Memory issues with Core Graphics - ios

Question

I draw a table "by hand", by using primitives of Core Graphics.
The view is re-draw when I click a button.
The problem is that when I profile the code in Instruments, the VM Regions keep increase, while Heap and Anonymous VM oscillate (and I would expect it).
And the details about CoreAnimation:
An excerpt of my drawRect:
- (void)drawRect:(CGRect)rect
{
// Drawing code
CGContextRef context = UIGraphicsGetCurrentContext();
CGRect paperRect = CGRectMake(self.bounds.origin.x+hourLabelSize+self.marginX,
10 +self.cellBorder ,
self.bounds.size.width,
self.cellHeight * 48
);
// custom shadow
drawLinearGradient(context, paperRect, whiteColor.CGColor, lightGrayColor.CGColor);
CGContextSaveGState(context);
CGFloat outerMargin = 5.0f;
CGFloat eventSize;
// Draw table
CGRect hourRect;
CGRect outerRect;
CGMutablePathRef outerPath;
CGRect strokeRect;
CGRect rowRect;
for (int j=0; j < 7;j++)
{
for (int i=0; i < numberOfRows; i++)
{
// Odd index means we are in the half of an hour
if ( (i%2) == 0)
{
[hour setString:[NSString stringWithFormat:#"%d:00",(int)floor(i/2)]];
// Draw box around hours //
if (j == 0 && i >0)
{
CGContextSaveGState(context);
hourRect = CGRectMake(5, i*cellHeight-5, hourLabelSize, 28);
outerRect = CGRectInset(hourRect, outerMargin, outerMargin);
outerPath = newRoundedRectForRect(outerRect, 6.0);
CGContextAddPath(context, outerPath);
CFRelease(outerPath); // <--- This solve the leak!!
// Draw gradient
strokeRect = CGRectInset(hourRect, 5.0, 5.0);
CGContextSetStrokeColorWithColor(context, boxColor.CGColor);
CGContextSetLineWidth(context, 1.0);
CGContextStrokeRect(context, strokeRect);
drawLinearGradient(context, strokeRect, whiteColor.CGColor, lightGrayColor.CGColor);
CGContextRestoreGState(context);
}
}
else
{
[hour setString:[NSString stringWithFormat:#"%d:30",(int)floor(i/2)]];
}
// Draw hours
if (j == 0 && i > 0)
[hour drawInRect:CGRectMake(0, i*cellHeight, hourLabelSize+10, 26) withFont:font lineBreakMode:NSLineBreakByClipping alignment:NSTextAlignmentCenter];
// Draw row
CGContextBeginPath(context);
CGContextSetStrokeColorWithColor(context, boxColor.CGColor);
CGContextSetLineWidth(context, self.cellBorder);
rowRect = CGRectMake(j*cellWidth + hourLabelSize +self. marginX - self.cellBorder/2, i*cellHeight+10 + self.cellBorder / 2, cellWidth , cellHeight);
CGContextStrokeRect(context, rowRect);
} //
CGContextFlush(context);
CGContextRestoreGState(context);
The first thing I do not understand is why I see VM:CoreAnimation. CoreGraphics is part of Core Animation?
Secondly, what I shall watch as syntoms of bad allocation: VM Regions, XCode measurements or Head and Anonymous?
Regards!
[EDIT]
The createRoundedRect is as follows
CGMutablePathRef newRoundedRectForRect(CGRect rect, CGFloat radius)
{
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, CGRectGetMidX(rect), CGRectGetMinY(rect));
CGPathAddArcToPoint(path, NULL, CGRectGetMaxX(rect), CGRectGetMinY(rect), CGRectGetMaxX(rect), CGRectGetMaxY(rect), radius);
CGPathAddArcToPoint(path, NULL, CGRectGetMaxX(rect), CGRectGetMaxY(rect), CGRectGetMinX(rect), CGRectGetMaxY(rect), radius);
CGPathAddArcToPoint(path, NULL, CGRectGetMinX(rect), CGRectGetMaxY(rect), CGRectGetMinX(rect), CGRectGetMinY(rect), radius);
CGPathAddArcToPoint(path, NULL, CGRectGetMinX(rect), CGRectGetMinY(rect), CGRectGetMaxX(rect), CGRectGetMinY(rect), radius);
CGPathCloseSubpath(path);
return path;
}:
and the drawLineGradient.m :
void drawLinearGradient(CGContextRef context, CGRect rect, CGColorRef startColor, CGColorRef endColor)
{
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGFloat locations[] = { 0.0, 1.0 };
NSArray *colors = #[(__bridge id) startColor, (__bridge id) endColor];
CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, (__bridge CFArrayRef) colors, locations);
CGPoint startPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
CGPoint endPoint = CGPointMake(CGRectGetMidX(rect), CGRectGetMaxY(rect));
CGContextSaveGState(context);
CGContextAddRect(context, rect);
CGContextClip(context);
CGContextDrawLinearGradient(context, gradient, startPoint, endPoint, 0);
CGContextRestoreGState(context);
CGGradientRelease(gradient);
CGColorSpaceRelease(colorSpace);
colors = nil;
}

Answer 1

The reason you see core animation is because all iOS views are layer-backed views.
The reason for your leak is that you release the path.
ARC does not manage Core Foundation objects.