NSView in cocoa refuses to redraw, whatever I try - xcode

Question

I'm writing an application on mac to measure colors on screen. For that I have a ColorView that fills a bezierpath with a specific color. When measuring it goes well for most of the patches, but at a given moment the redraw staggers and the view does not get updated anymore. I have been looking for a while now, tried many proposed solutions. None of them are waterproof.
My actual code:
[colorView setColor:[colorsForMeasuring objectAtIndex:index]];
[colorView setNeedsDisplay:YES];
[colorView setNeedsLayout:YES];
dispatch_queue_t mainQueue = dispatch_get_main_queue();
dispatch_async(mainQueue,^{
[colorView setNeedsDisplay:YES];
[colorView setNeedsLayout:YES];
[colorView updateLayer];
[colorView displayIfNeeded];
[colorView display];
});
[[NSRunLoop currentRunLoop] runUntilDate:[NSDate dateWithTimeIntervalSinceNow:1]];
[NSApp runModalSession:aSession];
The drawcode of my colorView is as follows:
- (void)display
{
CALayer *layer = self.layer;
[layer setNeedsDisplay];
[layer displayIfNeeded];
}
- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)context
{
[self internalDrawWithRect:self.bounds];
}
- (void)internalDrawWithRect:(CGRect)rect
{
NSRect bounds = [self bounds];
[color set];
[NSBezierPath fillRect:bounds];
}
- (void)drawRect:(CGRect)rect {
[self internalDrawWithRect:rect];
}
Any help would be very welcome! My original code was much simpler, but I kept on adding things that might have helped.

Answer 1

As I said, the original code was rather straightfoward and simple:
The measuring loop:
for ( uint32 index = 0; index < numberOfColors && !stopMeasuring; index++ )
{
#ifndef NDEBUG
NSLog( #"Color on screen:%#", [colorsForMeasuring objectAtIndex:index] );
#endif
[colorView setColor:[colorsForMeasuring objectAtIndex:index]];
[colorView setNeedsDisplay:YES];
[colorView displayIfNeeded];
// Measure the displayed color in XYZ values
CGFloat myRed, myGreen, myBlue, myAlpha;
[[colorsForMeasuring objectAtIndex:index] getRed:&myRed green:&myGreen blue:&myBlue alpha:&myAlpha];
float theR = (float) myRed;
float theG = (float) myGreen;
float theB = (float) myBlue;
xyzData = [measDeviceController measureOnceXYZforRed:255.0f*theR Green:255.0f*theG Blue:255.0f*theB];
if ( [xyzData count] > 0 )
{
measuringResults[index*3] = [[xyzData objectAtIndex:0] floatValue];
measuringResults[(index*3) + 1] = [[xyzData objectAtIndex:1] floatValue];
measuringResults[(index*3) + 2] = [[xyzData objectAtIndex:2] floatValue];
#ifndef NDEBUG
printf("Measured value X=%f, Y=%f, Z=%f\n", measuringResults[index*3], measuringResults[(index*3) + 1], measuringResults[(index*3) + 2]);
#endif
} }
The drawing of the MCTD_ColorView which just is inherited from NSView:
- (void)setColor:(NSColor *)aColor;
{
[aColor retain];
[color release];
color = aColor;
}
- (void)drawRect:(NSRect)rect
{
NSRect bounds = [self bounds];
[color set];
[NSBezierPath fillRect:bounds];
}
- (void)dealloc
{
[color release];
[super dealloc];
}
When running my measurement loop and after putting breakpoints in "setColor" and "drawRect", debugging always stops in setColor but never in drawRect. Without debugging, the view remains white while I should see all different colors appearing.
As can be seen in my first post, I have tried many things to get it drawing, but they all failed.