processing.core
Class PApplet

java.lang.Object
  java.awt.Component
      java.awt.Container
          java.awt.Panel
              java.applet.Applet
                  processing.core.PApplet

All Implemented Interfaces:

javax.accessibility.Accessible, java.util.EventListener, java.awt.event.FocusListener, java.awt.image.ImageObserver, java.awt.event.KeyListener, java.awt.MenuContainer, java.awt.event.MouseListener, java.awt.event.MouseMotionListener, PConstants, java.lang.Runnable, java.io.Serializable

public class PApplet

extends java.applet.Applet

implements PConstants, java.lang.Runnable, java.awt.event.MouseListener, java.awt.event.MouseMotionListener, java.awt.event.KeyListener, java.awt.event.FocusListener

Base class for all sketches that use processing.core.

Note that you should not use AWT or Swing components inside a Processing applet. The surface is made to automatically update itself, and will cause problems with redraw of components drawn above it. If you'd like to integrate other Java components, see below.

This class extends Applet instead of JApplet because 1) we will eventually be returning Java 1.1 support, which does not include Swing (without an additional, sizable, download), and 2) Swing is a bloated piece of crap. A Processing applet is a heavyweight AWT component, and can be used the same as any other AWT component, with or without Swing.

Similarly, Processing runs in a Frame and not a JFrame. However, there's nothing to prevent you from embedding a PApplet into a JFrame, it's just that the base version uses a regular AWT frame because there's simply no need for swing in that context. If people want to use Swing, they can embed themselves as they wish.

It is possible to use PApplet, along with core.jar in other projects. In addition to enabling you to use Java 1.5+ features with your sketch, this also allows you to embed a Processing drawing area into another Java application. This means you can use standard GUI controls with a Processing sketch. Because AWT and Swing GUI components cannot be used on top of a PApplet, you can instead embed the PApplet inside another GUI the wayyou would any other Component.

Because the default animation thread will run at 60 frames per second, an embedded PApplet can make the parent sluggish. You can use frameRate() to make it update less often, or you can use noLoop() and loop() to disable and then re-enable looping. If you want to only update the sketch intermittently, use noLoop() inside setup(), and redraw() whenever the screen needs to be updated once (or loop() to re-enable the animation thread). The following example embeds a sketch and also uses the noLoop() and redraw() methods. You need not use noLoop() and redraw() when embedding if you want your application to animate continuously.

 public class ExampleFrame extends Frame {

     public ExampleFrame() {
         super("Embedded PApplet");

         setLayout(new BorderLayout());
         PApplet embed = new Embedded();
         add(embed, BorderLayout.CENTER);

         // important to call this whenever embedding a PApplet.
         // It ensures that the animation thread is started and
         // that other internal variables are properly set.
         embed.init();
     }
 }

 public class Embedded extends PApplet {

     public void setup() {
         // original setup code here ...
         size(400, 400);

         // prevent thread from starving everything else
         noLoop();
     }

     public void draw() {
         // drawing code goes here
     }

     public void mousePressed() {
         // do something based on mouse movement

         // update the screen (run draw once)
         redraw();
     }
 }
 

Processing on multiple displays

I was asked about Processing with multiple displays, and for lack of a better place to document it, things will go here.

You can address both screens by making a window the width of both, and the height of the maximum of both screens. In this case, do not use present mode, because that's exclusive to one screen. Basically it'll give you a PApplet that spans both screens. If using one half to control and the other half for graphics, you'd just have to put the 'live' stuff on one half of the canvas, the control stuff on the other. This works better in windows because on the mac we can't get rid of the menu bar unless it's running in present mode.

For more control, you need to write straight java code that uses p5. You can create two windows, that are shown on two separate screens, that have their own PApplet. this is just one of the tradeoffs of one of the things that we don't support in p5 from within the environment itself (we must draw the line somewhere), because of how messy it would get to start talking about multiple screens. It's also not that tough to do by hand w/ some Java code.

