Instrument Simulation

[Anon]

My project involves using PHP to display data from MySQL simulating a gauge, instrument like a speedometer for example.
Is this possible? Can anyone help me w/ clues to achieve this.
Thanks,
Al Borges

[Anon]

An easier way is a bar graph. Use a single pixel and modify the width and height. You could use image manipulation in php to do it too...probably by starting with two images and merging them as needed.

[Anon]

You want to draw a fancy graphic, or is a horizontal
bar-graph created with a table good enough? For
the former, you're going to need GD installed and do
some fancy programming with it, but the latter can
be accomplished with a simple table by creating
two cells containing   with the desired
background colors. You change the length of the
bar by manipulating the width of the cells.

[Anon]

If you have the GD library installed, you can have your fancy instrument panel background, then use the GD functions to "draw" the red needles onto the instrument panel. As long as you knew some reference points, it shouldn't be to hard. I haven't used the GD functions, though, so I can't give you a definite example.

---John Holmes...

[Anon]

Using GD you can graph any instrument you want, I'd use a fixed gif/jpg background
and draw the needles/bars/whatever over it
using GD (see articles about dynamic image
generation in this site or the GD documentation)

But that was already said by John, what
I wanted to add is that you would have
to deal with the refreshing problem since
you will like the instrument to be refreshed,
if so just add a

<meta http-equiv="Refresh" content="10">

This tells the browser to autorefresh the page each 10 seconds you can use 1 second if you like. For finer granularity you can use
JavaScript setInterval function from the
window object.

You CAN'T refresh the instrument from the server whenever you want. There're some
tricky avoidance plays to deal with this problem but it seems to me that a META
refresh tag will do the work.

Luis.