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copied!<pre><code>// This WILL NOT increment the image's retain count. CGImageRef iRef = (__bridge CGImageRef)array[0]; // This WILL increment the image's retain count. CGImageRef iRef = (__bridge_retained CGImageRef)array[0]; </code></pre> <p>Since <code>__bridge_retained</code> increments the retain count, you need to decrement the retain count at some point later. Because <code>__bridge_retained</code> acts like <code>CFRetain</code>, Apple created a <code>__bridge_retained</code> wrapper called <code>CFBridgingRetain</code> that reminds you of this:</p> <pre><code>// This WILL increment the image's retain count. CGImageRef iRef = CFBridgingRetain(array[0]); </code></pre> <p>Whenever you see <code>CFRetain</code> <strong>or</strong> <code>CFBridgingRetain</code>, you know you need to release the object at some point later.</p> <p>Similarly, you can use <code>CFBridgingRelease</code> instead of <code>__bridge_transfer</code> to decrement the retain count of a CF object. Example:</p> <pre><code>[_array addObject:CFBridgingRelease(renderedRef)]; </code></pre> <p>You can use <code>CFBridgingRelease</code> to balance a <code>CFRetain</code> or a <code>CFBridgingRetain</code>. It returns an <code>id</code> that ARC manages.</p> <p>A normal <code>NSMutableArray</code> retains each of its elements. You can tell it to become empty:</p> <pre><code>[_array removeAllObjects]; </code></pre> <p>When you do this, it will release each of its elements, balancing the retain it performed on each element.</p> <p>Thus there is no memory leak in this code:</p> <pre><code>CGImageRef image = CGImageCreate(...); [_array addObject:CFBridgingRelease(image)]; [_array removeAllObjects]; </code></pre> <p>or in this code:</p> <pre><code>CGImageRef image = CGImageCreate(...); [_array addObject:CFBridgingRelease(image)]; CGImageRef image2 = CFBridgingRetain([_array lastObject]); [_array removeLastObject]; CGContextDrawImage(gc, rect, image2); CGImageRelease(image2); </code></pre>

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