ProcessingTricks.txt

### INIT

void init()
{
  // Do stuff
  // ...
  super.init();
}

Called before setup()!

### STOP

void stop()
{
  // Do stuff
  // ...
  super.stop();
}

Called when closing the sketch.

### Titleless sketch window

[url=http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Programs;action=display;num=1228323183;start=1#1]Re: hiding windows controls[/url]

// Avoids java.awt.IllegalComponentStateException: The frame is displayable.
// Can put this code in init()
frame.removeNotify();
frame.setUndecorated(true);
frame.addNotify();

frame.isUndecorated();

### Window always on top

frame.setAlwaysOnTop(true);

### Resize sketch window

// Any time
frame.setSize(w, h);
setSize(w, h); // Optional? Or not?

Or, to allow users to resize:

frame.setResizable(true); // in setup()

### Resize OpenGL canvas

[url=http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Integrate;action=display;num=1227629232;start=4#4]Re: OpenGL canvas does not resize when embeded[/url]

pgl = (PGraphicsOpenGL) g;
gl = pgl.beginGL();
gl.glViewport(0, 0, width, height);
pgl.endGL();

### Resize canvas to given size

[url=http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Programs;action=display;num=1217592683]Re: problem resizing a window on the fly[/url]

int w = 200;
final static int INCR = 50;
Insets insets;

void setup()
{
  size(200, 400);
  background(100);
  frame.pack();  // Get insets. Get more!
  insets = frame.getInsets();
}

void draw()
{
  background(100);
  line(0, 0, width, height);
  line(0, height, width, 0);
  fill(#55AAFF);
  for (int i = 0; i < width; i += INCR)
  {
    ellipse(i + INCR/2, height/2, INCR, INCR);
  }
}

void mousePressed()
{
  w = w + INCR;
  // Change internal canvas size
  setSize(w, height);
  // width variable isn't updated yet, will be on draw()
  println("Press: " + w + " => " + width);

  int windowW = Math.max(w, MIN_WINDOW_WIDTH) +
      insets.left + insets.right;
  int windowH = Math.max(height, MIN_WINDOW_HEIGHT) +
      insets.top + insets.bottom;

  // Change frame size, taking in account the insets (borders, title bar)
  frame.setSize(windowW, windowH);
}

### Sketch (frame) location

frame.getLocation();
frame.getLocationOnScreen(); // Identical result!

// In OpenGL mode put in the setup(), in normal mode put in the draw(). (?)
frame.setLocation(0, 0);

### Where to put libraries

[url=http://processing.org/discourse/yabb2/YaBB.pl?num=1269728211]Libraries -still confused about where to put...[/url]

### Rotate a shape around a given point

// Where we want the shape drawn, depending on its mode: that's where the 0, 0 drawing will occur
translate(600, 400);
// Move the center by offset
translate(-OFFSET, 0);
// Do the rotation
rotate(angle);
// Restore the center where it was
translate(OFFSET, 0);
// Draw the shape
fill(202);
ellipse(0, 0, ELLIPSE_WIDTH, 180);

### Handling Ctrl+Char

boolean ctrlPressed;

void keyPressed()
{
  // special key
  if (key == CODED)
  {
    if (keyCode == CONTROL)
    {
      ctrlPressed = true;
    }
  }
  // regular key
  else
  {
    if (ctrlPressed)
    {
      // CTRL + KEY
    }
    else
    {
      // OTHER
    }
  }
}

void keyReleased()
{
  if (key == CODED)
  {
    if (keyCode == CONTROL)
    {
      ctrlPressed = false;
    }
  }
}

### Java syntax

If the code is in a .pde file, you must use untyped Collections:
Processing uses Java 1.6 but is currently (1.0) stuck on 1.4 syntax. The 1.6 syntax is only usable within .java files in the sketch.

