Can i create a mask from a shape (in this case an ellipse) and change background color but keep the mask untouched? This ellipse would have its size changed according to the screen and i would have a function windowResized()

Thanks! :)

... the rule saying that the size() call must be the first one in setup(). For some reason, code before it tends to be run twice, which is annoying when loading a possibly large file.

But why does that occur? Is it because size() internally calls setup() again after setting the size of the sketch, and subsequent calls to size() just skip right through to end?

By changing to P2D render it works fine in Processing, but I need it to work in Processing.js, where the problem persists.

Here's a link to a sketch to show the problem http://studio.sketchpad.cc/sp/pad/view/P0CunpgdMc/rev.7

I know this is a processing.js issue but the processing.js google forum seems inactive.

Thanks for any help on this..

PImage img;
PImage picture;
Integer[] palette;

void setup(){
  img = loadImage("palette.jpg");
  palette = getPalette(img);
  picture = loadImage("picture.jpg");
  size(picture.width,picture.height);
  background(255);
}

void draw(){
  colour(picture, palette);
  noLoop();
} 

I have installed the last GL video version, to see if I can solve my "jump" problems (https://forum.processing.org/two/discussion/13673/jump-in-videolibrary-causes-java-error#latest).

But, with version 1.2.1 playing the videos the image freezes constantly.

I'm testing it in 5 different Raspberry at the same time, with the same results (253% CPU!). All software updated.

PID USER      PR  NI    VIRT    RES       SHR S    %CPU  %MEM     TIME+ COMMAND                 
1033 pi        20   0  457288  91032  13084 S 253.2 23.2 351:44.38 java 

I'm also playing the same video file in 8 Raspberry, same hardware and software, but with GL video 1.2. Better performance:

PID USER      PR  NI    VIRT    RES        SHR S      %CPU   %MEM   TIME+ COMMAND                 
1069 pi         0 -20  371956  58540  12232 S  48.3 14.9 136:07.68 java   

Video file:

Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, smpte170m/smpte170m/bt709), 800x480, 9462 kb/s, SAR 1:1 DAR 5:3, 60 fps, 60 tbr, 60 tbn, 120 tbc (default)
Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, 1 channels, s16, 768 kb/s (default)

Any help is welcome!

Best.

So, I'm following D. Shiffman's "Nature of Code" course on Youtube.

class Mover {

  PVector position;
  PVector velocity;
  PVector acceleration;
  float mass;

  Mover() {
    position = new PVector(random(width), 0);
    velocity = new PVector(0,0);
    acceleration = new PVector(0,0);
    mass = random(0.5, 4);
  }

  void applyForce(PVector force) {
     PVector f = PVector.div(force, mass);
     acceleration.add(f);
  }

  void update() {
    velocity.add(acceleration);
    position.add(velocity);
    acceleration.mult(0);
  }

  void display() {
    stroke(0);
    fill(127);
    ellipse(position.x,position.y, mass * 20, mass * 20);
  }

  void checkEdges() {

    if (position.x > width) {
      position.x = width;
      velocity.x *= -1;
    } else if (position.x < 0) {
      velocity.x *= -1;
      position.x = 0;
    }

    if (position.y > height) {
      velocity.y *= -1;
      position.y = height;
    }

  }

}

Mover[] movers;


void setup() {
  size(640, 360);
  movers = new Mover[5];
  for(int i = 0; i < movers.length; i++) {
    movers[i] = new Mover();
  }
}

void draw() {
   background(255);

  for(Mover m: movers) {
    PVector gravity = new PVector(0, 0.3);
    gravity.mult(m.mass);
    m.applyForce(gravity);



    if(mousePressed) {
      PVector friction = m.velocity.copy();
      friction.normalize();
      friction.mult(-1);
      float c = 0.1;
      friction.mult(c);
      m.applyForce(friction);
    }


    m.update();
    m.checkEdges();
    m.display();
  }
}

This example works perfectly fine when placed in a single tab. But then I decided to leave the class in one tab and the rest of the stuff in another one. And as soon as my setup() gets moved to a new tab, I get an error "size() cannot be used here" when trying to run the sketch.

Processing considers multiple tabs to be just one big file, doesn't it? So how does this make sense?

Basic slider class and driver the code runs with a small window .For any value larger than (100 100) I get a weird message about size() cannot be used here .

What am I doing wrong? Error

(if I print the value, it's ok).

def setup():

 photo = loadImage("Photo.jpg")
 print(photo.height)
 image(photo, 0, 0)

Thank you!

