CGContextStrokePath

CGContextStrokePath is a function in the Core Graphics (Quartz 2D) API used to render (stroke) the current path in a graphics context. It draws the outline of the path using the current graphics state, including the stroke color, line width, line join and cap styles, dash pattern, and miter limit. The operation applies the current transformation matrix and clipping region when rendering.

To use CGContextStrokePath, a path is first constructed in a graphics context, typically by issuing calls such as CGContextBeginPath, CGContextMoveToPoint, CGContextAddLineToPoint, or by adding an existing CGPath with CGContextAddPath. Before stroking, the developer can configure stroke attributes with functions like CGContextSetStrokeColorWithColor, CGContextSetLineWidth, CGContextSetLineJoin, CGContextSetLineCap, CGContextSetLineDash, and CGContextSetMiterLimit. Once configured, calling CGContextStrokePath(context) strokes the path and clears it from the context.

A key behavioral note is that CGContextStrokePath consumes the current path: after stroking, the path is no longer in the context. If the same shape needs to be stroked again, the path must be recreated or retained elsewhere (for example, by using a CGPath copy). This function only performs stroking and does not fill the path.

CGContextStrokePath is available on macOS and iOS and is commonly used in immediate-mode drawing routines where paths are built and stroked within a single drawing pass. For combined stroke and fill in one pass, developers may use alternative functions such as CGContextDrawPath with appropriate mode flags (e.g., kCGPathFillStroke) or perform separate fill and stroke operations.