Learning Processing: A Beginner's Guide to Programming Images ...

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Java 425 instead of Processing , specifying all libraries would always be required. Processing , however, assumes a base set of libraries from Java (e.g., java.applet.*) and from Processing (e.g., processing.core.* ) which is why we do not see these in every sketch. • public —In Java, variables, functions, and classes can be “ public ” or “ private. ” This designation indicates what level of access should be granted to a particular piece of code. It is not something we have to worry much about in the simpler Processing environment, but it becomes an important consideration when moving on to larger Java programs. As an individual programmer, you are most often granting or denying access to yourself, as a means for protecting against errors. We encountered some examples of this in Chapter 22’s discussion about encapsulation. • class JavaExample —Sound somewhat familiar? Java, it turns out, is a true object-oriented language. There is nothing written in Java that is not part of a class! We are used to the idea of the Zoog class, Car class, PImage class, and so on, but it is important to note that the sketch as a whole is a class, too! Processing fills this stuff in for us so we do not have to worry about classes when we are first learning to program. • extends PApplet —Well, after reading Chapter 22, we should be quite comfortable with what this means. This is just another example of inheritance. Here, the class JavaExample is a child of the class PApplet (or, equivalently, PApplet is the parent of JavaExample). PApplet is a class developed by the creators of Processing and by extending it, our sketch has access to all of the Processing goodies— setup( ), draw( ) , mouseX , mouseY , and so on. This little bit of code is the secret behind how almost everything works in a Processing sketch. Processing has served us so well because it eliminates the need to worry about the above four elements, all the while providing access to the benefi ts of the Java programming language. Th e rest of this chapter will show how we can begin to make use of access to the full Java API. (We briefl y began this journey when we worked with String parsing in Chapters 17 and 18.) 23.3 Exploring the Java API Th e Processing reference quickly became our best friend forever while learning to program. Th e Java API will start off more as an acquaintance we bump into from time to time. Th at acquaintance might turn into a really excellent friend someday, but for now, small doses will be just fi ne. We can explore the full Java documentation by visiting: http://java.sun.com/ Th ere, we can click over to API specifi cations: http://java.sun.com/reference/api/index.html and fi nd a selection of versions of Java. On a Mac, Processing will run with the selected version of Java (run Java Preferences, found, e.g., in: /Applications/Utilities/Java/J2SE 5.0/). On a PC, the Processing “ standard ” download comes with Java version 1.4.2 (the Windows expert version allows you to install your own version of Java). Versions of Java will change in the future with updated info at processing.org. In any case, while there are diff erences between the version of Java, for what we are doing, they will not be terribly relevant, and we can look at the API for J2SE 1.4.2 for pretty much whatever we want to do. See Figure 23.1 .
426 Learning Processing fi g. 23.1 http://java.sun.com/j2se/1.4.2/docs/api/ And so, very quickly, you will fi nd yourself completely lost. And that is OK. Th e Java API is huge. Humongous. It is not really meant to be read or even perused . It is really pure reference, for looking up specifi c classes that you know you need to look up. For example, you might be working on a program that requires sophisticated random number generation beyond what random( ) can do, and you overheard a conversation about the class “ Random ” and thought “ Hey, maybe I should check that out! ” Th e reference page for a specifi c class can be found by scrolling down the “ All Classes ” list or else by selecting the right package (in this case the package java.util). A package, much like a library, is a collection of classes (the API organizes them by topic). Th e easiest way to fi nd a class, though, is to just type the name of the class and Java (i.e., “ Java Random ” ) into google. Th e documentation page is just about always the fi rst result. See Figure 23.2 .
