feat: EPUB阅读器搜索、注释、CFI模块及大书远距跳转优化

- 实现EPUB阅读器搜索功能及选中注释功能 - 优化CFI模块，修复代码审查发现的11个问题 - 实现大书远距目录跳转与后台补全优化方案 - 优化设置面板与章节运行时联动 - 重构及大量改进优化
2026-06-22 20:26:34 +08:00
parent f50495ad91
commit c65c190b71
178 changed files with 11380 additions and 6728 deletions
@@ -5,10 +5,9 @@ import Foundation
 import DTCoreText
 #endif

-// MARK: - 文本内容视图代理
-
 protocol RDEPUBTextContentViewDelegate: AnyObject {
    func textContentView(_ contentView: RDEPUBTextContentView, didChangeSelection selection: RDEPUBSelection?)
+    func textContentView(_ contentView: RDEPUBTextContentView, didRequestReaderTapAt point: CGPoint)
    func textContentView(
        _ contentView: RDEPUBTextContentView,
        didRequestSelectionAction action: RDEPUBAnnotationMenuAction,
@@ -27,22 +26,46 @@ protocol RDEPUBTextContentViewDelegate: AnyObject {
    )
 }

-// MARK: - 文本内容视图
-
-/// EPUB 流式排版的文本内容视图
-/// 对齐 WXRead 架构：选区和高亮共享 CoreText 命中测试与 drawRect 绘制结果。
 final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
+
+    enum SelectionInteractionState: Equatable {
+        case idle
+        case selectionPending
+        case selecting
+        case selectionActive
+        case adjustingHandle
+    }
+
    private static let darkAdjustedImageCache = NSCache<NSString, UIImage>()

    private var contentInsets: UIEdgeInsets = .zero
+
    private var currentPage: RDEPUBTextPage?
+    private var currentChapterCFIMap: RDEPUBCFIMap?
+    private var currentChapterFragmentOffsets: [String: Int] = [:]
+
    private var currentSelection: RDEPUBSelection?
+
    private var menuSelection: RDEPUBSelection?
+
+    private var activeSelectionHandle: RDEPUBTextSelectionController.BoundaryHandle?
+
+    private let selectionLoupeView = RDEPUBSelectionLoupeView()
+
+    private var selectionInteractionState: SelectionInteractionState = .idle
+
    private var currentHighlights: [RDEPUBHighlight] = []
+
    private var currentSearchState: RDEPUBSearchState?
+
    weak var delegate: RDEPUBTextContentViewDelegate?

+    var selectionTapSuppressionDidChange: ((Bool) -> Void)?
+
+    var selectionPagingSuppressionDidChange: ((Bool) -> Void)?
+
 #if canImport(DTCoreText)
+
    private let coreTextContentView: RDEPUBTextPageRenderView = {
        let view = RDEPUBTextPageRenderView()
        view.backgroundColor = .clear
@@ -53,10 +76,12 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
    }()

    private var coreTextDisplayContent: NSAttributedString?
+
    private var coreTextDisplayRange: NSRange?
 #endif

    private let interactionController = RDEPUBPageInteractionController()
+
    private let selectionController = RDEPUBTextSelectionController()

    private let backgroundOverlayView: RDEPUBTextPageDecorationView = {
@@ -91,7 +116,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {

    private lazy var panGestureRecognizer: UIPanGestureRecognizer = {
        let gesture = UIPanGestureRecognizer(target: self, action: #selector(handlePan(_:)))
-        gesture.isEnabled = false
        gesture.delegate = self
        return gesture
    }()
@@ -102,8 +126,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        return gesture
    }()

