MBStronglyTintedNavigationBar.h

//
//  MBStronglyTintedNavigationBar.h
//
//  Created by Matej Bukovinski on 21. 10. 13.
//  Copyright (c) 2013 Matej Bukovinski. All rights reserved.
//

#import <UIKit/UIKit.h>


@interface MBStronglyTintedNavigationBar : UINavigationBar

@end

MBStronglyTintedNavigationBar.m

//
//  MBStronglyTintedNavigationBar.m
//
//  Created by Matej Bukovinski on 21. 10. 13.
//  Copyright (c) 2013 Matej Bukovinski. All rights reserved.
//

#import "MBStronglyTintedNavigationBar.h"


#define IS_WIDESCREEN_PHONE UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone && [UIScreen mainScreen].bounds.size.height > 480.f
#define IS_IOS703_OR_NEWER [[[UIDevice currentDevice] systemVersion] compare:@"7.0.3" options:NSNumericSearch] != NSOrderedAscending


static CGFloat const kSpaceToCoverStatusBars = 20.f;
static CGFloat const kSatIncrease = 13.f;


@interface MBStronglyTintedNavigationBar ()

@property (nonatomic, strong) CALayer *colorLayer;

@end


@implementation MBStronglyTintedNavigationBar

#pragma mark - Tint color

- (void)setBarTintColor:(UIColor *)barTintColor {
	// No translucency, no problems
	if (!self.translucent) {
		return [super setBarTintColor:barTintColor];;
	}
	
	BOOL supportsBlurOnMap = IS_WIDESCREEN_PHONE;
	BOOL updatedTintRenderingAvailable = IS_IOS703_OR_NEWER;
	
	// Increase the bar tint color saturation, to com pensate for the desaturation the bar applies
	// (in all cases, except when using a solid overlay layer)
	if (supportsBlurOnMap || updatedTintRenderingAvailable) {
		barTintColor = [self colorByIncreasingSaturationFromColor:barTintColor];
	}
	
	if (supportsBlurOnMap && updatedTintRenderingAvailable) {
		// Newer devices with iOS 7.0.3+ remove blur almost completeley,
		// so we decrease the color opacity of the nativ background
		[super setBarTintColor:[barTintColor colorWithAlphaComponent:0.5]];
	} else if (!supportsBlurOnMap) {
		// Old devices will have problems rendering the bar background when a map view
		// is involved, so we rather set a translucent background
		[super setBarTintColor:[UIColor clearColor]];
	} else {
		[super setBarTintColor:barTintColor];
	}
	
	// Otherwise we add a new layer on top of the navigation bar background
    if (self.colorLayer == nil) {
        self.colorLayer = [CALayer layer];
		if (supportsBlurOnMap) {
			// New device, pre iOS 7.0.3 - adding an additonal layer to improve the color saturation
			// and tone down the heavy translucent blur effect
			self.colorLayer.opacity = 0.7f;
		} else {
			if (updatedTintRenderingAvailable) {
				// Old device, iOS 7.0.3 - this case exhibits animation glitches during view controller transitions,
				// so we previously set the bar background to a transpaent color and we use a slightly translucent colored layer
				self.colorLayer.opacity = 0.95f;
			} else {
				// Old device, pre iOS 7.0.3 - the bar background will always be black translcucent,
				// so we need to cover the system bar background with a non-translucent layer
				self.colorLayer.opacity = 1.f;
				// Use the normal color here instrad of the saturated version
				barTintColor = [VBAppearanceManager highlightColor];
			}
		}
		
        [self.layer addSublayer:self.colorLayer];
    }
    
    self.colorLayer.backgroundColor = barTintColor.CGColor;
}

- (UIColor *)colorByIncreasingSaturationFromColor:(UIColor *)color {
	CGFloat h, s, b, a;
	BOOL ok = [color getHue:&h saturation:&s brightness:&b alpha:&a];
	if (!ok) {
		return color;
	}
	s = MIN(s + kSatIncrease, 1.f);
	return [UIColor colorWithHue:h saturation:s brightness:b alpha:a];
}

#pragma mark - Layout

- (void)layoutSubviews {
    [super layoutSubviews];
	
    if (self.colorLayer != nil) {
		CGRect bounds = self.bounds;
		CGFloat w = CGRectGetWidth(bounds);
		CGFloat topExtend = self.barPosition == UIBarPositionTopAttached ? kSpaceToCoverStatusBar : 0.f;
		CGFloat h = CGRectGetHeight(bounds) + topExtend;
        self.colorLayer.frame = CGRectMake(0.f, -topExtend, w, h);
        [self.layer insertSublayer:self.colorLayer atIndex:1];
    }
}

@end