/* A decorative applet that draws symmetric pictures of moving shapes, looking something like a view in a kaleidoscope. Many aspects of the image are chosen randomly. A given random animation plays for about 10 seconds, then a new selection is made. There are four types of symmetry that are possible: no symmetry, two-fold symmetry obtained by reflecting each shape horizontally, four-fold symmetry obtained by vertical and horizontal reflection, and eight-fold symmetry which adds diagonal reflections. This applet works well at a size of 200 by 200 pixels. If the applet is larger, you might want to increase the size or the number of shapes created in the makeFigures() method. */ import java.awt.*; import java.awt.event.*; import javax.swing.*; import java.util.Vector; public class KaleidoAnimate extends JApplet { int symmetryStyle; // A number between 0 and 18 specifying the type of symmetry that // the animation displays. The value is set in makeFigures() // and is used in putMultiFigure(). The meaning of the values: // 0 for none, 1-2 for two-way, 2-8 for four-way, 8-19 for 8-way. Vector figureList = new Vector(); // Contains the figures in the current animation. // The figures belong to the class Figure, defined below. int frameNumber = 109; public void init() { setContentPane( new JPanel() { public void paintComponent(Graphics g) { drawFrame(g); } }); Timer t = new Timer(100, new ActionListener() { public void actionPerformed(ActionEvent evt) { frameNumber++; if (frameNumber >= 110) { frameNumber = 0; makeFigures(); } repaint(); } }); t.setInitialDelay(500); t.start(); } public void drawFrame(Graphics g) { // Draw one frame in the animation. A new random animation is // begun each time the frame number is zero (including the first // frame that is shown). For frames numbered 100 to 109, only a // black rectangle is shown. ((Graphics2D)g).setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON); ((Graphics2D)g).setStroke( new BasicStroke(2) ); if (frameNumber >= 100) { g.setColor(Color.black); // For frames 100-109, just draw a black rectangle. g.fillRect(0, 0, getWidth(), getHeight()); } else { // Draw the figures over the applet's background color. g.setColor(getBackground()); // Fill the frame with the background color. g.fillRect(0,0,getWidth(),getHeight()); for (int i = 0; i < figureList.size(); i++) { Figure fig = (Figure)figureList.elementAt(i); // Get the figure from the vector. fig.drift(); // The figure moves itself a bit. putMultiFigure(g, fig); // Draw the figure, plus required reflections. } g.setColor(Color.black); // Draw a 1-pixel black border around the frame. g.drawRect(0,0,getWidth()-1,getHeight()-1); } } // end drawFrame() private void makeFigures() { // Create the random data for a new random animation. figureList.removeAllElements(); int figureCt = 3 + (int)(Math.random()*50); // Number of figures. int figStyle = (int)(Math.random()*5); // What type if figures will be used? // 0 = all lines, 1 = all rectangles, // 2 = all ovals, 3 or 4 = a mixture boolean monochrome = Math.random() < 0.1; // A 10% chance that the picture will be in grayscale. boolean useOneColor = Math.random() < 0.15; // A 15% change that all the figures will be the same color. Color useColor = null; // If useOneColor is true, this will be the color used. if (useOneColor) { if (monochrome) useColor = Color.getHSBColor(0.0F, 0.0F, (float)Math.random()); // A random gray. else useColor = Color.getHSBColor((float)Math.random(), 1.0F, 1.0F); // A random bright color. } symmetryStyle = (int)(Math.random()*20); // Determines the type of symmetry used in // the animation. See comment on the declaration // of this instance variable, above. /* Set a random background color. */ if (Math.random() < 0.1) // A 10% chance that the background is white. setBackground(Color.white); else if (Math.random() < 0.11) // A 10% chance (1/9 of 9/10) that the color is black setBackground(Color.black); else if (monochrome) setBackground(Color.gray); // A gray background for most monochrome images. else setBackground(Color.getHSBColor((float)Math.random(), 0.5F, 0.5F)); // A random not-so-bright color. for (int i = 0; i < figureCt; i++) { // Create a random