-    // MARK: - Init
-
    override init(frame: CGRect) {
        super.init(frame: frame)
        accessibilityIdentifier = "epub.reader.content.view"
@@ -114,10 +136,12 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
 #endif
        addSubview(overlayView)
        addSubview(pageNumberLabel)
+        addSubview(selectionLoupeView)
        addGestureRecognizer(longPressGestureRecognizer)
        addGestureRecognizer(panGestureRecognizer)
        addGestureRecognizer(tapGestureRecognizer)
        tapGestureRecognizer.require(toFail: longPressGestureRecognizer)
+        selectionLoupeView.isHidden = true

        selectionController.onSelectionChanged = { [weak self] selection in
            guard let self else { return }
@@ -130,17 +154,30 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
            self.updateAccessibilityDecorationSummary()
            self.delegate?.textContentView(self, didChangeSelection: selection)
        }
+        selectionController.interactionStateDidChange = { [weak self] state in
+            self?.handleSelectionControllerStateChange(state)
+        }
        selectionController.pageProvider = { [weak self] in self?.currentPage }
+        selectionController.chapterCFIMapProvider = { [weak self] in self?.currentChapterCFIMap }
+        selectionController.chapterFragmentOffsetsProvider = { [weak self] in
+            self?.currentChapterFragmentOffsets ?? [:]
+        }
    }

    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }

-    // MARK: - First Responder
-
    override var canBecomeFirstResponder: Bool { true }

+    var selectionLongPressGestureRecognizer: UILongPressGestureRecognizer {
+        longPressGestureRecognizer
+    }
+
+    var isSelectionInteractionInProgress: Bool {
+        selectionInteractionState != .idle
+    }
+
    override func canPerformAction(_ action: Selector, withSender sender: Any?) -> Bool {
        action == #selector(rd_copy(_:))
            || action == #selector(rd_highlight(_:))
@@ -159,8 +196,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        performSelectionAction(.annotate)
    }

-    // MARK: - Layout
-
    override func layoutSubviews() {
        super.layoutSubviews()

@@ -181,19 +216,22 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        )
    }

-    // MARK: - Configure
-
    func configure(
        page: RDEPUBTextPage,
        pageNumber: Int,
        totalPages: Int,
        configuration: RDEPUBReaderConfiguration,
+        chapterCFIMap: RDEPUBCFIMap? = nil,
+        chapterFragmentOffsets: [String: Int] = [:],
        highlights: [RDEPUBHighlight] = [],
        searchState: RDEPUBSearchState? = nil
    ) {
        currentPage = page
+        currentChapterCFIMap = chapterCFIMap
+        currentChapterFragmentOffsets = chapterFragmentOffsets
        currentSelection = nil
        menuSelection = nil
+        updateSelectionInteractionState(.idle)
        currentHighlights = highlights
        currentSearchState = searchState
        selectionController.clearSelection(renderView: coreTextRenderView)
@@ -228,7 +266,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
            value: configuration.theme.contentTextColor,
            range: fullRange
        )
-        // 注入高亮/下划线自定义属性（对齐 WXRead 的 WRChapterData.addHighlightInRange:）
+
        applyHighlightsToContent(displayContent, highlights: highlights, page: page)
        coreTextContentView.isHidden = false
        coreTextContentView.backgroundColor = .clear
@@ -263,7 +301,9 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        currentSelection = nil
        menuSelection = nil
        currentSearchState = nil
-        panGestureRecognizer.isEnabled = false
+        activeSelectionHandle = nil
+        updateSelectionInteractionState(.idle)
+        selectionLoupeView.dismiss()
        selectionController.clearSelection(renderView: coreTextRenderView)
        overlayView.clearSelection()
        backgroundOverlayView.clearSelection()
@@ -271,8 +311,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        UIMenuController.shared.setMenuVisible(false, animated: true)
    }

-    // MARK: - 选择操作
-
    private func performSelectionAction(_ action: RDEPUBAnnotationMenuAction) {
        let selection = currentSelection ?? menuSelection
        delegate?.textContentView(self, didRequestSelectionAction: action, selection: selection)
@@ -280,8 +318,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        hideSelectionMenu()
    }

