Basic Graphics Chapter 5 3/19/15 Thursday Section Only Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

This Week's Topics Creating a Window The Class Graphics Getting Ready to Draw A Sample Drawing Panel Displaying a Panel The Class Graphics The Coordinate System Drawing Lines, Shapes, and Text Painting Shapes Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Objectives After studying this chapter, you should be able to: Write a program that creates a window with graphics Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Objectives Display in a window Lines Rectangles Ovals Arcs Strings Use color in Graphics Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Creating a Window A rectangular area Figure 5-1 An empty frame Part of a user interface Called a frame Contains title bar Figure 5-1 An empty frame Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Creating a Window Construct object of class JFrame From package javax.swing JFrame aWindow = new JFrame(); Specify size aWindow.setSize(400, 600); Window must be made visible. aWindow.setVisible(true); Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Creating a Window setTitle() puts a title in the title bar: aWindow.setTitle(“Bronco Window”); View sample program, EmptyWindow Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Creating a Window If the user closes the window with the control button, the window closes. The program keeps running. aWindow.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE); Exits program when window closes. Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Preparing to Draw Cannot draw directly on JFrame object This is a container Contains other objects Can create a JPanel object and add it to the JFrame, but it would be blank. The JPanel class is in javax.swing Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Preparing to Draw Create a class of panels upon which to draw. DrawingPanel inherits JPanel. Graphics g parameter allows it to draw. Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Simple Drawing Panel Some basic shapes. Now we create a window and add an instance of class DrawingPanel to the window. Example in WindowWithDrawing Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Class Graphics Java runtime environment instantiates a Graphics object The graphics context Made available to method paintComponent Use methods of Graphics object to display shapes Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Coordinate System Figure 5-2 The axes and some points on the coordinate system used for graphics Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Lines, Shapes, Text Methods: g.drawline (x1, y1, x2, y2); g.drawRect(x, y, width, height); Note pixels on edges of 5 x 4 rectangle Figure 5-3 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Lines, Shapes, Text Ovals, Circles g.drawOval(x, y, width, height); ( for circle, height = width) Imaginary rectangle encloses oval Figure 5-4 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Example I will: Create a java class displays a JFrame. Create JPanel that has a drawing of a circle with a rectangle in it. Make it look like a DO NOT ENTER sign Add the JPanel to the JFrame to display the sign

Questions Study questions 1-4 in Chapter 5. Study exercises 1-6 on page 130.

Lines, Shapes, Text Arc – a portion of an oval Figure 5-5 Additional specification of beginning and ending angle g.drawArc(x, y, width, height, startAngle, extentAngle) Figure 5-5 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Lines, Shapes, Text Strings – text “drawn” onto the panel g.drawString ("Square", 50, 90); Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Lines, Shapes, Text Filled rectangles and squares Specify position, dimensions g.fillRect(x, y, width, height); Pixels in 5 x 4 rectangle painted by fillRect Figure 5-6 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Lines, Shapes, Text Filled ovals, circles, arcs Similar to use of drawOval, drawArc g.fillOval (250, 100, 40, 20); Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Participation #16 on page 131 Create a Jframe (window) Create a Panel and add it to the JFrame Use the paintComponent to draw basic shapes. Start with the largest rectangle of the house Add windows, doors and roof

import javax.swing.JFrame; public class WindowWithDrawing { public static void main(String[] args) { //set up a JFrame window JFrame bWindow = new JFrame(); bWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); bWindow.setSize(400,300); bWindow.setTitle("Shapes"); //Put a DrawingPanel in the Window //Make the window visible bWindow.setVisible(true); }

import javax.swing.JPanel; import java.awt.Graphics; public class DrawingPanel extends JPanel { //A panel to draw on. public void paintComponent(Graphics pen){ //Statements that draw go here }

Problem: Display Temperature* Program that draws a thermometer Display temp in analog, digital Note Figure 5-7 *See text for this example Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Problem: Display Temperature Discussion Rectangles Filled rectangle Text Locate in panel Figure 5-8 Schematic of Thermometer Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Problem: Display Temperature A panel that draws the thermometer Listing 5-4 Now we create a program that displays the panel specified above Listing 5-5 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Class Font-Skip Specify a Font object to set for the drawString method Font aFont = new Font(name, style, size); Physical name Name of an actual font Logical name Name of a font family Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Class Font Figure 5-9 Names of fonts and families written in the fonts they represent Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Class Color In java.awt.Color Create a color by specifying RGB values Each primary color given by integer 0 – 255 Predefined color constants from Color Figure 5-10 Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Class Color A demonstration of the use of color Listing 5-6 A program that displays the panel defined in previous listing, Listing 5-7 Resulting output Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Problem Solved: Happy Face See text for this example We desire a program to display a happy face as shown in Figure 5-11 Must decide shape, size, color, positions of Face Eyes Mouth Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Problem Solved: Happy Face Positions to be specified Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Problem Solved: Happy Face View source code for happy-face panel Figure 5-8 The program which would display this panel is left as an exercise. Imagine! Java: Programming Concepts in Context by Frank M. Carrano, (c) Pearson Education - Prentice Hall, 2010

Imagine! Java: Programming Concepts in Context by Frank M. Carrano Basic Graphics Chapter 5 Imagine! Java: Programming Concepts in Context by Frank M. Carrano