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

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fi g. 2.2 Once you have opened the example, click the “ run ” button as indicated in Figure 2.3 . If a new window pops open running the example, you are all set! If this does not occur, visit the online FAQ “ Processing won’t start! ” for possible solutions. Th e page can be found at this direct link: http://www.processing.org/faq/ bugs.html#wontstart . Exercise 2-2: Open a sketch from the Processing examples and run it. fi g. 2.3 Processing programs can also be viewed full-screen (known as “ present mode ” in Processing ). Th is is available through the menu option: Sketch → Present (or by shift-clicking the run button). Present will not resize your screen resolution. If you want the sketch to cover your entire screen, you must use your screen dimensions in size( ) . 2.4 The Sketchbook Processing 19 To make sure everything is working, it is a good idea to try running one of the Processing examples. Go to FILE → EXAMPLES → (pick an example, suggested: Topics → Drawing → ContinuousLines) as shown in Figure 2.2 . Processing programs are informally referred to as sketches , in the spirit of quick graphics prototyping, and we will employ this term throughout the course of this book. Th e folder where you store your sketches is called your “sketchbook.” Technically speaking, when you run a sketch in processing , it runs as a local application on your computer. As we will see both in this Chapter and in Chapter 18, Processing also allows you to export your sketches as web applets (mini-programs that run embedded in a browser) or as platform-specifi c stand-alone applications (that could, for example, be made available for download). Once you have confi rmed that the Processing examples work, you are ready to start creating your own sketches. Clicking the “ new ” button will generate a blank new sketch named by date. It is a good idea to “ Save as ” and create your own sketch name. (Note: Processing does not allow spaces or hyphens, and your sketch name cannot start with a number.)
20 Learning Processing When you fi rst ran Processing , a default “ Processing ” directory was created to store all sketches in the “ My Documents ” folder on Windows and in “ Documents ” on OS X. Although you can select any directory on your hard drive, this folder is the default. It is a pretty good folder to use, but it can be changed by opening the Processing preferences (which are available under the FILE menu). Each Processing sketch consists of a folder (with the same name as your sketch) and a fi le with the extension “ pde. ” If your Processing sketch is named MyFirstProgram , then you will have a folder named MyFirstProgram with a fi le MyFirstProgram.pde inside. Th e “ pde ” fi le is a plain text fi le that contains the source code. (Later we will see that Processing sketches can have multiple pde’s, but for now one will do.) Some sketches will also contain a folder called “ data ” where media elements used in the program, such as image fi les, sound clips, and so on, are stored. 2.5 Exercise 2-3: Type some instructions from Chapter 1 into a blank sketch. Note how certain words are colored. Run the sketch. Does it do what you thought it would? Coding in Processing It is fi nally time to start writing some code, using the elements discussed in Chapter 1. Let’s go over some basic syntax rules. Th ere are three kinds of statements we can write: • Function calls • Assignment operations • Control structures For now, every line of code will be a function call. See Figure 2.4 . We will explore the other two categories in future chapters. Functions have a name, followed by a set of arguments enclosed in parentheses. Recalling Chapter 1, we used functions to describe how to draw shapes (we just called them “ commands ” or “ instructions ” ). Th inking of a function call as a natural language sentence, the function name is the verb ( “ draw ” ) and the arguments are the objects ( “ point 0,0 ” ) of the sentence. Each function call must always end with a semicolon. See Figure 2.5 . Function name fi g. 2.4 Line (0,0,200,200); Arguments in parentheses Ends with semi-colon We have learned several functions already, including background( ), stroke( ), fi ll( ), noFill ( ), noStroke( ), point( ), line( ), rect( ), ellipse( ), rectMode( ), and ellipseMode( ) . Processing will execute a sequence of functions one by one and fi nish by displaying the drawn result in a window. We forgot to learn one very important function in Chapter 1, however— size( ). size( ) specifi es the dimensions of the window you want to create and takes two arguments, width and height. Th e size( ) function should always be fi rst. size(320,240); Opens a window of width 320 and height 240.
