Re: Comparing NSColor instances
Re: Comparing NSColor instances
- Subject: Re: Comparing NSColor instances
- From: Ricky Sharp <email@hidden>
- Date: Sun, 4 Nov 2007 20:58:22 -0600
On Nov 4, 2007, at 8:29 PM, Ricky Sharp wrote:
I have the need to compare multiple NSColor instances to see if they
all represent the same color. This is so I can correctly support
multiple selection in a new IB 3.0 plugin.
My first approach was to "normalize" all colors like so:
NSColor* normalizedColor = [aColor colorUsingColorSpace:
[NSColorSpace genericRGBColorSpace]];
Then, extract the RGB components with getRed:green:blue:alpha: so I
could do a simple comparison of them.
But, when calling getRed::::, I get the following in the Console:
*** -getRed:green:blue:alpha: not defined for the NSColor
NSCustomColorSpace Generic RGB colorspace 0 0 0 1; need to first
convert colorspace.
Also tried deviceRGBColorSpace, but got the same results.
My assumption above was that since I was using an 'RGB' color space,
that one could then call getRed:green:blue:alpha:.
I do have a working solution to where I still normalize to the same
color space, but then use numberOfComponents followed by a
getComponents: with a CGFloat array. I then compare the values in the
array.
I should beef up the code though to handle the case where calling
numberOfComponents can raise an exception (if no floating point
components exist for the color).
Also, I'm never keen on doing exact compares on floating point values,
so I may add in a bit of "slop" to the compare. On the other hand, if
I do normalize two colors to the same color space, it should be
reasonable to assume it will have identical valued components.
___________________________________________________________
Ricky A. Sharp mailto:email@hidden
Instant Interactive(tm) http://www.instantinteractive.com
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