draw CGPaths to UIView then save view as Png - ios4

Question

In the drawrect function of a UIView I use CGContext to draw some shapes. This Works fine, I can see my shapes.
Now I'm trying to save what has been drawn on the view as a png on disk. I've read various docs / articles but nothing gets saved. Im testing on the simulator for ios 4.3.
Edit 1
I changed my code and uncommented the context part. I can save the png but it is blank.
- (void)drawRect:(CGRect)rect
{
CGContextRef ctx= UIGraphicsGetCurrentContext();
CGContextSetRGBFillColor(ctx, 0, 0, 0, .5);
CGContextBeginPath(ctx);
CGContextAddPath(ctx, mutatablepath);
//CGContextStrokePath(ctx);
CGContextFillPath(ctx);
CFRelease(mutatablepath);
NSString *path0;
NSArray *paths0=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
path0=[[paths0 objectAtIndex:0]stringByAppendingPathComponent:#"images"];
NSError *error;
if (![[NSFileManager defaultManager]fileExistsAtPath:path0]) {
if(![[NSFileManager defaultManager]createDirectoryAtPath:path0 withIntermediateDirectories:NO attributes:nil error:&error])
{
NSLog(#"Create directory error %#",error);
}
}
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
NSData *imagedata=UIImagePNGRepresentation(image);
NSString *namepath=[NSString stringWithFormat:#"%#.png",#"test"];
NSString *path;
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
path=[[paths objectAtIndex:0]stringByAppendingPathComponent:#"images"];
NSString *savepath=[NSString stringWithFormat:#"%#/%#",path,namepath ];
// NSError
NSLog(#"%#",savepath);
[imagedata writeToFile:savepath atomically:YES];
}

Answer 1

You can do so by taking the image saving code out of your drawRect method, since the renderInContext method implicitly calls drawRect as necessary:
UIView *myView = [[MyViewClass alloc] initWithFrame:CGRectMake(/*...*/)];
UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
Source: http://pastie.org/244916