How to animate inside UIView?

I have my custom UIView inside which I have a two dimensional array. This array contains pixels that I draw on my custom UIView with drawRect method.

Now I want to change this pixels (my 2-dim array) with 100 steps (or just with the result array). How do I make this effect animated? It is no problem to display previous state and then actual state, but I need animation between this states.

Thank You for any help.

Best regards, Wojtek

[UPDATE, same day, 14:15]

For now I did it in the following way:

- (void)calculate:(NSTimer *)timer {

int result = [myView calc];
if(result > 0)
{
    [NSTimer scheduledTimerWithTimeInterval:0.00001f
                                     target:self selector:@selector(calculate:)
                                   userInfo:nil
                                    repeats:NO];
}
[myView setNeedsDisplay];}

but it is not so good, because refreshing makes it very slow. If I refresh every 2-4 calculations my animation is not smooth.

MY drawing method:

- (void)drawRect:(CGRect)rect{
int i = 0, j = 0;

CGContextRef myContext = UIGraphicsGetCurrentContext();


// ****************** drawing ********************
for(i = 0; i < 768; i++)
{
    for(j = 0; j < 768; j++)
    {
         if(board[i][j] == 1)
         {
             CGContextSetRGBFillColor (myContext, 1, 0, 0, 1);
             CGContextFillRect (myContext, CGRectMake (i, j, 1, 1));
         }
        else
        {
            CGContextSetRGBFillColor (myContext, 0, 0, 1, 1);
            CGContextFillRect (myContext, CGRectMake (i, j, 1, 1));
        }
    }
}

}

Answers

Drawing one pixel at a time with fill rect will take some time.

I'd suggest that you setup a memory area as the image you want to draw and then use CGImageCreate to create an image you can draw in the UIView.

For example uses see

http://www.iphonedevsdk.com/forum/iphone-sdk-development/23525-cgimagecreate-alpha.html

http://iphonedevelopment.blogspot.com/2009/04/creating-uiimages-from-tga-data.html

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