### How to Increase the Java Applet Memory Limit
[url=http://www.duckware.com/pmvr/howtoincreaseappletmemory.html]Sun Java Plugin - How to Increase the Java Applet Memory Limit[/url]

### Maximum memory usable by Java

The [url=http://processing.org/discourse/yabb2/YaBB.pl?num=1263007499]memory increase[/url] thread might be relevant. Basically, you need a 64bit Java on a 64bit OS (on a 64bit processor, of course).
See also [url=http://forums.sun.com/thread.jspa?threadID=5433568]The truth about JVM max memory usage. Does it use only 2gb?[/url] and [url=http://rsbweb.nih.gov/ij/docs/install/windows.html]ImageJ: Windows Installation[/url].

### Get a BI from a PImage:

BufferedImage bufimg = new BufferedImage(
      smallImage.width, smallImage.height,
      smallImage.format == ARGB ?
          BufferedImage.TYPE_INT_ARGB :
          BufferedImage.TYPE_INT_RGB);
bufimg.setRGB(0, 0, smallImage.width, smallImage.height,
      smallImage.pixels, 0, smallImage.width);

Or just use PImage.getImage()...

### Create image from byte array
http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Syntax;action=display;num=1215762729;start=3#3

import java.awt.Toolkit;

Image GetFromJPEG(byte[] jpegBytes)
{
  Image jpegImage = null;
  println("Jpeg data length: " + jpegBytes.length);

  try
  {
    jpegImage = Toolkit.getDefaultToolkit().createImage(jpegBytes);
  }
  catch (Exception e)
  {
    println("Problem creating image: " + e.toString() + ": " + e.getMessage());
  }
  // Image isn't loaded yet, we have to wait for end of processing of the data
  // Stupid way, I suppose I should use an ImageObserver...
  float waitTime = 0;
  while (jpegImage.getHeight(null) == -1)
  {
    delay(25); // Don't hog CPU!
    waitTime += 0.025;
  }
  println("After " + int(waitTime) + "s, I get an image of width " +
 jpegImage.getWidth(null) + " and height " + jpegImage.getHeight(null));

  return jpegImage;
}

byte[] bytes = null;
Image img = null;

void setup()
{
  noLoop();
  try
  {
    InputStream in = new FileInputStream("D:/_PhiLhoSoft/Processing/Johnson.jpg");
    int l = in.available();
    println("L: " + l);
    bytes = new byte[l];
    in.read(bytes);
  }
  catch (Exception e)
  {
    println("Problem reading image: " + e.toString() + ": " + e.getMessage());
  }
  // Initial load
  img = GetFromJPEG(bytes);
  println(img.getClass().toString());
//  sun.awt.image.ToolkitImage tki = (sun.awt.image.ToolkitImage) img;
//  BufferedImage bi = tki.getBufferedImage();
//  println(bi.getClass().toString());
  size(img.getWidth(null), img.getHeight(null));
}

void draw() // In noLoop mode!
{
  PImage pimg = new PImage(img);
  image(pimg, 0, 0);
}

### Drag'n'drop from a file explorer to an applet window

[url=http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Integrate;action=display;num=1147684168;start=5#5]Re: tomc filechooser in a class[/url]

import java.awt.dnd.*;
import java.awt.datatransfer.*;

DropTarget dt = new DropTarget(this, new DnDListener());

class DnDListener implements DropTargetListener
{
  public void dragEnter(DropTargetDragEvent event)
  {
    //System.out.println("dragEnter " + event);
    event.acceptDrag(DnDConstants.ACTION_COPY);
  }

  public void dragExit(DropTargetEvent event)
  {
    //System.out.println("dragExit " + event);
  }

  public void dragOver(DropTargetDragEvent event)
  {
    //System.out.println("dragOver " + event);
    event.acceptDrag(DnDConstants.ACTION_COPY);
  }

  public void dropActionChanged(DropTargetDragEvent event)
  {
    //System.out.println("dropActionChanged " + event);
  }

  public void drop(DropTargetDropEvent event)
  {
    //System.out.println("drop " + event);
    event.acceptDrop(DnDConstants.ACTION_COPY);

