add docstrings to path.go

path.go

@@ -3,25 +3,37 @@
 
 package draw2d
 
+// Path describes the interface for path drawing.
 type Path interface {
-	// Return the current point of the path
+	// LastPoint returns the current point of the path
 	LastPoint() (x, y float64)
-	// Create a new subpath that start at the specified point
+	// MoveTo creates a new subpath that start at the specified point
 	MoveTo(x, y float64)
-	// Create a new subpath that start at the specified point
+	// RMoveTo creates a new subpath that start at the specified point
 	// relative to the current point
 	RMoveTo(dx, dy float64)
-	// Add a line to the current subpath
+	// LineTo adds a line to the current subpath
 	LineTo(x, y float64)
-	// Add a line to the current subpath
+	// RLineTo adds a line to the current subpath
 	// relative to the current point
 	RLineTo(dx, dy float64)
-
+	// QuadCurveTo adds a quadratic Bézier curve to the current subpath
 	QuadCurveTo(cx, cy, x, y float64)
+	// QuadCurveTo adds a quadratic Bézier curve to the current subpath
+	// relative to the current point
 	RQuadCurveTo(dcx, dcy, dx, dy float64)
+	// CubicCurveTo adds a cubic Bézier curve to the current subpath
 	CubicCurveTo(cx1, cy1, cx2, cy2, x, y float64)
+	// RCubicCurveTo adds a cubic Bézier curve to the current subpath
+	// relative to the current point
 	RCubicCurveTo(dcx1, dcy1, dcx2, dcy2, dx, dy float64)
+	// ArcTo adds an arc to the current subpath
 	ArcTo(cx, cy, rx, ry, startAngle, angle float64)
+	// RArcTo adds an arc to the current subpath
+	// relative to the current point
 	RArcTo(dcx, dcy, rx, ry, startAngle, angle float64)
+	// Close creates a line from the current point to the last MoveTo
+	// point (if not the same) and mark the path as closed so the
+	// first and last lines join nicely.
 	Close()
 }