Drawing Arbitrary Shapes

This class implements the Shape interface and represents a geometric path constructed from lines, and quadratic and cubic curves. The three constructors in this class can create the GeneralPath object with the default winding rule (WIND_NON_ZERO), the given winding rule (WIND_NON_ZERO or WIND_EVEN_ODD), or the specified initial coordinate capacity. The winding rule specifies how the interior of a path is determined.

public void Paint (Graphics g) {
    Graphics2D g2 = (Graphics2D) g;
    ...
}

To create an empty GeneralPath instance call new GeneralPath() and then add segments to the shape by using the following methods:

• moveTo(float x, float y) – Moves the current point of the path to the given point
• lineTo(float x, float y) – Adds a line segment to the current path
• quadTo(float ctrlx, float ctrly, float x2, floaty2) – Adds a quadratic curve segment to the current path
• curveTo(float ctrlx1, float ctrly1, float ctrlx2, float ctrly2, float x3, floaty3) – Adds a cubic curve segment to the current path
• closePath() – Closes the current path

The following example illustrates how to draw a polyline by using GeneralPath:

// draw GeneralPath (polyline) int x2Points[] = {0, 100, 0, 100}; int y2Points[] = {0, 50, 50, 0}; GeneralPath polyline = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x2Points.length); polyline.moveTo (x2Points[0], y2Points[0]); for (int index = 1; index < x2Points.length; index++) { polyline.lineTo(x2Points[index], y2Points[index]); }; g2.draw(polyline);

This example illustrates how to draw a polygon by using GeneralPath:

// draw GeneralPath (polygon) int x1Points[] = {0, 100, 0, 100}; int y1Points[] = {0, 50, 50, 0}; GeneralPath polygon = new GeneralPath(GeneralPath.WIND_EVEN_ODD, x1Points.length); polygon.moveTo(x1Points[0], y1Points[0]); for (int index = 1; index < x1Points.length; index++) { polygon.lineTo(x1Points[index], y1Points[index]); }; polygon.closePath(); g2.draw(polygon);

Note that the only difference between two last code examples is the closePath() method. This method makes a polygon from a polyline by drawing a straight line back to the coordinates of the last moveTo.

To add a specific path to the end of your GeneralPath object you use one of the append() methods. The ShapesDemo2D.java code example contains additional implementations of arbitrary shapes.