Support Math rendering1.2.0

1 files changed, 52 insertions, 0 deletions

diff --git a/Sources/NorgUI/Math/NorgInlineText.swift b/Sources/NorgUI/Math/NorgInlineText.swift
new file mode 100644
index 0000000..0d607f5
--- /dev/null
+++ b/Sources/NorgUI/Math/NorgInlineText.swift
@@ -0,0 +1,52 @@
+import NorgKit
+import SwiftUI
+
+/// Renders a run of inline spans as a single `Text`, splicing in rendered
+/// images for `.math` spans when a ``NorgMathRenderer`` is configured.
+struct NorgInlineText: View {
+  @Environment(\.norgTheme) private var theme
+
+  let spans: [InlineSpan]
+  var baseFont: Font = .body
+
+  @State private var images: [Int: NorgMathImage] = [:]
+
+  var body: some View {
+    text
+      .task(id: renderKey) { await renderMath() }
+  }
+
+  private var text: Text {
+    var result = Text(verbatim: "")
+    for (index, span) in spans.enumerated() {
+      if span.styles.contains(.math), let image = images[index] {
+        result = result + Text(image.swiftUIImage).baselineOffset(-image.descent)
+      } else {
+        result = result + Text(AttributedString(norg: [span], baseFont: baseFont, theme: theme))
+      }
+    }
+    return result
+  }
+
+  private var mathSpans: [(offset: Int, element: InlineSpan)] {
+    spans.enumerated().filter { $0.element.styles.contains(.math) }.map { ($0.offset, $0.element) }
+  }
+
+  private var renderKey: String {
+    mathSpans.map { "\($0.offset):\($0.element.text)" }.joined(separator: "|")
+      + "@\(theme.mathFontSize)"
+  }
+
+  @MainActor
+  private func renderMath() async {
+    guard let renderer = theme.mathRenderer, !mathSpans.isEmpty else { return }
+    for (index, span) in mathSpans where images[index] == nil {
+      if let image = await renderer.render(
+        latex: span.text, mode: .inline, fontSize: theme.mathFontSize, color: nil)
+      {
+        images[index] = image
+      }
+      await Task.yield()
+    }
+  }
+}