See Also:

Serialized Form

Nested Class Summary

class

PApplet.RegisteredMethods

Field Summary

java.lang.String[]	args Command line options passed in from main().
static java.lang.String	ARGS_BGCOLOR
static java.lang.String	ARGS_DISPLAY
static java.lang.String	ARGS_EDITOR_LOCATION Position of the upper-lefthand corner of the editor window that launched this applet.
static java.lang.String	ARGS_EXTERNAL Location for where to position the applet window on screen.
static java.lang.String	ARGS_HIDE_STOP
static java.lang.String	ARGS_LOCATION
static java.lang.String	ARGS_PRESENT
static java.lang.String	ARGS_SKETCH_FOLDER Allows the user or PdeEditor to set a specific sketch folder path.
static java.lang.String	ARGS_STOP_COLOR
static int	DEFAULT_HEIGHT
static int	DEFAULT_WIDTH Default width and height for applet when not specified
boolean	defaultSize true if no size() command has been executed.
java.lang.Exception	exception Set to the an exception that occurs inside run() and is not caught.
static java.lang.String	EXTERNAL_MOVE When run externally to a PdeEditor, this is sent by the applet whenever the window is moved.
static java.lang.String	EXTERNAL_QUIT When run externally to a PdeEditor, this is sent by the applet when it quits.
static char	EXTERNAL_STOP Message from parent editor (when run as external) to quit.
boolean	finished true if this applet has had it.
boolean	firstMouse Used to set pmouseX/Y to mouseX/Y the first time mouseX/Y are used, otherwise pmouseX/Y are always zero, causing a nasty jump.
boolean	focused Gets set to true/false as the applet gains/loses focus.
java.awt.Frame	frame The frame containing this applet (if any)
int	frameCount How many frames have been displayed since the applet started.
float	frameRate The current value of frames per second.
PGraphics	g The PGraphics renderer associated with this PApplet
int	height height of this applet's associated PGraphics
static float	javaVersion Version of Java that's in use, whether 1.1 or 1.3 or whatever, stored as a float.
static java.lang.String	javaVersionName Full name of the Java version (i.e.
char	key Last key pressed.
int	keyCode When "key" is set to CODED, this will contain a Java key code.
java.awt.event.KeyEvent	keyEvent the last KeyEvent object passed into a mouse function.
boolean	keyPressed true if the mouse is currently pressed.
static java.lang.String	LEECH_WAKEUP
java.io.PrintStream	leechErr
static int	MIN_WINDOW_HEIGHT
static int	MIN_WINDOW_WIDTH Minimum dimensions for the window holding an applet.
int	mouseButton Last mouse button pressed, one of LEFT, CENTER, or RIGHT.
java.awt.event.MouseEvent	mouseEvent
boolean	mousePressed
int	mouseX current x position of the mouse
int	mouseY current y position of the mouse
boolean	online true if the applet is online.
int[]	pixels Pixel buffer from this applet's PGraphics.
static int	platform Current platform in use, one of the PConstants WINDOWS, MACOSX, MACOS9, LINUX or OTHER.
static java.lang.String	platformName Current platform in use.
int	pmouseX Previous x/y position of the mouse.
int	pmouseY Previous x/y position of the mouse.
PGraphics	recorder A leech graphics object that is echoing all events.
java.awt.Dimension	screen The screen size when the applet was started.
java.lang.String	sketchPath Path to sketch folder
int	width width of this applet's associated PGraphics

