Files
letro-ios/ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift
2024-01-08 12:04:29 +02:00

254 lines
11 KiB
Swift

//
// Copyright 2022 New Vector Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
import SwiftUI
struct FormattedBodyText: View {
@Environment(\.timelineStyle) private var timelineStyle
@Environment(\.layoutDirection) private var layoutDirection
private let attributedString: AttributedString
private let additionalWhitespacesCount: Int
private let boostEmojiSize: Bool
private let defaultAttributesContainer: AttributeContainer = {
var container = AttributeContainer()
// Equivalent to compound's bodyLG
container.font = UIFont.preferredFont(forTextStyle: .body)
container.foregroundColor = UIColor.compound.textPrimary
return container
}()
private var attributedComponents: [AttributedStringBuilderComponent] {
var adjustedAttributedString = attributedString + AttributedString(additionalWhitespacesSuffix)
// If this is not a list, force the writing direction by adding the correct unicode character.
if !String(attributedString.characters).starts(with: "\t") {
adjustedAttributedString = AttributedString(layoutDirection.isolateLayoutUnicodeString) + adjustedAttributedString
}
// Required to allow the underlying TextView to use body font when no font is specifie in the AttributedString.
adjustedAttributedString.mergeAttributes(defaultAttributesContainer, mergePolicy: .keepCurrent)
let string = String(attributedString.characters)
if boostEmojiSize,
string.containsOnlyEmoji,
let range = adjustedAttributedString.range(of: string) {
adjustedAttributedString[range].font = UIFont.systemFont(ofSize: 48.0)
}
return adjustedAttributedString.formattedComponents
}
init(attributedString: AttributedString,
additionalWhitespacesCount: Int = 0,
boostEmojiSize: Bool = false) {
self.attributedString = attributedString
self.additionalWhitespacesCount = additionalWhitespacesCount
self.boostEmojiSize = boostEmojiSize
}
init(text: String, additionalWhitespacesCount: Int = 0, boostEmojiSize: Bool = false) {
self.init(attributedString: AttributedString(text),
additionalWhitespacesCount: additionalWhitespacesCount,
boostEmojiSize: boostEmojiSize)
}
// These is needed to create the slightly off inlined timestamp effect
private var additionalWhitespacesSuffix: String {
.generateBreakableWhitespaceEnd(whitespaceCount: additionalWhitespacesCount, layoutDirection: layoutDirection)
}
var body: some View {
mainContent
.accessibilityElement(children: .ignore)
.accessibilityLabel(Text(attributedString))
}
@ViewBuilder
var mainContent: some View {
if timelineStyle == .bubbles {
bubbleLayout
.tint(.compound.textLinkExternal)
} else {
plainLayout
.tint(.compound.textLinkExternal)
}
}
/// The attributed components laid out for the bubbles timeline style.
var bubbleLayout: some View {
TimelineBubbleLayout(spacing: 8) {
ForEach(attributedComponents) { component in
// Ignore if the string contains only the layout correction
if String(component.attributedString.characters) == layoutDirection.isolateLayoutUnicodeString {
EmptyView()
} else if component.isBlockquote {
// The rendered blockquote with a greedy width. The custom layout prevents the
// infinite width from increasing the overall width of the view.
MessageText(attributedString: component.attributedString.mergingAttributes(blockquoteAttributes))
.fixedSize(horizontal: false, vertical: true)
.frame(maxWidth: .infinity, alignment: .leading)
.padding(.leading, 12.0)
.overlay(alignment: .leading) {
// User an overlay here so that the rectangle's infinite height doesn't take priority
Capsule()
.frame(width: 2.0)
.padding(.leading, 5.0)
.foregroundColor(.compound.textSecondary)
.padding(.vertical, 2)
}
.layoutPriority(TimelineBubbleLayout.Priority.visibleQuote)
} else {
MessageText(attributedString: component.attributedString)
.padding(.horizontal, timelineStyle == .bubbles ? 4 : 0)
.fixedSize(horizontal: false, vertical: true)
.layoutPriority(TimelineBubbleLayout.Priority.regularText)
}
}
// Make a second iteration through the components adding fixed width blockquotes
// which are used for layout calculations but won't be rendered.
