/*

     File: QuartzBlendingViewController.m

 Abstract: A UIViewController subclass that manages a QuartzBlendingView and a UI to allow for the selection of foreground color, background color and blending mode to demonstrate.

  Version: 3.0

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 */

#import "QuartzBlendingViewController.h"

#import "QuartzBlending.h"

/*

 These strings represent the actual blend mode constants that are passed to CGContextSetBlendMode and so should not be localized in the context of this sample.

 */

static NSString *blendModes[] = {

    // PDF Blend Modes.

    @"Normal",

    @"Multiply",

    @"Screen",

    @"Overlay",

    @"Darken",

    @"Lighten",

    @"ColorDodge",

    @"ColorBurn",

    @"SoftLight",

    @"HardLight",

    @"Difference",

    @"Exclusion",

    @"Hue",

    @"Saturation",

    @"Color",

    @"Luminosity",

    // Porter-Duff Blend Modes.

    @"Clear",

    @"Copy",

    @"SourceIn",

    @"SourceOut",

    @"SourceAtop",

    @"DestinationOver",

    @"DestinationIn",

    @"DestinationOut",

    @"DestinationAtop",

    @"XOR",

    @"PlusDarker",

    @"PlusLighter",

    // If Quartz provides more blend modes in the future, add them here.

};

static NSInteger blendModeCount = sizeof(blendModes) / sizeof(blendModes[0]);

// Calculate the luminance for an arbitrary UIColor instance

CGFloat luminanceForColor(UIColor *color)

{

    CGColorRef cgColor = color.CGColor;

    const CGFloat *components = CGColorGetComponents(cgColor);

    CGFloat luminance = 0.0;

    switch(CGColorSpaceGetModel(CGColorGetColorSpace(cgColor)))

    {

        case kCGColorSpaceModelMonochrome:

            // For grayscale colors, the luminance is the color value

            luminance = components[0];

            break;

        case kCGColorSpaceModelRGB:

            /*

             For RGB colors, we calculate luminance assuming sRGB Primaries as per http://en.wikipedia.org/wiki/Luminance_(relative).

            */

            luminance = 0.2126 * components[0] + 0.7152 * components[1] + 0.0722 * components[2];

            break;

        default:

            /*

             We don't implement support for non-gray, non-rgb colors at this time. Because our only consumer is colorSortByLuminance, we return a larger than normal value to ensure that these types of colors are sorted to the end of the list.

             */

            luminance = 2.0;

    }

    return luminance;

}

@interface QuartzBlendingViewController()

@property (nonatomic, weak) IBOutlet QuartzBlendingView *quartzBlendingView;

@property (nonatomic, weak) IBOutlet UIPickerView *picker;

@property (nonatomic, readonly) NSArray *colors;

@end

@implementation QuartzBlendingViewController

-(void)viewDidLoad

{

    [super viewDidLoad];

    // Setup the view's and picker's default components.

    QuartzBlendingView *qbv = self.quartzBlendingView;

    qbv.sourceColor = [UIColor whiteColor];

    qbv.destinationColor = [UIColor blackColor];

    qbv.blendMode = kCGBlendModeNormal;

    [self.picker selectRow:[self.colors indexOfObject:qbv.destinationColor] inComponent:0 animated:NO];

    [self.picker selectRow:[self.colors indexOfObject:qbv.sourceColor] inComponent:1 animated:NO];

    [self.picker selectRow:qbv.blendMode inComponent:2 animated:NO];

}

- (NSArray*)colors

{

    static NSArray *colorArray = nil;

    if (colorArray == nil)

    {

        /*

         If you want to add more colors, do so here. You can also add patterns, they will simply be sorted to the end of the list.

         */

        NSArray *unsortedArray = @[[UIColor redColor], [UIColor greenColor], [UIColor blueColor], [UIColor yellowColor], [UIColor magentaColor], [UIColor cyanColor], [UIColor orangeColor], [UIColor purpleColor], [UIColor brownColor], [UIColor whiteColor], [UIColor lightGrayColor], [UIColor darkGrayColor], [UIColor blackColor]];

        colorArray = [unsortedArray sortedArrayUsingComparator:^NSComparisonResult(id color1, id color2) {

            // Sort two colors by luminance.

            CGFloat luminance1 = luminanceForColor(color1);

            CGFloat luminance2 = luminanceForColor(color2);

            if (luminance1 == luminance2)

            {

                return NSOrderedSame;

            }

            else if (luminance1 < luminance2)

            {

                return NSOrderedAscending;

            }

            else

            {

                return NSOrderedDescending;

            }

        }];

    }

    return colorArray;

}

#pragma mark UIPickerViewDelegate & UIPickerViewDataSource methods

-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView

{

    return 3;

}

-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component

{

    if (component == 2) {

        return blendModeCount;

    }

    return [self.colors count];

}

-(CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component

{

    if (component == 2) {

        return 200.0;

    }

    return 40.0;

}

#define kColorTag 1

#define kLabelTag 2

/*

 Return an attributes string that shows the color or the name of the blend mode as appropriate.

 */

- (NSAttributedString *)pickerView:(UIPickerView *)pickerView attributedTitleForRow:(NSInteger)row forComponent:(NSInteger)component

{

    if (component == 2) {

        return [[NSAttributedString alloc] initWithString:blendModes[row]];

    }

    static NSString *squareString = nil;

    if (squareString == nil) {

        // This is a Unicode character for a simple square block.

        unichar squareCharacter = 0x2588;

        squareString = [[NSString alloc] initWithFormat:@"%C", squareCharacter];

    }

    NSDictionary *attributes = @{ NSForegroundColorAttributeName : self.colors[row], NSBackgroundColorAttributeName : [UIColor lightGrayColor] };

    NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString:squareString attributes:attributes];

    return attributedString;

}

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component

{

    QuartzBlendingView *qbv = (QuartzBlendingView*)self.quartzBlendingView;

    qbv.destinationColor = (self.colors)[[self.picker selectedRowInComponent:0]];

    qbv.sourceColor = (self.colors)[[self.picker selectedRowInComponent:1]];

    qbv.blendMode = [self.picker selectedRowInComponent:2];

}

@end