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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/
import Foundation
import UIKit
/// Context containing all necessary information for layout calculations
struct LayoutContext {
/// The root view size for the `SummarizeController`
let viewSize: CGSize
let traitCollection: UITraitCollection
let tabSnapshotTopOffset: CGFloat
var isLandscapeLayout: Bool {
let size = viewSize
// Use portrait layout when on iPad's regular size class
return size.width > size.height && traitCollection.horizontalSizeClass != .regular
}
}
/// Protocol for calculating the tab snapshot transforms for the different UI states
protocol SnapshotLayoutCalculator {
/// Wether the interface was rotated
var didRotateInterface: Bool { get set }
/// Calculate transform for showing summary content
func calculateSummaryTransform(context: LayoutContext) -> CGAffineTransform
/// Calculate transform for showing error/info content
func calculateInfoTransform(context: LayoutContext) -> CGAffineTransform
/// Calculate transform for dismissing the view
func calculateDismissTransform(context: LayoutContext) -> CGAffineTransform
/// Calculate transform for the `viewDidAppear` state
func calculateViewDidAppearTransform(context: LayoutContext) -> CGAffineTransform
/// Calculate the transform for rotation state change
func calculateDidRotateTransform(context: LayoutContext) -> CGAffineTransform
}
/// Default implementation of `SnapshotLayoutCalculator`
struct DefaultSnapshotLayoutCalculator: SnapshotLayoutCalculator {
struct Configuration {
let summaryTransformBottomPaddingPortrait: CGFloat
let transformPercentagePortrait: CGFloat
let transformPercentageLandscape: CGFloat
static let `default` = Configuration(
summaryTransformBottomPaddingPortrait: 110.0,
transformPercentagePortrait: 0.5,
transformPercentageLandscape: 1.0
)
}
private let configuration: Configuration
var didRotateInterface = false
init(configuration: Configuration = .default) {
self.configuration = configuration
}
func calculateSummaryTransform(context: LayoutContext) -> CGAffineTransform {
guard !didRotateInterface else {
return calculateDidRotateTransform(context: context)
}
if context.isLandscapeLayout {
return CGAffineTransform(translationX: 0, y: context.viewSize.height)
} else {
let y = context.viewSize.height
- configuration.summaryTransformBottomPaddingPortrait
- context.tabSnapshotTopOffset
return CGAffineTransform(translationX: 0, y: y)
}
}
func calculateInfoTransform(context: LayoutContext) -> CGAffineTransform {
guard !didRotateInterface else {
return calculateDidRotateTransform(context: context)
}
let multiplier = context.isLandscapeLayout ?
configuration.transformPercentageLandscape :
configuration.transformPercentagePortrait
return CGAffineTransform(translationX: 0, y: context.viewSize.height * multiplier)
}
func calculateDismissTransform(context: LayoutContext) -> CGAffineTransform {
guard !didRotateInterface else {
return calculateDidRotateTransform(context: context)
}
return .identity
}
func calculateViewDidAppearTransform(context: LayoutContext) -> CGAffineTransform {
guard !didRotateInterface else {
return calculateDidRotateTransform(context: context)
}
let multiplier = context.isLandscapeLayout ?
configuration.transformPercentageLandscape :
configuration.transformPercentagePortrait
return CGAffineTransform(translationX: 0, y: context.viewSize.height * multiplier)
}
func calculateDidRotateTransform(context: LayoutContext) -> CGAffineTransform {
// On rotation the transform invalidates the snapshot and moves it off screen
return CGAffineTransform(translationX: 0.0, y: context.viewSize.height)
}
}