Impressia/Vernissage/Widgets/ImagesViewer.swift

147 lines
5.1 KiB
Swift

//
// https://mczachurski.dev
// Copyright © 2023 Marcin Czachurski and the repository contributors.
// Licensed under the MIT License.
//
import SwiftUI
struct ImagesViewer: View {
@State var statusViewModel: StatusModel
@State var selectedAttachmentId: String = String.empty()
@Environment(\.dismiss) private var dismiss
// Opacity usied during close dialog animation.
@State private var opacity = 1.0
private let closeDragDistance = 100.0
// Zoom.
@State private var zoomScale = 1.0
// Magnification.
@State private var currentAmount = 0.0
@State private var finalAmount = 1.0
// Draging.
@State private var currentOffset = CGSize.zero
@State private var accumulatedOffset = CGSize.zero
var body: some View {
ZStack {
TabView(selection: $selectedAttachmentId) {
ForEach(statusViewModel.mediaAttachments, id: \.id) { attachment in
if let data = attachment.data, let image = UIImage(data: data) {
Image(uiImage: image)
.resizable()
.aspectRatio(contentMode: .fit)
.tag(attachment.id)
.offset(currentOffset)
.scaleEffect(finalAmount + currentAmount)
// .opacity(self.opacity)
//.gesture((finalAmount + currentAmount) > 1.0 ? dragGesture : nil)
.gesture(dragGesture)
.gesture(magnificationGesture)
.gesture(doubleTapGesture)
.gesture(tapGesture)
}
}
}
.tabViewStyle(PageTabViewStyle())
}
}
private func close() {
withoutAnimation {
dismiss()
}
}
var magnificationGesture: some Gesture {
MagnificationGesture()
.onChanged { amount in
currentAmount = amount - 1
}
.onEnded { amount in
let finalMagnification = finalAmount + currentAmount
// self.revertToPrecalculatedMagnification(magnification: finalMagnification)
self.resetMagnification(magnification: finalMagnification)
}
}
var doubleTapGesture: some Gesture {
TapGesture(count: 2)
.onEnded { _ in
withAnimation {
currentOffset = CGSize.zero
currentAmount = 0
finalAmount = 1.0
}
}
}
var dragGesture: some Gesture {
DragGesture(minimumDistance:20)
.onChanged { amount in
self.currentOffset = CGSize(width: amount.translation.width + self.accumulatedOffset.width,
height: amount.translation.height + self.accumulatedOffset.height)
let pictureOpacity = (self.closeDragDistance - self.currentOffset.height) / self.closeDragDistance
self.opacity = pictureOpacity >= 0 ? pictureOpacity : 0
} .onEnded { amount in
let offset = CGSize(width: amount.translation.width + self.accumulatedOffset.width,
height: amount.translation.height + self.accumulatedOffset.height)
if offset.height < closeDragDistance {
withAnimation(.easeInOut) {
self.currentOffset = CGSize.zero
self.accumulatedOffset = CGSize.zero
self.opacity = 1.0
}
} else {
withAnimation(.easeInOut) {
self.currentOffset = amount.predictedEndTranslation
self.accumulatedOffset = CGSize.zero
self.opacity = 1.0
}
self.close()
}
}
}
var tapGesture: some Gesture {
TapGesture().onEnded({ _ in
self.close()
})
}
private func revertToPrecalculatedMagnification(magnification: Double) {
if magnification < 1.0 {
// When image is small we are returning to starting point.
withAnimation(.default) {
finalAmount = 1.0
currentAmount = 0
// Also we have to move image to orginal position.
currentOffset = CGSize.zero
}
} else if magnification > 2.0 {
// When image is magnified to much we are rturning to 1.5 maginification.
withAnimation(.default) {
finalAmount = 1.5
currentAmount = 0
}
} else {
finalAmount = magnification
currentAmount = 0
}
}
private func resetMagnification(magnification: Double) {
withAnimation(.default) {
finalAmount = 1.0
currentAmount = 0
}
}
}