From 1ab4c071be58033d5452f69797ca8e2c32240cff Mon Sep 17 00:00:00 2001
From: Gabriel Schneider <gbrls@0x4200.cafe>
Date: Tue, 15 Sep 2026 16:28:57 -0300
Subject: Separate tag text geometry from physical pane grips

---
 src/macos/Sources/PardesView.swift | 77 ++++++++++++++++++++++++++++++++++----
 src/macos/pardes.h                 |  3 ++
 2 files changed, 72 insertions(+), 8 deletions(-)

(limited to 'src/macos')

diff --git a/src/macos/Sources/PardesView.swift b/src/macos/Sources/PardesView.swift
index 2d43cc38..0b16458e 100644
--- a/src/macos/Sources/PardesView.swift
+++ b/src/macos/Sources/PardesView.swift
@@ -911,6 +911,7 @@ final class PardesView: NSView {
         if !animatedPanels {
             presentedImages = frameImages
             presentedBodyLayers = snapshotBodyLayers()
+            presentedTagLayers = snapshotTagLayers()
         }
         presentationSerial &+= 1
         let animationWoke = pardes_frame_presented(animatedPanels)
@@ -1167,7 +1168,13 @@ final class PardesView: NSView {
         }
         if frozenImages == nil {
             drawBodyLayers(ctx, hideCursor:hideCursor)
+            drawTagLayers(ctx, hideCursor:hideCursor)
         } else {
+            for layer in presentedTagLayers {
+                layer.cells.withUnsafeBufferPointer { cells in
+                    if let base = cells.baseAddress { drawTagLayer(ctx, values:layer.values, cells:base, hideCursor:true) }
+                }
+            }
             for layer in presentedBodyLayers {
                 layer.cells.withUnsafeBufferPointer { cells in
                     if let base = cells.baseAddress { drawBodyLayer(ctx, values:layer.values, cells:base, hideCursor:true) }
@@ -1176,6 +1183,67 @@ final class PardesView: NSView {
         }
     }
 
+    private var presentedTagLayers: [FrozenBodyLayer] = []
+
+    private func snapshotTagLayers() -> [FrozenBodyLayer] {
+        var result: [FrozenBodyLayer] = []
+        for index in 0..<pardes_tag_layer_limit() {
+            let values = (0...10).map { Int(pardes_tag_layer_value(index, UInt32($0))) }
+            if values[0] == 0 { continue }
+            if let cells = pardes_tag_layer_cells(index) {
+                result.append(FrozenBodyLayer(values: values, cells: Array(UnsafeBufferPointer(start: cells, count: values[0]))))
+            }
+        }
+        return result
+    }
+
+    private func drawTagLayers(_ ctx: CGContext, hideCursor: Bool) {
+        for index in 0..<pardes_tag_layer_limit() {
+            let values = (0...10).map { Int(pardes_tag_layer_value(index, UInt32($0))) }
+            if values[0] == 0 { continue }
+            if let cells = pardes_tag_layer_cells(index) { drawTagLayer(ctx, values: values, cells: cells, hideCursor: hideCursor) }
+        }
+    }
+
+    private func drawTagLayer(_ ctx: CGContext, values: [Int], cells: UnsafePointer<pardes_cell_s>, hideCursor: Bool) {
+        let left = CGFloat(values[4]) * cellWidth
+        let y = CGFloat(values[5]) * cellHeight + taglines.top(row: values[5], canvasHeight: bounds.height)
+        let viewport = CGRect(x: left, y: y, width: CGFloat(values[6]) * cellWidth, height: taglines.height)
+        ctx.saveGState()
+        ctx.clip(to: viewport)
+        fill(ctx, viewport, UInt32(values[10]), 1)
+        for pass in 0...1 {
+            for col in 0..<values[0] {
+                var cell = cells[col]
+                let isCursor = !hideCursor && col == values[8]
+                let style = resolve(cell, block: isCursor && values[9] == 0, ground: UInt32(values[10]), clearGround: false)
+                let x = left + CGFloat(col) * taglines.width
+                if pass == 0 {
+                    fill(ctx, CGRect(x: x, y: y, width: taglines.width, height: taglines.height), style.bg, 1)
+                    continue
+                }
+                let text = withUnsafeBytes(of: &cell.text) { String(decoding: $0.prefix(Int(cell.len)), as: UTF8.self) }
+                if style.visible && !text.isEmpty && text != " " {
+                    let face = Face(bold: cell.attrs & UInt16(PARDES_ATTR_BOLD) != 0, italic: cell.attrs & UInt16(PARDES_ATTR_ITALIC) != 0)
+                    ctx.saveGState()
+                    ctx.translateBy(x: 0, y: bounds.height)
+                    ctx.scaleBy(x: 1, y: -1)
+                    let baseline = bounds.height - y - taglines.ascent
+                    drawRules(ctx, cell, style, x: x, width: taglines.width, baseline: baseline)
+                    setFill(ctx, style.fg, style.alpha)
+                    ctx.textPosition = CGPoint(x: x, y: baseline)
+                    let line = NSAttributedString(string: text, attributes: [fontAttribute: taglines.fonts[face.rawValue]])
+                    CTLineDraw(CTLineCreateWithAttributedString(line as CFAttributedString), ctx)
+                    ctx.restoreGState()
+                }
+                if isCursor && values[9] != 0 {
+                    fill(ctx, CGRect(x: x, y: y, width: max(1, taglines.width / 8), height: taglines.height), style.fg, 1)
+                }
+            }
+        }
+        ctx.restoreGState()
+    }
+
     private struct FrozenBodyLayer {
         let values: [Int]
         let cells: [pardes_cell_s]
@@ -2012,14 +2080,7 @@ final class PardesView: NSView {
         }
         sampledBodyPointer = sampled
         let row = min(max(Int(sampled.y / cellHeight), 0), rows - 1)
-        // The column comes from the core, because a tag row's glyphs step at
-        // the tagline face's narrower pitch and a body-pitch click drifts one
-        // word further right for every word along the row. The SDL shell asks
-        // the identical rule (`pardes.gridColAt`). Points on both sides: only
-        // the ratio of x to the two widths is read.
-        let col = min(max(Int(pardes_grid_col_at(
-            Float(sampled.x), UInt16(clamping: row),
-            Float(cellWidth), Float(taglines.width))), 0), cols - 1)
+        let col = min(max(Int(sampled.x / cellWidth), 0), cols - 1)
         return GridPoint(col: UInt16(col), row: UInt16(row))
     }
 
diff --git a/src/macos/pardes.h b/src/macos/pardes.h
index 9f9aef60..e72f134a 100644
--- a/src/macos/pardes.h
+++ b/src/macos/pardes.h
@@ -341,6 +341,9 @@ void pardes_mouse_pixel(pardes_mouse_button_e button, pardes_mouse_kind_e kind,
     uint16_t col, uint16_t row, uint32_t mods, float x, float y,
     float body_w, float body_h, float tagline_w, float tagline_h);
 void pardes_row_metrics(uint16_t body_w, uint16_t body_h, uint16_t tagline_w, uint16_t tagline_h);
+uint32_t pardes_tag_layer_limit(void);
+uint32_t pardes_tag_layer_value(uint32_t index, uint32_t field);
+const pardes_cell_s *pardes_tag_layer_cells(uint32_t index);
 uint32_t pardes_body_layer_limit(void);
 uint32_t pardes_body_layer_value(uint32_t index, uint32_t field);
 const pardes_cell_s *pardes_body_layer_cells(uint32_t index);
-- 
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