제 10 주 그래픽프로그래밍 2

제 10 주 그래픽프로그래밍 2

제 10 주 강의 목표• Graphics 를 사용하여 임의의 Shape 을 그리는 법을 익힘• 마우스이벤트 이용법을 익힘• 타이머 이벤트 처리 및 애니메이션 효과를 구현하는 법을 익힘

객체지향프로그래밍 강원대학교 1

강원대학교객체지향프로그래밍

Frame

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import javax.swing.JFrame;

public class EmptyFrameViewer{ public static void main(String[] args) { JFrame frame = new JFrame();

final int FRAME_WIDTH = 300; final int FRAME_HEIGHT = 400;

frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setTitle("An Empty Frame"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.setVisible(true); }}

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도형 그리기

• 프레임 안에 도형을 그리기 위해서는 그림 그리는 기능을 가진 부품(JComponent) 을 프레임에 넣어주어야 함

• JComponent 객체는 paintComponent 메소드를 가짐• paintComponent 메소드는 필요할 때마다 시스템에 의해

자동으로 호출됨• 필요한 때

– 프로그램이 처음 실행될 때– 프레임을 아이콘으로 최소화했다가 다시 창으로 복원시킬 때– 프레임이 다른 윈도우에 의해 가려졌다가 나타날 때– 마우스 드래그를 이용해 프레임을 이동시킬 때 등

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import javax.swing.*;

public class EmptyFrameViewer{ public static void main(String[] args) { JFrame frame = new JFrame();


frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setTitle("An Empty Frame"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

JComponent component = new JComponent(); // 부품을 구성 frame.add(component); // 부품을 프레임에 넣음


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도형 그리기• JComponent 객체가 가지고 있는 paintComponent 메소드는

화면에 아무것도 그리지 않음• 화면에 도형을 그리려면 도형 그리는 기능을 갖도록 Jcomponent 를

수정하여 프레임에 넣어 줘야 함

• Jcomponent 를 수정하여 새로운 부품을 만드는 방법

public class RectangleComponent extends JComponent{ public void paintComponent(Graphics g) { // Recover Graphics2D Graphics2D g2 = (Graphics2D) g; . . . }}

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public class RectangleComponent extends JComponent{ public void paintComponent(Graphics g) { // Recover Graphics2D Graphics2D g2 = (Graphics2D) g;

Rectangle box = new Rectangle(5, 10, 20, 30); g2.draw(box); }}

• RectanlgeComponent 클래스는 수퍼클래스인 JComponent의 paintComponent 메소드를 상속하여 이를 재정의(override) 함

• JComponent 의 paintComponent 메소드는 아무것도 그리지 않음

• 재정의된 paintComponent 메소드는 사각형 인스턴스를 하나 구성하고 이것을 화면에 그림

RectangleComponent.java

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import javax.swing.*;

public class RectangleViewer{ public static void main(String[] args) { JFrame frame = new JFrame();


frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setTitle("A Rectangle Frame"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

RectangleComponent component = new RectangleComponent(); frame.add(component); // 부품을 프레임에 넣음


RectangleViewer.java

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import javax.swing.JComponent;import java.awt.Rectangle;import java.awt.Graphics;import java.awt.Graphics2D;

public class RectangleComponent extends JComponent{ public void paintComponent(Graphics g) { // Recover Graphics2D Graphics2D g2 = (Graphics2D) g;

Rectangle box = new Rectangle(5, 10, 20, 30); g2.draw(box); box.translate(15, 25); g2.draw(box); }}

RectangleComponent.java

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컴파일할 때의 파일간 종속성• ( 같은 폴더에 ) RectanlgeComponent.java 파일 없이

RectanlgeViewer.java 를 컴파일하려고 하면 안됨• RectangleViewer 가 RectangleComponet 를 사용하기

때문

• 반면 RectanlgeComponent.java 는 RectanlgeViewer.-java 파일 없이도 컴파일 가능

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Graphical Shapes• Rectangle, Ellipse2D.Double, Line2D.Double 등• API 문서에서 java.awt.Shape 을 찾아보면 Shape 에 속하는

