1 files changed, 29 insertions, 0 deletions
diff --git a/src/macos.zig b/src/macos.zig
index bbfb8c08..d0d379de 100644
--- a/src/macos.zig
+++ b/src/macos.zig
@@ -92,6 +92,7 @@ pub const Image = extern struct {
     iw: u32,
     ih: u32,
     rgba: [*]const u8,
+    paper_bg: u32,
 };
 
 pub const Runtime = extern struct {
@@ -902,6 +903,11 @@ export fn pardes_window_opacity() u8 {
     return st.core.settings.window_opacity;
 }
 
+/// Public AppKit backdrop strength, independent of background paint opacity.
+export fn pardes_window_blur() u8 {
+    return if (state) |st| st.core.settings.window_blur else 0;
+}
+
 fn taglineFontPercent(core: ?*const pardes.Pardes) u8 {
     return if (core) |p| p.settings.font.tagline_percent else pardes.config.gui_tagline_font_percent;
 }
@@ -1879,6 +1885,10 @@ fn collectImages(st: *State, surface: *const pardes.Surface) void {
             .iw = @intCast(place.iw),
             .ih = @intCast(place.ih),
             .rgba = place.rgba.ptr,
+            .paper_bg = if (place.native.paper_bg) |bg|
+                @as(u32, bg[0]) << 16 | @as(u32, bg[1]) << 8 | bg[2]
+            else
+                color_default,
         };
         st.images_len += 1;
     }
@@ -2611,6 +2621,7 @@ test "pardes.h declares every export the way it is defined" {
     try expectSameAbi(@TypeOf(c.pardes_active_dirty), @TypeOf(pardes_active_dirty));
     try expectSameAbi(@TypeOf(c.pardes_theme_bg), @TypeOf(pardes_theme_bg));
     try expectSameAbi(@TypeOf(c.pardes_window_opacity), @TypeOf(pardes_window_opacity));
+    try expectSameAbi(@TypeOf(c.pardes_window_blur), @TypeOf(pardes_window_blur));
 }
 
 test "pardes.h matches the Zig boundary" {
@@ -2941,3 +2952,21 @@ test "mac tag layer ABI preserves logical capacity and physical grip" {
     try std.testing.expectEqual(@as(u8, 'G'), canonical[18].text[0]);
     try std.testing.expectEqual(encodeCell(.{}).len, canonical[10].len);
 }
+
+test "mac window blur builtin reaches the ABI without changing opacity" {
+    try std.testing.expectEqual(@as(u8, 0), pardes_window_blur());
+    const gpa = std.testing.allocator;
+    const core = try pardes.Pardes.init(gpa, .{ .tty_only = true, .cols = 8, .rows = 3 });
+    defer core.deinit();
+    state = .{ .gpa = gpa, .threaded = undefined, .io = std.testing.io, .core = core, .runtime = .{}, .config_arena = .init(gpa), .prompt_rcs = .{} };
+    defer {
+        state.?.config_arena.deinit();
+        state = null;
+    }
+    try std.testing.expect(core.executeBuiltinLine(0, "WindowOpacity 71"));
+    for ([_][]const u8{ "WindowBlur 0", "WindowBlur 40", "WindowBlur 100", "WindowBlur 101", "WindowBlur 0" }, [_]u8{ 0, 40, 100, 100, 0 }) |command, expected| {
+        try std.testing.expect(core.executeBuiltinLine(0, command));
+        try std.testing.expectEqual(expected, pardes_window_blur());
+        try std.testing.expectEqual(@as(u8, 71), pardes_window_opacity());
+    }
+}