Page 2 and 3: Learning Processing A Beginner’s
Page 4 and 5: Learning Processing A Beginner’s
Page 6 and 7: Contents Acknowledgments vii Introd
Page 8 and 9: Acknowledgments In the fall of 2001
Page 10 and 11: Introduction What is this book? Th
Page 12 and 13: Introduction xi While both of these
Page 14 and 15: Introduction xiii Th e book is desi
Page 16 and 17: Introduction xv Th is book’s web
Page 18 and 19: Introductory Exercise: Write instru
Page 20 and 21: Lesson One The Beginning 1 Pixels 2
Page 22 and 23: 1 Pixels “ A journey of a thousan
Page 24 and 25: 1.2 Simple Shapes Pixels 5 Th e vas
Page 26 and 27: 0 1 2 3 4 5 6 7 8 9 fi g. 1.9 top l
Page 28 and 29: 1.3 Pixels 9 Exercise 1-3: Reverse
Page 30 and 31: Example 1-2: noFill ( ) background(
Page 32 and 33: fi g. 1.19 Pixels 13 Exercise 1-5:
Page 34 and 35: colorMode(RGB,100); Pixels 15 Th e
Page 36 and 37: 2 2.1 Processing “ Computers in t
Page 40 and 41: Let’s write a fi rst example ( se
Page 42 and 43: Line 9 fi g. 2.6 Processing is case
Page 44 and 45: fi g. 2.7 Processing 25 Processing
Page 46 and 47: Example 2-1: Zoog again size(200,20
Page 48 and 49: Processing 29 To see the applet wor
Page 50 and 51: 3 3.1 Interaction “ Always rememb
Page 52 and 53: Let’s look at what will surely be
Page 54 and 55: 3.3 Variation with the Mouse Intera
Page 56 and 57: Draw Zoog's eyes fill(0); ellipse(8
Page 58 and 59: 3.4 Mouse Clicks and Key Presses In
Page 60 and 61: Draw Zoog's eyes fill(mo useX,0,mou
Page 62 and 63: Lesson Two Everything You Need to K
Page 64 and 65: 4 4.1 Variables “ All of the book
Page 66 and 67: 4.2 Variable Declaration and Initia
Page 68 and 69: A variable can also be initialized
Page 70 and 71: x = 5; x = a + b; x = y - 10 * 20;
Page 72 and 73: void draw() { // Draw the backgroun
Page 74 and 75: 4.6 Random: Variety is the spice of
Page 76 and 77: 4.7 Example 4-7: Filling variables
Page 78 and 79: 5 5.1 Conditionals Conditionals 59
Page 80 and 81: Finally, for testing multiple condi
Page 82 and 83: Conditionals 63 It is worth pointin
Page 84 and 85: Conditionals 65 Getting into the ha
Page 86 and 87: 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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Data Streams 375 of information, ca
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Corresponding Arduino code: int sen
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Lesson Nine Making Noise 20 Sound 2
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20 Sound “ Check. Check. Check 1.
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void setup() { Sonia.start(this); }
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void mousePressed() { // If the use
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Sound 387 check and see if a sound
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Is a point inside the doorbell (use
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Pressing the mouse stops and starts
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20.6 void draw() { background(255,1
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In code, this translates to: // If
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21 Exporting “ Wait a minute. I t
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Th is code can be inserted anywhere
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void setup() { size(400, 400); begi
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Exporting 403 save( ) takes one arg
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Exporting 405 Example 21-5 records
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Lesson Ten Beyond Processing 22 Adv
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22 Advanced Object-Oriented Program
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class Point { float x,y; Point(floa
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Advanced Object-Oriented Programmin
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Advanced Object-Oriented Programmin
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class Circle extends Shape { // inh
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for (int i = 0; i < dogs.length; i
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22.5 Example 22-2: Polymorphism //
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23 23.1 Java “ I l o ve c off ee,
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Java 425 instead of Processing , sp
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fi g. 23.2 Java 427 Just as with th
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Particle p = parray[i]; p.run(); p.
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Hint: Add a function that returns a
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Example 23-4: Super fancy ArrayList
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Java 435 It is sad when these error
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Th e tutorials will cover the same
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Appendix: Common Errors Appendix 43
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Error: No accessible fi eld named
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void draw() { thing.display(); } Co
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Error: Perhaps you wanted the overl
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Index AIFF (Audio Interchange File
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Fill( ) function 10 , 11 , 256 , 30
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One-dimensional Perlin noise 208 OP
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solar system, processing 247-9 vert
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