LBGradientButton

LBGradientButton.h

//
//  TBRButton.h
//  TBR
//
//  Created by andrei tchijov on 2/7/11.
//  Copyright 2011 Leaping Bytes, LLC. All rights reserved.
//

#import <Foundation/Foundation.h>


@interface LBGradientButton : UIButton {
    UIButtonType        tbrButtonType;

    NSMutableDictionary*    tintForState;
@private
    
}
@property(nonatomic, assign) UIButtonType           tbrButtonType;
@property(nonatomic, retain) NSMutableDictionary*   tintForState;
@property(nonatomic, assign, setter = setInvertIcon: ) BOOL                   invertIcon;

+(LBGradientButton*) buttonWithType: (UIButtonType) type;

+ (void) enumerateAllGradientButtonsInside: (UIView*) aView usingBlock: (void (^)( LBGradientButton* aButton )) aBlock;

-(void) setTint: (UIColor*) tintColor forState: (UIControlState) state;
@end

LBGradientButton.m

//
//  TBRButton.m
//  TBR
//
//  Created by andrei tchijov on 2/7/11.
//  Copyright 2011 Leaping Bytes, LLC. All rights reserved.
//

#import <QuartzCore/QuartzCore.h>
#import "LBGradientButton.h"
#import "UIImage+LBToolbox.h"

float scaleColorComponent( float value, float factor );

float scaleColorComponent( float value, float factor ) {
    return value + ( 1 - value ) * factor;
}

@implementation LBGradientButton

@synthesize tbrButtonType, tintForState;
@synthesize invertIcon=_invertIcon;

static float r = 8.0;

+(LBGradientButton*) buttonWithType: (UIButtonType) type {
    LBGradientButton* result = [[ LBGradientButton alloc ] initWithFrame: CGRectMake( 0.0, 0.0, 10.0, 10.0 )];    
    result.tbrButtonType = type;
    
    return result;
}

+ (void) enumerateAllGradientButtonsInside: (UIView*) aView usingBlock: (void (^)( LBGradientButton* aButton )) aBlock {
    for ( UIView* aSubView in aView.subviews ) {
        if([ aSubView isKindOfClass: [ LBGradientButton class ]] ) {
            aBlock( (LBGradientButton*)aSubView );
        } else {
            [ LBGradientButton enumerateAllGradientButtonsInside: aSubView usingBlock: aBlock ];
        }
    }
}

-(void) setTint: (UIColor*) tintColor forState: (UIControlState) state {
    if( self.tintForState == nil ) {
        self.tintForState = [ NSMutableDictionary dictionary ];
    }
    
    [ self.tintForState setObject: tintColor forKey: [ NSNumber numberWithInt: state ]];
}

- (void) setup {
    [ self.layer setMasksToBounds: YES ];
    [ self.layer setCornerRadius: r ];
}

- (void) setInvertIcon:(BOOL)invertIcon {
    _invertIcon = invertIcon;
    if( invertIcon ) {
        UIImage* image = [ self.imageView.image invertImage ];
        [ self setImage: image forState: UIControlStateNormal ];
        [ self setImage: image forState: UIControlStateSelected ];
        [ self setNeedsDisplay ];
    }    
}

- (id) initWithCoder:(NSCoder *)aDecoder {
    self = [ super initWithCoder: aDecoder ];
    
    [ self setup ];
    
    return self;
}

- (id) initWithFrame:(CGRect)frame {
    self = [ super initWithFrame: frame ];
    
    [ self setup ];
    
    return self;
}

#define   DEGREES_TO_RADIANS(degrees)  (( M_PI * degrees)/ 180)

- (UIColor*) tintColor {
    UIColor* result = [ self.tintForState objectForKey: [ NSNumber numberWithInt: self.state ]];
    
    if( result == nil ) {
        [ self.tintForState objectForKey: [ NSNumber numberWithInt: UIControlStateNormal ]];
    }
    
    result = result == nil ? [ UIColor colorWithRed: 1.0 green: 1.0 blue: 1.0 alpha: 1.0 ] : result;
    
    return result;
}

- (void) drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx {
    
    UIBezierPath* path = [ UIBezierPath bezierPath ];
    
