3.22 Java3022: scaling, rotating, and translating images using

Revised: Mon Apr 04 09:24:13 CDT 2016

This page is included in the following Books:

• ITSE 2321 - Object-Oriented Programming (Java)
• Object-Oriented Programming (OOP) with Java

Table of contents

• Preface
  • Viewing tip
    • Figures
    • Listings
• Preview
• General background information
• Discussion and sample code
• Run the program
• Summary
• What's next?
• Online video link
• Miscellaneous
• Complete program listing

Preface

This module is one of a series of modules designed to teach you about Object-Oriented Programming (OOP) using Java.

The program described in this module requires the use of the Guzdial-Ericson multimedia class library. You will find download, installation, and usageinstructions for the library at Java OOP: The Guzdial-Ericson Multimedia Class Library .

Viewing tip

I recommend that you open another copy of this document in a separate browser window and use the following links to easily find and view the Figures and Listings while you are reading about them.

Figures

• Figure 1 . Input file named Prob01.jpg.
• Figure 2 . First output image.
• Figure 3 . Second output image.
• Figure 4 . Required output text.

Listings

• Listing 1 . The driver class named Prob01.
• Listing 2 . Beginning of the class named Prob01Runner.
• Listing 3 . The run method.
• Listing 4 . Beginning of the method named rotatePicture.
• Listing 5 . Compute the dimensions of the new Picture object.
• Listing 6 . Prepare the translation transform.
• Listing 7 . Concatenate the transforms.
• Listing 8 . Instantiate the new Picture object .
• Listing 9 . Perform the concatenated transform.
• Listing 10 . Complete program listing.

Preview

In this module, you will learn how to scale images and how to rotate and translate images using the AffineTransform class.

Program specifications

Write a program named Prob01 that uses the class definition shown in Listing 1 and Ericson's media library along with the image file named Prob01.jpg (see Figure 1 ) to produce the output images shown in Figure 2 and Figure 3 .

Figure 1 - Input file named Prob01.jpg.

Figure 2 - First output image.

Figure 3 - Second output image.

Scale and rotate

The image from the file named Prob01.jpg must be scaled and then rotated 30 degrees clockwise. A scale factor of 0.95 must be applied to thehorizontal and a scale factor of 0.9 must be applied to the vertical.

New classes

You may define new classes as necessary to cause your program to behave as required, but you may not modify the class definition for the class named Prob01 shown in Listing 1 .

Required output text

In addition to the two output images mentioned above, your program must display your name and the other line of text shown in Figure 4 on the command-line screen.

General background information

Writing the code from scratch to rotate an image can be a daunting task. However, the task is made much easier through the use of the standard AffineTransform class, which is included in the standard Java library.