도형들을 더 볼 수 있음

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Graphical Shapes• Ellipse2D.Double 은 Ellipse2D 의 내부클래스 (innerclass) 임• Ellipse2D.Double 를 사용하기 위해서는

import java.awt.geom.Ellipse2D

Ellipse2D.Double ellipse = new Ellipse2D.Double(x, y, width, height);g2.draw(ellipse);

Ellipse

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Drawing Lines• To construct a line:

or,Line2D.Double segment = new Line2D.Double(x1, y1, x2, y2);

Point2D.Double from = new Point2D.Double(x1, y1);Point2D.Double to = new Point2D.Double(x2, y2);Line2D.Double segment = new Line2D.Double(from, to);

• To draw the line:g.draw(segment);

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Drawing Strings

g2.drawString("Message", 50, 100);

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Colors• Standard colors: Color 클래스에 static 필드로

정의되어 있음• Color.BLUE, Color.RED, Color.PINK etc.

• static 필드 : 개별 인스턴스에 속하지 않고 클래스에 하나만 정의되는 필드

• 필드 : 클래스 내부이면서 메소드 외부에 선언된 변수 , 상수 , 객체

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칼라 사각형 그리기

public void paintComponent(Graphics g){

Graphics2D g2 = (Graphics2D) g;

g2.setColor(Color.RED);g2.fill(new Rectangle(0, 0, 200, 200));

g2.setColor(Color.YELLOW);g2.fill(new Rectangle(50, 50, 100, 100));

}

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임의 칼라 사각형 그리기

public void paintComponent(Graphics g){

Graphics2D g2 = (Graphics2D) g;

g2.setColor(new Color(0.5f, 0.6f, 0.3f));g2.fill(new Rectangle(0, 0, 200, 200));

g2.setColor(new Color(25, 200, 224));g2.fill(new Rectangle(50, 50, 100, 100));

}

Color(float r, float g, float b) – r, g, b 는 0.0-1.0Color(int r, int g, int b) - r, g, b 는 0-255

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복잡한 모양 그리기

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import javax.swing.JFrame;

public class CarViewer{ public static void main(String[] args) { JFrame frame = new JFrame();


frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setTitle("Two cars"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

CarComponent component = new CarComponent(); frame.add(component);


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import java.awt.Graphics;import java.awt.Graphics2D;import javax.swing.JComponent;

public class CarComponent extends JComponent{ public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g;

Car car1 = new Car(0, 0); int x = getWidth() - Car.WIDTH; int y = getHeight() - Car.HEIGHT;

Car car2 = new Car(x, y);

car1.render(g2); car2.render(g2); }}

위치

WIDTH

HEIGHT

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import java.awt.Graphics;import java.awt.Graphics2D;import javax.swing.JComponent;

public class CarComponent extends JComponent{ public void paintComponent(Graphics g) { Graphics2D g2 = (Graphics2D) g;

Car car1 = new Car(0, 0); int x = getWidth() - Car.WIDTH; int y = getHeight() - Car.HEIGHT;

Car car2 = new Car(x, y);

car1.render(g2); car2.render(g2); }}

• getWidth, getHeight 는 paint-Component 를 실행하고 있는 Car-Component 객체에 호출됨

• 윈도우 크기를 조정하면 paintCom-ponent 가 호출되고 자동차의 위치가 재계산됨 ( 프로그램을 실행한 후 마우스를 드래그하여 윈도우 크기를 바꿔보세요 !)

CarComponent 에 그림을 그리기 위한 도구

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복잡한 모양 그리기

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public class Car{ public Car(int x, int y) { xLeft = x; yTop = y; } public void render(Graphics2D g2) { g2.draw(body); g2.draw(frontTire); g2.draw(rearTire); g2.draw(frontWindshield); g2.draw(roofTop); g2.draw(rearWindshield); }

public static int WIDTH = 60; // static field public static int HEIGHT = 30; // static field

private int xLeft; // 인스턴스 필드 private int yTop; // 인스턴스 필드

}

미완성 !