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Learning Processing A Beginner’s
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Learning Processing A Beginner’s
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Contents Acknowledgments vii Introd
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Acknowledgments In the fall of 2001
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Introduction What is this book? Th
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Introduction xi While both of these
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Introduction xiii Th e book is desi
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Introduction xv Th is book’s web
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Introductory Exercise: Write instru
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Lesson One The Beginning 1 Pixels 2
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1 Pixels “ A journey of a thousan
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1.2 Simple Shapes Pixels 5 Th e vas
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0 1 2 3 4 5 6 7 8 9 fi g. 1.9 top l
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1.3 Pixels 9 Exercise 1-3: Reverse
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Example 1-2: noFill ( ) background(
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fi g. 1.19 Pixels 13 Exercise 1-5:
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colorMode(RGB,100); Pixels 15 Th e
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2 2.1 Processing “ Computers in t
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fi g. 2.2 Once you have opened the
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Let’s write a fi rst example ( se
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Line 9 fi g. 2.6 Processing is case
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fi g. 2.7 Processing 25 Processing
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Example 2-1: Zoog again size(200,20
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Processing 29 To see the applet wor
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3 3.1 Interaction “ Always rememb
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Let’s look at what will surely be
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3.3 Variation with the Mouse Intera
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Draw Zoog's eyes fill(0); ellipse(8
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3.4 Mouse Clicks and Key Presses In
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Draw Zoog's eyes fill(mo useX,0,mou
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Lesson Two Everything You Need to K
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4 4.1 Variables “ All of the book
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4.2 Variable Declaration and Initia
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A variable can also be initialized
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x = 5; x = a + b; x = y - 10 * 20;
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void draw() { // Draw the backgroun
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4.6 Random: Variety is the spice of
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4.7 Example 4-7: Filling variables
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5 5.1 Conditionals Conditionals 59
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Finally, for testing multiple condi
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Conditionals 63 It is worth pointin
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Conditionals 65 Getting into the ha
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Our fi rst instinct might be to wri
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5.5 Multiple Rollovers Conditionals
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Conditionals 71 We can then check t
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5.7 Conditionals 73 Exercise 5-8: E
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Reversing the Polarity of a Number
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One way to solve this problem is to
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Display the square fill(0); noStrok
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6 Loops “ Repetition is the reali
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Loops 83 (see Chapter 5). However,
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while (y < 100) { // Loop! } 3. Wha
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while (x < = endLegs) { line(x,y,x,
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Th e same exact loop can be program
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Loops 91 Th is was a nice simplifi
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6.6 Loop Inside the Main Loop Loops
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6.7 float distance = abs(mouseX - i
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Draw Zoog's legs stroke(0); line(x-
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Lesson Three Organization 7 Functio
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7 7.1 Functions “ When it’s all
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7.2 “ User Defi ned ” Functions
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Example 5-6: Bouncing ball // Decla
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7.5 Functions 107 Exercise 7-3: Tak
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Functions 109 It should be fairly a
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int globalX = 0; int globalY = 100;
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void setup() { println( "a"); funct
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If we did not include a return stat
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7.8 Zoog Reorganization Zoog is now
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void draw() { } background(0); // D
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8 8.1 Objects “ No object is so b
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Setup: Draw: Initialize car color.
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Objects 125 • The Class Name—Th
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Objects 127 One other thing; with t
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fi g. 8.1 fi g. 8.2 fi g. 8.4 fi g.
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Objects 131 Nevertheless, this is q
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void draw() { } background(100); ba
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Objects 135 modular, reusable packa
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Lesson Three Project Step 1. Take y
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Lesson Four More of the Same 9 Arra
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9 Arrays “ I might repeat to myse
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Car myCar80 Car myCar81 Car myCar82
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9.3 Declaring and Creating an Array
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9.4 Initializing an Array One way t
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Example 9-5: Using a for loop to in
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Arrays 151 Now comes the hard part.
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9.7 Arrays 153 Exercise 9-7: Rewrit
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9.8 Interactive Objects Arrays 155
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Check if point is inside of Stripe
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alls[i].gravity(); balls[i].move();
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Draw Zoog's arms with a for loop fo
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Lesson Five Putting It All Together
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10 10.1 Algorithms “ Lather. Rins
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Translating the preceding algorithm
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void draw() { background(255); stro
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Example 10-2: Bouncing ball class c
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Now that the function is complete,
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10.6 // Constructor Ball(float temp
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Algorithms 177 With the above logic
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Drop() { r = 8; // All raindrops ar
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Example 10-7: Drops one at a time /
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Algorithms 183 Notice how every sin
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oolean intersecting = ball1.interse
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} void setLocation(float tempX, flo
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Algorithms 189 It is important to r
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11 Debugging “ Th e diff erence b
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Debugging 193 Once all the code is
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12 Libraries “ If truth is beauty
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or /Applications/Processing 0135/ c
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Lesson Six The World Revolves Aroun
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13 Mathematics Mathematics 201 “
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Mathematics 203 Th erefore, modulo
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Th e probability of a coin fl ippin
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13.6 Perlin Noise Mathematics 207 O
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Mathematics 209 How quickly we incr
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It is fairly intuitive for us to th
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fi g. 13.9 y-axis sine(theta) � y
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Example 13-6: Oscillation float the
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Mathematics 217 In 1975, Benoit Man
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Mathematics 219 said about recursio
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Mathematics 221 A two-dimensional a
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Example 13-10: Two-dimensional arra
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} void display() { } // FILL IN Mat
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14 14.1 Translation and Rotation (i
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Our fi rst instinct might be to add
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Example 14-3: A rectangle moving al
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When using the OPENGL mode, you mus
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Translation and Rotation (in 3D!) 2
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14.5 fill(150,150); vertex(-t, t,-t
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14.6 Example 14-5: Rectangle rotati
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fill(0,100); // Note the use of pus
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14.9 Example 14-17: Nested push and
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stroke(0); fill(175); ellipse(0,0,d
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Lesson Seven Pixels Under a Microsc
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15 Images Images 255 “ Politics w
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And yet: PImage img = loadImage( "f
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15.3 My Very First Image Processing
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Images 261 Even better, if we just
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Images 263 // Create a grayscale co
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Images 265 15.6 Intro to Image Proc
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Images 267 Since we are altering th
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15.9 More on fi lter( ): fi lter(mo
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Images 271 Example 15-13 performs a
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Example 15-14: “ Pointillism ”
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16 16.1 Video “ I have no memory.
