macos: return valid selection range

include/ghostty.h

@@ -557,6 +557,7 @@ uintptr_t ghostty_surface_selection(ghostty_surface_t, char*, uintptr_t);
 #ifdef __APPLE__
 void ghostty_surface_set_display_id(ghostty_surface_t, uint32_t);
 void* ghostty_surface_quicklook_font(ghostty_surface_t);
+void ghostty_surface_selection_range(ghostty_surface_t, uint32_t*, uint32_t*);
 #endif
 
 ghostty_inspector_t ghostty_surface_inspector(ghostty_surface_t);

macos/Sources/Ghostty/SurfaceView_AppKit.swift

@@ -931,12 +931,14 @@ extension Ghostty.SurfaceView: NSTextInputClient {
 
     func selectedRange() -> NSRange {
         guard let surface = self.surface else { return NSRange() }
-        guard ghostty_surface_has_selection(surface) else { return NSRange() }
         
-        // If we have a selection, we just return a non-empty range. The actual
+        // Get our range from the Ghostty API. There is a race condition between getting the
-        // values are meaningless but the non-emptiness of it tells AppKit we
+        // range and actually using it since our selection may change but there isn't a good
-        // have a selection.
+        // way I can think of to solve this for AppKit.
-        return NSRange(location: 0, length: 1)
+        var start: UInt32 = 0;
+        var len: UInt32 = 0;
+        ghostty_surface_selection_range(surface, &start, &len);
+        return NSRange(location: Int(start), length: Int(len))
     }
 
     func setMarkedText(_ string: Any, selectedRange: NSRange, replacementRange: NSRange) {
@@ -961,12 +963,18 @@ extension Ghostty.SurfaceView: NSTextInputClient {
     }
 
     func attributedSubstring(forProposedRange range: NSRange, actualRange: NSRangePointer?) -> NSAttributedString? {
-        // We ignore the proposed range and always return the selection from
+        Ghostty.logger.warning("pressure substring range=\(range) selectedRange=\(self.selectedRange())")
-        // this (if we have one). This enables features like QuickLook. I don't
-        // know if this breaks anything else...
         guard let surface = self.surface else { return nil }
         guard ghostty_surface_has_selection(surface) else { return nil }
         
+        // If the range is empty then we don't need to return anything
+        guard range.length > 0 else { return nil }
+        
+        // I used to do a bunch of testing here that the range requested matches the
+        // selection range or contains it but a lot of macOS system behaviors request
+        // bogus ranges I truly don't understand so we just always return the
+        // attributed string containing our selection which is... weird but works?
+        
         // Get our selection. We cap it at 1MB for the purpose of this. This is
         // arbitrary. If this is a good reason to increase it I'm happy to.
         let v = String(unsafeUninitializedCapacity: 1000000) {

src/Surface.zig

@@ -849,6 +849,38 @@ pub fn selectionString(self: *Surface, alloc: Allocator) !?[]const u8 {
     });
 }
 
+/// This returns the selection range offset from the beginning of the
+/// viewport. If the selection is not entirely within the viewport then
+/// this will return null.
+///
+/// This is a oddly specific function that is used with macOS to enable
+/// NSTextInputClient to work properly for features such as the IME Emoji
+/// keyboard and QuickLook amongst other things.
+pub fn selectionRange(self: *Surface) ?struct {
+    start: u32,
+    len: u32,
+} {
+    self.renderer_state.mutex.lock();
+    defer self.renderer_state.mutex.unlock();
+
+    // Get the TL/BR pins for the selection
+    const sel = self.io.terminal.screen.selection orelse return null;
+    const tl = sel.topLeft(&self.io.terminal.screen);
+    const br = sel.bottomRight(&self.io.terminal.screen);
+
+    // Convert the pins to coordinates (x,y)
+    const tl_pt = self.io.terminal.screen.pages.pointFromPin(.viewport, tl) orelse return null;
+    const br_pt = self.io.terminal.screen.pages.pointFromPin(.viewport, br) orelse return null;
+    const tl_coord = tl_pt.coord();
+    const br_coord = br_pt.coord();
+
+    // Utilize viewport sizing to convert to offsets
+    const start = tl_coord.y * self.io.terminal.screen.pages.cols + tl_coord.x;
+    const end = br_coord.y * self.io.terminal.screen.pages.cols + br_coord.x;
+
+    return .{ .start = start, .len = end - start };
+}
+
 /// Returns the pwd of the terminal, if any. This is always copied because
 /// the pwd can change at any point from termio. If we are calling from the IO
 /// thread you should just check the terminal directly.

src/apprt/embedded.zig

@@ -1803,6 +1803,26 @@ pub const CAPI = struct {
             return copy;
         }
 
+        /// This returns the start and length of the current selection range
+        /// in viewport coordinates. If the selection is not visible in the
+        /// viewport completely then this will return 0,0. This rather odd
+        /// detail is due to the current usage of this in the macOS app where
+        /// selections are only meaningful if they're in the viewport. We can
+        /// change this behavior if we have something useful to do with the
+        /// selection range outside of the viewport in the future.
+        export fn ghostty_surface_selection_range(
+            ptr: *Surface,
+            start: *u32,
+            len: *u32,
+        ) void {
+            start.* = 0;
+            len.* = 0;
+
+            const range = ptr.core_surface.selectionRange() orelse return;
+            start.* = range.start;
+            len.* = range.len;
+        }
+
         export fn ghostty_inspector_metal_init(ptr: *Inspector, device: objc.c.id) bool {
             return ptr.initMetal(objc.Object.fromId(device));
         }