---
title: "init(xStart:xEnd:y:)"
framework: charts
role: symbol
role_heading: Initializer
path: "charts/rulemark/init(xstart:xend:y:)-444cp"
---

# init(xStart:xEnd:y:)

Creates a horizontal rule mark that plots a value on y.

## Declaration

```swift
nonisolated init<Y>(xStart: CGFloat? = nil, xEnd: CGFloat? = nil, y: PlottableValue<Y>) where Y : Plottable
```

## Parameters

- `xStart`: The x start position. If xStart is nil the rule will start at the leading edge of the plotting area.
- `xEnd`: The x end position. If xEnd is nil the rule will end at the trailing edge of the plotting area.
- `y`: The value plotted with y.

## Discussion

Discussion Use this initializer to create a horizontal rule across a chart’s plotting area at a y position: Chart {     ForEach(data) {         BarMark(             x: .value("Department", $0.department),             y: .value("Profit", $0.profit)         )     }     RuleMark(y: .value("Break Even Threshold", 9000))         .foregroundStyle(.red) }

See the first code example in RuleMark for the setup of the structure that contains the department and profit properties.