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Index › Programming Questions & Help › Syntax Questions › Load images on-the-fly
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Load images on-the-fly (Read 359 times)
joelindley
Load images on-the-fly
Feb 18th, 2009, 1:28pm  
Hia,

Been playing with Processing for about 2 hours. What a fantastic thing..! Love it.

I'm trying to adapt the Examples > Topics > Animation > Sequential example. What I want it to do is monitor the files in the data directory (which are all named 01.jpg, 02.jpg and so on....) if/when a new file is added into the data directory I want the program to realise this and add that to the PImage object that is being looped.

I can't seem to figure out how to dynamically add (or remove) items from a PImage object. How would be a good way of going about this?

Hope this is clear.

Cheers,
Joe
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odin4000
Re: Load images on-the-fly
Reply #1 - Feb 18th, 2009, 2:21pm  
http://www.processing.org/reference/PImage.html

You should find anything you need there... this is the reference, when you encounter a problem in Processing, before posting on the forum go there and have a look at images functions and all the related things. After a few minutes you should be able to load and display images.

Have a good day,
Odin
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joelindley
Re: Load images on-the-fly
Reply #2 - Feb 18th, 2009, 2:30pm  
I've been going through the reference pages for some time, but I haven't managed to figure out how to do what I want.

My code is like this;

int numFrames = 11; //starting number of frames
int frame = 0;
PImage[] images = new PImage[numFrames];
   
void setup()
{
 size(600, 400);
 frameRate(5);
 loadimages(numFrames);
}


void loadimages(int frames)
{  
   for(int i=0; i<frames; i++) {
   String imageName = nf(i, 2) + ".JPG";
   images[i] = loadImage(imageName);
}



So I end up with this PImage object with 11 images in it.

I want to re-run loadimages(), but with 12 frames, or 13, or 14- but of course I get the out of bounds error message, because it is already set to 11. How do I redefine images[] so it has more elements?

I do apologise if this is in the reference, but I can't seem to find it it - causing me to think "maybe this is impossible, in this way"...

Thanks for your patience.

Joe
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PhiLho 
Re: Load images on-the-fly
Reply #3 - Feb 18th, 2009, 4:05pm  
I think append() is what you need.
Note you don't need to reload all the images: to detect if a file exists, you can use the code:
File f = new File(imageName);
if (f.exists()) {
// load image and append to array
}
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WWW  
joelindley
Re: Load images on-the-fly
Reply #4 - Feb 19th, 2009, 6:23pm  
Yes! That has sorted it, thanks.

I did try to use append, where I ran into troubles was getting it to actually run. The mistake I made was with syntax I think; I didn't realise that the line

PImage[] images_updated = append(images_original, loadImage("03.JPG");

actually needed to be written like this;

PImage[] images_updated = (PImage[]) append(images_original, loadImage("03.JPG");

It is in the docs, I just missed it.

Anyway, many thanks for your help, the f.exists bit looks v useful too.

Best,
Joe
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