Question

Just wondering how difficult it would be to convert the following library to Objective-C to be used on the iPhone?

I guess I’m after some similar image processing libraries that would lead me in the right direction? I’m aware that it’s not easy to apply the same filters as existing applications like Instragram, Path and Hipstamatic.

However, I’d like to be able to do something similar.

Here is the JavaScript library:

https://github.com/alexmic/filtrr/blob/master/filtrr.js

A demo of its functionality can be found here:

http://alexmic.net/demos/filtrr

Answer 1

I’ve started a bit of converting, here is a sample. Now of course, fully converting it would a lot of time, too much for me to do it. But just see how I’ve done it. I’m hoping you have prior experience with Obj-C?

Also, perhaps you could look at some existing libraries.

http://code.google.com/p/simple-iphone-image-processing/

http://mattgemmell.com/2010/07/05/mgimageutilities/

http://developer.apple.com/library/ios/#samplecode/GLImageProcessing/Introduction/Intro.html

Also, dont forget that XCode can compile C++ into your project so also investigate C or C++ libraries.

 NSObject canvas;
 int w;
 int h;
 int ctx;
 NSData imageData;

 @implementation filtr
 {
    -(id) initWithCanvas:(id)_canvas
    {
        if (!_canvas) {
            throw "Canvas supplied to filtr was null or undefined.";
        }

        canvas    = _canvas;
        w         = canvas.width;
        h         = canvas.height;
        ctx       = canvas.getContext("2d");
        imageData = ctx.getImageData(0, 0, w, h);
    }

    /**
     * Clamps the intensity level between 0 - 255.
     *
     * @param i The intensity level.
     */
     -(int)safe:(int)i
    {
        return MIN(255, MAX(0, i));
    }