[UIFont fontWithName: size] memory leak on iPhone iOS4?

Question

I have function for adding UILabel to my view:

UILabel* AddLabel(UIView* view,CGRect labelRect, UIStyle* labelStyle, NSString* labelText)
{
    UILabel* label = [[[UILabel alloc] initWithFrame:labelRect] autorelease];
    label.textColor = [UIColor colorWithCGColor:[ labelStyle.textColor CGColor]];
    label.backgroundColor = [UIColor colorWithCGColor:[labelStyle.backgroundColor CGColor]];
    label.font =[UIFont fontWithName: labelStyle.fontName] size:labelStyle.fontSize];

    label.frame = labelRect;
    label.text = labelText;
    [view addSubview:label];
    return label;
}

where UIStyle has this interface:

@interface UIStyle : NSObject {
    NSString * fontName;
    CGFloat fontSize;
    UIColor* textColor;
    UIColor* backgroundColor;
}

so when I add such label to view, I get memory leak. Here is the trace from Instruments:

   0 libSystem.B.dylib calloc
   1 CoreGraphics CGGlyphBitmapCreate
   2 CoreGraphics CGFontCreateGlyphBitmap8
   3 CoreGraphics CGFontCreateGlyphBitmap
   4 CoreGraphics create_missing_bitmaps
   5 CoreGraphics CGGlyphLockLockGlyphBitmaps
   6  0x317c173f
   7  0x317c3e59
   8 CoreGraphics CGContextDelegateDrawGlyphs
   9 CoreGraphics draw_glyphs
  10 CoreGraphics CGContextShowGlyphsWithAdvances
  11 WebCore WebCore::Font::drawGlyphs(WebCore::GraphicsContext*, WebCore::SimpleFontData const*, WebCore::GlyphBuffer const&, int, int, WebCore::FloatPoint const&, bool) const
  12 WebCore WebCore::Font::drawGlyphBuffer(WebCore::GraphicsContext*, WebCore::GlyphBuffer const&, WebCore::TextRun const&, WebCore::FloatPoint&) const
  13 WebCore WebCore::Font::drawSimpleText(WebCore::GraphicsContext*, WebCore::TextRun const&, WebCore::FloatPoint const&, int, int) const
  14 WebCore WebCore::Font::drawText(WebCore::GraphicsContext*, WebCore::TextRun const&, WebCore::FloatPoint const&, int, int) const
  15 WebCore drawAtPoint(unsigned short const*, int, WebCore::FloatPoint const&, WebCore::Font const&, WebCore::GraphicsContext*, WebCore::BidiStatus*, int)
  16 WebCore -[NSString(WebStringDrawing) __web_drawInRect:withFont:ellipsis:alignment:letterSpacing:lineSpacing:includeEmoji:truncationRect:measureOnly:]
  17 WebCore -[NSString(WebStringDrawing) _web_drawInRect:withFont:ellipsis:alignment:lineSpacing:includeEmoji:truncationRect:measureOnly:]
  18 WebCore -[NSString(WebStringDrawing) _web_drawInRect:withFont:ellipsis:alignment:lineSpacing:includeEmoji:truncationRect:]
  19 UIKit -[NSString(UIStringDrawing) _drawInRect:withFont:lineBreakMode:alignment:lineSpacing:includeEmoji:truncationRect:]
  20 UIKit -[NSString(UIStringDrawing) drawInRect:withFont:lineBreakMode:alignment:lineSpacing:includeEmoji:]
  21 UIKit -[NSString(UIStringDrawing) drawInRect:withFont:lineBreakMode:alignment:lineSpacing:]
  22 UIKit -[UILabel _drawTextInRect:baselineCalculationOnly:]
  23 UIKit -[UILabel drawTextInRect:]
  24 UIKit -[UILabel drawRect:]
  25 UIKit -[UIView(CALayerDelegate) drawLayer:inContext:]
  26 QuartzCore -[CALayer drawInContext:]
  27 QuartzCore backing_callback(CGContext*, void*)
  28 QuartzCore CABackingStoreUpdate
  29 QuartzCore -[CALayer _display]
  30 QuartzCore -[CALayer display]
  31 QuartzCore CALayerDisplayIfNeeded
  32 QuartzCore CA::Context::commit_transaction(CA::Transaction*)
  33 QuartzCore CA::Transaction::commit()
  34 QuartzCore CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*)
  35 CoreFoundation __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__
  36 CoreFoundation __CFRunLoopDoObservers
  37 CoreFoundation __CFRunLoopRun
  38 CoreFoundation CFRunLoopRunSpecific
  39 CoreFoundation CFRunLoopRunInMode
  40 GraphicsServices GSEventRunModal
  41 GraphicsServices GSEventRun
  42 UIKit -[UIApplication _run]
  43 UIKit UIApplicationMain
  44 Cuisine main /iPhone/Projects/iCookProFullSix/iCookPrototype/main.m:14

And I have hundreds of them for several calls of function AddLabel. I call it this way:

AddLabel(self.view, CGRectMake(56, 60, 88, 15), style2, @"text");

The thing is that if I comment label.font =[UIFont fontWithName: labelStyle.fontName] size:labelStyle.fontSize]; - there is no leaks..

Why is it so? Is it a bug of iOS or anything I am doing wrong?

P.S. This leak is only visible on device.

Can anybody help? Thanks in advance!

Answer 1

Unless this leak occurs for every UIFont you create, it's not something to worry about--the OS will cleanup the leak when your application exits.

If it occurs each time a UIFont is created, perhaps your UIStyle class (which collides with Apple's namespace by the way) should cache the UIFont instead of having it recreated.

Also, you don't need the [UIColor colorWithCGColor:[labelStyle.textColor CGColor]] bit, you can just assign labelStyle.textColor

Answer 2

Try retaining the UIfont that's returned, and release it manually.

I tried this just now and it seemed to fix it for me.

Answer 3

Nan, I tried retaining the font and released it manually like the following: Blockquote

UIFont *font=[[UIFont boldSystemFontOfSize:20] retain];
reportNameTextField.font=font;
[font release];

but the leaks still present, can you see what I did wrong? Thanks in advance...