Table border style now has multiple colors and selectors

Sources/MarkdownUI/Theme/BlockStyle/TableBorderStyle.swift

@@ -31,15 +31,37 @@ import SwiftUI
 ///
 /// ![](CustomTableBorders)
 public struct TableBorderStyle {
-  /// The visible table borders.
-  public var visibleBorders: TableBorderSelector
+  public struct Border {
+    /// The visible table borders.
+    public var visibleBorders: TableBorderSelector
 
-  /// The table border color.
-  public var color: Color
+    /// The table border color.
+    public var color: Color
+
+    public init(visibleBorders: TableBorderSelector, color: Color) {
+      self.visibleBorders = visibleBorders
+      self.color = color
+    }
+  }
+
+  /// The table's list of borders
+  public var borders: [Border]
 
   /// The table border stroke style.
   public var strokeStyle: StrokeStyle
 
+  /// Creates a table border style with the given borders and stroke style.
+  /// - Parameters:
+  ///   - borders: The visible table borders.
+  ///   - strokeStyle: The table border stroke style.
+  public init(
+    _ borders: [Border],
+    strokeStyle: StrokeStyle
+  ) {
+    self.borders = borders
+    self.strokeStyle = strokeStyle
+  }
+
   /// Creates a table border style with the given visible borders, color, and stroke style.
   /// - Parameters:
   ///   - visibleBorders: The visible table borders.
@@ -50,8 +72,7 @@ public struct TableBorderStyle {
     color: Color,
     strokeStyle: StrokeStyle
   ) {
-    self.visibleBorders = visibleBorders
-    self.color = color
+    self.borders = [.init(visibleBorders: visibleBorders, color: color)]
     self.strokeStyle = strokeStyle
   }
 

Sources/MarkdownUI/Views/Blocks/TableBorderSelector.swift

@@ -57,6 +57,78 @@ extension TableBorderSelector {
     }
   }
 
+  /// A table border selector that selects the inside borders of a table's first row.
+  public static var insideBordersFirstRow: TableBorderSelector {
+    TableBorderSelector { tableBounds, borderWidth in
+      guard tableBounds.rowCount > 0 else { return [] }
+      let firstRowBounds = tableBounds.bounds(forRow: 0)
+
+      return [
+        CGRect(
+          origin: .init(x: firstRowBounds.minX, y: firstRowBounds.maxY - borderWidth),
+          size: .init(width: firstRowBounds.width, height: borderWidth)
+        )
+      ] + (0..<tableBounds.columnCount - 1)
+        .map {
+          tableBounds.bounds(forColumn: $0)
+            .insetBy(dx: -borderWidth, dy: -borderWidth)
+        }
+        .map {
+          CGRect(
+            origin: .init(x: $0.maxX - borderWidth, y: firstRowBounds.minY),
+            size: .init(width: borderWidth, height: firstRowBounds.height)
+          )
+        }
+    }
+  }
+
+  /// A table border selector that selects the inside borders of a table, except for the first row.
+  public static var insideBordersExceptFirstRow: TableBorderSelector {
+    TableBorderSelector { tableBounds, borderWidth in
+      Self.insideHorizontalBordersExceptFirstRow.rectangles(tableBounds, borderWidth)
+        + Self.insideVerticalBordersExceptFirstRow.rectangles(tableBounds, borderWidth)
+    }
+  }
+
+  /// A table border selector that selects the inside horizontal borders of a table, except for the first row.
+  public static var insideHorizontalBordersExceptFirstRow: TableBorderSelector {
+    TableBorderSelector { tableBounds, borderWidth in
+      let rowCount = tableBounds.rowCount
+      guard rowCount > 1 else { return [] }
+      return (1..<rowCount - 1)
+        .map {
+          tableBounds.bounds(forRow: $0)
+            .insetBy(dx: -borderWidth, dy: -borderWidth)
+        }
+        .map {
+          CGRect(
+            origin: .init(x: $0.minX, y: $0.maxY - borderWidth),
+            size: .init(width: $0.width, height: borderWidth)
+          )
+        }
+    }
+  }
+
+  /// A table border selector that selects the inside vertical borders of a table, except for the first row.
+  public static var insideVerticalBordersExceptFirstRow: TableBorderSelector {
+    TableBorderSelector { tableBounds, borderWidth in
+      let rowCount = tableBounds.rowCount
+      guard rowCount > 1 else { return [] }
+      let firstRowBounds = tableBounds.bounds(forRow: 0)
+      return (0..<tableBounds.columnCount - 1)
+        .map {
+          tableBounds.bounds(forColumn: $0)
+            .insetBy(dx: -borderWidth, dy: -borderWidth)
+        }
+        .map {
+          CGRect(
+            origin: .init(x: $0.maxX - borderWidth, y: firstRowBounds.maxY),
+            size: .init(width: borderWidth, height: $0.height - firstRowBounds.maxY)
+          )
+        }
+    }
+  }
+
   /// A table border selector that selects the horizontal borders of a table.
   public static var horizontalBorders: TableBorderSelector {
     TableBorderSelector { tableBounds, borderWidth in

Sources/MarkdownUI/Views/Blocks/TableBorderView.swift

@@ -11,15 +11,18 @@ struct TableBorderView: View {
 
   var body: some View {
     ZStack(alignment: .topLeading) {
-      let rectangles = self.tableBorderStyle.visibleBorders.rectangles(
-        self.tableBounds, self.borderWidth
-      )
-      ForEach(0..<rectangles.count, id: \.self) {
-        let rectangle = rectangles[$0]
-        Rectangle()
-          .strokeBorder(self.tableBorderStyle.color, style: self.tableBorderStyle.strokeStyle)
-          .offset(x: rectangle.minX, y: rectangle.minY)
-          .frame(width: rectangle.width, height: rectangle.height)
+      ForEach(0..<self.tableBorderStyle.borders.count, id: \.self) {
+        let border = self.tableBorderStyle.borders[$0]
+        let rectangles = border.visibleBorders.rectangles(
+          self.tableBounds, self.borderWidth
+        )
+        ForEach(0..<rectangles.count, id: \.self) {
+          let rectangle = rectangles[$0]
+          Rectangle()
+            .strokeBorder(border.color, style: self.tableBorderStyle.strokeStyle)
+            .offset(x: rectangle.minX, y: rectangle.minY)
+            .frame(width: rectangle.width, height: rectangle.height)
+        }
       }
     }
   }