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import java.awt.Graphics2D;import java.awt.Rectangle;import java.awt.geom.Ellipse2D;import java.awt.geom.Line2D;import java.awt.geom.Point2D;

/** A car shape that can be positioned anywhere on the screen.*/public class Car{ /** Constructs a car with a given top left corner @param x the x coordinate of the top left corner @param y the y coordinate of the top left corner */ public Car(int x, int y) { xLeft = x; yTop = y; }

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/** Draws the car. @param g2 the graphics context */ public void render(Graphics2D g2) { Rectangle body = new Rectangle(xLeft, yTop + 10, 60, 10); Ellipse2D.Double frontTire = new Ellipse2D.Double(xLeft + 10, yTop + 20, 10, 10); Ellipse2D.Double rearTire = new Ellipse2D.Double(xLeft + 40, yTop + 20, 10, 10);

// The bottom of the front windshield Point2D.Double r1 = new Point2D.Double(xLeft + 10, yTop + 10); // The front of the roof Point2D.Double r2 = new Point2D.Double(xLeft + 20, yTop); // The rear of the roof Point2D.Double r3 = new Point2D.Double(xLeft + 40, yTop); // The bottom of the rear windshield Point2D.Double r4

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Line2D.Double frontWindshield = new Line2D.Double(r1, r2); Line2D.Double roofTop = new Line2D.Double(r2, r3); Line2D.Double rearWindshield = new Line2D.Double(r3, r4); g2.draw(body); g2.draw(frontTire); g2.draw(rearTire); g2.draw(frontWindshield); g2.draw(roofTop); g2.draw(rearWindshield); }

public static int WIDTH = 60; public static int HEIGHT = 30; private int xLeft; private int yTop;}

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Reading Text Input

String input = JOptionPane.showInputDialog("Enter x");double x = Double.parseDouble(input);

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마우스 이벤트 처리


객체지향프로그래밍 강원대학교

Mouse Events• 마우스 이벤트를 처리하기 위해서는 마우스리스너를

사용• 마우스리스너는 MouseListener 인터페이스를

구현해야 함public interface MouseListener { void mousePressed(MouseEvent event); // Called when a mouse button has been pressed on a component void mouseReleased(MouseEvent event); // Called when a mouse button has been released on a component void mouseClicked(MouseEvent event); // Called when the mouse has been clicked on a component void mouseEntered(MouseEvent event); // Called when the mouse enters a component void mouseExited(MouseEvent event); // Called when the mouse exits a component }

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마우스 리스너 구현과 등록

public class MyMouseListener implements MouseListener { // Implements five methods } MouseListener listener = new MyMouseListener(); component.addMouseListener(listener);

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Mouse Event 처리 프로그램 예• RectangleComponentViewer• 마우스를 클릭하면 그 위치로 사각형이 이동

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public class RectangleComponent extends JComponent{ public RectangleComponent() { box = new Rectangle(BOX_X, BOX_Y, BOX_WIDTH, BOX_HEIGHT); } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D) g; g2.draw(box); } public void moveTo(int x, int y) { box.setLocation(x, y); repaint(); } private Rectangle box;}

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public class RectangleComponentViewer{ public static void main(String[] args) { final RectangleComponent component = new Rectangle-

Component(); class MousePressListener implements MouseListener { public void mousePressed(MouseEvent event) { int x = event.getX(); int y = event.getY(); component.moveTo(x, y); } public void mouseReleased(MouseEvent event) {} public void mouseClicked(MouseEvent event) {} public void mouseEntered(MouseEvent event) {} public void mouseExited(MouseEvent event) {} } MouseListener listener = new MousePressListener(); component.addMouseListener(listener); JFrame frame = new JFrame(); frame.add(component); frame.setSize(FRAME_WIDTH, FRAME_HEIGHT); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); }} 33