-    // MARK: - Cover Image
-
    private func configureCoverIfNeeded(for page: RDEPUBTextPage) -> Bool {
        guard page.pageIndexInChapter == 0,
              page.href.lowercased().contains("cover"),
@@ -327,9 +363,8 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        return nil
    }

-    // MARK: - Dark Image Adjustment
-
 #if canImport(DTCoreText)
+
    private func darkImageAdjustedContentIfNeeded(
        _ content: NSMutableAttributedString,
        configuration: RDEPUBReaderConfiguration
@@ -409,8 +444,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
    }
 #endif

-    // MARK: - 高亮属性注入（对齐 WXRead 的 WRChapterData.addHighlightInRange:）
-
    private func applyHighlightsToContent(
        _ content: NSMutableAttributedString,
        highlights: [RDEPUBHighlight],
@@ -435,8 +468,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        }
    }

-    // MARK: - Content Normalization
-
    private func normalizedPageContent(from page: RDEPUBTextPage) -> NSMutableAttributedString {
        let content = NSMutableAttributedString(attributedString: page.content)
        guard shouldNormalizeContinuationParagraph(for: page) else { return content }
@@ -463,9 +494,8 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        return !CharacterSet.newlines.contains(previousScalar)
    }

-    // MARK: - CoreText Layout
-
 #if canImport(DTCoreText)
+
    private func updateCoreTextLayoutFrameIfNeeded() {
        guard !coreTextContentView.isHidden,
              let displayContent = coreTextDisplayContent,
@@ -502,8 +532,6 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
    }
 #endif

-    // MARK: - Gestures
-
    @objc private func handleLongPress(_ gesture: UILongPressGestureRecognizer) {
 #if canImport(DTCoreText)
        layoutIfNeeded()
@@ -514,12 +542,19 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        )
        switch gesture.state {
        case .began:
-            panGestureRecognizer.isEnabled = true
+            activeSelectionHandle = nil
+            updateSelectionInteractionState(.selecting)
+            hideSelectionMenu()
+            updateSelectionLoupe(for: gesture.location(in: coreTextRenderView ?? self))
+        case .changed:
+            updateSelectionInteractionState(.selecting)
+            updateSelectionLoupe(for: gesture.location(in: coreTextRenderView ?? self))
        case .ended:
-            panGestureRecognizer.isEnabled = false
+            selectionLoupeView.dismiss()
            showSelectionMenuIfNeeded()
        case .cancelled, .failed:
-            panGestureRecognizer.isEnabled = false
+            activeSelectionHandle = nil
+            selectionLoupeView.dismiss()
        default:
            break
        }
@@ -528,17 +563,46 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {

    @objc private func handlePan(_ gesture: UIPanGestureRecognizer) {
 #if canImport(DTCoreText)
-        selectionController.handlePan(
-            gesture,
-            renderView: coreTextRenderView,
-            interactionController: interactionController
-        )
+        layoutIfNeeded()
+        let point = gesture.location(in: coreTextRenderView ?? self)
+        if gesture.state == .began, activeSelectionHandle == nil {
+            if let renderView = coreTextRenderView,
+               let handle = renderView.selectionHandle(at: point) {
+                activeSelectionHandle = handle == .start ? .start : .end
+                updateSelectionInteractionState(.adjustingHandle)
+                hideSelectionMenu()
+                updateSelectionLoupe(for: point)
+            }
+        }
+
+        if let activeSelectionHandle, let renderView = coreTextRenderView {
+            selectionController.updateSelection(
+                byAdjusting: activeSelectionHandle,
+                at: point,
+                renderView: renderView,
+                interactionController: interactionController
+            )
+            updateSelectionLoupe(for: point)
+        } else {
+            selectionController.handlePan(
+                gesture,
+                renderView: coreTextRenderView,
+                interactionController: interactionController
+            )
+            if selectionController.isSelecting {
+                updateSelectionLoupe(for: point)
+            }
+        }
        switch gesture.state {
        case .ended:
-            panGestureRecognizer.isEnabled = false
+            activeSelectionHandle = nil
+            updateSelectionInteractionState(currentSelection == nil ? .idle : .selectionActive)
+            selectionLoupeView.dismiss()
            showSelectionMenuIfNeeded()
        case .cancelled, .failed:
-            panGestureRecognizer.isEnabled = false
+            activeSelectionHandle = nil
+            updateSelectionInteractionState(currentSelection == nil ? .idle : .selectionActive)
+            selectionLoupeView.dismiss()
        default:
            break
        }
@@ -547,7 +611,20 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {

