Creating your own image data files

Simple ASCII file output in Javaimport java.io.FileOutputStream;import java.io.PrintWriter;…PrintWriter out = null;try { out = new PrintWriter( new FileOutputStream("fred.txt") );} catch (Exception e) { System.err.println( "error: " + e ); return;}out.println( "hello" );…out.close();

P2 = ASCII grey PGM

• Each pixel has one integer (grey) value.

P2w hmaxvalv1 v2 v3 …. . .. . . . . . vw*h

P3 = ASCII color PPM

• Each pixel’s color is represented as three consecutive values, <red,green,blue>.

P3w hmaxvalv1r

v1g v1b

v2r v2g

v2b

. . .

. . . . . . vw*hr vw*hg

vw*hb

Write a simple program that creates an image of the sin function.– file format: pgm (P2 / grey)– file name: out.pgm– Don’t use code other than your own.

Exercise

Write a simple program that creates an image of the sin function.– sin function:• width/domain/x: [0..2Pi]• y: real numbers [-1.0..+1.0]

– image:• width: 500 pixels ({0,..,499})• height: 250 pixels (repeat values from sin 250 times)• pixel values: integers {0,…,255}

Exercise

Part A.– Download GIMP (gimp.org), and load your PGM file into

GIMP.– Email your code (including doxygen/javadoc comments)

that produced the image data file to me.– The email subject must be: CV sin A assignment.

Exercise (cont’d.)

Same values across each line repeated over and over and over for every line.

Transfer files to and from the Android and PCs

• When you connect the Android to a PC, it will mount the Android file system on the PC.– From the PC, click on Computer. Then click on the

Android (mounted as Portable Media Player). Then click on Tablet. Then click on Download.• Copy images to and from the Android’s Download folder.

• On the Android, Apps --> My Files. Then navigate to /storage/sdcard0/Download.– These are the same Download folder.

Part B.1. Download and build Albie.2. Copy your pgm file from PC to Albie Download folder.3. Run Albie. (Note: Loading this ASCII file on a Samsung

Galaxy Tab 3 takes 30 seconds.)4. Use Albie’s Save option, and email the resulting JPEG to

me.– The email subject must be: CV sin B assignment.

Exercise (cont’d.)

Same values across each line repeated over and over and over for every line.