Word Cloud and Network Graph lay themselves out from an unseeded generator, so the same input never renders the same picture twice #7326

What happened?

Two operators lay their output out from an unseeded generator, so the same input never renders the same picture twice.

Word Cloud builds its image with WordCloud(width=1920, height=1080, stopwords=set(STOPWORDS), max_words=..., background_color='white', include_numbers=True) and passes no random_state. Network Graph calls nx.spring_layout(G, k=0.5, iterations=50) with no seed. In both, rendering the same data twice produces two different pictures; passing a seed makes them identical.

Only the arrangement moves. Taking Word Cloud's layout apart across two unseeded renders of the same text, the words and their frequencies are identical — bus at 1.0, transit at 0.8, plan at 0.8 and so on — while every position, orientation and colour differs. Which words appear and how large they are is decided by frequency alone, and Network Graph's nodes and edges are likewise unaffected. Nothing about either analysis is at stake here.

(The scattered zero-degree points are unrelated, and #7327 removes them.)

What is at stake is reproducibility. Re-running a workflow rearranges everything, a saved screenshot stops matching what the operator now produces, and two people opening the same workflow see different pictures of the same data — with no way to recover the earlier rendering, including one the user happened to prefer. Every other visualization in Texera returns the same picture for the same input.

Two ways to fix it, and the choice is a product call rather than a technical one:

• Pass a fixed seed in both operators. Smallest change, makes them behave like every other chart. Existing workflows render one last different picture and are stable from then on.
• Expose the seed as a setting with a fixed default. Same reproducible default, and a user who wants a different arrangement can change the number and can get that arrangement back later, which is not possible today.

Expected either way: a given input renders the same picture every time.

How to reproduce?

Point a Word Cloud at any text column, or a Network Graph at two columns of node labels, and run the workflow twice without changing anything. Word Cloud places the same words at the same sizes in different positions, angles and colours; Network Graph draws the same nodes and edges at different coordinates.

Version/Branch

1.3.0-incubating-SNAPSHOT (main)