Received Memory Warning in DrawRect Method - iphone

Question

I am developing an app in which i have recording of main screen and SetNeedsDisplay method is used.
But the problem is that it takes lot of memory and even i am not recording the screen.
I want to reduce the memory usage of the below mentioned code.
Any solution to this?
Thanks in advance.
- (void) drawRect:(CGRect)rect
{
NSDate* start = [NSDate date];
CGContextRef context = [self createBitmapContextOfSize:self.frame.size];
//NSLog(#"context value %#",context);
//not sure why this is necessary...image renders upside-down and mirrored
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, self.frame.size.height);
CGContextConcatCTM(context, flipVertical);
[self.layer renderInContext:context];
CGImageRef cgImage = CGBitmapContextCreateImage(context);
UIImage* background = [UIImage imageWithCGImage: cgImage];
CGImageRelease(cgImage);
self.currentScreen = background;
if (_recording) {
float millisElapsed = [[NSDate date] timeIntervalSinceDate:startedAt] * 1000.0;
[self writeVideoFrameAtTime:CMTimeMake((int)millisElapsed, 1000)];
}
float processingSeconds = [[NSDate date] timeIntervalSinceDate:start];
delayRemaining = (1.0 / self.frameRate) - processingSeconds;
//redraw at the specified framerate
[self performSelector:#selector(setNeedsDisplay) withObject:nil afterDelay:delayRemaining > 0.0 ? delayRemaining : 0.01];
}
-(CGContextRef) createBitmapContextOfSize:(CGSize) size
{
CGContextRef context = NULL;
CGColorSpaceRef colorSpace;
int bitmapByteCount;
int bitmapBytesPerRow;
bitmapBytesPerRow = (size.width * 4);
bitmapByteCount = (bitmapBytesPerRow * size.height);
colorSpace = CGColorSpaceCreateDeviceRGB();
if (bitmapData != NULL) {
free(bitmapData);
}
bitmapData = malloc( bitmapByteCount );
if (bitmapData == NULL) {
fprintf (stderr, "Memory not allocated!");
return NULL;
}
context = CGBitmapContextCreate (bitmapData,
size.width,
size.height,
8, // bits per component
bitmapBytesPerRow,
colorSpace,
kCGImageAlphaNoneSkipFirst);
CGContextSetAllowsAntialiasing(context,NO);
if (context== NULL) {
free (bitmapData);
fprintf (stderr, "Context not created!");
return NULL;
}
CGColorSpaceRelease( colorSpace );
return context;
}

Answer 1

You create a context every frame, but never release it, try adding this to the end:
CGContextRelease(context);