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Video 277 Th e above line of code i
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void draw() { // Check to see if a
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16.3 Recorded Video Video 281 Displ
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16.4 Video 283 Exercise 16-3: Using
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Video 285 For every square at colum
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} } // Each rect is colored white w
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16.5 Video as Sensor, Computer Visi
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Now, we are ready to compare the co
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16.6 Video 293 Exercise 16-5: Take
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void setup() { size(320,240); video
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Example 16-13: Simple motion detect
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16.8 // Step 4, compare colors (pre
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Lesson Seven Project Develop a soft
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Lesson Eight The Outside World 17 T
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17 17.1 Text “ I could entertain
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Exercise 17-2: Loop through and pri
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17.3 Displaying Text Text 309 We wi
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println(PFont.list()); For demonstr
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X = �50 fi g. 17.4 float w = text
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Example 17-4: Text mirror import pr
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textFont(f); // Set the font transl
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Exercise 17-9: Using textWidth( ) ,
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Example 17-7: Boxes along a curve P
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Text 323 Exercise 17-10: Create a s
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18 Data Input “ A million monkeys
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Example 18-1: User input PFont f; /
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Data Input 329 Th e reverse of spli
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Example 18-2: Graphing comma separa
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Data Input 333 Th e rollover( ) fun
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18.4 diameter = diameter_; } // Tru
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} // Find the index of the end tag
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void mousePressed() { // Increment
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18.6 for (int i = 0; i < kinglear.l
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Create and make an asynchronous req
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� student � � id � 002 �
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Requests for XML data are made via
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18.8 Using the Processing XML Libra
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XMLElement diameterElement = childr
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Example 18-10: A Yahoo search impor
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However, if you request a URL on a
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19 19.1 Data Streams “ I’m mad
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import processing.net.* ; Server se
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Data Streams 361 Once the server is
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19.4 void draw() { background(255);
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Data Streams 365 must be networked
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Data Streams 367 will send X , Y co
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Data Streams 369 Here is the full S
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Here is the entire client sketch: 1
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Data Streams 373 Serial communicati
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Page 396 and 397: Corresponding Arduino code: int sen
Page 398 and 399: Lesson Nine Making Noise 20 Sound 2
Page 400 and 401: 20 Sound “ Check. Check. Check 1.
Page 402 and 403: void setup() { Sonia.start(this); }
Page 404 and 405: void mousePressed() { // If the use
Page 406 and 407: Sound 387 check and see if a sound
Page 408 and 409: Is a point inside the doorbell (use
Page 410 and 411: Pressing the mouse stops and starts
Page 412 and 413: 20.6 void draw() { background(255,1
Page 414 and 415: In code, this translates to: // If
Page 416 and 417: 21 Exporting “ Wait a minute. I t
Page 418 and 419: Th is code can be inserted anywhere
Page 420 and 421: void setup() { size(400, 400); begi
Page 422 and 423: Exporting 403 save( ) takes one arg
Page 424 and 425: Exporting 405 Example 21-5 records
Page 426 and 427: Lesson Ten Beyond Processing 22 Adv
Page 428 and 429: 22 Advanced Object-Oriented Program
Page 430 and 431: class Point { float x,y; Point(floa
Page 432 and 433: Advanced Object-Oriented Programmin
Page 434 and 435: Advanced Object-Oriented Programmin
Page 436 and 437: class Circle extends Shape { // inh
Page 438 and 439: for (int i = 0; i < dogs.length; i
Page 440 and 441: 22.5 Example 22-2: Polymorphism //
Page 442 and 443: 23 23.1 Java “ I l o ve c off ee,
Page 446 and 447: fi g. 23.2 Java 427 Just as with th
Page 448 and 449: Particle p = parray[i]; p.run(); p.
Page 450 and 451: Hint: Add a function that returns a
Page 452 and 453: Example 23-4: Super fancy ArrayList
Page 454 and 455: Java 435 It is sad when these error
Page 456 and 457: Th e tutorials will cover the same
Page 458 and 459: Appendix: Common Errors Appendix 43
Page 460 and 461: Error: No accessible fi eld named
Page 462 and 463: void draw() { thing.display(); } Co
Page 464 and 465: Error: Perhaps you wanted the overl
Page 466 and 467: Index AIFF (Audio Interchange File
Page 468 and 469: Fill( ) function 10 , 11 , 256 , 30
Page 470 and 471: One-dimensional Perlin noise 208 OP
Page 472: solar system, processing 247-9 vert
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