    Transferable transferable = event.getTransferable();
    DataFlavor flavors[] = transferable.getTransferDataFlavors();
    int successful = 0;

    for (int i = 0; i < flavors.length; i++)
    {
      try
      {
        Object stuff = transferable.getTransferData(flavors[i]);
        if (!(stuff instanceof java.util.List)) continue;
        java.util.List list = (java.util.List) stuff;

        for (int j = 0; j < list.size(); j++)
        {
          Object item = list.get(j);
          if (item instanceof File)
          {
            File file = (File) item;

            String filename = file.getPath();
            if (filename.lastIndexOf(".jp") != -1)
            {
              img = loadImage(filename);
            }
            else
            {
              println("Wrong filetype! Only jpg supported");
            }
          }
        }
      }
      catch (Exception e)
      {
        e.printStackTrace();
      }
    }
  }
}

### Image upload

[url=http://processing.org/discourse/yabb_beta/YaBB.cgi?board=Syntax;action=display;num=1212658813;start=15#15]Re: save to web --- image export[/url]

You can find the code in three parts:
http://philho.pastebin.com/f68e779ad -- Upload.php
http://philho.pastebin.com/f26b7f366 -- ImageUpload.pde
http://philho.pastebin.com/f6783c437 -- DataUpload.java

Obviously the Upload.php must be on the server, and you have to adjust some parameters, mostly the $destDir path (should be dedicated to uploads, because of the auto-deletion feature) and the $maxFiles parameter.

ImageUpload is a sample / example Processing script using my image upload class, DataUpload.

### Code in Zoho

<ol class="code" style="background-color: rgb(224, 248, 238); font-family: 'andale mono',monospace; font-size: 0.9em;">

### Compact Discourse Page (Stylish)

@namespace url(http://www.w3.org/1999/xhtml);

@-moz-document url("http://processing.org/discourse/yabb2/YaBB.pl") {
/* I reduce headers height and widen the section list table
   to try and display the state of as much sections as possible
   without scrolling.
 */
/* Widen the display */
#container, #maincontainer { width: 1250px !important; }
/* Don't skip space before the list of board links */
#mainnav_noSub { margin-bottom: 5px !important; }
/* Give less space around the message nb line */
#container .content td[height] { height: 15px !important; }
/* Hide "Processing 1.0" above the section list */
#board_nav { display: none !important; }
/* Reduce the left and right margins of the section list */
#container .content { margin: 0 10px !important; }
/* Second (windowbg) column of the table: the section name and description */
td.windowbg:first-child + td.windowbg { width: 64% !important; }
/* The Last Post column */
td.windowbg2 { width: 18% !important; }
/* Hide moderator info (these are always the same... :-P) */
/*td.windowbg div.small { display: none !important; }*/
/* Or float them to the right, so they take less room */
td.windowbg div.small { float: right !important; margin-top: -21px !important; background-color: #EEFFEE !important; font-size: 0.9em !important; }
}

@-moz-document url-prefix("http://processing.org/discourse/yabb2/YaBB.pl?board=")
{
/* Widen the display */
#container, #maincontainer { width: 1250px !important; }
td.titlebg:first-child, td.titlebg:nth-child(3)
  { width: 50px !important; }
/* Second (titlebg) column of the table: the subject */
td.titlebg:first-child + td.titlebg { width: 30% !important; }
}

### Export to applet from command line (Windows)

From Processing install dir

java -cp lib/pde.jar;lib/jna.jar;lib/ecj.jar;lib/core.jar;lib/antlr.jar;C:/Java/jdk1.6.0_13/lib/tools.jar processing.app.Commander --sketch=E:/Dev/PhiLhoSoft/Processing/Bezier --export-applet --output=E:/Dev/PhiLhoSoft/Processing/Bezier/applet

### Sign jar

> keytool -genkey -keystore plKeyStore -alias PhiLho
Tapez le mot de passe du Keystore : Tagada!
Ressaisissez le nouveau mot de passe :
Quels sont vos prÚnom et nom ?
  [Unknown] :  Philippe Lhoste
Quel est le nom de votre unitÚ organisationnelle ?
  [Unknown] :
Quelle est le nom de votre organisation ?
  [Unknown] :  PhiLhoSoft
Quel est le nom de votre ville de rÚsidence ?
  [Unknown] :  Sevran
Quel est le nom de votre Útat ou province ?
  [Unknown] :  93270
Quel est le code de pays Ó deux lettres pour cette unitÚ ?
  [Unknown] :  fr
Est-ce CN=Philippe Lhoste, OU=Unknown, O=PhiLhoSoft, L=Sevran, ST=93270, C=fr ?
  [non] :  oui