    CGRect f = self.frame;
    
    int d = 0;
    
    f = CGRectInset( f, d, d );
    
    float w = f.size.width;
    float h = f.size.height;
    
    [ path moveToPoint: CGPointMake( d + r, d ) ];
    [ path addLineToPoint: CGPointMake( w - r - d, d )];
    [ path addArcWithCenter: CGPointMake( w - r - d , r + d ) radius: r startAngle: DEGREES_TO_RADIANS( 270 ) endAngle: 0.0 clockwise: YES ];
    [ path addLineToPoint: CGPointMake( w - d, h - r - d )];
    [ path addArcWithCenter: CGPointMake( w - r - d , h - r - d ) radius: r startAngle: 0.0 endAngle: DEGREES_TO_RADIANS( 90 ) clockwise: YES ];
    [ path addLineToPoint: CGPointMake( r + d, h - d )];
    [ path addArcWithCenter: CGPointMake( r + d , h - r - d ) radius: r startAngle: DEGREES_TO_RADIANS( 90 ) endAngle: DEGREES_TO_RADIANS( 180 ) clockwise: YES ];
    [ path addLineToPoint: CGPointMake( d, r + d  )];
    [ path addArcWithCenter: CGPointMake( r + d , r + d ) radius: r startAngle: DEGREES_TO_RADIANS( 180 ) endAngle: DEGREES_TO_RADIANS( 270 ) clockwise: YES ];
        
    CGContextSaveGState( ctx );
    
    CGColorSpaceRef bgColorspace = CGColorSpaceCreateDeviceRGB();
    
    CGFloat locations[3] = {0.0, 0.5, 0.5 };
    UIColor* tintColor = [ self tintColor ];
    const CGFloat* tintComponents = CGColorGetComponents( tintColor.CGColor );
    
    float b1 = 0.5;
    float b2 = 0.3;
    
    UIColor* bgColor1 = [ UIColor 
        colorWithRed: scaleColorComponent( tintComponents[0], b1 ) 
               green: scaleColorComponent( tintComponents[1], b1 )  
                blue: scaleColorComponent( tintComponents[2], b1 )  
               alpha: 1.0 
    ];
    
    UIColor* bgColor2 = [ UIColor 
        colorWithRed: scaleColorComponent( tintComponents[0], b2 ) 
               green: scaleColorComponent( tintComponents[1], b2 )  
                blue: scaleColorComponent( tintComponents[2], b2 )  
               alpha: 1.0 
    ];

    CGGradientRef bgGradient = CGGradientCreateWithColors( 
        bgColorspace, 
        (__bridge CFArrayRef)[ NSArray arrayWithObjects: (id)bgColor1.CGColor, (id)bgColor2.CGColor, tintColor.CGColor, nil ], 
        locations 
    );
    
    CGColorSpaceRelease( bgColorspace );
    
    CGContextDrawLinearGradient( ctx, bgGradient, CGPointMake( 0.0, 0.0 ), CGPointMake( 0.0, f.size.height ), kCGGradientDrawsBeforeStartLocation| kCGGradientDrawsAfterEndLocation );
    
    CGGradientRelease( bgGradient );
    
    CGContextRestoreGState( ctx );
    
    CGContextSetLineWidth( ctx, 2.0 );
    CGContextSetStrokeColorWithColor( ctx, [ UIColor colorWithWhite: ( _invertIcon ? 0.8 : 0.624 ) alpha: 1.0 ].CGColor );
    CGContextAddPath( ctx, path.CGPath );
    CGContextStrokePath( ctx );
}

- (void) drawRect:(CGRect)rect {
//    [ super drawRect: rect ];    
}

@end

LBGradientButtonExample.m

//
// To tint one button
//
LBGradientButton* aButton;

UIColor* tintColor = [ UIColor blueColor ];

[ aButton setTint: tintColor forState: UIControlStateNormal ];

//
// To tint all buttons under some view
//

[ LBGradientButton enumerateAllGradientButtonsInside: self.view usingBlock:^(LBGradientButton* aButton) {
      [ aButton setTint: tintColor forState: UIControlStateNormal ];
      [ aButton setTint: tintColor forState: UIControlStateSelected ];
      [ aButton setTint: tintColor forState: UIControlStateHighlighted ];
}];