Fields inherited from class java.awt.Component

BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT

Fields inherited from interface processing.core.PConstants

ADD, ALPHA, ALPHA_MASK, ALT, AMBIENT, ARGB, ARROW, BACKSPACE, BASELINE, BEVEL, BLEND, BLUE_MASK, BLUR, BOTTOM, BURN, CENTER, CENTER_RADIUS, CHATTER, CLOSE, CODED, COMPLAINT, CONTROL, CORNER, CORNERS, CROSS, CUSTOM, DARKEST, DEG_TO_RAD, DELETE, DIFFERENCE, DILATE, DIRECTIONAL, DISABLE_AUTO_GZIP, DISABLE_DEPTH_TEST, DISABLE_ERROR_REPORT, DISABLE_TEXT_SMOOTH, DODGE, DOWN, DXF, ENABLE_ACCURATE_TEXTURES, ENABLE_DEPTH_SORT, ENABLE_NATIVE_FONTS, ENTER, EPSILON, ERODE, ESC, EXCLUSION, GIF, GRAY, GREEN_MASK, HALF_PI, HAND, HARD_LIGHT, HINT_COUNT, HSB, IMAGE, INVERT, JAVA2D, JPEG, LEFT, LIGHTEST, LINES, LINUX, MACOS9, MACOSX, MAX_FLOAT, MAX_INT, MIN_FLOAT, MIN_INT, MITER, MODEL, MOVE, MULTIPLY, NO_FLYING_POO, NORMALIZED, OPAQUE, OPEN, OPENGL, ORTHOGRAPHIC, OTHER, OVERLAY, P2D, P3D, PDF, PERSPECTIVE, PI, PIXEL_CENTER, POINT, POINTS, POLYGON, POSTERIZE, PROBLEM, PROJECT, QUAD_STRIP, QUADS, QUARTER_PI, RAD_TO_DEG, RADIUS, RED_MASK, REPLACE, RETURN, RGB, RIGHT, ROUND, SCREEN, SHAPE, SHIFT, SOFT_LIGHT, SPOT, SQUARE, SUBTRACT, TAB, TARGA, TEXT, THIRD_PI, THRESHOLD, TIFF, TOP, TRIANGLE_FAN, TRIANGLE_STRIP, TRIANGLES, TWO_PI, UP, WAIT, WHITESPACE, WINDOWS

Fields inherited from interface java.awt.image.ImageObserver

ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH

Constructor Summary

PApplet()