figure. Figure fig = new Figure(); fig.x1 = (int)(Math.random()*getWidth()); // Somewhere on the screen, horizontally. fig.x2 = fig.x1 + (int)(Math.random()*20) + 10; // 10 to 29 pixels wide. fig.y1 = (int)(Math.random()*getHeight()); // Somewhere on the screen, vertically. fig.y2 = fig.y1 + (int)(Math.random()*20) + 10; // 10 to 29 pixels tall. fig.driftx = (int)(Math.random()*13) - 6; // Moves horizontally between -6 and 6 pixels per frame. fig.drifty = (int)(Math.random()*13) - 6; // Moves vertically between -6 and 6 pixels per frame. if (figStyle > 2) fig.style = (int)(Math.random()*3); // Randomly make it a line, rect, or oval. else fig.style = figStyle; if (useOneColor) fig.color = useColor; else if (monochrome) fig.color = Color.getHSBColor(0.0F, 0.0F, (float)Math.random()); // A random gray. else fig.color = Color.getHSBColor((float)Math.random(), 1.0F, 1.0F); // A random bright color. figureList.addElement(fig); // Add the figure to the vector. } } // end makeFigures(); private void put(Graphics g, int figureType, int x1, int y1, int x2, int y2) { // Draws a figure of the specified type, between (x1,y1) and (x2,y2); if (figureType == 0) { // If the figure is a line, just draw it. g.drawLine(x1,y1,x2,y2); } else { // For a rect or oval, we need the top-left corner, the height, and the width. // The height and width must be positive. int x, y, w, h; if (x2 > x1) { x = x1; w = x2 - x1; } else { x = x2; w = x1 - x2; } if (y2 > y1) { y = y1; h = y2 - y1; } else { y = y2; h = y1 - y2; } if (figureType == 1) g.fillRect(x,y,w,h); else g.fillOval(x,y,w,h); } } // end put() private void putMultiFigure(Graphics g, Figure figure) { // Draw the figure and its reflections in the graphics context g. // The reflections that we need are specified by the instance // variable, symmetryStyle. g.setColor(figure.color); // Use the color specified by figure. put(g, figure.style, figure.x1, figure.y1, // Draw the figure. figure.x2, figure.y2); if (symmetryStyle > 0) { // Draw the horizontal reflection. put(g, figure.style, getWidth() - figure.x1, figure.y1, getWidth() - figure.x2, figure.y2); } if (symmetryStyle > 2) { // Draw the vertical reflection and the figure obtained // by reflecting both horizontally and vertically. put(g, figure.style, figure.x1, getHeight() - figure.y1, figure.x2, getHeight() - figure.y2); put(g, figure.style, getWidth() - figure.x1, getHeight() - figure.y1, getWidth() - figure.x2, getHeight() - figure.y2); } if (symmetryStyle > 8) { // Calculate the diagonal reflection of the figure. // Draw that reflection, then draw its three reflections. int a1 = (int)(((double)figure.y1 / getHeight()) * getWidth()); int b1 = (int)(((double)figure.x1 / getWidth()) * getHeight()); int a2 = (int)(((double)figure.y2 / getHeight()) * getWidth()); int b2 = (int)(((double)figure.x2 / getWidth()) * getHeight()); put(g, figure.style, a1, b1, a2, b2); put(g, figure.style, getWidth() - a1, b1, getWidth() - a2, b2); put(g, figure.style, a1, getHeight() - b1, a2, getHeight() - b2); put(g, figure.style, getWidth() - a1, getHeight() - b1, getWidth() - a2, getHeight() - b2); } } // end putMultiFigure() private class Figure { // This class holds all the data relevant to one of the // figures in an animation. The values of the instance // variables in this class are set when the figures // are created in the makeFigures() method. int x1, x2, y1, y2; // The two corners of the figure. // (These satisfy x2 > x1 and y2 > y1) int driftx, drifty; // How much this figure moves from frame to frame. int style; // Type of figure. 0 for line, 1 for rect, 2 for oval. Color color; // Color of this figure. void drift() { // Displace the figure by the amout given in the instance // variables driftx and drifty. If the figure has moved // off the applet, move it to the other side of the // applet so it will reappear. x1 += driftx; x2 += driftx; y1 += drifty; y2 += drifty; if (x2 < 0) { x2 = getWidth() + (x2 - x1); x1 = getWidth(); } else if (x1 > getWidth()) { x1 = -(x2 - x1); x2 = 0; } if (y2 < 0) { y2 = getHeight() + (y2 - y1); y1 = getHeight(); } else if (y1 > getHeight()) { y1 = -(y2 - y1); y2 = 0; } } } // end nested class Figure } // end class KaleidascopeAnimation