Improvement of gradient navigation bar api

CRGradientNavigationBar/CAGradientLayer+Extension.h

@@ -0,0 +1,15 @@
+//
+//  CAGradientLayer+Extension.h
+//  GradientNavigationBarDemo
+//
+//  Created by Sergey Popov on 30.03.15.
+//  Copyright (c) 2015 Sergey Popov. All rights reserved.
+//
+
+#import <QuartzCore/QuartzCore.h>
+
+@interface CAGradientLayer (Extension)
+
+@property (nonatomic, assign) CGFloat gradientAngle;
+
+@end

CRGradientNavigationBar/CAGradientLayer+Extension.m

@@ -0,0 +1,76 @@
+//
+//  CAGradientLayer+Extension.m
+//  GradientNavigationBarDemo
+//
+//  Created by Sergey Popov on 30.03.15.
+//  Copyright (c) 2015 Sergey Popov. All rights reserved.
+//
+
+#import "CAGradientLayer+Extension.h"
+#import <objc/runtime.h>
+
+#define SWAP(x, y) do { typeof(x) SWAP = x; x = y; y = SWAP; } while (0)
+
+@implementation CAGradientLayer (Extension)
+
+static void *CAGradientLayerGradientAnglePropertyKey;
+
+- (void)setGradientAngle:(CGFloat)gradientAngle
+{
+    gradientAngle = fmod(gradientAngle, 360);
+    if (gradientAngle < 0)
+        gradientAngle += 360;
+
+    CGFloat rad = gradientAngle * M_PI / 180.f;
+
+    CGFloat xa =0, ya=0, xb=0, yb=0;
+
+    for (int n = 0; n < 4; n++)
+    {
+        if ((-M_PI_4+M_PI*n) <= rad && rad < (M_PI_4+M_PI*n))
+        {
+            xa = 0;
+            xb = 1;
+            ya = (1 - tan(rad))/2;
+            yb = 1 - ya;
+
+            if (n % 2) {
+                SWAP(xa, xb);
+                SWAP(ya, yb);
+            }
+
+            break;
+        }
+        else if ((M_PI_4+M_PI*n) <= rad && rad < (M_PI_4*3+M_PI*n))
+        {
+            yb = 1;
+            ya = 0;
+
+            // xb > xa
+            xb = (1/tan(rad) + 1)/2;
+
+            if (n > 0)
+            {
+                // xb<xa
+                xb = (1 - 1/tan(rad))/2;
+                SWAP(ya, yb);
+            }
+
+            xa = 1 - xb;
+
+            break;
+        }
+    }
+
+    self.startPoint = CGPointMake(xa, ya);
+    self.endPoint = CGPointMake(xb, yb);
+
+    objc_setAssociatedObject(self, CAGradientLayerGradientAnglePropertyKey, @(gradientAngle), OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+- (CGFloat)gradientAngle
+{
+    return [objc_getAssociatedObject(self, CAGradientLayerGradientAnglePropertyKey) doubleValue];
+}
+
+@end

CRGradientNavigationBar/CRGradientNavigationBar.h

@@ -10,6 +10,19 @@
 
 @interface CRGradientNavigationBar : UINavigationBar
 
-- (void)setBarTintGradientColors:(NSArray *)barTintGradientColors;
+/*!
+ Opacity of navigation bar. Default is 0.5.
+ */
+@property (nonatomic, assign) CGFloat opacity;
+
+/*!
+ The array of UIColors or CGColors
+ */
+@property (nonatomic, strong) NSArray *barTintGradientColors;
+
+/*!
+ Angle for the gradient. Angle of gradient direction in degrees.
+ */
+@property (nonatomic, assign) CGFloat gradientAngle;
 
 @end

CRGradientNavigationBar/CRGradientNavigationBar.m

@@ -8,6 +8,7 @@
 
 #import "CRGradientNavigationBar.h"
 #import <QuartzCore/QuartzCore.h>
+#import "CAGradientLayer+Extension.h"
 
 @interface CRGradientNavigationBar ()
 
@@ -17,16 +18,42 @@ @interface CRGradientNavigationBar ()
 
 @implementation CRGradientNavigationBar
 
-static CGFloat const kDefaultOpacity = 0.5f;
+- (instancetype)initWithCoder:(NSCoder *)coder
+{
+    self = [super initWithCoder:coder];
+    if (self)
+    {
+        [self performInit];
+    }
+    return self;
+}
 