Method Summary

static float	abs(float n)
static int	abs(int n)
static float	acos(float value)
void	addListeners()
float	alpha(int what)
void	ambient(float gray)
void	ambient(float x, float y, float z)
void	ambient(int rgb)
void	ambientLight(float red, float green, float blue)
void	ambientLight(float red, float green, float blue, float x, float y, float z)
static byte[]	append(byte[] b, byte value)
static char[]	append(char[] b, char value)
static float[]	append(float[] b, float value)
static int[]	append(int[] b, int value)
static java.lang.Object	append(java.lang.Object b, java.lang.Object value)
static java.lang.String[]	append(java.lang.String[] b, java.lang.String value)
void	applyMatrix(float n00, float n01, float n02, float n10, float n11, float n12)
void	applyMatrix(float n00, float n01, float n02, float n03, float n10, float n11, float n12, float n13, float n20, float n21, float n22, float n23, float n30, float n31, float n32, float n33)
void	arc(float a, float b, float c, float d, float start, float stop)
static void	arraycopy(java.lang.Object src, int srcPosition, java.lang.Object dst, int dstPosition, int length) Calls System.arraycopy(), included here so that we can avoid people needing to learn about the System object before they can just copy an array.
static void	arraycopy(java.lang.Object src, java.lang.Object dst) Shortcut to copy the entire contents of the source into the destination array.
static void	arraycopy(java.lang.Object src, java.lang.Object dst, int length) Convenience method for arraycopy().
static float	asin(float value)
static float	atan(float value)
static float	atan2(float a, float b)
void	background(float gray)
void	background(float gray, float alpha)
void	background(float x, float y, float z)
void	background(float x, float y, float z, float a)
void	background(int rgb)
void	background(int rgb, float alpha)
void	background(PImage image)
void	beginCamera()
void	beginRaw(PGraphics rawGraphics)
PGraphics	beginRaw(java.lang.String renderer, java.lang.String filename)
void	beginRecord(PGraphics recorder)
PGraphics	beginRecord(java.lang.String renderer, java.lang.String filename)
void	beginShape()
void	beginShape(int kind)
void	bezier(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4)
void	bezier(float x1, float y1, float z1, float x2, float y2, float z2, float x3, float y3, float z3, float x4, float y4, float z4)
void	bezierDetail(int detail)
float	bezierPoint(float a, float b, float c, float d, float t)
float	bezierTangent(float a, float b, float c, float d, float t)
void	bezierVertex(float x2, float y2, float x3, float y3, float x4, float y4)
void	bezierVertex(float x2, float y2, float z2, float x3, float y3, float z3, float x4, float y4, float z4)
static java.lang.String	binary(byte what) Returns a String that contains the binary value of a byte.
static java.lang.String	binary(char what) Returns a String that contains the binary value of a char.
static java.lang.String	binary(int what) Returns a String that contains the binary value of an int.
static java.lang.String	binary(int what, int digits) Returns a String that contains the binary value of an int.
void	blend(int sx1, int sy1, int sx2, int sy2, int dx1, int dy1, int dx2, int dy2, int mode)
void	blend(PImage src, int sx1, int sy1, int sx2, int sy2, int dx1, int dy1, int dx2, int dy2, int mode)
static int	blendColor(int c1, int c2, int mode)
float	blue(int what)
void	box(float size)
void	box(float w, float h, float d)
void	breakShape()
float	brightness(int what)
void	camera()
void	camera(float eyeX, float eyeY, float eyeZ, float centerX, float centerY, float centerZ, float upX, float upY, float upZ)
static int	ceil(float what)
int	color(float fgray)
int	color(float fgray, float falpha)
int	color(float x, float y, float z)
int	color(float x, float y, float z, float a)
int	color(int gray)
int	color(int gray, int alpha) As of 0116 this also takes color(#FF8800, alpha)
int	color(int x, int y, int z)
int	color(int x, int y, int z, int a)
void	colorMode(int mode)
void	colorMode(int mode, float max)
void	colorMode(int mode, float maxX, float maxY, float maxZ)
void	colorMode(int mode, float maxX, float maxY, float maxZ, float maxA)
static boolean[]	concat(boolean[] a, boolean[] b)
static byte[]	concat(byte[] a, byte[] b)
static char[]	concat(char[] a, char[] b)
static float[]	concat(float[] a, float[] b)
static int[]	concat(int[] a, int[] b)
static java.lang.Object	concat(java.lang.Object a, java.lang.Object b)
static java.lang.String[]	concat(java.lang.String[] a, java.lang.String[] b)
static float	constrain(float amt, float low, float high)
