G'MIC exercises

Software G'MIC
1176

I have not touched G’MIC in a long time. Currently, I have a work problem involving large CSVs, my rationalization for returning to G’MIC. :slight_smile: Excel has been giving me a hard time with lots of manual preparatory work to make the data processing possible. For example, I need to use Power Query because the CSVs have more rows than Excel proper can handle, but I do not know enough M code to do everything in that environment. I would rather use G’MIC where possible.

Topics:

  1. Handling CSVs efficiently. Input specific columns? Output into manageable chunks?
  2. For each CSV, I would like to output multiple CSVs based on IDs containing certain strings.
  3. For each ID dataset, I would like to make calculations based on current and previous rows.

Any pointers would be greatly appreciated. Thank you.

1177

Some time ago, I passed by input_csv whilst going in a tangential direction toward wheelie animations. It uses an orders-of-magnitude smaller CSV file than what you are likely using, but is one that input_csv can consume. That said, I see nothing in the command’s composition that would prevent it from consuming arbitrarily large files.

goudyampersand_plots.txt (51.0 KB)

Attached is the CSV file used in the tutorial. It is a CSV file pretending to be a text file and each row is an x,y plot of a data point. My purposes in writing that tutorial are not your purposes, so you’ll have some (a lot of) adaptation to do, but this should give you some kind of starting point for reading comma separated value files in G’MIC.

You will get an image and, likely, implement what you need to do using other G’MIC image processing commands and math expressions. Hopefully, you haven’t become too rusty in these. I can recommend some tutorials that might help un-rusting efforts. :wink:

1178

Thank you. I have been incredibly busy, but it may be a good un-rusting exercise, more of a curiosity to get back into G’MIC. No urgency at the moment: basically, someone asked for impossible numbers from bad data, wondering why they do not make sense. Made my team feel things that were then communicated to me. Coming here for the px therapy, ha ha.

1179

It would be nice to see someone fill the void. I’m still too occupied with other things to do G’MIC things, but from times to times, I do a little exercise reading G’MIC codes at least so that I can get back to track when I feel ready.

1180

Why does this not work?

foo_recursive:
	eval "
		const N=5;
		recur_foo(v)=(
				tv=sqr(v);
				tv>50?tv:recur_foo(tv);
			);
		recur_foo(N);
		"

Should result in 625, according to Python.

EDIT: This works.

foo_recursive:
	eval "
		const N=5;
		recur_foo(v)=(
				v>50?v:recur_foo(v*v);
			);
		recur_foo(N);
		"
1181

I guess this thread is quite old now because people decided to make their equivalents, but I think it still has a place for asking questions about G’MIC.

I recently did use G’MIC for something. When I split channels to do the good old slice roll with the mouse wheel, it didn’t work. I remember something changed a while back. Could I have a refresher? Not having this will affect one of my filters I made for @Silvio_Grosso a long time ago.

1182

Are you talking about interactive window upon display? I think I used to do something like that with a keyboard. Check PAGEUP/PAGEDOWN.