Txtzyme Javascope Feeds Java's 2D Graphics

By: WardCunningham

2010-06-13 09:28:02

In my last post I described plotting Txtzyme output with a perl one-liner. I wondered, can I do better with a real graphics library? I was looking for something portable, like GD, but chose the already installed Graphics2D in Java 5 for convenience.


As a once Tektronix engineer I have strong opinions about what a waveform should look like. I'm pleased with the look I get with Graphics2D. I would have never thought that the joint and end-cap choices would matter, but they do, and anti-aliasing is a must also.

Once Scope.java is running and listening to a Teensy, one has only to send data-generating Txtzyme nano-programs down the other way to light the screen with waveforms.

Here is an included script called Timebase.sh that does exactly this, alternating between real-time and equivalent-time acquisition of my favorite source, 60Hz hum.

while true
do echo _slow_6d1o500{5sp16m600u}0o >/dev/cu.usbmodem
sleep 10
for i in 1 2 3 4 5 6 7 8 9 10
do echo _fast_1o500{5sp}0o >/dev/cu.usbmodem
sleep .348

Scope.java is organized as three separate threads. One reads Txtzyme data, another displays it, and a third handles user-input. Refreshing at 30Hz, Scope.java takes 15% to 25% of my MacBook Pro cpu resources.

The Javascope demo project joins several others in the Txtzyme repo on GitHub.

Evolved from other projects, Scope.java is a mixture of about three different coding styles each from a different era. I would love for someone to help me with a code review so I can bring this up-to-date.

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