CODE:

void setup() { background(33); source = loadImage("5.jpg"); size(source.width, source.height); }

ERROR: "The size of this sketch could not be determined from your code....."

any idea how I can set the size of the sketch to the PImage size?

Code below

            // by d whyte

int[][] result;
float t;

float ease(float p) {
  return 3*p*p - 2*p*p*p;
}

float ease(float p, float g) {
  if (p < 0.5) 
    return 0.5 * pow(2*p, g);
  else
    return 1 - 0.5 * pow(2*(1 - p), g);
}

float mn = .5*sqrt(3);

void setup() {
  setup_();
  result = new int[width*height][3];
}

void draw() {

  if (!recording) {
    t = mouseX*1.0/width;
    draw_();
  } else {
    for (int i=0; i<width*height; i++)
      for (int a=0; a<3; a++)
        result[i][a] = 0;

    for (int sa=0; sa<samplesPerFrame; sa++) {
      t = map(frameCount-1 + sa*shutterAngle/samplesPerFrame, 0, numFrames, 0, 1);
      draw_();
      loadPixels();
      for (int i=0; i<pixels.length; i++) {
        result[i][0] += pixels[i] >> 16 & 0xff;
        result[i][1] += pixels[i] >> 8 & 0xff;
        result[i][2] += pixels[i] & 0xff;
      }
    }

    loadPixels();
    for (int i=0; i<pixels.length; i++)
      pixels[i] = 0xff << 24 | 
        int(result[i][0]*1.0/samplesPerFrame) << 16 | 
        int(result[i][1]*1.0/samplesPerFrame) << 8 | 
        int(result[i][2]*1.0/samplesPerFrame);
    updatePixels();

    saveFrame("f###.gif");
    if (frameCount==numFrames)
      exit();
  }
}

//////////////////////////////////////////////////////////////////////////////

int samplesPerFrame = 16;
int numFrames = 96;        
float shutterAngle = .5;

boolean recording = true;

void setup_() {
  size(800, 600, P3D);
  smooth(8);
  rectMode(CENTER);
  stroke(70,150,200);
  noFill();
  strokeWeight(2);
}

float x, y, z, tt;
int N = 24, M = 16;
float l = 500, w = 320;
int n = 120;
float h = 120;
float q = 0.00011, ll = .000035;

void draw_() {
  background(250); 
  pushMatrix();
  translate(width/2, height/2 - 25);
  rotateX(PI*.24);
  for (int i=0; i<N; i++) {
    x = map(i, 0, N-1, -l/2, l/2);
    strokeWeight(1.6);
    if(i==0 || i==N-1)
      strokeWeight(4);
    beginShape();
    for (int j=0; j<n; j++) {
      y = map(j, 0, n-1, -w/2-1, w/2+1);
      z = h*sin(TWO_PI*t - q*(x*x + y*y))*exp(-ll*(x*x + y*y));
      vertex(x, y, z);
    }
    endShape();
  }
  for (int i=0; i<M; i++) {
    y = map(i, 0, M-1, -w/2, w/2);
    strokeWeight(1.6);
    if(i==0 || i==M-1)
      strokeWeight(4);
    beginShape();
    for (int j=0; j<n; j++) {
      x = map(j, 0, n-1, -l/2-1, l/2+1);
      z = h*sin(TWO_PI*t - q*(x*x + y*y))*exp(-ll*(x*x + y*y));
      vertex(x, y, z);
    }
    endShape();
  }
  popMatrix();
}

When I try and changed the size in settings it does not work but it does in setup. Why is this the case?

Thanks

PImage sourceImg;
int dw, dh;

void setup () {
  sourceImg = loadImage("test2.jpg");
  surface.setResizable(true);
  dw = sourceImg.width;
  dh = sourceImg.height;
  surface.setSize(dw, dh);
  background(sourceImg); //HERE IT GIVES ME THE ERROR
}

void draw() {
  //background(sourceImg); //HERE IT WORKS
}

I don't know how to fix this. I need the background image to be drawn one time at the start of the program. What does that error mean?

Thx in advance!

PImage img = loadImage("background.jpg"); //a 100x100 background image.
size(100,100);
background(img);

However, since size() does not take in variables, how are we suppose to define a background with variable dimensions?

I have tested with the surface.setSize() function but it does not see to work.

Example:

PImage img = loadImage("background.jpg"); //a 100x100 background image.
surface.setSize(img.width,img.height);
background(img);

The error I get is: "The size of this sketch could not be determined from your code. Use only numbers (not variables) for the size() command. Read the size() reference for more details.".

void setup(){ PImage img = loadImage("image.jpg"); size(img.width*2, img.height, P2D); }

instead of the same thing in the Startup of Processing. I can't find anyone else with this problem, though. And no matter how I change the size setting it doesn't effect the resulting window.

