resize

jeffmarc

If I use resize on a loaded image, does it change the resize the actual image in memory?

memimg = loadImage("c:dirtscan.png"); 
memimg.resize(480,480);              // scale to fit screen 480x480
sclimg=memimg;
image(sclimg,imgstartcol,imgstartrow);

So now memimage.height and memimage.width =480?

If I want to get back to the full scale raw image in memory to execute image processing on I have to reload the image each time after i resize it?

Is that correct?

KevinWorkman

What happened when you put together a little test program to find out yourself?

The resize() function is destructive. Once you resize an image, you can't get its exact original without reloading the file again.

Other than creating a little example program (which should always be your first step), we can look at the source for PImage to be sure:

public void resize(int w, int h) {  // ignore
    if (w <= 0 && h <= 0) {
      throw new IllegalArgumentException("width or height must be > 0 for resize");
    }

    if (w == 0) {  // Use height to determine relative size
      float diff = (float) h / (float) height;
      w = (int) (width * diff);
    } else if (h == 0) {  // Use the width to determine relative size
      float diff = (float) w / (float) width;
      h = (int) (height * diff);
    }

    BufferedImage img =
      shrinkImage((BufferedImage) getNative(), w*pixelDensity, h*pixelDensity);

    PImage temp = new PImage(img);
    this.pixelWidth = temp.width;
    this.pixelHeight = temp.height;

    // Get the resized pixel array
    this.pixels = temp.pixels;

    this.width = pixelWidth / pixelDensity;
    this.height = pixelHeight / pixelDensity;

    // Mark the pixels array as altered
    updatePixels();
  }

From this, you can see that the internal pixels, width, and height variables are changed, and no copies are kept around.

GoToLoop

https://forum.Processing.org/two/discussion/15473/readme-how-to-format-code-and-text

Get a clone of the original PImage w/ get() before using resize(): *-:)

1. https://Processing.org/reference/PImage_get_.html
2. https://Processing.org/reference/PImage_resize_.html

PImage img, ori;

void setup() {
  ori = ( img = loadImage("dirtscan.png") ).get();
  img.resize(480,480);
}