theme-picker

name

theme-picker

description

Presents a menu of available visual themes when the user asks for a chart, plot, graph, or any visualization interactively and has not already chosen a look. Trigger on requests like "make a bar chart", "plot this", "chart revenue by category", "visualize this", "show me a graph". Skip the menu when the user named a theme, a session default theme is set, or the chart is being generated inside a pipeline run.

Theme Picker

When the user asks for a chart interactively and no theme is decided yet, offer the choice before rendering. Theme choice changes which palette flows through the chart helpers — it never replaces them: swd_style() is still always the entry point (CLAUDE.md Rule 8).

When to SKIP the menu (check in this order)

1. User named a theme in their request ("make a 538-style bar chart") — use it directly.
2. A session default is set — read working/session_state.yaml key default_theme; if present, use it silently.
3. The chart is part of a pipeline run (Chart Maker agent, /run-pipeline, deck generation) — never interrupt a pipeline with a menu. Use the run's {{THEME}} or the session default or analytics.
4. A menu was already shown this session and the user picked — reuse their pick; don't re-ask on every chart.

If any of these apply, proceed straight to rendering.

Steps (interactive chart, no theme decided)

1. List the themes. Call list_themes() from helpers.theme_loader. It returns analytics (the default) plus every brand theme found in themes/brands/. Themes students build appear here automatically once their theme.yaml exists.

2. Show a short menu. For each brand theme, read theme.display_name and theme.description from themes/brands/{name}/theme.yaml.

   Which theme should I use for this chart?
     1. analytics       — the default look
     2. example         — Acme Corp: teal/coral reference theme
     3. fivethirtyeight — FiveThirtyEight: bold blue/red on gray canvas
   

3. Ask, and wait for the user's choice.

4. Render with the chosen theme — through the standard helpers, never around them:

   from helpers.chart_helpers import load_theme_colors, swd_style
   theme = load_theme_colors("<choice>")
   swd_style(theme=theme)
   

   Pass theme=theme to the chart builders (highlight_bar, highlight_line, and the rest) so highlight colors come from the theme.

5. Offer to remember. After rendering, offer once: "Want me to use this theme for the rest of the session?" If yes, write default_theme: <name> into working/session_state.yaml.

New or edited themes

If the user is building or modifying a theme, point them at the autograder before using it:

python scripts/check_theme.py <name>

A theme must pass all three gates (color conflicts, WCAG contrast, base-key sync) before it ships in a deliverable. The worked example lives at themes/brands/fivethirtyeight/.

Note on dark themes

The chart helpers apply a theme's background, text, and highlight colors, but title and data-label text is fixed dark — so themes here are light themes. A dark-background theme would render an unreadable title. Keep brand themes light-background.