objective-ccocoanscolorpanelnscolorwell

Add opacity slider to the color panel for one color well but not others

I'd like to add a opacity slider to the NSColorPanel that is shown for 1 specific NSColorWell. All other color wells should not show the opacity slider.

I know I can set this for the sharedColorPanel like so: 

 [[NSColorPanel sharedColorPanel] setShowsAlpha:YES];

But how do I do this when I only want this behavior for a single color well?

I tried adding an IBAction, but this IBAction is not called when you click the color well. (So I can't make any changes before the panel is displayed). It is called when you choose another color in the color panel.

Solution

  • OK, here's the code that works. Set the colorwell class in IB to AlphaColorWell:**

    @implementation AlphaColorWell

- (void)activate:(BOOL)exclusive
{
    [[NSColorPanel sharedColorPanel] setShowsAlpha:YES];
    [super activate:exclusive];
}

- (void)deactivate
{
    [super deactivate];
    [[NSColorPanel sharedColorPanel] setShowsAlpha:NO];
}

@end