143 lines
4.6 KiB
Java
143 lines
4.6 KiB
Java
import java.awt.*;
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import java.awt.geom.*;
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import java.util.Date;
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/**
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* An example for an animation based on on convex combinations of
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* control points of two objects (the letters D and C).
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*
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* @author Frank Klawonn
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* Last change 04.02.2005
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*/
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public class DToCMorphing extends Frame
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{
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//Constructor
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public DToCMorphing()
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{
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//Enables the closing of the window.
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addWindowListener(new MyFinishWindow());
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}
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public void paint(Graphics g)
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{
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Graphics2D g2d = (Graphics2D) g;
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//Use of antialiasing to have nicer lines.
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g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
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//The lines should have a thickness of 3.0 instead of 1.0.
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BasicStroke bs = new BasicStroke(5.0f);
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g2d.setStroke(bs);
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//Control points for the letter D.
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int[] xd = new int[6]; //The index 0 is not used.
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int[] yd = new int[6]; //The index 0 is not used.
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xd[1] = 50;
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yd[1] = 50;
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xd[2] = 50;
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yd[2] = 450;
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xd[3] = 400;
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yd[3] = 250;
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xd[4] = 50;
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yd[4] = 450;
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xd[5] = 50;
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yd[5] = 250;
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//Control points for the letter C.
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int[] xc = new int[6]; //The index 0 is not used.
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int[] yc = new int[6]; //The index 0 is not used.
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xc[1] = 50;
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yc[1] = 250;
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xc[2] = 250;
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yc[2] = 50;
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xc[3] = 50;
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yc[3] = 50;
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xc[4] = 250;
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yc[4] = 450;
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xc[5] = 50;
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yc[5] = 450;
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//Both letters are composed of two quadratic curves. The first curve has
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//the first, third and second as control points, the second curve the
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//first, fifth and fourth point.
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QuadCurve2D.Double q1;
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QuadCurve2D.Double q2;
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//Draw the letter D.
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q1 = new QuadCurve2D.Double(xd[1],yd[1],xd[3],yd[3],xd[2],yd[2]);
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q2 = new QuadCurve2D.Double(xd[1],yd[1],xd[5],yd[5],xd[4],yd[4]);
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g2d.draw(q1);
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g2d.draw(q2);
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//Wait 1 second before starting the transformation from D to C.
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sustain(1000);
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//ArraysC for the convex combinations of the control point of D and C
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double x[] = new double[xc.length];
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double y[] = new double[x.length];
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double alpha;
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//Number of steps (frames) that the transform from D to C should take.
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int steps = 500;
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double stepsDouble = steps; //Number of steps as a Double-value to avoid
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//repeated casting.
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for (int i=1; i<=steps; i++)
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{
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alpha = i/stepsDouble;
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//Computation of the convex combinations for the five pairs of points.
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for (int j=1; j<x.length; j++)
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{
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x[j] = (1-alpha)*xd[j] + alpha*xc[j];
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y[j] = (1-alpha)*yd[j] + alpha*yc[j];
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}
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//Generation of the two quadratic curves defined by the control points
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//given by the convex combinations.
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q1 = new QuadCurve2D.Double(x[1],y[1],x[3],y[3],x[2],y[2]);
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q2 = new QuadCurve2D.Double(x[1],y[1],x[5],y[5],x[4],y[4]);
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//Clear the window.
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clearWindow(g2d);
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//Draw the two quadratic curves.
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g2d.draw(q1);
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g2d.draw(q2);
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//A short waiting time until the next frame is drawn.
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sustain(10);
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}
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}
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/**
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* A method for clearing a window (drawing all white) of fixed size (600x300).
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*
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* @param g2d Graphics2D object used for drawing.
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*/
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public static void clearWindow(Graphics2D g)
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{
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g.setPaint(Color.white);
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g.fill(new Rectangle(0,0,270,470));
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g.setPaint(Color.black);
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}
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/**
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* A method for a delay of t milliseconds.
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* This method is used here only to keep the program simple.
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* This method involves active waiting, consuming unnecessary processor capicity.
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* For real applications threads should be used.
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*
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* @param t Waiting time in milliseconds
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*/
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public static void sustain(long t)
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{
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long finish = (new Date()).getTime() + t;
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while( (new Date()).getTime() < finish ) {}
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}
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public static void main(String[] argv)
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{
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DToCMorphing f = new DToCMorphing();
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f.setTitle("Transforming D -> C");
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f.setSize(270,470);
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f.setVisible(true);
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}
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}
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