# XWUIChartSurvival

A survival chart: a fixed-type wrapper around `XWUIChart` that plots a survival curve - the fraction of a population still "surviving" as the x-axis (typically time) advances, stepping down at each event. Pass `{ series }` (one curve per cohort) plus a `block` preset (1-4) and `size`. Use it for Kaplan-Meier-style analysis: retention, churn, or time-to-event comparisons between groups.

## Basic Usage

Two cohorts (Series A and Series B) of six monthly values, Jan through Jun, rendered at medium size as two stepped curves declining across the months, each step a drop in the surviving fraction.

```example
file: examples/BasicUsage.ts
html: examples/BasicUsage.html
title: Basic Usage
description: Two cohorts drawn as stepped survival curves declining across six months.
```

## Clinical Trial Survival

Kaplan-Meier survival curves from a Phase III trial, stepping percent surviving down over twelve months so the treatment arm's separation above placebo is immediately visible.

```example
file: examples/ClinicalTrial.ts
html: examples/ClinicalTrial.html
title: Clinical Trial Survival
description: Treatment-versus-placebo survival curves stepping down over twelve months of a Phase III trial.
```

## Subscriber Retention

Retention curves for monthly versus annual SaaS plans over the first year, drawn with dashed lines and a crosshair so the monthly plan's steep early churn stands out.

```example
file: examples/SubscriberRetention.ts
html: examples/SubscriberRetention.html
title: Subscriber Retention
description: Monthly-versus-annual plan retention curves over a year, with crosshair and dashed lines.
```

```api
```