Files
letro-ios/ElementX/Sources/Other/Extensions/Snapshotting.swift
Doug 28556da516 Remove eraseToStream now that any AsyncSequence is available to us. (#4836)
* Remove `eraseToStream` now that `any AsyncSequence` is available to us.

* Remove the now unnecessary backport of Mutex.

* Silence a couple more deprecation warnings.
2025-12-10 18:33:15 +00:00

83 lines
3.6 KiB
Swift

//
// Copyright 2025 Element Creations Ltd.
// Copyright 2022-2025 New Vector Ltd.
//
// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial.
// Please see LICENSE files in the repository root for full details.
//
import Combine
import SwiftUI
struct SnapshotPrecisionPreferenceKey: PreferenceKey {
static var defaultValue: Float = 1.0
static func reduce(value: inout Float, nextValue: () -> Float) {
value = nextValue()
}
}
struct SnapshotPerceptualPrecisionPreferenceKey: PreferenceKey {
static var defaultValue: Float = 0.98
static func reduce(value: inout Float, nextValue: () -> Float) {
value = nextValue()
}
}
struct SnapshotFulfillmentPreferenceKey: PreferenceKey {
static var defaultValue: Wrapper?
static func reduce(value: inout Wrapper?, nextValue: () -> Wrapper?) {
value = nextValue()
}
enum Source {
case publisher(AnyPublisher<Bool, Never>)
case sequence(any AsyncSequence<Bool, Never>)
}
struct Wrapper: Equatable {
let id = UUID()
let source: Source
static func == (lhs: Wrapper, rhs: Wrapper) -> Bool {
lhs.id == rhs.id // Not ideal, but it's good enough for snapshots.
}
}
}
extension SwiftUI.View {
/// Use this modifier when you want to apply snapshot-specific preferences,
/// like delay and precision, to the view.
/// These preferences can then be retrieved and used elsewhere in your view hierarchy.
///
/// - Parameters:
/// - expect: A publisher that indicates when the preview is ready for snapshotting.
/// - precision: The percentage of pixels that must match.
/// - perceptualPrecision: The percentage a pixel must match the source pixel to be considered a match. 98-99% mimics the precision of the human eye.
func snapshotPreferences(expect fulfillmentPublisher: (any Publisher<Bool, Never>)? = nil,
precision: Float = 1.0,
perceptualPrecision: Float = 0.98) -> some SwiftUI.View {
preference(key: SnapshotPrecisionPreferenceKey.self, value: precision)
.preference(key: SnapshotPerceptualPrecisionPreferenceKey.self, value: perceptualPrecision)
.preference(key: SnapshotFulfillmentPreferenceKey.self, value: fulfillmentPublisher.map { SnapshotFulfillmentPreferenceKey.Wrapper(source: .publisher($0.eraseToAnyPublisher())) })
}
/// Use this modifier when you want to apply snapshot-specific preferences,
/// like delay and precision, to the view.
/// These preferences can then be retrieved and used elsewhere in your view hierarchy.
///
/// - Parameters:
/// - expect: An async sequence that indicates when the preview is ready for snapshotting.
/// - precision: The percentage of pixels that must match.
/// - perceptualPrecision: The percentage a pixel must match the source pixel to be considered a match. 98-99% mimics the precision of the human eye.
func snapshotPreferences(expect fulfillmentSequence: (any AsyncSequence<Bool, Never>)? = nil,
precision: Float = 1.0,
perceptualPrecision: Float = 0.98) -> some SwiftUI.View {
preference(key: SnapshotPrecisionPreferenceKey.self, value: precision)
.preference(key: SnapshotPerceptualPrecisionPreferenceKey.self, value: perceptualPrecision)
.preference(key: SnapshotFulfillmentPreferenceKey.self, value: fulfillmentSequence.map { SnapshotFulfillmentPreferenceKey.Wrapper(source: .sequence($0)) })
}
}