-- (void)setBarTintGradientColors:(NSArray *)barTintGradientColors
+- (instancetype)initWithFrame:(CGRect)frame
 {
-    // create the gradient layer
-    if (self.gradientLayer == nil) {
-        self.gradientLayer = [CAGradientLayer layer];
-        self.gradientLayer.opacity = self.translucent ? kDefaultOpacity : 1.0f;
+    self = [super initWithFrame:frame];
+    if (self)
+    {
+        [self performInit];
     }
-
+    return self;
+}
+
+#pragma mark - Properties
+
+- (void)setOpacity:(CGFloat)opacity
+{
+    self.gradientLayer.opacity = self.translucent ? opacity : 1.0f;
+    _opacity = opacity;
+}
+
+- (void)setTranslucent:(BOOL)translucent
+{
+    [super setTranslucent:translucent];
+    self.opacity = _opacity;
+}
+
+- (void)setBarTintGradientColors:(NSArray *)barTintGradientColors
+{
     NSMutableArray * colors = nil;
     if (barTintGradientColors != nil)
     {
@@ -35,6 +62,7 @@ - (void)setBarTintGradientColors:(NSArray *)barTintGradientColors
         // determine elements in the array are colours
         // and add them to the colors array
         [barTintGradientColors enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
+
             if ([obj isKindOfClass:[UIColor class]])
             {
                 // UIColor class
@@ -69,6 +97,13 @@ - (void)setBarTintGradientColors:(NSArray *)barTintGradientColors
 
     // set the graident colours to the laery
     self.gradientLayer.colors = colors;
+    _barTintGradientColors = barTintGradientColors;
+}
+
+- (void)setGradientAngle:(CGFloat)gradientAngle
+{
+    self.gradientLayer.gradientAngle = gradientAngle;
+    _gradientAngle = gradientAngle;
 }
 
 #pragma mark - UIView
@@ -97,4 +132,12 @@ - (void)layoutSubviews
     }
 }
 
+#pragma mark - Private
+
+- (void)performInit
+{
+    _gradientLayer = [CAGradientLayer layer];
+    self.opacity = .5f;
+}
+
 @end

GradientNavigationBarDemo/GradientNavigationBarDemo.xcodeproj/project.pbxproj

@@ -22,6 +22,7 @@
 		228F3D761814750100DB93BA /* DemoViewController.m in Sources */ = {isa = PBXBuildFile; fileRef = 228F3D751814750100DB93BA /* DemoViewController.m */; };
 		228F3D7E1814756C00DB93BA /* CRGradientNavigationBar.m in Sources */ = {isa = PBXBuildFile; fileRef = 228F3D7D1814756C00DB93BA /* CRGradientNavigationBar.m */; };
 		22A74011181999FF008F2C92 /* QuartzCore.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 22A74010181999FF008F2C92 /* QuartzCore.framework */; };
+		5203F5D61AC95860001331DB /* CAGradientLayer+Extension.m in Sources */ = {isa = PBXBuildFile; fileRef = 5203F5D51AC95860001331DB /* CAGradientLayer+Extension.m */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -56,6 +57,8 @@
 		228F3D7C1814756C00DB93BA /* CRGradientNavigationBar.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = CRGradientNavigationBar.h; sourceTree = "<group>"; };
 		228F3D7D1814756C00DB93BA /* CRGradientNavigationBar.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = CRGradientNavigationBar.m; sourceTree = "<group>"; };
 		22A74010181999FF008F2C92 /* QuartzCore.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = QuartzCore.framework; path = System/Library/Frameworks/QuartzCore.framework; sourceTree = SDKROOT; };
+		5203F5D41AC95860001331DB /* CAGradientLayer+Extension.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "CAGradientLayer+Extension.h"; sourceTree = "<group>"; };
+		5203F5D51AC95860001331DB /* CAGradientLayer+Extension.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "CAGradientLayer+Extension.m"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -162,6 +165,8 @@
 			children = (
 				228F3D7C1814756C00DB93BA /* CRGradientNavigationBar.h */,
 				228F3D7D1814756C00DB93BA /* CRGradientNavigationBar.m */,
+				5203F5D41AC95860001331DB /* CAGradientLayer+Extension.h */,
+				5203F5D51AC95860001331DB /* CAGradientLayer+Extension.m */,
 			);
 			name = CRGradientNavigationBar;
 			path = ../CRGradientNavigationBar;
@@ -266,6 +271,7 @@
 				228F3D761814750100DB93BA /* DemoViewController.m in Sources */,
 				228F3D56181474AE00DB93BA /* AppDelegate.m in Sources */,
 				228F3D52181474AE00DB93BA /* main.m in Sources */,
+				5203F5D61AC95860001331DB /* CAGradientLayer+Extension.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};

GradientNavigationBarDemo/GradientNavigationBarDemo/AppDelegate.m

@@ -21,14 +21,17 @@ - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(
     [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
 
     UINavigationController *navigationController = [[UINavigationController alloc] initWithNavigationBarClass:[CRGradientNavigationBar class] toolbarClass:nil];
+//    
+//    UIColor *firstColor = [UIColor colorWithRed:255.0f/255.0f green:42.0f/255.0f blue:104.0f/255.0f alpha:1.0f];
+//    UIColor *secondColor = [UIColor colorWithRed:255.0f/255.0f green:90.0f/255.0f blue:58.0f/255.0f alpha:1.0f];
+//    
+//    NSArray *colors = [NSArray arrayWithObjects:(id)firstColor.CGColor, (id)secondColor.CGColor, nil];
+    NSArray *colors = [NSArray arrayWithObjects:(id)UIColorFromRGB(0x0000ff).CGColor, (id)UIColorFromRGB(0xff0000).CGColor, nil];
 
