OEProgressIndicator.h

//
//  OEProgressIndicator.h
//  Seene
//
//  Copyright (c) 2014 Obvious Engine. All rights reserved.
//

#import <UIKit/UIKit.h>

IB_DESIGNABLE

@interface OEProgressIndicator : UIView

- (void)startAnimating;
- (void)stopAnimating;

- (void)showProgress:(CGFloat)progress;

@end

OEProgressIndicator.m

//
//  OEProgressIndicator.m
//  Seene
//
//  Copyright (c) 2014 Obvious Engine. All rights reserved.
//

#import "OEProgressIndicator.h"
#import "OETheme.h"


const CGFloat OEProgressIndicatorRingThickness = 1.8;

@interface OEProgressIndicator ()

@property (nonatomic, strong) CAShapeLayer *ringLayer;
@property (nonatomic, strong) CAShapeLayer *backgroundRingLayer;

@property (nonatomic) CGFloat ringRadius;
@property (strong, nonatomic) UIColor *ringForegroundColor;
@property (strong, nonatomic) UIColor *ringBackgroundColor;

@property (nonatomic, getter = isAnimating) BOOL animating;

@end


@implementation OEProgressIndicator

- (instancetype)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (!self) { return nil; }
    
    [self commonProgressIndicatorInit];

    return self;
}

- (instancetype)initWithCoder:(NSCoder *)aDecoder
{
    self = [super initWithCoder:aDecoder];
    if (!self) { return nil; }
    
    [self commonProgressIndicatorInit];
    
    return self;
}

- (void)commonProgressIndicatorInit
{
//    self.layer.borderWidth = 0.5;
//    self.layer.borderColor = [UIColor whiteColor].CGColor;
    
    self.backgroundColor = [UIColor clearColor];
    
    self.ringRadius = CGRectGetWidth(self.frame)/2
        - ceil(OEProgressIndicatorRingThickness/2)
    ;
    
    self.ringForegroundColor = [[OETheme defaultTheme] colorForKey:@"feed.progressIndicator.tintColor"];
    self.ringBackgroundColor = [UIColor colorWithWhite:1 alpha:0.25];
    
    CGPoint center = CGPointMake(CGRectGetWidth(self.bounds)/2,
                                 CGRectGetHeight(self.bounds)/2);
    self.ringLayer = [self createRingLayerWithCenter:center
                                              radius:self.ringRadius
                                           lineWidth:OEProgressIndicatorRingThickness
                                               color:self.ringForegroundColor];
    self.ringLayer.anchorPoint = CGPointMake(0.5, 0.5);
    [self.layer addSublayer:self.ringLayer];
    
    self.backgroundRingLayer = [self createRingLayerWithCenter:center
                                                        radius:self.ringRadius
                                                     lineWidth:OEProgressIndicatorRingThickness
                                                         color:self.ringBackgroundColor];
    self.backgroundRingLayer.strokeEnd = 1;
    [self.layer addSublayer:self.backgroundRingLayer];
    
    [self startAnimating];
}

- (void)startAnimating
{
    if (!self.isAnimating)
    {
        self.animating = YES;
        self.hidden = NO;
        
        [self cancelRingLayerAnimation];
        
        self.ringLayer.strokeEnd = 15.0/360.f;
        
        [self runSpinAnimationWithDuration:0.35];
        
        self.alpha = 0;
        [UIView animateWithDuration:0.65
                         animations:^{
                             self.alpha = 1;
                         }];
    }
}

- (void)stopAnimating
{
    [self cancelRingLayerAnimation];
    self.animating = NO;
    self.hidden = YES;
}

- (void)showProgress:(CGFloat)progress
{
    self.hidden = NO;
    
    if (self.isAnimating)
    {
        [self stopAnimating];
    }
    
    if (progress < 0) progress = 0.f;
    
    self.ringLayer.strokeEnd = progress;
}

- (void)runSpinAnimationWithDuration:(CGFloat)duration;
{
    CABasicAnimation* rotationAnimation;
    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.toValue = [NSNumber numberWithFloat: M_PI * 2.0 /* full rotation*/ * duration];
    rotationAnimation.duration = duration;
    rotationAnimation.cumulative = YES;
    rotationAnimation.repeatCount = HUGE_VALF;
    