File RectangleComponent.java01: import java.awt.Graphics;02: import java.awt.Graphics2D;03: import java.awt.Rectangle;04: import javax.swing.JComponent;05: 06: /**07: This component lets the user move a rectangle by08: clicking the mouse.09: */10: public class RectangleComponent extends JComponent11: { 12: public RectangleComponent()13: { 14: // The rectangle that the paint method draws15: box = new Rectangle(BOX_X, BOX_Y, 16: BOX_WIDTH, BOX_HEIGHT); 17: }18:

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File RectangleComponent.java19: public void paintComponent(Graphics g)20: { 21: super.paintComponent(g);22: Graphics2D g2 = (Graphics2D) g;23: 24: g2.draw(box);25: }26: 27: /**28: Moves the rectangle to the given location.29: @param x the x-position of the new location30: @param y the y-position of the new location31: */32: public void moveTo(int x, int y)33: {34: box.setLocation(x, y);35: repaint(); 36: }

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File RectangleComponent.java37: 38: private Rectangle box;39: 40: private static final int BOX_X = 100;41: private static final int BOX_Y = 100;42: private static final int BOX_WIDTH = 20;43: private static final int BOX_HEIGHT = 30;44: }

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마우스 리스너 구현

class MousePressListener implements MouseListener { public void mousePressed(MouseEvent event) { int x = event.getX(); int y = event.getY(); component.moveTo(x, y); } // Do-nothing methods public void mouseReleased(MouseEvent event) {} public void mouseClicked(MouseEvent event) {} public void mouseEntered(MouseEvent event) {} public void mouseExited(MouseEvent event) {} }

• MouseListener 인터페이스에 정해져 있는 다섯개의 메소드를 모두 구현해야 함

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RectangleComponentViewer2.java01: import java.awt.event.MouseListener;02: import java.awt.event.MouseEvent;03: import javax.swing.JFrame;04: 05: /**06: This program displays a RectangleComponent.07: */08: public class RectangleComponentViewer09: { 10: public static void main(String[] args)11: { 12: final RectangleComponent component = new RectangleComponent();13: 14: // Add mouse press listener 15: 16: class MousePressListener implements MouseListener17: {

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RectangleComponentViewer2.java18: public void mousePressed(MouseEvent event)19: { 20: int x = event.getX();21: int y = event.getY();22: component.moveTo(x, y);23: }24: 25: // Do-nothing methods26: public void mouseReleased(MouseEvent event) {}27: public void mouseClicked(MouseEvent event) {}28: public void mouseEntered(MouseEvent event) {}29: public void mouseExited(MouseEvent event) {}30: }31: 32: MouseListener listener = new MousePressListener();33: component.addMouseListener(listener);34:

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RectangleComponentViewer2.java

35: JFrame frame = new JFrame();36: frame.add(component);37: 38: frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);39: frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);40: frame.setVisible(true);41: }42: 43: private static final int FRAME_WIDTH = 300;44: private static final int FRAME_HEIGHT = 400;45: }

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타이머 이벤트 처리 애니메이션


Processing Timer Events• javax.swing.Timer 는 일정 시간 간격으로

액션이벤트를 발생시킨다 . • 객체 상태를 일정 시간 간격으로 갱신하고자 할 때 사용• 타이머에게 액션이벤트 리스너를 등록해 놓으면

액션이벤트가 발생될 때마다 액션이벤트 리스너의 ac-tionPerformed 메소드가 호출됨 - callback!class MyListener implements ActionListener{ void actionPerformed(ActionEvent event) { // 타이머에서 액션이벤트가 발생할 때마다 // 이곳에 적어주는 액션이 실행됨 }}


Processing Timer Events• 액션 리스너를 타이머에 등록함

MyListener listener = new MyListener();Timer t = new Timer(interval, listener);t.start(); // 타이머 쓰레드 시작

Timer MyListeneractionPerformed

등록

주기적으로 이벤트 발생actionPerformed 메소드 실행 (callback)


