Subclassing NSView to have a transparent background

objective-c cocoa macos subclass nsview
Andrew M picture Andrew M · Jan 8, 2011 · Viewed 11.5k times · Source

I am creating an app where I need to have a transparent NSView with a transparent PNG image inside. The problem is, the NSView I'm drawing has a gray background on it. I have it subclassed (as TransparentRectangleView) but don't know what to put in drawRect to make it transparent.

I have already overridden the isOpaque method to return NO but it doesn't seem to help...

Alternatively, is there already a subclassed NSView that is similar to the iPhone's UIImageView (as long as I can add subviews inside, I need to add some text inside).

Answer

ughoavgfhw picture ughoavgfhw · Jan 8, 2011

To make a view transparent, simply fill it with [NSColor clearColor].

- (void)drawRect:(NSRect)rect {
    [[NSColor clearColor] set];
    NSRectFill(rect);
}

The default implementation of isOpaque returns NO, so if you are subclassing NSView and not some other view you don't need to worry about overriding it.

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