sRGB to NSColor - cocoa

Question

I am trying to draw an inner shadow in an NSView. The shadow itself is not the problem, but the color setting is driving me nuts :/
#define ShadowBlurRadius 10.0
#define SRGB (CGFloat [4]){184.0, 184.0, 184.0, 1.0}
#implementation SWShadowedView
- (void)drawRect:(NSRect)dirtyRect {
NSGraphicsContext *context = [NSGraphicsContext currentContext];
[context saveGraphicsState];
[context setCompositingOperation:NSCompositePlusDarker];
NSBezierPath *path = [NSBezierPath bezierPathWithRect:NSMakeRect(0, dirtyRect.size.height -ShadowBlurRadius, self.superview.frame.size.width, ShadowBlurRadius)];
[[NSColor whiteColor] setStroke];
NSShadow * shadow = [[NSShadow alloc] init];
NSColorSpace *colorSpace = [NSColorSpace sRGBColorSpace];
NSColor *color = [NSColor colorWithColorSpace:colorSpace components:SRGB count:4];
[shadow setShadowColor:color];
[shadow setShadowBlurRadius:ShadowBlurRadius];
[shadow set];
[path stroke];
[context restoreGraphicsState];
[super drawRect:dirtyRect];
}
#end
If I replace the shadow color with [NSColor redColor] it works but with the wrong color. This is where I got the sRGB from: link
The way to convert sRGB to NSColor is taken from another post from here but obviously it's not working.
best regards

Answer 1

Your code is almost completely correct, the only problem is that you're using numerical values from 0-255 in your array. All the NSColor creation methods use CGFloat values from 0-1.0.
All you need to do is define your SRGB array like so:
#define SRGB (CGFloat [4]){184.0/255.0, 184.0/255.0, 184.0/255.0, 1.0}
Your code will then work correctly. Please note that using the colorWithCalibratedRed:green:blue:alpha: method of NSColor will not give you the correct color from your sRGB values.
To get correct sRGB values, you must use the method in your original code, which specifically uses the sRGB color space to create the color. A category on NSColor that creates colors using 255-based sRGB values might look something like this:
#implementation NSColor (sRGB_Additions)
+ (NSColor *)colorWith255sRGBRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue alpha:(CGFloat)alpha
{
CGFloat sRGBComponents[4] = {red / 255.0, green / 255.0, blue / 255.0, alpha};
NSColorSpace *colorSpace = [NSColorSpace sRGBColorSpace];
return [NSColor colorWithColorSpace:colorSpace components:sRGBComponents count:4];
}
#end
Then you could just do this:
NSColor* someColor = [NSColor colorWith255sRGBRed:184.0 green:184.0 blue:184.0 alpha:1.0];

Answer 2

Here is the simplest, most modern way of creating the color that you need:
NSColor *color = [NSColor colorWithSRGBRed:(184.0 / 255.5) green:(184.0 / 255.5) blue:(184.0 / 255.5) alpha:1.0];

Answer 3

Use RGB not sRGB:
You can create color with RGB like this:
float red = 182.0f/256.0f;
float green = 182.0f/256.0f;
float blue = 182.0f/256.0f;
NSColor *color = [NSColor colorWithCalibratedRed:red green:green blue:blue alpha:1.0f];