# init(xStart:xEnd:yStart:yEnd:) Creates a rectangle mark with fixed x and y intervals. ``` nonisolated init(xStart: CGFloat? = nil, xEnd: CGFloat? = nil, yStart: CGFloat? = nil, yEnd: CGFloat? = nil) ``` ## Discussion - xStart: The x start position. If `xStart` is `nil` then the rectangle will start at the leading edge of the plotting area. - xEnd: The x end position. If `xEnd` is `nil` then the rectangle will end at the trailing edge of the plotting area. - yStart: The y start position. If `yStart` is `nil` then the rectangle will start at the leading edge of the plotting area. - yEnd: The y end position. If `yEnd` is `nil` then the rectangle will end at the trailing edge of the plotting area. ### Discussion Use this initializer to create one rectangle with any optional x start, x end, y start, and y end position. If no parameters are specified the rectangle will fill the plotting area of the chart. The example below uses a number scale starting at (0,0) and ending at (6,6). The rectangle has the coordinates: (2,2), (2,4), (4,4), (4,2). ```swift Chart(data) { RectangleMark() .opacity(0.2) PointMark( x: .value("X", $0.x), y: .value("Y", $0.y) ) } ```  --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)