'What unicode characters are best for drawing a squarewave in a string

I am trying to represent a square wave pulse train in a string, from an array of stored GPIO events and timings. the code is working but I need better Unicode characters for the transitions.

this is my current method

    public String waveform()
    {
    String s = "";
    int pulses;
    int pulseWidth;

    pulseWidth = events.get(1).duration; //mostly right!
    for (RF433Event e: events)
    {
        pulses = e.duration/pulseWidth;
        if (e.gpioEvent.getEdge() == PinEdge.RISING)
        {
            // rising edge so for the duration it was low
            for (int i = 0; i<pulses; i++) s = s+'_';
            s = s+"\u02E9";
        } else
        {
            // falling edge so for the duration it was high
            for (int i = 0; i<pulses; i++) s = s+"\u0305";
            s = s+"\u02E5";
        }

    }
    return s;
    }

The output looks like this in the Intellij console window enter image description here

but strangely is not appearing on the RPi, do I need to install something else on the Pi?

javaraspberry-pi


Solution 1:[1]

After much experimentation this works for me

public String waveform()
{
    String s = "";
    int pulses;
    int pulseWidth;
    // Characters tried for drawing the pulse train
    // Low line - "_", "\u0332" Combining Low Line, "\uFF3F"; FULLWIDTH LOW LINE
    // High line - "\u0305" COMBINING OVERLINE, "\u203E" over line 
    // Vertical -  "\u20D2" COMBINING LONG VERTICAL LINE OVERLAY, "\u007C" Vertical line, "\u02E9" MODIFIER LETTER EXTRA-LOW TONE BAR
    if (events.get(0).duration > 50000) {return "Excessive duration in pluse 0 "+events.get(0).duration;}
    pulseWidth = 100; //gives a reasonable pulse train
    for (RF433Event e: events)
    {
        pulses = e.duration/pulseWidth;
        if (e.gpioEvent.getEdge() == PinEdge.RISING)
        {
            // rising edge so for the duration it was low
            for (int i = 0; i<pulses; i++) s = s+ "_";
            s = s+"\u20D2";
        } else
        {
            // falling edge so for the duration it was high
            for (int i = 0; i<pulses; i++) s = s+"\u0305";
            s = s+"\u20D2";
        }
    }
    return s;
}

these are the results Pulse Trains

Solution 2:[2]

I like the idea of using "combining characters", but find them harder to edit. Here are other unicode options I've used or tried.

  1. box drawings (light or heavy), which (as noted) need 2 rows:
1   ??????      ??????
0 ???    ???  ???    ???
  1. "lower one eighth block" (2581) with "lower three quarters block" (2586) or "full block" (2588). (Depending on font and line spacing, "full block" can reach the previous line.)
??????????
??????????
  1. "solidus" (slash), "reverses solidus" (backslash), "horizontal scan line 1" (23BA), and "horizontal scan line 9" (23BD) - for non-vertical transitions.
?????\???????????/?????\??

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 gjwo
Solution 2 Clif Kussmaul

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