FileDocCategorySizeDatePackage
Smooth.javaAPI DocExample4910Thu Aug 08 12:38:34 BST 1996None

Smooth

public class Smooth extends Applet implements Runnable

Fields Summary
static final int
deltax
static final int
deltay
static final String
message
int
x
int
y
Color
c1
Color
c2
Font
font
Image
offscreen
int
imagewidth
int
imageheight
int
stringwidth
int
stringheight
int
stringascent
Thread
animator
boolean
please_stop
Constructors Summary
Methods Summary
voiddrawBackground(java.awt.Graphics gr, java.awt.Color c1, java.awt.Color c2, int numsteps)

        int r, g, b;
        int dr = (c2.getRed() - c1.getRed())/numsteps;
        int dg = (c2.getGreen() - c1.getGreen())/numsteps;
        int db = (c2.getBlue() - c1.getBlue())/numsteps;
        Dimension size = this.size();
        int w = size.width, h = size.height;
        int dw = size.width/numsteps;
        int dh = size.height/numsteps;

        gr.setColor(c1);
        gr.fillRect(0, 0, w, h);
        
        for(r = c1.getRed(), g = c1.getGreen(), b = c1.getBlue();
            h > 0;
            h -= dh, w -= dw, r += dr, g += dg, b += db) {
            gr.setColor(new Color(r, g, b));
            gr.fillArc(-w, -h, 2*w, 2*h, 0, -90);
        }
    
public voidinit()


    // Measure the size of the text we'll be animating.  We need this
    // information later to do clipping.
       
        FontMetrics fm = this.getFontMetrics(font);
        stringwidth = fm.stringWidth(message);
        stringheight = fm.getHeight();
        stringascent = fm.getAscent();
    
public booleanmouseDown(java.awt.Event e, int x, int y)

        // if running, stop it.  Otherwise, start it.
        if (animator != null) please_stop = true;
        else { please_stop = false; start(); } 
        return true;
    
public voidpaint(java.awt.Graphics g)

            drawBackground(g, c1, c2, 25);
            g.setColor(Color.black);
            g.setFont(font);
            g.drawString(message, x, y);
    
public voidrun()

        while(!please_stop) {
            Dimension d = this.size();
            
            // Make sure the offscreen image is created and is the right size.
            if ((offscreen == null) ||
                ((imagewidth != d.width) || (imageheight != d.height))) {
                // if (offscreen != null) offscreen.flush();
                offscreen = this.createImage(d.width, d.height);
                imagewidth = d.width;
                imageheight = d.height;
            }
            
            // Set up clipping.  We only need to draw within the
            // old rectangle that needs to be cleared and the new
            // one that is being drawn.

            // the old rectangle
            Rectangle oldrect = new Rectangle(x, y-stringascent,
                              stringwidth, stringheight);
            // Update the coordinates for animation.
            x = ((x + deltax)%d.width);
            y = ((y + deltay)%d.height);

            // the new rectangle
            Rectangle newrect = new Rectangle(x, y-stringascent,
                              stringwidth, stringheight);
            // Compute the union of the rectangles
            Rectangle r = newrect.union(oldrect);
                
            // Use this rectangle as the clipping region when
            // drawing to the offscreen image, and when copying
            // from the offscreen image to the screen.
            Graphics g = offscreen.getGraphics();
            g.clipRect(r.x, r.y, r.width, r.height);
            // Draw into the off-screen image.
            paint(g);
            // Copy it all at once to the screen, using clipping.
            g = this.getGraphics();
            g.clipRect(r.x, r.y, r.width, r.height);
            g.drawImage(offscreen, 0, 0, this);

            // wait a tenth of a second, then draw it again!
            try { Thread.sleep(100); } catch (InterruptedException e) { ; }
        }
        animator = null;
    
public voidstart()

 
        animator = new Thread(this);
        animator.start();
    
public voidstop()

 
        if (animator != null) animator.stop();
        animator = null;