    @objc private func handleTap(_ gesture: UITapGestureRecognizer) {
        let point = gesture.location(in: overlayView)
-        if currentSelection != nil {
+        if let renderView = coreTextRenderView {
+            let renderPoint = gesture.location(in: renderView)
+            if renderView.selectionHandle(at: renderPoint) != nil {
+                return
+            }
+            if currentSelection != nil {
+                if renderView.selectionContains(renderPoint) {
+                    showSelectionMenuIfNeeded()
+                    return
+                }
+                clearSelection()
+                return
+            }
+        } else if currentSelection != nil {
            clearSelection()
            return
        }
@@ -563,6 +640,7 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        }
        guard let highlight = highlight(at: point),
              let sourceRect = highlightSourceRect(for: highlight, fallbackPoint: point) else {
+            delegate?.textContentView(self, didRequestReaderTapAt: convert(point, from: overlayView))
            return
        }
        delegate?.textContentView(self, didRequestHighlightActions: highlight, sourceRect: sourceRect)
@@ -589,6 +667,57 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        UIMenuController.shared.setMenuVisible(false, animated: true)
    }

+    private func updateSelectionLoupe(for point: CGPoint) {
+#if canImport(DTCoreText)
+        guard let renderView = coreTextRenderView else { return }
+        let localPoint = convert(point, from: renderView)
+        selectionLoupeView.present(
+            sourceView: renderView,
+            focusPoint: point,
+            hostBounds: bounds.inset(by: contentInsets),
+            targetPoint: localPoint
+        )
+#endif
+    }
+
+    private func handleSelectionControllerStateChange(_ state: RDEPUBTextSelectionController.InteractionState) {
+        switch state {
+        case .idle:
+            if currentSelection == nil, activeSelectionHandle == nil {
+                updateSelectionInteractionState(.idle)
+            }
+        case .selecting:
+            updateSelectionInteractionState(.selecting)
+        case .selectionActive:
+            updateSelectionInteractionState(currentSelection == nil ? .idle : .selectionActive)
+        case .adjustingHandle:
+            updateSelectionInteractionState(.adjustingHandle)
+        }
+    }
+
+    private func updateSelectionInteractionState(_ state: SelectionInteractionState) {
+        let previousTapSuppressed = selectionInteractionState != .idle
+        let previousPagingSuppressed = shouldSuppressPagingInteraction(for: selectionInteractionState)
+        selectionInteractionState = state
+        let currentTapSuppressed = selectionInteractionState != .idle
+        let currentPagingSuppressed = shouldSuppressPagingInteraction(for: selectionInteractionState)
+        if previousTapSuppressed != currentTapSuppressed {
+            selectionTapSuppressionDidChange?(currentTapSuppressed)
+        }
+        if previousPagingSuppressed != currentPagingSuppressed {
+            selectionPagingSuppressionDidChange?(currentPagingSuppressed)
+        }
+    }
+
+    private func shouldSuppressPagingInteraction(for state: SelectionInteractionState) -> Bool {
+        switch state {
+        case .idle, .selectionPending, .selectionActive:
+            return false
+        case .selecting, .adjustingHandle:
+            return true
+        }
+    }
+
    private var coreTextRenderView: RDEPUBTextPageRenderView? {
 #if canImport(DTCoreText)
        return coreTextContentView
@@ -678,23 +807,140 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
        return overlayView.convert(fallbackRect, to: self)
    }

