The dial image of the requested size is generated on the server side using the GLG Graphics Server in the form of a JSP Servlet or an ASP.NET Handler. The size of the dial image is specified using the width and height parameters of the URL. Click here to display the dial's URL directly to see its parameters.
The dial Servlet or Handler used by the demo is written in a generic way and may be used to display various types of dials by using the dial_type URL parameter. The same image URL may be used as a component in multiple web pages. For example, the AJAX Dashboard Demo uses the URL to render three instances of dials in a larger dashboard. JSP Servlet or ASP.NET Handler source code is provided and may be further customized if required.
The value to be displayed in the dial may be provided as the value parameter of the URL. If the value parameter is not specified, the data will be supplied by the Servlet or Handler from a data source on the server side. The "Label:" entry field demonstrates how to supply Servlet or Handler parameters for the dial from HTML.
The demo uses a few pre-built dials from the Dials and Meters palette provided with the controls widget set. The dials' drawings may be customized using the GLG Graphics Builder. Custom dials may be built from scratch using the Graphics Builder as well.
The dial Servlet or Handler loads dial drawings just once and reuses
between all Servlet or Handler instances and threads for increased