I can see the top left corner of what I'm trying to draw if that helps. Thank you

I'm working on a game currently and I'm trying to setup the playground with the setup() function of processing. I tried to break down the problem into easy code.

Consider the following sketch:

 void setup(){
     surface.setSize(300, 300);
     background(0);
     fill(255);
     rect(100, 100, 30, 30);
 }

 void draw(){
 }

When i execute this code, I'd expect a canvas of size=300x300 with black background and a white rectangle of size=30x30 at x=100 and y=100 on the canvas.

However the rectangle does not appear. Could anybody clarify why you can't draw rectangles in the setup function?

I'm using Processing 3.0.2

I've already looked at the processing references pages for:
setup() : https://processing.org/reference/setup_.html
background() : https://processing.org/reference/background_.html
rect() : https://processing.org/reference/rect_.html

It also appears to me that the reference page is not updated on all the issues that may break processing 2.0 code when updating on 3.0 https://github.com/processing/processing/wiki/Changes-in-3.0#things-that-may-break-your-2x-sketches
, so I'm not sure if I'm missing something.

I haven't found anything on this issue yet. Maybe I'm just misunderstanding the behavior of the setup function.

Tab 1:

void setup() {
  size(500, 500);

  String[] args = {"TwoFrameTest"};
  SecondApplet sa = new SecondApplet();
  PApplet.runSketch(args, sa);

  ThirdApplet ta = new ThirdApplet();
  PApplet.runSketch(args, ta);
}

void draw() {
  background(0);
  ellipse(50, 50, 10, 10);
}    

Tab 2:

public class SecondApplet extends PApplet {

  public void settings() {
    size(300, 300);
  }
  public void draw() {
    background(255);
    fill(0);
    ellipse(100, 50, 10, 10);
  }
}

public class ThirdApplet extends PApplet {

  public void settings() {
    size(400, 400);
  }
  public void draw() {
    background(255);
    fill(0);
    ellipse(100, 50, 10, 10);
  }
}

There is an issue however; when I run the code, the original window is displayed as its default size, even if a size method with different values is called. Strangely this even seems to happen if the other windows aren't called; the code in the second tab just has to be in the sketch folder and doesn't have to be referenced in any way. Does anybody have any idea what is happening and how I might fix it?

void setup() { img = loadImage("Typist.jpg");
size(img.width,img.height); //set the window size to match the image }

where "Typist.jpg" is in a "data" folder. I get the following error:

"The size of this image could not be determined from your code. Use only numbers (not variables) for the size() command. Read the size() reference for more details"

If I put numbers in in place of .width and .height it works just fine. I see lots of examples where code just like that works. Any suggestions? Thanks.

I'm really new at processing - and i've run into my first problem:

Every test i try to run it says that i can't have variables in my size collumn. How do i change this? It says this in every file, do i need to download anything from the library?

Thanks a lot!

PImage image;

void setup() {
  image = loadImage("image.jpg");
  size(image.width, image.height);
}

However, running that under Processing 3.0 spits out the following:

The size of your sketch could not be determined from your code. Use only numbers (not variables) for the size() command. Read the size() reference for more details.

Now, from what I've figured out you need to use void settings() to use variables in size() but here is the catch 22: the image can be be loaded earliest in setup() and settings() need to be called before setup().

I.e. neither of the following code snippets are valid solutions:

PImage image;

void settings() {
  image = loadImage("image.jpg");  // can't load image before setup()
  size(image.width, image.height);
}

void setup() {
}

nor:

PImage image;

void setup() {
  image = loadImage("image.jpg");
}

void settings() {  // can't call settings() after setup()
  size(image.width, image.height);
}

Is there a way around this that I'm not seeing?

My question is: is it safe to specify the parameters to size() as constants, for example as follows:

final int H=100; size (2*H, H);

This technique has worked in my tests, but is it safe?

I know that it would be possible to first define the constants outside setup(), and then use them as parameters to size() in setup(), but as a programming teacher I would like to introduce the use of constants before I introduce setup() and draw() and defining functions in general.

I have two reasons for wanting to specify parameters to size() as constants.

First, assume that the width:height ratio of the sketch should always be 2:1, but the actual size might change. Then good programming practice states that size should be specified as above, not by size(200,100), where you would have to change two values if size of the sketch were changed.

Second, I would prefer that the students specify the width and height of the sketch with their own constants, and use those constants in calculations at other places in the code, rather than the students using the internal variables "width" and "height".