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//
// HeaderOverlayView.m
// Mobile Buy SDK
//
// Created by Shopify.
// Copyright (c) 2015 Shopify Inc. All rights reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//
#import "HeaderOverlayView.h"
#import "VisualEffectView.h"
@interface HeaderOverlayView ()
@property (nonatomic, strong) UIView *overlayView;
@property (nonatomic, strong) UIView *visualEffectContainerView;
@end
@implementation HeaderOverlayView
- (instancetype)init
{
self = [super init];
if (self) {
self.userInteractionEnabled = NO;
self.backgroundColor = [UIColor clearColor];
_visualEffectContainerView = [[UIView alloc] init];
_visualEffectContainerView.translatesAutoresizingMaskIntoConstraints = NO;
_visualEffectContainerView.alpha = 0;
[self addSubview:_visualEffectContainerView];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_visualEffectContainerView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_visualEffectContainerView)]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_visualEffectContainerView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_visualEffectContainerView)]];
VisualEffectView *visualEffectView = [[VisualEffectView alloc] init];
visualEffectView.translatesAutoresizingMaskIntoConstraints = NO;
[_visualEffectContainerView addSubview:visualEffectView];
[_visualEffectContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[visualEffectView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(visualEffectView)]];
[_visualEffectContainerView addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[visualEffectView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(visualEffectView)]];
_overlayView = [[UIView alloc] init];
_overlayView.alpha = 0;
_overlayView.translatesAutoresizingMaskIntoConstraints = NO;
[self addSubview:_overlayView];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"V:|[_overlayView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_overlayView)]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:@"H:|[_overlayView]|" options:0 metrics:nil views:NSDictionaryOfVariableBindings(_overlayView)]];
}
return self;
}
-(void)setOverlayBackgroundColor:(UIColor *)overlayBackgroundColor
{
_overlayView.backgroundColor = overlayBackgroundColor;
}
static CGFloat visualEffectViewThreshold = 200.0f;
static CGFloat overlayViewThreshold = 100.0f;
- (void)scrollViewDidScroll:(UIScrollView *)scrollView withNavigationBarHeight:(CGFloat)navigationBarHeight
{
if (scrollView.contentOffset.y > 0) {
CGFloat opaqueOffset = CGRectGetHeight(self.bounds) - navigationBarHeight;
CGFloat overlayStartingOffset = opaqueOffset - overlayViewThreshold;
self.overlayView.alpha = (scrollView.contentOffset.y - overlayStartingOffset) / (opaqueOffset - overlayStartingOffset);
CGFloat blurStartingOffset = opaqueOffset - visualEffectViewThreshold;
self.visualEffectContainerView.alpha = (scrollView.contentOffset.y - blurStartingOffset) / (opaqueOffset - blurStartingOffset);
} else {
self.overlayView.alpha = 0;
self.visualEffectContainerView.alpha = 0;
}
}
@end