+    func shouldSuppressReaderTap(at point: CGPoint) -> Bool {
+#if canImport(DTCoreText)
+        if selectionInteractionState == .selectionPending {
+            return true
+        }
+
+        guard let renderView = coreTextRenderView else {
+            return false
+        }
+        let renderPoint = convert(point, to: renderView)
+        if renderView.selectionHandle(at: renderPoint) != nil {
+            return true
+        }
+        if selectionController.hasActiveSelection, renderView.selectionContains(renderPoint) {
+            return true
+        }
+        switch selectionInteractionState {
+        case .idle:
+            return false
+        case .selectionPending, .selecting, .selectionActive, .adjustingHandle:
+            return true
+        }
+#else
+        return false
+#endif
+    }
+
+    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesBegan(touches, with: event)
+#if canImport(DTCoreText)
+        guard selectionInteractionState == .idle,
+              activeSelectionHandle == nil,
+              currentPage != nil,
+              let touch = touches.first,
+              let renderView = coreTextRenderView else {
+            return
+        }
+        let point = touch.location(in: renderView)
+        guard renderView.selectionHandle(at: point) == nil else { return }
+        updateSelectionInteractionState(.selectionPending)
+#endif
+    }
+
+    override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesEnded(touches, with: event)
+        resetSelectionPendingIfNeeded()
+    }
+
+    override func touchesCancelled(_ touches: Set<UITouch>, with event: UIEvent?) {
+        super.touchesCancelled(touches, with: event)
+        resetSelectionPendingIfNeeded()
+    }
+
+    private func resetSelectionPendingIfNeeded() {
+        guard selectionInteractionState == .selectionPending else { return }
+        if currentSelection != nil {
+            updateSelectionInteractionState(.selectionActive)
+        } else {
+            updateSelectionInteractionState(.idle)
+        }
+    }
+
    override func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        if gestureRecognizer === panGestureRecognizer {
-            return selectionController.isSelecting
+            if selectionController.isSelecting {
+                return true
+            }
+            guard let pan = gestureRecognizer as? UIPanGestureRecognizer,
+                  let renderView = coreTextRenderView else {
+                return false
+            }
+            let point = pan.location(in: renderView)
+            return renderView.selectionHandle(at: point) != nil
+        }
+        if gestureRecognizer === longPressGestureRecognizer {
+            guard let longPress = gestureRecognizer as? UILongPressGestureRecognizer,
+                  let renderView = coreTextRenderView else {
+                return true
+            }
+            let point = longPress.location(in: renderView)
+            if renderView.selectionHandle(at: point) != nil {
+                return false
+            }
+            if selectionController.hasActiveSelection, renderView.selectionContains(point) {
+                return false
+            }
+            return true
        }
        if gestureRecognizer === tapGestureRecognizer {
            guard let tapGestureRecognizer = gestureRecognizer as? UITapGestureRecognizer else {
                return false
            }
            if selectionController.hasActiveSelection {
+                if let renderView = coreTextRenderView {
+                    let point = tapGestureRecognizer.location(in: renderView)
+                    if renderView.selectionHandle(at: point) != nil {
+                        return false
+                    }
+                }
                return true
            }
            let point = tapGestureRecognizer.location(in: overlayView)
-            return attachmentText(at: point) != nil || highlight(at: point) != nil
+            if attachmentText(at: point) != nil || highlight(at: point) != nil {
+                return true
+            }
+            return currentPage != nil
        }
        return true
    }

