/*
* Copyright (c) 2004 David Flanagan. All rights reserved.
* This code is from the book Java Examples in a Nutshell, 3nd Edition.
* It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
* You may study, use, and modify it for any non-commercial purpose,
* including teaching and use in open-source projects.
* You may distribute it non-commercially as long as you retain this notice.
* For a commercial use license, or to purchase the book,
* please visit http://www.davidflanagan.com/javaexamples3.
*/
package je3.graphics;
import java.applet.*;
import java.awt.*;
/**
* An applet that demonstrates most of the graphics primitives in
* java.awt.Graphics.
**/
public class GraphicsSampler extends Applet {
Color fill, outline, textcolor; // The various colors we use
Font font; // The font we use for text
FontMetrics metrics; // Information about font size
Image image, background; // Some images we draw with
// This method is called when the applet is first created.
// It performs initialization, such as creating the resources
// (graphics attribute values) used by the paint() method.
public void init() {
// Initialize color resources. Note the use of the Color() constructor
// and the use of pre-defined color constants.
fill = new Color(200, 200, 200); // Equal red, green, and blue == gray
outline = Color.blue; // Same as new Color(0, 0, 255)
textcolor = Color.red; // Same as new Color(255, 0, 0)
// Create a font for use in the paint() method. Get its metrics, too.
font = new Font("sansserif", Font.BOLD, 14);
metrics = this.getFontMetrics(font);
// Load some Image objects for use in the paint() method.
image = this.getImage(this.getDocumentBase(), "tiger.gif");
background = this.getImage(this.getDocumentBase(), "background.gif");
// Set a property that tells the applet its background color
this.setBackground(Color.lightGray);
}
// This method is called whenever the applet needs to be drawn or redrawn
public void paint(Graphics g) {
g.setFont(font); // Specify the font we'll be using throughout
// Draw a background by tiling an image tile() is defined below
tile(g, this, background);
// Draw a line
g.setColor(outline); // Specify the drawing color
g.drawLine(25, 10, 150, 80); // Draw a line from (25,10) to (150,80)
// Draw some text. See the centerText() method below.
centerText("drawLine()", null, g, textcolor, 25, 10, 150, 80);
// Draw and fill an arc
g.setColor(fill);
g.fillArc(225, 10, 150, 80, 90, 135);
g.setColor(outline);
g.drawArc(225, 10, 150, 80, 90, 135);
centerText("fillArc()", "drawArc()", g, textcolor,225,10,150,80);
// Draw and fill a rectangle
g.setColor(fill);
g.fillRect(25, 110, 150, 80);
g.setColor(outline);
g.drawRect(25, 110, 150, 80);
centerText("fillRect()", "drawRect()", g, textcolor, 25, 110, 150, 80);
// Draw and fill a rounded rectangle
g.setColor(fill);
g.fillRoundRect(225, 110, 150, 80, 20, 20);
g.setColor(outline);
g.drawRoundRect(225, 110, 150, 80, 20, 20);
centerText("fillRoundRect()", "drawRoundRect()", g, textcolor,
225, 110, 150, 80);
// Draw and fill an oval
g.setColor(fill);
g.fillOval(25, 210, 150, 80);
g.setColor(outline);
g.drawOval(25, 210, 150, 80);
centerText("fillOval()", "drawOval()", g, textcolor, 25, 210, 150, 80);
// Define an octagon using arrays of X and Y coordinates
int numpoints = 8;
int[] xpoints = new int[numpoints+1];
int[] ypoints = new int[numpoints+1];
for(int i=0; i < numpoints; i++) {
double angle = 2*Math.PI * i / numpoints;
xpoints[i] = (int)(300 + 75*Math.cos(angle));
ypoints[i] = (int)(250 - 40*Math.sin(angle));
}
// Draw and fill the polygon
g.setColor(fill);
g.fillPolygon(xpoints, ypoints, numpoints);
g.setColor(outline);
g.drawPolygon(xpoints, ypoints, numpoints);
centerText("fillPolygon()", "drawPolygon()", g, textcolor,
225, 210, 150, 80);
// Draw a 3D rectangle (clear an area for it first)
g.setColor(fill);
g.fillRect(20, 305, 160, 90);
g.draw3DRect(25, 310, 150, 80, true);
g.draw3DRect(26, 311, 148, 78, true);
g.draw3DRect(27, 312, 146, 76, true);
centerText("draw3DRect()", "x 3", g, textcolor, 25, 310, 150, 80);
// Draw an image (centered within an area)
int w = image.getWidth(this);
int h = image.getHeight(this);
g.drawImage(image, 225 + (150-w)/2, 310 + (80-h)/2, this);
centerText("drawImage()", null, g, textcolor, 225, 310, 150, 80);
}
// Utility method to tile an image on the background of the component
protected void tile(Graphics g, Component c, Image i) {
// Use bounds() instead of getBounds() if you want
// compatibility with Java 1.0 and old browsers like Netscape 3
Rectangle r = c.getBounds(); // How big is the component?
int iw = i.getWidth(c); // How big is the image?
int ih = i.getHeight(c);
if ((iw <= 0) || (ih <= 0)) return;
for(int x=0; x < r.width; x += iw) // Loop horizontally
for(int y=0; y < r.height; y += ih) // Loop vertically
g.drawImage(i, x, y, c); // Draw the image
}
// Utility method to center two lines of text in a rectangle.
// Relies on the FontMetrics obtained in the init() method.
protected void centerText(String s1, String s2, Graphics g, Color c,
int x, int y, int w, int h)
{
int height = metrics.getHeight(); // How tall is the font?
int ascent = metrics.getAscent(); // Where is the font baseline?
int width1=0, width2 = 0, x0=0, x1=0, y0=0, y1=0;
width1 = metrics.stringWidth(s1); // How wide are the strings?
if (s2 != null) width2 = metrics.stringWidth(s2);
x0 = x + (w - width1)/2; // Center the strings horizontally
x1 = x + (w - width2)/2;
if (s2 == null) // Center one string vertically
y0 = y + (h - height)/2 + ascent;
else { // Center two strings vertically
y0 = y + (h - (int)(height * 2.2))/2 + ascent;
y1 = y0 + (int)(height * 1.2);
}
g.setColor(c); // Set the color
g.drawString(s1, x0, y0); // Draw the strings
if (s2 != null) g.drawString(s2, x1, y1);
}
}
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