Image distortion

[KolNedra]

I've been googling and looking on other threads, but I can't seem to find a solid solution.

I want to accomplish the following:


So I have this UIImage(View) and I want to distort it according to 4 points (topleft, topright, bottomright, bottomleft)

I came across a Flash AS3 equivalant which I try to port to an objective-c one:

/*!
 * Use like: [imageView setAffineTransform:compute_transform_matrix(320, 480, 200, 200, 500, 220, 600, 800, 200, 680)];

- (CGAffineTransform) compute_transform_matrix:(float)W
                                     H:(float)H 
                                   tlx:(float)tlx
                                   tly:(float)tly
                                   trx:(float)trx 
                                   trY:(float)trY
                                   brx:(float)brx 
                                   bry:(float)bry
                                   blx:(float)blx
                                   bly:(float)bly {

    NSMutableArray *_p = [[NSMutableArray alloc] init];
    NSMutableArray *_tri = [[NSMutableArray alloc] init];
    float ix;
    float iy;
    float _xMin = 0;
    float _yMin = 0;
    float _hsLen = W / (SEGMENTS + 1);
    float _vsLen = H / (SEGMENTS + 1);
    
    float x;
    float y;
    for (ix = 0; ix < SEGMENTS + 2; ix++) {
        for (iy = 0; iy < SEGMENTS + 2; iy++) {
            x = ix * _hsLen;
            y = iy * _vsLen;
            [_p addObject:[NSMutableDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithFloat:x], @"x", [NSNumber numberWithFloat:y], @"y",[NSNumber numberWithFloat:x], @"sx", [NSNumber numberWithFloat:y], @"sy", nil]];
        }
    }
    
    for (ix = 0; ix < SEGMENTS + 1; ix++) {
        for (iy = 0; iy < SEGMENTS + 1; iy++) {
            [_tri addObject:[NSMutableArray arrayWithObjects:[_p objectAtIndex:(iy + ix * (SEGMENTS + 2))], [_p objectAtIndex:(iy + ix * (SEGMENTS + 2) + 1)], [_p objectAtIndex:(iy + (ix + 1) * (SEGMENTS + 2))], nil]];
            [_tri addObject:[NSMutableArray arrayWithObjects:[_p objectAtIndex:(iy + (ix + 1) * (SEGMENTS + 2) + 1)], [_p objectAtIndex:(iy + (ix + 1) * (SEGMENTS + 2))], [_p objectAtIndex:(iy + ix * (SEGMENTS + 2) + 1)], nil]];
        }
    }
    
    float dx30 = blx - tlx;
    float dy30 = bly - tly;
    float dx21 = brx - trx;
    float dy21 = bry - trY;
    int l = [_p count];
    NSMutableDictionary *point;
    float _x;
    float _y;
    float gx;
    float gy;
    float bx;
    float by;
    float _sx;
    float _sy;
    while(--l > -1) {
        point = [_p objectAtIndex:l];
        _x = [[point objectForKey:@"x"] floatValue];
        _y = [[point objectForKey:@"y"] floatValue];
        gx = (_x - _xMin) / W;
        gy = (_y - _yMin) / H;
        bx = (tlx + gy * (dx30));
        by = (tly + gy * (dy30));
        _sx = bx + gx * ((trx + gy * (dx21)) - bx);
        _sy = by + gx * ((trY + gy * (dy21)) - by);
        [point setObject:[NSNumber numberWithFloat:_sx] forKey:@"sx"];
        [point setObject:[NSNumber numberWithFloat:_sy] forKey:@"sy"];
        [_p replaceObjectAtIndex:l withObject:point];        
    }
    
    l = [_tri count];
    NSMutableDictionary *p0;
    NSMutableDictionary *p1;
    NSMutableDictionary *p2;
    
    float x0;
    float y0;
    float x1;
    float y1;
    float x2;
    float y2;
    float u0;
    float v0;
    float u1;
    float v1;
    float u2;
    float v2;
    CGAffineTransform _tMat = CGAffineTransformIdentity;
    CGAffineTransform _sMat = CGAffineTransformIdentity;
    NSMutableArray *a;    
    while (--l > -1) {
        a = [_tri objectAtIndex:l];
        p0 = [a objectAtIndex:0];
        p1 = [a objectAtIndex:1];
        p2 = [a objectAtIndex:2];
        x0 = [[p0 objectForKey:@"sx"] floatValue];
        y0 = [[p0 objectForKey:@"sy"] floatValue];
        x1 = [[p1 objectForKey:@"sx"] floatValue];
        y1 = [[p1 objectForKey:@"sy"] floatValue];
        x2 = [[p2 objectForKey:@"sx"] floatValue];
        y2 = [[p2 objectForKey:@"sy"] floatValue];
        u0 = [[p0 objectForKey:@"x"] floatValue];
        v0 = [[p0 objectForKey:@"y"] floatValue];
        u1 = [[p1 objectForKey:@"x"] floatValue];
        v1 = [[p1 objectForKey:@"y"] floatValue];
        u2 = [[p2 objectForKey:@"x"] floatValue];
        v2 = [[p2 objectForKey:@"y"] floatValue];
        
        _tMat.tx = u0;
        _tMat.ty = v0;
        _tMat.a = (u1 - u0) / W;
        _tMat.b = (v1 - v0) / W;
        _tMat.c = (u2 - u0) / H;
        _tMat.d = (v2 - v0) / H;
        
        _sMat.a = (x1 - x0) / W;
        _sMat.b = (y1 - y0) / W;
        _sMat.c = (x2 - x0) / H;
        _sMat.d = (y2 - y0) / H;
        _sMat.tx = x0;
        _sMat.ty = y0;        
        CGAffineTransformInvert(_tMat);
        CGAffineTransformConcat(_tMat, _sMat);
    }
    
    return _tMat;
}

But nothing exciting happens.
I came across a thread on stackoverflow with the same 'problem', only the solution didn't do it for me.

Anyone who can give me a pointer or even maybe a working example?