50,50' color='606417, 000000' fillPattern='linear' borderColor='FFFFFF' borderThickness='2'/>
      </annotationGroup>
   </annotations>
   ...
</chart>