Trying to get color value of pixel - macos

Question

I'm trying to read the color value of a pixel in a tif image but I can't fihure out the correct way to do it. I'm using OSX and my approach is as follows:
NSImage *picture = [[NSImage alloc] initWithContentsOfFile:#"bais2.tif"]; //file is located in resoureces folder.
NSBitmapImageRep *imageRep = [[picture representations] objectAtIndex:0];
NSColor* color = [imageRep colorAtX:10 y:10];
NSLog(#"%f %f, %f", [color redComponent], [color blueComponent], [color greenComponent]);
The problem is that for some reason the logged values in NSLog always becomes 0.0000000....
I have also tried to use:
NSBitmapImageRep* imageRep = [[NSBitmapImageRep alloc] initWithData:[picture TIFFRepresentation]];
instead of [[picture representations] objectAtIndex:0] but the result is the same.
I get no error messages or warnings, but I think there is something wrong when i load the picture?
Please help me, what am i doing wrong? And is there a better way to read pixel color data?

Answer 1

Your error is here:
NSImage *picture = [[NSImage alloc] initWithContentsOfFile:#"bais2.tif"];
-------------------------------------------------------------------^^^^
You can use:
NSImage *picture= [NSImage imageNamed:#"bais2.tiff"];
Or :
NSImage *picture = [[NSImage alloc] initWithContentsOfFile:#"bais2.tiff"];

Answer 2

NSData *someNSData = [Image TIFFRepresentation];
NSBitmapImageRep *someNSBitmapImageRepData = [[NSBitmapImageRep alloc] initWithData:someNSData];
NSSize imageSizee = [someNSBitmapImageRepData size];
CGFloat y = imageSize.height - 100.0;
NSColor* color = [someNSBitmapImageRepData colorAtX:100.0 y:y];
NSLog(#"color = %#",color);
output : color = NSCalibratedRGBColorSpace 1 1 1 1