+    func gestureRecognizer(
+        _ gestureRecognizer: UIGestureRecognizer,
+        shouldReceive touch: UITouch
+    ) -> Bool {
+        guard let renderView = coreTextRenderView else {
+            return true
+        }
+
+        let point = touch.location(in: renderView)
+        if let handle = renderView.selectionHandle(at: point) {
+            if gestureRecognizer === panGestureRecognizer {
+                activeSelectionHandle = handle == .start ? .start : .end
+                updateSelectionInteractionState(.adjustingHandle)
+                hideSelectionMenu()
+                return true
+            }
+            if gestureRecognizer === longPressGestureRecognizer || gestureRecognizer === tapGestureRecognizer {
+                return false
+            }
+        }
+
+        return true
+    }
+
    func gestureRecognizer(
        _ gestureRecognizer: UIGestureRecognizer,
        shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer
@@ -703,9 +949,85 @@ final class RDEPUBTextContentView: UIView, UIGestureRecognizerDelegate {
    }
 }

-// MARK: - UIColor Extension
+private final class RDEPUBSelectionLoupeView: UIView {
+
+    private let imageView = UIImageView()
+
+    private let magnification: CGFloat = 1.45
+
+    private let captureSize = CGSize(width: 84, height: 84)
+
+    override init(frame: CGRect) {
+        super.init(frame: CGRect(origin: .zero, size: CGSize(width: 96, height: 96)))
+        isUserInteractionEnabled = false
+        backgroundColor = .clear
+        layer.shadowColor = UIColor.black.cgColor
+        layer.shadowOpacity = 0.18
+        layer.shadowRadius = 10
+        layer.shadowOffset = CGSize(width: 0, height: 5)
+
+        imageView.frame = bounds
+        imageView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
+        imageView.layer.cornerRadius = bounds.width / 2
+        imageView.layer.cornerCurve = .continuous
+        imageView.layer.borderWidth = 1.5
+        imageView.layer.borderColor = UIColor(white: 0.82, alpha: 0.95).cgColor
+        imageView.clipsToBounds = true
+        addSubview(imageView)
+    }
+
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    func present(sourceView: UIView, focusPoint: CGPoint, hostBounds: CGRect, targetPoint: CGPoint) {
+        imageView.image = snapshot(from: sourceView, focusPoint: focusPoint)
+
+        let targetCenter = CGPoint(
+            x: min(max(targetPoint.x, hostBounds.minX + bounds.width / 2), hostBounds.maxX - bounds.width / 2),
+            y: min(
+                max(hostBounds.minY + bounds.height / 2, targetPoint.y - 74),
+                hostBounds.maxY - bounds.height / 2
+            )
+        )
+
+        center = targetCenter
+        if isHidden {
+            alpha = 0
+            transform = CGAffineTransform(scaleX: 0.92, y: 0.92)
+            isHidden = false
+            UIView.animate(withDuration: 0.12) {
+                self.alpha = 1
+                self.transform = .identity
+            }
+        }
+    }
+
+    func dismiss() {
+        guard !isHidden else { return }
+        isHidden = true
+        alpha = 0
+        imageView.image = nil
+    }
+
+    private func snapshot(from sourceView: UIView, focusPoint: CGPoint) -> UIImage {
+        let renderer = UIGraphicsImageRenderer(size: captureSize)
+        return renderer.image { context in
+            let cgContext = context.cgContext
+            cgContext.setFillColor(UIColor.systemBackground.cgColor)
+            cgContext.fill(CGRect(origin: .zero, size: captureSize))
+            cgContext.translateBy(
+                x: captureSize.width / 2 - focusPoint.x * magnification,
+                y: captureSize.height / 2 - focusPoint.y * magnification
+            )
+            cgContext.scaleBy(x: magnification, y: magnification)
+            sourceView.layer.render(in: cgContext)
+        }
+    }
+}

 private extension UIColor {
+
    var rd_isDarkReaderBackground: Bool {
        var red: CGFloat = 0, green: CGFloat = 0, blue: CGFloat = 0, alpha: CGFloat = 0
        guard getRed(&red, green: &green, blue: &blue, alpha: &alpha) else { return false }