This GUI Application can be used to visualize multiple Waveforms that can contain high amount of samples. OpenGL is used for the waveform visualization with extensive alpha blending. It still works nice when displaying 10 Millions of sample points.
The program is developed in Lazarus (modern Pascal), releases available for Windows and Linux.
A minimal VScope JSON file look like this:
{
"WAVES": [
{
"NAME": "Wave1",
"SAMPLT": 0.00025,
"VALUES": "1.2|1.0|1.04|1.43E2|1.22E-2",
"STARTT": 0,
"DATAUNIT": "m"
},
{
"NAME": "Wave2",
"SAMPLT": 0.00025,
"VALUES": "0.2|0.3|1.0E2|0.002|0.021",
"STARTT": 0,
"DATAUNIT": "A"
}
]
}
All time units are given in seconds.
The single VALUES field stores all the wave data in string format, where the samples are floating point values separated by the "|" (pipe) character. This format was chosen in order not to overload the JSON parsers creating huge amount of data nodes. (The VSCope uses a special, optimized parser to parse the VALUE field). In python you can use '|'.join(value_array) to have a better performance creating the VALUES field.
The SAMPLT field contains the sampling time of the wave data (in seconds).
The STARTT field contains the wave start time (in seconds).
There are some more additional data in the VSCope data files. A more complete file looks like this:
{
"VIEW": {
"TIMEDIV": 1,
"VIEWSTART": 1.28412621443668
},
"MARKERS": [
{
"VISIBLE": true,
"MTIME": 2.3151481122469
},
{
"VISIBLE": true,
"MTIME": 4.03960066699143
}
],
"WAVES": [
{
"NAME": "Wave1",
"SAMPLT": 0.00025,
"VALUES": "1.2|1.0|1.04|1.43E2|1.22E-2",
"STARTT": 0,
"DATAUNIT": "m",
"COLOR": 4278255615,
"ALPHA": 0.5,
"VIEWSCALE": 0.5,
"VIEWOFFSET": 3
},
{
"NAME": "Wave2",
"SAMPLT": 0.00025,
"VALUES": "0.2|0.3|1.0E2|0.002|0.021",
"STARTT": 0,
"DATAUNIT": "A",
"COLOR": 4294734599,
"ALPHA": 0.5,
"VIEWSCALE": 0.5,
"VIEWOFFSET": 1
}
]
}
The COLOR field is a 32-bit integer value. The highest 8 bits are 255 usually (this is the alpha value, which is usually ignored). The bits[0..7] = red, bits[8..15] = green, bits[16..25] = blue values.