Hi Ted,
Try closing your original shape with genPath.closePath(). That should
cause a join between the last and first segments. We specifically
distinguish between the case of an explicitly closed shape and one where
you simply ended up back at the original start point so that you have
control over whether a join or an end cap is placed there. This is
mentioned in the description of the end caps parameter in the class
comments for BasicStroke...
...jim
--On Monday, December 02, 2002 12:38:28 -0600 Ted Hill
<[EMAIL PROTECTED]> wrote:
> Hi Jim,
>
> I'm trying to implement your suggested technique of using a stroke and
> areas to expand a shape. I'm experiencing some difficulty at the 'initial
> corner' even though I've specified a JOIN_MITER.
>
> Included is a small test program. Also attaching a jpeg that shows the
> orig shape in the center surrounded by the expanded shape.
>
> Am I doing something wrong?
>
> Thanks,
>
> Ted Hill
>
>
> ==== begin code sample ====
> import javax.swing.JPanel;
> import javax.swing.JFrame;
>
> import java.awt.BorderLayout;
> import java.awt.Dimension;
> import java.awt.Color;
> import java.awt.Graphics;
> import java.awt.Shape;
> import java.awt.Graphics2D;
> import java.awt.BasicStroke;
> import java.awt.geom.GeneralPath;
> import java.awt.geom.Point2D;
> import java.awt.geom.Area;
>
>
>
> /**
> * Test use of Area and Stroke to expand a shape by a constant margin.
> */
> public class AreaTest extends JPanel
> {
> // the shape to expand
> private Shape origShape;
>
> // constuctor
> public AreaTest()
> {
> setPreferredSize(new Dimension(600, 600));
> setBackground(Color.white);
>
> origShape = createTestShape();
> }
>
> /**
> * Paint the original shape, then paint the expanded shape surrounding
> it
> */
> protected void paintComponent(Graphics g)
> {
> super.paintComponent(g);
>
> Graphics2D g2 = (Graphics2D) g;
>
> g2.draw(origShape);
>
> g2.draw(getExpandedShape(origShape, 40));
> }
>
> private Shape getExpandedShape(Shape inShape, int pixelExpansion)
> {
> /** times 2 because half goes inside shape and half outside */
> BasicStroke stroke = new BasicStroke(2 * pixelExpansion,
> BasicStroke.CAP_SQUARE, BasicStroke.JOIN_MITER);
>
> Shape outlineShape = stroke.createStrokedShape(inShape);
>
> Area outlineArea = new Area(outlineShape);
> Area origArea = new Area(inShape);
>
> // expand the orig by adding the outline
> origArea.add(outlineArea);
>
> return origArea;
> }
>
> private GeneralPath createTestShape()
> {
> GeneralPath genPath = new GeneralPath();
>
> Point2D startEndPoint = new Point2D.Float(200, 200);
>
> genPath.moveTo((float) startEndPoint.getX(), (float)
> startEndPoint.getY());
> genPath.lineTo(250, 250);
> genPath.lineTo(300, 300);
> genPath.lineTo(250, 400);
> genPath.lineTo((float) startEndPoint.getX(), (float)
> startEndPoint.getY());
>
> return genPath;
> }
>
>
> public static void main(String[ ] args)
> {
> JFrame frame = new JFrame("Area Test");
>
> frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
>
> frame.getContentPane( ).add(new AreaTest( ), BorderLayout.CENTER);
> frame.pack( );
> frame.setVisible(true);
> }
> }
> ==== end code sample ====
>
> ----- Original Message -----
> From: "Jim Graham" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, November 26, 2002 4:37 PM
> Subject: [JAVA2D] Path fun (in Re: to both STROKE_CONTROL and GeneralPath
> expansion)
>
>
> > Ted and Ram�n,
> >
> > Using the Area and BasicStroke classes, you can achieve any of the
> > effects that you two have been asking for. Assuming a source Shape
> > object "S",
> and
> > wanting to outsideline, insideline, expand or contract it by N pixels...
> >
> > First get all your variables set up:
> >
> > BasicStroke bs = new BasicStroke(N*2);
> > Shape outline = bs.createStrokedShape(S);
> > Area a1 = new Area(outline);
> > Area a2 = new Area(S);
> >
> > Then plug in the appropriate Area operation depending on what you want
> > to
> do:
> >
> > - Outline N pixels outside of a shape (S):
> >
> > Area result = a1.subtract(a2);
> >
> > - Outline N pixels inside of a shape (S):
> >
> > Area result = a1.intersect(a2);
> >
> > - Expand a shape (S) by N pixels:
> >
> > Area result = a1.union(a2);
> >
> > - Contract a shape (S) by N pixels:
> >
> > Area result = a2.subtract(a1);
> >
> > I've left out the various attributes on constructing the BasicStroke
> > above since it depends on the "look" that you are going for. I would
> > imagine
> that
> > the expand/contract operations would want to specify a MITER join so
> > that it doesn't cause the corners to get rounded or chopped off, but
> > the inside and outside outlines could probably use all sorts of
> > variations depending on personal taste...
> >
> > ...jim
> >
> > To unsubscribe, send email to [EMAIL PROTECTED] and include in the
> body
> > of the message "signoff JAVA2D-INTEREST". For general help, send email
> > to [EMAIL PROTECTED] and include in the body of the message "help".
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