读书笔记：数据结构与算法分析java语言描述随书代码学习.zip

/****************************************************************************** * Compilation: javac StdDraw.java * Execution: java StdDraw * Dependencies: none * * Standard drawing library. This class provides a basic capability for * creating drawings with your programs. It uses a simple graphics model that * allows you to create drawings consisting of points, lines, and curves * in a window on your computer and to save the drawings to a file. * * Todo * ---- * - Add support for gradient fill, etc. * - Fix setCanvasSize() so that it can only be called once. * - On some systems, drawing a line (or other shape) that extends way * beyond canvas (e.g., to infinity) dimensions does not get drawn. * * Remarks * ------- * - don't use AffineTransform for rescaling since it inverts * images and strings * ******************************************************************************/ package edu.princeton.cs.algs4; import java.awt.BasicStroke; import java.awt.Color; import java.awt.FileDialog; import java.awt.Font; import java.awt.FontMetrics; import java.awt.Graphics2D; import java.awt.Image; import java.awt.MediaTracker; import java.awt.RenderingHints; import java.awt.Toolkit; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import java.awt.event.KeyEvent; import java.awt.event.KeyListener; import java.awt.geom.Arc2D; import java.awt.geom.Ellipse2D; import java.awt.geom.GeneralPath; import java.awt.geom.Line2D; import java.awt.geom.Rectangle2D; import java.awt.image.BufferedImage; import java.awt.image.DirectColorModel; import java.awt.image.WritableRaster; import java.io.File; import java.io.IOException; import java.net.MalformedURLException; import java.net.URL; import java.util.LinkedList; import java.util.TreeSet; import java.util.NoSuchElementException; import javax.imageio.ImageIO; import javax.swing.ImageIcon; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; import javax.swing.KeyStroke; /** * The {@code StdDraw} class provides a basic capability for * creating drawings with your programs. It uses a simple graphics model that * allows you to create drawings consisting of points, lines, squares, * circles, and other geometric shapes in a window on your computer and * to save the drawings to a file. Standard drawing also includes * facilities for text, color, pictures, and animation, along with * user interaction via the keyboard and mouse. * <p> * <b>Getting started.</b> * To use standard drawing, you must have {@code StdDraw.class} in your * Java classpath. If you used our autoinstaller, you should be all set. * Otherwise, download * <a href = "https://introcs.cs.princeton.edu/java/stdlib/StdDraw.java">StdDraw.java</a> * and put a copy in your working directory. * <p> * Now, type the following short program into your editor: * <pre> * public class TestStdDraw { * public static void main(String[] args) { * StdDraw.setPenRadius(0.05); * StdDraw.setPenColor(StdDraw.BLUE); * StdDraw.point(0.5, 0.5); * StdDraw.setPenColor(StdDraw.MAGENTA); * StdDraw.line(0.2, 0.2, 0.8, 0.2); * } * } * </pre> * If you compile and execute the program, you should see a window * appear with a thick magenta line and a blue point. * This program illustrates the two main types of methods in standard * drawing—methods that draw geometric shapes and methods that * control drawing parameters. * The methods {@code StdDraw.line()} and {@code StdDraw.point()} * draw lines and points; the methods {@code StdDraw.setPenRadius()} * and {@code StdDraw.setPenColor()} control the line thickness and color. * <p> * <b>Points and lines.</b> * You can draw points and line segments with the following methods: * <ul> * <li> {@link #point(double x, double y)} * <li> {@link #line(double x1, double y1, double x2, double y2)} * </ul> * <p> * The <em>x</em>- and <em>y</em>-coordinates must be in the drawing area * (between 0 and 1 and by default) or the points and lines will not be visible. * <p> * <b>Squares, circles, rectangles, and ellipses.</b> * You can draw squares, circles, rectangles, and ellipses using * the following methods: * <ul> * <li> {@link #circle(double x, double y, double radius)} * <li> {@link #ellipse(double x, double y, double semiMajorAxis, double semiMinorAxis)} * <li> {@link #square(double x, double y, double radius)} * <li> {@link #rectangle(double x, double y, double halfWidth, double halfHeight)} * </ul> * <p> * All of these methods take as arguments the location and size of the shape. * The location is always specified by the <em>x</em>- and <em>y</em>-coordinates * of its <em>center</em>. * The size of a circle is specified by its radius and the size of an ellipse is * specified by the lengths of its semi-major and semi-minor axes. * The size of a square or rectangle is specified by its half-width or half-height. * The convention for drawing squares and rectangles is parallel to those for * drawing circles and ellipses, but may be unexpected to the uninitiated. * <p> * The methods above trace outlines of the given shapes. The following methods * draw filled versions: * <ul> * <li> {@link #filledCircle(double x, double y, double radius)} * <li> {@link #filledEllipse(double x, double y, double semiMajorAxis, double semiMinorAxis)} * <li> {@link #filledSquare(double x, double y, double radius)} * <li> {@link #filledRectangle(double x, double y, double halfWidth, double halfHeight)} * </ul> * <p> * <b>Circular arcs.</b> * You can draw circular arcs with the following method: * <ul> * <li> {@link #arc(double x, double y, double radius, double angle1, double angle2)} * </ul> * <p> * The arc is from the circle centered at (<em>x</em>, <em>y</em>) of the specified radius. * The arc extends from angle1 to angle2. By convention, the angles are * <em>polar</em> (counterclockwise angle from the <em>x</em>-axis) * and represented in degrees. For example, {@code StdDraw.arc(0.0, 0.0, 1.0, 0, 90)} * draws the arc of the unit circle from 3 o'clock (0 degrees) to 12 o'clock (90 degrees). * <p> * <b>Polygons.</b> * You can draw polygons with the following methods: * <ul> * <li> {@link #polygon(double[] x, double[] y)} * <li> {@link #filledPolygon(double[] x, double[] y)} * </ul> * <p> * The points in the polygon are ({@code x[i]}, {@code y[i]}). * For example, the following code fragment draws a filled diamond * with vertices (0.1, 0.2), (0.2, 0.3), (0.3, 0.2), and (0.2, 0.1): * <pre> * double[] x = { 0.1, 0.2, 0.3, 0.2 }; * double[] y = { 0.2, 0.3, 0.2, 0.1 }; * StdDraw.filledPolygon(x, y); * </pre> * <p> * <b>Pen size.</b> * The pen is circular, so that when you set the pen radius to <em>r</em> * and draw a point, you get a circle of radius <em>r</em>. Also, lines are * of thickness 2<em>r</em> and have rounded ends. The default pen radius * is 0.005 and is not affected by coordinate scaling. This default pen * radius is about 1/200 the width of the default canvas, so that if * you draw 100 points equally spaced along a horizontal or vertical line, * you will be able to see individual circles, but if you draw 200 such * points, the result will look like a line. * <ul> * <li> {@link #setPenRadius(double radius)} * </ul> * <p> * For example, {@code StdDraw.setPenRadius(0.025)} makes * the thickness of the lines and the size of the points to be five times * the 0.005 default. * To draw points with the minimum possible radius (one pixel on typical * displays), set the pen radius to 0.0. * <p>