Example: Countdown• Example: a timer that counts down to zero


File TimeTester.java01: import java.awt.event.ActionEvent;02: import java.awt.event.ActionListener;03: import javax.swing.JOptionPane;04: import javax.swing.Timer;05: 06: /**07: This program tests the Timer class.08: */09: public class TimerTester10: {11: public static void main(String[] args)12: {13: class CountDown implements ActionListener14: {15: public CountDown(int initialCount)16: {17: count = initialCount;18: }


File TimeTester.java19: 20: public void actionPerformed(ActionEvent event)21: {22: if (count >= 0)23: System.out.println(count);24: if (count == 0)25: System.out.println("Liftoff!");26: count--;27: }28: 29: private int count;30: }31: 32: CountDown listener = new CountDown(10);33: 34: final int DELAY = 1000; // Milliseconds between // timer ticks


File TimeTester.java35: Timer t = new Timer(DELAY, listener);36: t.start();37: 38: JOptionPane.showMessageDialog(null, "Quit?");39: System.exit(0);40: }41: }



애니메이션 프로그램 기본 형식

class Mover implements ActionListener { public void actionPerformed(ActionEvent event) { // Move the rectangle } }

ActionListener listener = new Mover(); final int DELAY = 100; // Milliseconds between timer ticks Timer t = new Timer(DELAY, listener); t.start();

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Accessing Surrounding Variables• Inner 클래스의 메소드에서는 바깥 클래스의 변수에 접근할 수

있음public static void main(String[] args) { . . . final Rectangle box = new Rectangle(5, 10, 20, 30);

class Mover implements ActionListener { public void actionPerformed(ActionEvent event) { // Move the rectangle box.translate(1, 1); } } . . . }

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File TimeTester2.java01: import java.awt.Rectangle;02: import java.awt.event.ActionEvent;03: import java.awt.event.ActionListener;04: import javax.swing.JOptionPane;05: import javax.swing.Timer;06: 07: /**08: This program uses a timer to move a rectangle once per second.09: */10: public class TimerTester211: {12: public static void main(String[] args)13: {14: final Rectangle box = new Rectangle(5, 10, 20, 30);15: 16: class Mover implements ActionListener17: {

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File TimeTester2.java18: public void actionPerformed(ActionEvent event)19: {20: box.translate(1, 1);21: System.out.println(box);22: }23: }24: 25: ActionListener listener = new Mover();26: 27: final int DELAY = 100; // Milliseconds between timer ticks28: Timer t = new Timer(DELAY, listener);29: t.start();30: 31: JOptionPane.showMessageDialog(null, "Quit?");32: System.out.println("Last box position: " + box);33: System.exit(0);34: }35: }

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File TimeTester2.java

java.awt.Rectangle[x=6,y=11,width=20,height=30] java.awt.Rectangle[x=7,y=12,width=20,height=30] java.awt.Rectangle[x=8,y=13,width=20,height=30] . . . java.awt.Rectangle[x=28,y=33,width=20,height=30] java.awt.Rectangle[x=29,y=34,width=20,height=30] Last box position: java.awt.Rectangle[x=29,y=34,width=20,height=30]

Output:

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Animation Program


public class RectangleComponent extends JComponent{ private Rectangle box;public RectangleComponent(){

box = new Rectangle(BOX_X, BOX_Y, BOX_WIDTH,

BOX_HEIGHT); }public void paintComponent(Graphics g){

Graphics2D g2 = (Graphics2D) g;g2.draw(box);

}public void moveBy(int dx, int dy){

box.translate(dx, dy);repaint();

}}


public class RectangleMover{public static void main(String[] args){

JFrame frame = new JFrame();frame.setSize(FRAME_WIDTH, FRAME_HEIGHT);frame.setTitle("An animated rectangle");

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);final RectangleComponent component = new Rectan-

gleComponent();frame.add(component);frame.setVisible(true);class TimerListener implements ActionListener{

public void actionPerformed(ActionEvent event){

component.moveBy(1, 1);}

}ActionListener listener = new TimerListener();final int DELAY = 100; // Milliseconds between timer

ticksTimer t = new Timer(DELAY, listener);t.start();

}}


제 10 주 그래픽프로그래밍 2

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