SpÚcifiez le mot de passe de la clÚ pour <PhiLho>
        (appuyez sur EntrÚe s'il s'agit du mot de passe du Keystore) :

> keytool -selfcert -keystore plKeyStore -alias PhiLho
Tapez le mot de passe du Keystore :

> jarsigner -keystore ..\..\..\plKeyStore DisplayText.jar PhiLho
Enter Passphrase for keystore:

Warning:
The signer certificate will expire within six months.

### Perspective transform
http://download.java.net/media/jai/javadoc/1.1.2_01/jai-apidocs/javax/media/jai/PerspectiveTransform.html

A perspective transformation is capable of mapping an arbitrary quadrilateral into another arbitrary quadrilateral, while preserving the straightness of lines.
Such a coordinate transformation can be represented by a 3x3 matrix which transforms homogenous source coordinates (x, y, 1) into destination coordinates (x', y', w). To convert back into non-homogenous coordinates (X, Y), x' and y' are divided by w.

[ x']   [  m00  m01  m02  ] [ x ]   [ m00x + m01y + m02 ]
[ y'] = [  m10  m11  m12  ] [ y ] = [ m10x + m11y + m12 ]
[ w ]   [  m20  m21  m22  ] [ 1 ]   [ m20x + m21y + m22 ]

x' = (m00x + m01y + m02)
y' = (m10x + m11y + m12)
w  = (m20x + m21y + m22)

X = x' / w
Y = y' / w

http://knol.google.com/k/koen-samyn/perspective-transformation/2lijysgth48w1/19#

aspectRatio: width / height
fov: field of view (in radians) -- eg. 45° or 0.785398163 radians
far: the distance to the far clip plane -- eg. 1
near: the distance to the near clip plane -- eg. 1000
a = aspectRatio ; f = far ; n = near ; t = tan(fov/2)

[ 1/a/t  0        0       0 ]
[  0    1/t       0       0 ]
[  0     0    f/(f - n)  -1 ]
[  0     0  -n*f/(f - n)  0 ]

http://answers.google.com/answers/threadview/id/515829.html

I recently wrote a function that you pass:
x0,y0, x1,y1, x2,y2, x3,y3: Coordinates of four corners of a box, in
clockwise order.
x,y: coordinates of two points in a flat image from 0,0 to SX-1,SY-1.
It writes the result on *px, *py. The result is the point which
corresponds to x,y inside projection box. I used int because of
performance. Floating point would probably give better results. The
code is:

void corPix(int x0, int y0, int x1, int y1, int x2, int y2, int x3,
int y3, int x, int y, int *px, int *py) {

  intersectLines(px, py,
    ((SY-y)*x0 + (y)*x3)/SY, ((SY-y)*y0 + y*y3)/SY,
    ((SY-y)*x1 + (y)*x2)/SY, ((SY-y)*y1 + y*y2)/SY,
    ((SX-x)*x0 + (x)*x1)/SX, ((SX-x)*y0 + x*y1)/SX,
    ((SX-x)*x3 + (x)*x2)/SX, ((SX-x)*y3 + x*y2)/SX);
}

It uses two functions I defined:

int det(int a, int b, int c, int d) {
  return a*d-b*c;
}

void intersectLines(int *px, int *py, int x1, int y1, int x2, int y2,
int x3, int y3, int x4, int y4) {
  int d = det(x1-x2,y1-y2,x3-x4,y3-y4);

  if (d==0)
    d = 1;

  *px = det(det(x1,y1,x2,y2),x1-x2,det(x3,y3,x4,y4),x3-x4)/d;
  *py = det(det(x1,y1,x2,y2),y1-y2,det(x3,y3,x4,y4),y3-y4)/d;
}