UsyTrace: Online Frequency Response Tracer

• https://usyless.uk/trace
• All Processing is done on device and no analytics are performed.

• Feel free to contribute or suggest changes

• Found a bug? Report it to @usy_ on Discord!

General use

• Press "Choose Image" and choose an image to trace from, drop any images onto the page, or paste an image into the page using Ctrl+V
• Align the top and bottom lines for SPL and Frequency to known values, then input those in the sidebar
• The line should be traced initially, if it is not, refer below
• Press "Export Trace"

If auto trace fails

• Click "Clear Path" to make sure any auto traced line does not mess with your new trace
• Click "Select Path", then click on your line to trace
• If you find that it hasn't selected the whole line, you can click on the region it has not selected to try to select more (Adjust settings as a last resort)
• Made a mistake or cleared the trace? Use the "Undo" button
• Undone too much? Use the "Redo" button
• Use "Add Point" to add points manually to the trace

Mobile Specifics

• Move the SPL and Frequency lines by using the buttons, selecting the line to trace works as normal but may require more tries

Trace Settings:

Colour Tolerance

• Adjust the maximum tolerance for colours that the tracer takes into account when tracing the line
• Increase this if the tracer isn't selecting the whole line
• Decrease this if the trace is jittery

Export Settings

Points Per Octave

• The points per octave to export data with, applied smoothing is half of the export PPO

Delimitation

• Whether to use tab or space between exported frequency and spl pairs

Minimum Frequency

• The minimum frequency to export to, will draw a straight line from first data point to minimum frequency

Maximum Frequency

• The maximum frequency to export to, will draw a straight line from the last data point to maximum frequency

Compiling Instructions

1. Download and install emscripten
2. Compile with build.bat, or using the commands below.

Testing

emcc imageTracer.cpp -O3 -sWASM=1 -sALLOW_MEMORY_GROWTH=1 -sEXPORTED_RUNTIME_METHODS=cwrap -sASSERTIONS=1 -sNO_DISABLE_EXCEPTION_CATCHING -fno-rtti -flto -sENVIRONMENT=worker -sINITIAL_HEAP=104857600 -sFILESYSTEM=0

Release

emcc imageTracer.cpp -O3 -sWASM=1 -sALLOW_MEMORY_GROWTH=1 -sEXPORTED_RUNTIME_METHODS=cwrap -sINITIAL_HEAP=104857600 -sASSERTIONS=0 -fno-exceptions -flto -fno-rtti -sENVIRONMENT=worker -sFILESYSTEM=0

Info/Extras

• Default heap size set to 100mb
• Set stack size with -sSTACK_SIZE=size in bytes
• Set max memory with -sMAXIMUM_MEMORY=size in bytes (2gb by default, >2gb has performance penalty afaik)
• To use c++20 features: -std=c++20
• Pass -msimd128 to auto add SIMD, seems to make no noticeable performance difference for now