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BezierAnim.javaAPI DocExample11235Wed Aug 08 15:13:48 BST 2001demos.Arcs_Curves

BezierAnim

public class BezierAnim extends AnimatingControlsSurface
Animated Bezier Curve with controls for different draw & fill paints.

Fields Summary
private static final int
NUMPTS
protected BasicStroke
solid
protected BasicStroke
dashed
private float[]
animpts
private float[]
deltas
protected Paint
fillPaint
protected Paint
drawPaint
protected boolean
doFill
protected boolean
doDraw
protected GradientPaint
gradient
protected BasicStroke
stroke
Constructors Summary
public BezierAnim()



      
        setBackground(Color.white);
        gradient = new GradientPaint(0,0,Color.red,200,200,Color.yellow);
        fillPaint = gradient;
        drawPaint = Color.blue;
        stroke = solid;
        setControls(new Component[] { new DemoControls(this) });
Methods Summary
public voidanimate(float[] pts, float[] deltas, int index, int limit)

        float newpt = pts[index] + deltas[index];
        if (newpt <= 0) {
            newpt = -newpt;
            deltas[index] = (float) (Math.random() * 4.0 + 2.0);
        } else if (newpt >= (float) limit) {
            newpt = 2.0f * limit - newpt;
            deltas[index] = - (float) (Math.random() * 4.0 + 2.0);
        }
        pts[index] = newpt;
public static voidmain(java.lang.String[] argv)

        createDemoFrame(new BezierAnim());
public voidrender(int w, int h, java.awt.Graphics2D g2)

        float[] ctrlpts = animpts;
        int len = ctrlpts.length;
        float prevx = ctrlpts[len - 2];
        float prevy = ctrlpts[len - 1];
        float curx = ctrlpts[0];
        float cury = ctrlpts[1];
        float midx = (curx + prevx) / 2.0f;
        float midy = (cury + prevy) / 2.0f;
        GeneralPath gp = new GeneralPath(GeneralPath.WIND_NON_ZERO);
        gp.moveTo(midx, midy);
        for (int i = 2; i <= ctrlpts.length; i += 2) {
            float x1 = (midx + curx) / 2.0f;
            float y1 = (midy + cury) / 2.0f;
            prevx = curx;
            prevy = cury;
            if (i < ctrlpts.length) {
                curx = ctrlpts[i + 0];
                cury = ctrlpts[i + 1];
            } else {
                curx = ctrlpts[0];
                cury = ctrlpts[1];
            }
            midx = (curx + prevx) / 2.0f;
            midy = (cury + prevy) / 2.0f;
            float x2 = (prevx + midx) / 2.0f;
            float y2 = (prevy + midy) / 2.0f;
            gp.curveTo(x1, y1, x2, y2, midx, midy);
        }
        gp.closePath();
        if (doDraw) {
            g2.setPaint(drawPaint);
            g2.setStroke(stroke);
            g2.draw(gp);
        }
        if (doFill) {
            if (fillPaint instanceof GradientPaint) {
                fillPaint = gradient;
            }
            g2.setPaint(fillPaint);
            g2.fill(gp);
        }
public voidreset(int w, int h)

        for (int i = 0; i < animpts.length; i += 2) {
            animpts[i + 0] = (float) (Math.random() * w);
            animpts[i + 1] = (float) (Math.random() * h);
            deltas[i + 0] = (float) (Math.random() * 6.0 + 4.0);
            deltas[i + 1] = (float) (Math.random() * 6.0 + 4.0);
            if (animpts[i + 0] > w / 2.0f) {
                deltas[i + 0] = -deltas[i + 0];
            }
            if (animpts[i + 1] > h / 2.0f) {
                deltas[i + 1] = -deltas[i + 1];
            }
        }
        gradient = new GradientPaint(0,0,Color.red,w*.7f,h*.7f,Color.yellow);
public voidstep(int w, int h)

        for (int i = 0; i < animpts.length; i += 2) {
            animate(animpts, deltas, i + 0, w);
            animate(animpts, deltas, i + 1, h);
        }