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ferrum.render_config

Per-chart rendering policy configuration for auto-raster behavior.

RenderConfig — per-chart rendering policy configuration.

RenderConfig dataclass

Per-chart rendering configuration.

Controls the auto-raster policy that transparently substitutes mark_raster for per-element marks when the mark count exceeds raster_threshold. This prevents multi-million-row charts from producing impractically large SVG output.

For one-off overrides, prefer the raster= keyword on output methods (chart.show(raster=False), chart.save(..., raster=False), chart.show_svg(raster=False)). Use RenderConfig when you want to bake the policy into the chart object itself.

Parameters:

Name Type Description Default
raster_threshold int or None

Mark count above which auto-raster fires. None disables auto-raster entirely.

500_000
raster_behavior ('warn', 'silent', 'error')

"warn" emits a UserWarning when auto-raster substitutes. "silent" substitutes without warning. "error" raises ValueError instead of substituting.

"warn"
raster_aggregate str

Aggregation function for the substituted mark_raster.

"count"
raster_cmap str

Colormap for the substituted mark_raster.

"viridis"