Adobe illustrator tracing in js script

Question

I'm trying to trace a PNG image in Adobe Illustrator via js script. I've tried different approaches, but always have the same problem - I can't change Color setting automatically. Here is my simple script:

thisImage.tracing.tracingOptions.tracingMethod = TracingMethodType.TRACINGMETHODABUTTING;
thisImage.tracing.tracingOptions.cornerFidelity = 50;
thisImage.tracing.tracingOptions.pathFidelity = 55;
thisImage.tracing.tracingOptions.noiseFidelity = 5;
thisImage.tracing.tracingOptions.maxColors = 40;
thisImage.tracing.tracingOptions.colorFidelity = 50;
app.redraw();

So other parameters were changed during this script execution (Paths, Corners, Noise), but Colors is 100 again despite maxColors and colorFidelity. And I don't see any additional fields in tracing options that can be responsible for this.

Could you please give me any advise how to solve this issue?

Answer 1

1. What does this row mean: thisImage.tracing.tracingOptions.tracingMethod = TracingMethodType.TRACINGMETHODABUTTING; ? I could not find any property tracingMethod in TracingOptions in Adobe Illustrator CC Reference: JavaScript, p.233

2. From above mentioned doc for TracingOptions object: maxColors: The maximum number of colors allowed for automatic palette generation. Used only if tracingMode is color or grayscale. Range: 2 to 256

Hence, tracingOptions.tracingMode should be set to appropriate value. In your script this setting is absent.