A simple thermometer chart for ASP.NET

• Download jThermometer source files - 4.83 KB

Introduction

jThermometer is a class for creating thermometer charts of the type used generally to show progress towards a fund raising goal. It arose out of my involvement in a charity walkathon. The organizer wanted to have a thermometer-type chart on a the walkathon's home page to indicate progress towards fund raising goals. I was unable to find anything free that seemed appropriate for the site, so I decided to create my own and share it here on CodeProject.

The chart uses GDI+ to compose an image and stream it out to the browser.

Using the code

For the purposes of portability, I've separated the chart into two parts:

• jThermometer is a class that creates a bitmap using GDI+ and streams it out to the current request as a GIF image.
• Thermometer.aspx is a web page that accepts various parameters controlling the appearance of the Thermometer chart and that can be referenced by an <IMG> tag on another web page.

Thermometer.aspx uses these query string values:

MIN:	Value displayed at the bottom of the thermometer.
MAX:	Value displayed at the top of the thermometer
IV:	Value indicated on the thermometer.
T:	Title displayed at the top of the thermometer
VT:	Type of value (1=currency, 2=decimal, 3=integer)

Further work

At present, the thermometer does not scale. I'd like to have it automatically scale based on user-provided dimensions. There are also a lot of appearance-related aspects that should be controllable via properties, such as text color, indicator color, and the color of the mercury.