static int	constrain(int amt, int low, int high)
void	copy(int sx1, int sy1, int sx2, int sy2, int dx1, int dy1, int dx2, int dy2)
void	copy(PImage src, int sx1, int sy1, int sx2, int sy2, int dx1, int dy1, int dx2, int dy2)
static float	cos(float angle)
PFont	createFont(java.lang.String name, float size)
PFont	createFont(java.lang.String name, float size, boolean smooth)
PFont	createFont(java.lang.String name, float size, boolean smooth, char[] charset) Create a .vlw font on the fly from either a font name that's installed on the system, or from a .ttf or .otf that's inside the data folder of this sketch.
PGraphics	createGraphics(int iwidth, int iheight, java.lang.String irenderer) Create an offscreen PGraphics object for drawing.
PGraphics	createGraphics(int iwidth, int iheight, java.lang.String irenderer, java.lang.String ipath) Create an offscreen graphics surface for drawing, in this case for a renderer that writes to a file (such as PDF or DXF).
PImage	createImage(int wide, int high, int format) Preferred method of creating new PImage objects, ensures that a reference to the parent PApplet is included, which makes save() work without needing an absolute path.
static void	createPath(java.lang.String filename) Takes a path and creates any in-between folders if they don't already exist.
static java.io.BufferedReader	createReader(java.io.File file) I want to read lines from a file.
static java.io.BufferedReader	createReader(java.io.InputStream input) I want to read lines from a stream.
java.io.BufferedReader	createReader(java.lang.String filename) I want to read lines from a file.
static java.io.PrintWriter	createWriter(java.io.File file) I want to print lines to a file.
static java.io.PrintWriter	createWriter(java.io.OutputStream output) I want to print lines to a file.
java.io.PrintWriter	createWriter(java.lang.String filename) I want to print lines to a file.
void	cursor() Show the cursor after noCursor() was called.
void	cursor(int _cursor_type) Set the cursor type
void	cursor(PImage image) Replace the cursor with the specified PImage.
void	cursor(PImage image, int hotspotX, int hotspotY) Set a custom cursor to an image with a specific hotspot.
void	curve(float x1, float y1, float x2, float y2, float x3, float y3, float x4, float y4)
void	curve(float x1, float y1, float z1, float x2, float y2, float z2, float x3, float y3, float z3, float x4, float y4, float z4)
void	curveDetail(int detail)
float	curvePoint(float a, float b, float c, float d, float t)
float	curveTangent(float a, float b, float c, float d, float t)
void	curveTightness(float tightness)
void	curveVertex(float x, float y)
void	curveVertex(float x, float y, float z)
java.io.File	dataFile(java.lang.String where) Return a full path to an item in the data folder as a File object.
java.lang.String	dataPath(java.lang.String where) Return a full path to an item in the data folder.
static int	day() Get the current day of the month (1 through 31).
static float	degrees(float radians)
void	delay(int napTime) The delay() function causes the program to halt for a specified time.
void	destroy() Called by the browser or applet viewer to inform this applet that it is being reclaimed and that it should destroy any resources that it has allocated.
void	die(java.lang.String what) Function for an applet/application to kill itself and display an error.
void	die(java.lang.String what, java.lang.Exception e) Same as above but with an exception.
void	directionalLight(float red, float green, float blue, float nx, float ny, float nz)
boolean	displayable()
static float	dist(float x1, float y1, float x2, float y2)
static float	dist(float x1, float y1, float z1, float x2, float y2, float z2)
void	draw()
void	ellipse(float a, float b, float c, float d)
void	ellipseMode(int mode)
void	emissive(float gray)
void	emissive(float x, float y, float z)
void	emissive(int rgb)
void	endCamera()
void	endRaw()
void	endRecord()
void	endShape()
void	endShape(int mode)
static java.lang.Process	exec(java.lang.String[] argv)
void	exit() Call to safely exit the sketch when finished.
static float	exp(float a)
static boolean[]	expand(boolean[] list)
static boolean[]	expand(boolean[] list, int newSize)
static byte[]	expand(byte[] list)
static byte[]	expand(byte[] list, int newSize)
static char[]	expand(char[] list)
static char[]	expand(char[] list, int newSize)
static float[]	expand(float[] list)
static float[]	expand(float[] list, int newSize)
static int[]	expand(int[] list)
static int[]	expand(int[] list, int newSize)
static java.lang.Object	expand(java.lang.Object array)
static java.lang.Object	expand(java.lang.Object list, int newSize)
