Processing 1.0 - Processing Discourse - How to get a PImage of the sketch?

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How to get a PImage of the sketch? (Read 1350 times)

nardove

How to get a PImage of the sketch?
Jul 15^th, 2009, 1:50am

Hi, I am not sure if the subject is correct, but here it goes, I have the following code working fine

Code:

PImage img;
Ripple ripple;

img = loadImage("water_test.jpg");
ripple = new Ripple(img);

I need to change it so the ripples class gets a PImage of the screen, so whatever is draw get pass as PImage to the ripple class, hope this makes sence

I am aware of loadPixels() and createImage() but I cant get it to work

Any ideas are welcome!

Cheers
rS

PhiLho YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: How to get a PImage of the sketch? Reply #1 - Jul 15^th, 2009, 1:55am See also get().

nardove

Re: How to get a PImage of the sketch?
Reply #2 - Jul 15^th, 2009, 2:31am

Hi PhiLho, yes that did it

Code:

img.loadPixels();
  for (int y = 0; y < height; y++) { 
    for (int x = 0; x < width; x++) {
      int px = get(x, y);
      img.pixels[x + y * width] = px;
    }
  }
img.updatePixels();

Got that into a fucntion, because in order to work it needs to be refresh in the draw method

If there is a simpler or better way, please post it

On another note what is the difference in using createImage or new PImage?

Code:

img = createImage(width, height, RGB);
img = new PImage(width, height);

The Reference say "To create a new image, use the createImage() function (do not use new PImage())."

I get the same results using either, but there must be something to it, where is the catch, anyone?

Thanks
rS

PhiLho

Re: How to get a PImage of the sketch?
Reply #3 - Jul 15^th, 2009, 4:24am

nardove wrote on Jul 15^th, 2009, 2:31am:

If there is a simpler or better way, please post it

Yes: use get() without parameters...

Quote:

On another note what is the difference in using createImage or new PImage

The main difference is that you can use one and should not use the other, as pointed out... Tongue

No, seriously, as you guessed it, there is a catch: createImage() does a new PImage(wide, high, format) then does image.parent = this which, "makes save() work without needing an absolute path".
So if you do new PImage, and do the above additional init, or don't use save(), it should be OK.
Note: you have actually several constructors:
PImage() sets format to ARGB but doesn't allocate pixels.
PImage(int width, int height) sets format to RGB.
PImage(int width, int height, int format) allows to choose the format.
PImage(java.awt.Image img) takes a Java image and set format to RGB.

nardove

Re: How to get a PImage of the sketch?
Reply #4 - Jul 15^th, 2009, 4:37am

Thanks again, now why is it better to use get(), instead of get(x, y);

When I change it I got the error

Code:

void refreshImg() {
  img.loadPixels();
  for (int y = 0; y < height; y++) { 
    for (int x = 0; x < width; x++) {
      int px = get();
      img.pixels[x + y * width] = px;
    }
  }
  img.updatePixels();
}

cannot convert from PImage to int

What am I missing?

Cheers
rS

PhiLho YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: How to get a PImage of the sketch? Reply #5 - Jul 15^th, 2009, 4:48am Quote: What am I missing? Two parts of the reference page of get(): "PImage cp = get();" and "Reads the color of any pixel or grabs a section of an image. If no parameters* are specified, the entire image is returned.*"

nardove Full Member Offline Posts: 189 UK	Re: How to get a PImage of the sketch? Reply #6 - Jul 15^th, 2009, 4:56am The get() usage is not clear, I dont understant, can you show me in the funciton I wrote? Cheers rS

PhiLho YaBB Moderator Offline Posts: 4190 Near Paris (France)	Re: How to get a PImage of the sketch? Reply #7 - Jul 15^th, 2009, 8:17am Code: void refreshImg() { img = get(); // Get whole sketch image into img }

nardove Full Member Offline Posts: 189 UK	Re: How to get a PImage of the sketch? Reply #8 - Jul 15^th, 2009, 8:36am PhiLho thanks for the support, but it doesnt work, all I get is black, the only way the code works so far is as I have it using the for loops and get(x, y); I will research about that, as any optimization is always good Cheers rS

PhiLho

Re: How to get a PImage of the sketch?
Reply #9 - Jul 15^th, 2009, 9:02am

Let see. I take one of my sketches, drawing a little colorful animation.
I add:
Code:


void mousePressed()
{
  noLoop();
  PImage img = get();
  img.filter(THRESHOLD, 0.9);
  image(img, width / 2, 0);
}

When I click the mouse, the right half of the sketch displays the filtered (half of) sketch image. So it works for me.

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