Drawing aside of -drawRect

[Tima Vaisburd]

Hello everybody,

I have problems with drawing in any method but [NSView -drawRect].

I placed the drawing code directly in the mouse event processing
handler, like this:

// This is a method of NSView subclass

- (void) mouseDragged:(NSEvent *) event
{
        NSPoint sketch_origin = ... ;

        [self lockFocus];

        // NSImage * _sketch, * _mask defined elsewhere

        [_sketch compositeToPoint: sketch_origin operation: NSCompositeCopy];

        [_mask compositeToPoint: sketch_origin 
                    operation: NSCompositeSourceOver];

        [self unlockFocus];
    }
}

Nothing happens when the backing store is buffered or retained.
What do I miss?

Thank you,
Tima.