/*

Copyright (C) 2015 Apple Inc. All Rights Reserved.

See LICENSE.txt for this sample’s licensing information

Abstract:

A CAShapeLayer backed view to display the current score

*/

#import "ScoreView.h"

@import QuartzCore;

// We use a subclass of CAShapeLayer so that the path will animate when changed.

// Because UIView only allows certain animation keys to animate, we can't do this via

// the other means usually reserved for doing this, such as the layer's actions dictionary

// or the delegate's -actionForLayer:forKey: method.

@interface MyCAShapeLayer : CAShapeLayer

@end

@implementation MyCAShapeLayer

- (id<CAAction>)actionForKey:(NSString *)key {

    if ([key isEqualToString:@"path"]) {

        return [CABasicAnimation animationWithKeyPath:@"path"];

    }

    else {

        return [super actionForKey:key];

    }

}

@end

@interface ScoreView ()

@property (weak, nonatomic, readonly) CAShapeLayer *shapeLayer;

@end

@implementation ScoreView

    CGGradientRef top;

    CGGradientRef left;

    CGGradientRef bottom;

    CGGradientRef right;

+ (Class)layerClass {

    return [MyCAShapeLayer class];

}

CGGradientRef CreateWhiteToColorGradient(CGFloat r, CGFloat g, CGFloat b) {

    CGFloat colors[] = {

        1.0, 1.0, 1.0, 1.0,

        r, g, b, 1.0,

    };

    CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB();

    CGGradientRef gradient = CGGradientCreateWithColorComponents(rgb, colors, NULL, 2);

    CGColorSpaceRelease(rgb);

    return gradient;

}

- (void)commonInit {

    CAShapeLayer *shapeLayer = self.shapeLayer;

    shapeLayer.lineWidth = 3.0;

    shapeLayer.fillRule = kCAFillRuleEvenOdd;

    top = CreateWhiteToColorGradient(1.0, 0.0, 0.0);

    left = CreateWhiteToColorGradient(0.0, 0.0, 1.0);

    bottom = CreateWhiteToColorGradient(0.0, 1.0, 0.0);

    right = CreateWhiteToColorGradient(1.0, 0.625, 0.0);

}

- (instancetype)initWithFrame:(CGRect)frame {

    self = [super initWithFrame:frame];

    if (self != nil) {

        [self commonInit];

    }

    return self;

}

- (instancetype)initWithCoder:(NSCoder *)aDecoder {

    self = [super initWithCoder:aDecoder];

    if (self != nil) {

        [self commonInit];

    }

    return self;

}

- (void)drawRect:(CGRect)rect {

    CGContextRef context = UIGraphicsGetCurrentContext();

    // First convert the coordinate system to a unit system.

    // This allows the radial gradients to be ovals if the view is not square.

    // Center will be 0,0, coordinates will be ±1

    CGRect bounds = self.bounds;

    CGContextTranslateCTM(context, bounds.size.width / 2.0, bounds.size.height / 2.0);

    CGContextScaleCTM(context, bounds.size.width / 2.0, bounds.size.height / 2.0);

    // Top

    CGContextSaveGState(context);

    CGContextMoveToPoint(context, 0.0, 0.0);

    CGContextAddLineToPoint(context, -1.0, -1.0);

    CGContextAddLineToPoint(context, 1.0, -1.0);

    CGContextClip(context);

    CGContextDrawRadialGradient(context, top, CGPointZero, 0.0, CGPointZero, 1.0, kCGGradientDrawsBeforeStartLocation);

    CGContextRestoreGState(context);

    // Left

    CGContextSaveGState(context);

    CGContextMoveToPoint(context, 0.0, 0.0);

    CGContextAddLineToPoint(context, -1.0, -1.0);

    CGContextAddLineToPoint(context, -1.0, 1.0);

    CGContextClip(context);

    CGContextDrawRadialGradient(context, left, CGPointZero, 0.0, CGPointZero, 1.0, kCGGradientDrawsBeforeStartLocation);

    CGContextRestoreGState(context);

    // Bottom

    CGContextSaveGState(context);

    CGContextMoveToPoint(context, 0.0, 0.0);

    CGContextAddLineToPoint(context, -1.0, 1.0);

    CGContextAddLineToPoint(context, 1.0, 1.0);

    CGContextClip(context);

    CGContextDrawRadialGradient(context, bottom, CGPointZero, 0.0, CGPointZero, 1.0, kCGGradientDrawsBeforeStartLocation);

    CGContextRestoreGState(context);

    // Left

    CGContextSaveGState(context);

    CGContextMoveToPoint(context, 0.0, 0.0);

    CGContextAddLineToPoint(context, 1.0, -1.0);

    CGContextAddLineToPoint(context, 1.0, 1.0);

    CGContextClip(context);

    CGContextDrawRadialGradient(context, right, CGPointZero, 0.0, CGPointZero, 1.0, kCGGradientDrawsBeforeStartLocation);

    CGContextRestoreGState(context);

}

- (void)dealloc {

    CGGradientRelease(top);

    CGGradientRelease(left);

    CGGradientRelease(bottom);

    CGGradientRelease(right);

}

- (CAShapeLayer *)shapeLayer {

    return (CAShapeLayer *)self.layer;

}

- (UIBezierPath *)shape {

    return [UIBezierPath bezierPathWithCGPath:self.shapeLayer.path];

}

- (void)setShape:(UIBezierPath *)shape {

    self.shapeLayer.path = shape.CGPath;

}

- (UIColor *)fillColor {

    return [UIColor colorWithCGColor:self.shapeLayer.fillColor];

}

- (void)setFillColor:(UIColor *)fillColor {

    self.shapeLayer.fillColor = fillColor.CGColor;

}

- (UIColor *)strokeColor {

    return [UIColor colorWithCGColor:self.shapeLayer.strokeColor];

}

- (void)setStrokeColor:(UIColor *)strokeColor; {

    self.shapeLayer.strokeColor = strokeColor.CGColor;

}

@end