How do I set the text color of a Cocoa tooltip?

I am using BGHUDAppKit for an outline view within a HUD-style (black) NSPanel. As such the text in my outline view cells is light gray or white开发者_运维知识库. Unfortunately this means that when I hover to bring up a tooltip for a cell's value, it shows up as light gray text on yellow, which is illegible.

How can I set the text color for the tooltip, or is there a way that I can modify the control itself (without changing its appearance) to work better with the tooltip mechanism?

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You can override - (void)drawWithExpansionFrame:(NSRect)cellFrame inView:(NSView *)view in a NSCell subclass to draw whatever you want in the (tool tip) expansion frame.

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Based on Adem Preble's suggestion, I ended up with a NSTextField subclass, which overrides drawWithExpansionFrame, and uses a simple color toggle trick:

@implementation MyCustomTextField

- (void)drawWithExpansionFrame:(NSRect)contentFrame inView:(NSView *)view     {
    NSColor *originalColor = self.textColor;
    self.textColor = NSColor.labelColor; // Or any other NSColor
    [super drawWithExpansionFrame:contentFrame inView:view];
    self.textColor = originalColor;
}

@end

This works because the expansion tooltip with the adjusted color covers the text field behind it, with the freshly reset color.