Puranjay Savar Mattas
6e1ffb96fd
Convert from git submodule to plain vendored copy. No push access to upstream nodes-app/swift-markdown-engine meant our local fix commit (05c1720) was stranded and unreachable from any remote on fresh clones/CI. Vendoring as plain files folds it into normal repo history instead.
102 lines
3.8 KiB
Swift
102 lines
3.8 KiB
Swift
//
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// NativeTextView+Placeholder.swift
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// MarkdownEngine
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//
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// Created by Luca Chen on 11.06.26.
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//
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// Embedder-supplied ghost text shown while the document is empty. Lives inside
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// the text view, so it sits below the scroll-away header band, tracks its
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// animation, and scrolls with the content.
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//
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import AppKit
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/// Transparent, click-through label drawing the placeholder at the text
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/// container origin. A plain NSView — overriding `draw(_:)` here is safe
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/// (unlike on the TextKit-2 backed `NativeTextView` itself).
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final class PlaceholderLabelView: NSView {
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var attributedText: NSAttributedString? {
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didSet { needsDisplay = true }
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}
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/// Top-left origin to match the flipped text view's first-line position.
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override var isFlipped: Bool { true }
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/// Clicks fall through to the text view (focus + caret placement).
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override func hitTest(_ point: NSPoint) -> NSView? { nil }
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override func draw(_ dirtyRect: NSRect) {
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attributedText?.draw(
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with: bounds,
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options: [.usesLineFragmentOrigin, .usesFontLeading]
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)
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}
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}
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extension NativeTextView {
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/// Install, refresh, or remove the placeholder. Cheap when nothing changed —
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/// called from every `updateNSView`.
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func setPlaceholder(_ attributed: NSAttributedString?) {
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if let attributed {
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let view: PlaceholderLabelView
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if let existing = placeholderView {
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view = existing
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if existing.attributedText?.isEqual(to: attributed) != true {
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existing.attributedText = attributed
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}
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} else {
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view = PlaceholderLabelView()
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view.attributedText = attributed
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view.autoresizingMask = [.width, .height]
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addSubview(view)
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placeholderView = view
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}
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let target = placeholderFrame()
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if !view.frame.isApproximatelyEqual(to: target) {
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view.frame = target
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}
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} else if let placeholderView {
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placeholderView.removeFromSuperview()
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self.placeholderView = nil
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}
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refreshPlaceholderVisibility()
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// An empty doc's text view sits at its one-line content height, which
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// clips the placeholder subview. Stretch it to the viewport (its intended
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// height): the first layout can run before the scroll view is sized and
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// `restack` never re-measures height, so otherwise the quote stays clipped
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// after the editor is rebuilt (e.g. graph view and back).
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if let placeholderView, !placeholderView.isHidden {
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applyManagedFrameSize(width: frame.width)
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}
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}
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/// Visible only while the document is truly empty: the first typed character
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/// hides it, deleting everything brings it back.
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func refreshPlaceholderVisibility() {
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guard let placeholderView else { return }
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let shouldHide = (textStorage?.length ?? 0) > 0
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if placeholderView.isHidden != shouldHide {
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placeholderView.isHidden = shouldHide
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}
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}
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/// The text container's content area: where TextKit places the first line.
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private func placeholderFrame() -> NSRect {
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NSRect(
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x: textContainerInset.width,
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y: textContainerInset.height,
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width: max(bounds.width - textContainerInset.width * 2, 0),
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height: max(bounds.height - textContainerInset.height, 0)
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)
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}
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}
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private extension NSRect {
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func isApproximatelyEqual(to other: NSRect) -> Bool {
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abs(origin.x - other.origin.x) < 0.5
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&& abs(origin.y - other.origin.y) < 0.5
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&& abs(size.width - other.size.width) < 0.5
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&& abs(size.height - other.size.height) < 0.5
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}
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}
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