-    UIColor *firstColor = [UIColor colorWithRed:255.0f/255.0f green:42.0f/255.0f blue:104.0f/255.0f alpha:1.0f];
-    UIColor *secondColor = [UIColor colorWithRed:255.0f/255.0f green:90.0f/255.0f blue:58.0f/255.0f alpha:1.0f];
+    [[CRGradientNavigationBar appearance] setBarTintGradientColors:colors];
 
-    NSArray *colors = [NSArray arrayWithObjects:(id)firstColor.CGColor, (id)secondColor.CGColor, nil];
-    //NSArray *colors = [NSArray arrayWithObjects:(id)UIColorFromRGB(0xf16149).CGColor, (id)UIColorFromRGB(0xf14959).CGColor, nil];
+    [[CRGradientNavigationBar appearance] setGradientAngle:30];
 
-    [[CRGradientNavigationBar appearance] setBarTintGradientColors:colors];
     [[navigationController navigationBar] setTranslucent:NO]; // Remember, the default value is YES.
 
     DemoViewController *viewController = [[DemoViewController alloc] init];

GradientNavigationBarDemo/GradientNavigationBarDemo/DemoViewController.m

@@ -7,10 +7,12 @@
 //
 
 #import "DemoViewController.h"
+#import "CRGradientNavigationBar.h"
 
 @interface DemoViewController ()
 
 @property (nonatomic, strong) NSArray *items;
+@property (nonatomic, strong) NSTimer *timer;
 
 @end
 
@@ -46,6 +48,18 @@ - (void)viewDidLoad
 
     self.navigationController.navigationBar.titleTextAttributes = @{NSForegroundColorAttributeName : [UIColor whiteColor]};
 
+
+    self.timer = [NSTimer scheduledTimerWithTimeInterval:0.3 target:self selector:@selector(updateGradient:) userInfo:nil repeats:YES];
+}
+
+- (void)updateGradient:(NSTimer *)timer
+{
+    static double angle = 0.f;
+
+    CRGradientNavigationBar *bar = (CRGradientNavigationBar *)self.navigationController.navigationBar;
+    bar.gradientAngle = angle;
+
+    angle+=3.f;
 }
 
 - (void)didReceiveMemoryWarning

GradientNavigationBarDemo/GradientNavigationBarDemoTests/GradientNavigationBarDemoTests.m

@@ -31,4 +31,79 @@ - (void)testExample
     XCTFail(@"No implementation for \"%s\"", __PRETTY_FUNCTION__);
 }
 
+#define degreesToRadians(angleDegrees) (angleDegrees * M_PI / 180.0)
+#define radiansToDegrees(angleRadians) (angleRadians * 180.0 / M_PI)
+#define SWAP(x, y) do { typeof(x) SWAP = x; x = y; y = SWAP; } while (0)
+
+- (void)testNormalizeAngle
+{
+
+    for (int i = 0; i < 720; i = i + 5)
+    {
+        [self printCoordinates:i];
+    }
+
+
+}
+
+- (void)printCoordinates:(double)angle
+{
+
+    angle = constrainAngle(angle);
+
+    double rad = degreesToRadians(angle);
+
+    double xa, ya, xb, yb;
+
+    for (int N = 0; N < 2; N++)
+    {
+        if ((-M_PI_4+M_PI*N) <= rad && rad < (M_PI_4+M_PI*N))
+        {
+            xa = 0;
+            xb = 1;
+            ya = (1 - tan(rad))/2;
+            yb = 1 - ya;
+
+            if (N > 0) {
+                SWAP(xa, xb);
+                SWAP(ya, yb);
+            }
+
+            NSLog(@"First condition %d, (%f, %f) (%f, %f)", (int)angle, xa, ya, xb, yb);
+
+            break;
+        }
+        else if ((M_PI_4+M_PI*N) <= rad && rad < (M_PI_4*3+M_PI*N))
+        {
+            yb = 1;
+            ya = 0;
+
+            // xb > xa
+            xb = (1/tan(rad) + 1)/2;
+
+            if (N > 0)
+            {
+                // xb<xa
+                xb = (1 - 1/tan(rad))/2;
+                SWAP(ya, yb);
+            }
+
+            xa = 1 - xb;
+
+            NSLog(@"Second condition %d, (%f, %f) (%f, %f)", (int)angle, xa, ya, xb, yb);
+
+            break;
+        }
+    }
+
+}
+
+
+double constrainAngle(double x) {
+    x = fmod(x, 360);
+    if (x < 0)
+        x += 360;
+    return x;
+}
+
 @end