static java.lang.String[]	expand(java.lang.String[] list)
static java.lang.String[]	expand(java.lang.String[] list, int newSize)
void	fill(float gray)
void	fill(float gray, float alpha)
void	fill(float x, float y, float z)
void	fill(float x, float y, float z, float a)
void	fill(int rgb)
void	fill(int rgb, float alpha)
void	filter(int kind)
void	filter(int kind, float param)
static int	floor(float what)
void	focusGained()
void	focusGained(java.awt.event.FocusEvent e)
void	focusLost()
void	focusLost(java.awt.event.FocusEvent e)
void	frameRate(float newRateTarget) Set a target frameRate.
void	frustum(float left, float right, float bottom, float top, float znear, float zfar)
PImage	get()
int	get(int x, int y)
PImage	get(int x, int y, int w, int h)
java.awt.Dimension	getPreferredSize() This returns the last width and height specified by the user via the size() command.
float	green(int what)
void	handleDisplay()
static java.lang.String	hex(byte what)
static java.lang.String	hex(char what)
static java.lang.String	hex(int what)
static java.lang.String	hex(int what, int digits)
void	hint(int which)
static int	hour() Hour position of the current time in international format (0-23).
float	hue(int what)
void	image(PImage image, float x, float y)
void	image(PImage image, float x, float y, float c, float d)
void	image(PImage image, float a, float b, float c, float d, int u1, int v1, int u2, int v2)
void	imageMode(int mode)
void	init()
java.io.File	inputFile()
static java.io.File	inputFile(java.awt.Frame parent)
java.io.File	inputFile(java.lang.String prompt)
static java.io.File	inputFile(java.lang.String prompt, java.awt.Frame parentFrame) static version of inputFile usable by external classes.
java.lang.String	insertFrame(java.lang.String what) Check a string for #### signs to see if the frame number should be inserted.
static java.lang.String	join(java.lang.String[] str, char separator) Join an array of Strings together as a single String, separated by the whatever's passed in for the separator.
static java.lang.String	join(java.lang.String[] str, java.lang.String separator) Join an array of Strings together as a single String, separated by the whatever's passed in for the separator.
void	keyPressed() Called each time a single key on the keyboard is pressed.
void	keyPressed(java.awt.event.KeyEvent e) Overriding keyXxxxx(KeyEvent e) functions will cause the 'key', 'keyCode', and 'keyEvent' variables to no longer work; key events will no longer be queued until the end of draw(); and the keyPressed(), keyReleased() and keyTyped() methods will no longer be called.
void	keyReleased() See keyPressed().
void	keyReleased(java.awt.event.KeyEvent e)
void	keyTyped() Only called for "regular" keys like letters, see keyPressed() for full documentation.
void	keyTyped(java.awt.event.KeyEvent e)
static float	lerp(float start, float stop, float amt)
int	lerpColor(int c1, int c2, float amt)
static int	lerpColor(int c1, int c2, float amt, int mode)
void	lightFalloff(float constant, float linear, float quadratic)
void	lights()
void	lightSpecular(float x, float y, float z)
void	line(float x1, float y1, float x2, float y2)
void	line(float x1, float y1, float z1, float x2, float y2, float z2)
void	link(java.lang.String here)
void	link(java.lang.String url, java.lang.String frameTitle) Link to an external page without all the muss.
static byte[]	loadBytes(java.io.InputStream input)
byte[]	loadBytes(java.lang.String filename)
PFont	loadFont(java.lang.String filename) Set the font based on its filename.
PImage	loadImage(java.lang.String filename) Load an image from the data folder or a local directory.
PImage	loadImage(java.lang.String filename, java.lang.String extension) Identical to loadImage, but allows you to specify the type of image by its extension.
PImage	loadImageSync(java.awt.Image awtImage) Load an AWT image synchronously.
void	loadMatrix()
void	loadPixels() Override the g.pixels[] function to set the pixels[] array that's part of the PApplet object.
static java.lang.String[]	loadStrings(java.io.File file)
static java.lang.String[]	loadStrings(java.io.InputStream input)
java.lang.String[]	loadStrings(java.lang.String filename) Load data from a file and shove it into a String array.
static float	log(float a)
void	loop()
static float	mag(float a, float b)
static float	mag(float a, float b, float c)
static void	main(java.lang.String[] args) main() method for running this class from the command line.
static float	map(float value, float istart, float istop, float ostart, float ostop) Convenience function to map a variable from one coordinate space to another.
void	mask(int[] alpha)
void