    [self.ringLayer addAnimation:rotationAnimation forKey:@"rotationAnimation"];
}

// None of these drawRect: approaches work with Xcode 6's IB_DESIGNABLE
//- (void)drawRect:(CGRect)rect
//{
//    CGContextRef currentContext = UIGraphicsGetCurrentContext();
//    
//    // DLog(@"%@ %@", NSStringFromCGRect(self.ringLayer.frame), NSStringFromCGRect(self.backgroundRingLayer.frame) );
//    
//    CGContextTranslateCTM(currentContext, self.ringLayer.frame.origin.x, self.ringLayer.frame.origin.y);
//    [self.ringLayer renderInContext:currentContext];
//    CGContextTranslateCTM(currentContext, -self.ringLayer.frame.origin.x, -self.ringLayer.frame.origin.y);
//    
//    CGContextTranslateCTM(currentContext, self.backgroundRingLayer.frame.origin.x, self.backgroundRingLayer.frame.origin.y);
//    [self.backgroundRingLayer renderInContext:currentContext];
//    CGContextTranslateCTM(currentContext, -self.backgroundRingLayer.frame.origin.x, -self.backgroundRingLayer.frame.origin.y);
//    
////    CGRect myFrame = self.bounds;
////    CGContextSetLineWidth(currentContext, 10);
////    CGRectInset(myFrame, 5, 5);
////    [[UIColor greenColor] set];
////    UIRectFrame(myFrame);
//}

//- (void)drawRect:(CGRect)rect
//{
//    CGContextRef currentContext = NULL;
//    UIGraphicsBeginImageContext(self.bounds.size);
//    currentContext = UIGraphicsGetCurrentContext();
//    CGContextTranslateCTM(currentContext, self.ringLayer.frame.origin.x, self.ringLayer.frame.origin.y);
//    [self.ringLayer renderInContext:currentContext];
//    CGContextTranslateCTM(currentContext, -self.ringLayer.frame.origin.x, -self.ringLayer.frame.origin.y);
//    CGContextTranslateCTM(currentContext, self.backgroundRingLayer.frame.origin.x, self.backgroundRingLayer.frame.origin.y);
//    [self.backgroundRingLayer renderInContext:currentContext];
//    CGContextTranslateCTM(currentContext, -self.backgroundRingLayer.frame.origin.x, -self.backgroundRingLayer.frame.origin.y);
//    
//    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
//    UIGraphicsEndImageContext();
//    
//    //    NSString* pathToCreate = [NSTemporaryDirectory() stringByAppendingString:@"test.png"];
//    //    NSData *imageData = [NSData dataWithData:UIImagePNGRepresentation(image)];
//    //    [imageData writeToFile:pathToCreate atomically:YES];
//    
//    //    currentContext = UIGraphicsGetCurrentContext();
//    //    CGContextDrawImage(currentContext, self.bounds, image.CGImage);
//    [image drawInRect:self.bounds];
//}

#pragma mark - Ring progress animation

- (void)cancelRingLayerAnimation
{
    [CATransaction begin];
    [CATransaction setDisableActions:YES];
    [self.ringLayer removeAllAnimations];
    
    _ringLayer.strokeEnd = 0.0f;
    self.layer.transform = CATransform3DRotate(self.layer.transform, 0, 0, 0, 1.f);
    
    [CATransaction commit];
}

- (CAShapeLayer *)createRingLayerWithCenter:(CGPoint)center
                                     radius:(CGFloat)radius
                                  lineWidth:(CGFloat)lineWidth
                                      color:(UIColor *)color
{
    UIBezierPath *smoothedPath = [self createCirclePathWithCenter:center
                                                           radius:radius
                                                      sampleCount:72];
    
    CAShapeLayer *slice = [CAShapeLayer layer];
    slice.frame = CGRectMake(center.x-radius,
                             center.y-radius,
                             radius*2, radius*2);
    slice.fillColor = [UIColor clearColor].CGColor;
    slice.strokeColor = color.CGColor;
    slice.lineWidth = lineWidth;
    slice.lineCap = kCALineJoinBevel;
    slice.lineJoin = kCALineJoinBevel;
    slice.path = smoothedPath.CGPath;
    return slice;
}

- (UIBezierPath *)createCirclePathWithCenter:(CGPoint)center
                                      radius:(CGFloat)radius
                                 sampleCount:(NSInteger)sampleCount
{
    UIBezierPath *smoothedPath = [UIBezierPath bezierPath];
    CGPoint startPoint = [self pointOnCircleWithCenter:center radius:radius angleInDegrees:-90];
    
    [smoothedPath moveToPoint:startPoint];
    
    CGFloat delta = 360.0f/sampleCount;
    CGFloat angleInDegrees = -90;
    for (NSInteger i=1; i<sampleCount; i++)
    {
        angleInDegrees += delta;
        CGPoint point = [self pointOnCircleWithCenter:center radius:radius angleInDegrees:angleInDegrees];
        [smoothedPath addLineToPoint:point];
    }
    
    [smoothedPath addLineToPoint:startPoint];
    
    return smoothedPath;
}

- (CGPoint)pointOnCircleWithCenter:(CGPoint)center radius:(double)radius angleInDegrees:(double)angleInDegrees
{
    float x = (float)(radius * cos(angleInDegrees * M_PI / 180)) + radius;
    float y = (float)(radius * sin(angleInDegrees * M_PI / 180)) + radius;
    return CGPointMake(x, y);
}

@end