ForEach(attributedComponents) { component in
if component.isBlockquote {
MessageText(attributedString: component.attributedString.mergingAttributes(blockquoteAttributes))
.fixedSize(horizontal: false, vertical: true)
.padding(.leading, 12.0)
.layoutPriority(TimelineBubbleLayout.Priority.hiddenQuote)
.hidden()
}
}
}
}
/// The attributed components laid out for the plain timeline style.
var plainLayout: some View {
VStack(alignment: .leading, spacing: 8.0) {
ForEach(attributedComponents) { component in
if component.isBlockquote {
HStack(spacing: 4.0) {
Rectangle()
.foregroundColor(Color.red)
.frame(width: 4.0)
MessageText(attributedString: component.attributedString)
}
.fixedSize(horizontal: false, vertical: true)
} else {
MessageText(attributedString: component.attributedString)
.padding(.horizontal, timelineStyle == .bubbles ? 4 : 0)
.fixedSize(horizontal: false, vertical: true)
}
}
}
}
private var blockquoteAttributes: AttributeContainer {
// The paragraph style removes the block style paragraph that the parser adds by default
// Set directly in the constructor to avoid `Conformance to 'Sendable'` warnings
var container = AttributeContainer([.paragraphStyle: NSParagraphStyle.default])
// Sadly setting SwiftUI fonts do not work so we would need UIFont equivalents for compound, this one is bodyMD
container.font = UIFont.preferredFont(forTextStyle: .subheadline)
container.foregroundColor = UIColor.compound.textSecondary
return container
}
}
// MARK: - Previews
struct FormattedBodyText_Previews: PreviewProvider, TestablePreview {
static var previews: some View {
body
body
.environment(\.timelineStyle, .plain)
}
@ViewBuilder
static var body: some View {
let htmlStrings = [
"""
Text before blockquote
<blockquote>
<b>bold</b> <i>italic</i>
</blockquote>Text after blockquote
""",
"""
<blockquote>First blockquote with a <a href=\"https://www.matrix.org/\">link</a> in it</blockquote>
<blockquote>Second blockquote with a <a href=\"https://www.matrix.org/\">link</a> in it</blockquote>
<blockquote>Third blockquote with a <a href=\"https://www.matrix.org/\">link</a> in it</blockquote>
""",
"""
<blockquote>A blockquote that is long and goes onto multiple lines as the first item in the message</blockquote>
<p>Then another line of text here to reply to the blockquote, which is also a multiline component.</p>
<blockquote>Short line here.</blockquote>
<p>And a simple reply here.</p>
""",
"""
<code>Hello world</code>
<p>Text</p>
<code><b>Hello</b> <i>world</i></code>
<p>Text</p>
<code>Hello world</code>
""",
"<p>This is a list</p>\n<ul>\n<li>One</li>\n<li>Two</li>\n<li>And number 3</li>\n</ul>\n",
"<ul><li>First item</li><li>Second item</li><li>Third item</li></ul>",
"<p>test</p>\n<p>test</p>"
]
let attributedStringBuilder = AttributedStringBuilder(permalinkBaseURL: ServiceLocator.shared.settings.permalinkBaseURL, mentionBuilder: MentionBuilder())
ScrollView {
VStack(alignment: .leading, spacing: 24.0) {
ForEach(htmlStrings, id: \.self) { htmlString in
if let attributedString = attributedStringBuilder.fromHTML(htmlString) {
FormattedBodyText(attributedString: attributedString)
.previewBubble()
}
}
FormattedBodyText(attributedString: AttributedString("Some plain text wrapped in an AttributedString."))
.previewBubble()
FormattedBodyText(text: "Some plain text that's not an attributed component.")
.previewBubble()
FormattedBodyText(text: "Some plain text that's not an attributed component. This one is really long.")
.previewBubble()
FormattedBodyText(text: "❤️", boostEmojiSize: true)
.previewBubble()
}
.padding()
}
}
}
private struct PreviewBubbleModifier: ViewModifier {
@Environment(\.timelineStyle) private var timelineStyle
func body(content: Content) -> some View {
content
.padding(timelineStyle == .bubbles ? 8 : 0)
.background(timelineStyle == .bubbles ? Color.compound._bgBubbleOutgoing : nil)
.cornerRadius(timelineStyle == .bubbles ? 12 : 0)
.environmentObject(RoomScreenViewModel.mock.context)
}
}
private extension View {
func previewBubble() -> some View {
modifier(PreviewBubbleModifier())
}
}