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Index › Programming Questions & Help › Syntax Questions › capturing & rotating the processing display screen
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capturing & rotating the processing display screen (Read 644 times)
todicus
capturing & rotating the processing display screen
Mar 25th, 2010, 11:37am  
I'd like to grab an image of the current processing screen, rotate it a few degrees, and then draw it back to the screen.  I tried saving the current pixels[] array with loadPixels(), changing the coordinate frame of reference with rotate(), and then drawing the pixels[] back to the frame with updatePixels().  This didnt' work; I think pixels[] keeps the standard coordinate frame always.  

If I could convert pixels[] into a PImage, I could use image() to paste the PImage into the new coordinate frame (I checked with a regular imported image).  Does anyone know how to do this, or have other suggestions for capturing & rotating the display window?

                    thank you very much --

                                                 

                                               -- Todd
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phrontist
Re: capturing & rotating the processing display screen
Reply #1 - Mar 25th, 2010, 11:48am  
You could iterate through the pixel array like this... http://processing.org/reference/PImage_loadPixels_.html
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PhiLho 
Re: capturing & rotating the processing display screen
Reply #2 - Mar 25th, 2010, 12:00pm  
Create another PImage or PGraphics, copy the pixels of the sketch to this image, do your rotation and draw the offscreen image back to screen (with image()).
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todicus
Re: capturing & rotating the processing display screen
Reply #3 - Mar 28th, 2010, 6:02pm  
Yes thank you guys: the secret is to create a PImage, save the screen pixels into it, then draw that image in the next time step.

Code:
PImage img;

void setup(){
  img = createImage(width, height, RGB);
}

void draw(){
  // draw old screen...
  image(img, 0, 0);

  // change the screen...
  [screen modifiying code here]

  // save current screen pixels...
  loadPixels();
  img.pixels = pixels;
  img.updatePixels();
}
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