Add OSC 8 hyperlink support with click-to-open

Use the ghostty HTML formatter API to detect hyperlink spans and
their URIs, then apply text properties (help-echo, mouse-face,
keymap) so users can click or press RET on terminal hyperlinks
to open them in a browser.

Author: dakra

README.md

@@ -123,6 +123,7 @@ Soft-wrapped newlines are automatically stripped from copied text.
 ### Shell Integration
 - Directory tracking via OSC 7
 - Title tracking (buffer renamed from OSC 2)
+- OSC 8 hyperlinks — clickable URLs in terminal output (click or `RET` to open)
 - OSC 52 clipboard support (opt-in, for remote sessions)
 - `INSIDE_EMACS` and `EMACS_GHOSTEL_PATH` environment variables
 

ghostel.el

@@ -777,6 +777,31 @@ stripped so the copied text matches the original terminal content."
       (message "Copied to kill ring")))
   (ghostel-copy-mode-exit))
 
+;;; Hyperlinks (OSC 8)
+
+(defvar ghostel-link-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map [mouse-1] #'ghostel-open-link-at-click)
+    (define-key map [mouse-2] #'ghostel-open-link-at-click)
+    (define-key map (kbd "RET") #'ghostel-open-link-at-point)
+    map)
+  "Keymap for clickable hyperlinks in ghostel buffers.")
+
+(defun ghostel-open-link-at-click (event)
+  "Open the hyperlink at the mouse click position."
+  (interactive "e")
+  (let* ((pos (posn-point (event-start event)))
+         (url (get-text-property pos 'help-echo)))
+    (when (and url (stringp url) (string-match-p "\\`https?://" url))
+      (browse-url url))))
+
+(defun ghostel-open-link-at-point ()
+  "Open the hyperlink at point."
+  (interactive)
+  (let ((url (get-text-property (point) 'help-echo)))
+    (when (and url (stringp url) (string-match-p "\\`https?://" url))
+      (browse-url url))))
+
 ;;; Callbacks from native module
 
 (defun ghostel--osc52-handle (_selection base64-data)

src/emacs.zig

@@ -184,6 +184,52 @@ pub const Env = struct {
         _ = self.call1(self.intern("provide"), self.intern(feature));
     }
 
+    // --- Buffer helpers ---
+
+    pub fn point(self: Env) Value {
+        return self.call0(self.intern("point"));
+    }
+
+    pub fn gotoChar(self: Env, pos: Value) void {
+        _ = self.call1(self.intern("goto-char"), pos);
+    }
+
+    pub fn gotoCharN(self: Env, pos: i64) void {
+        _ = self.call1(self.intern("goto-char"), self.makeInteger(pos));
+    }
+
+    pub fn insert(self: Env, text: []const u8) void {
+        _ = self.call1(self.intern("insert"), self.makeString(text));
+    }
+
+    pub fn forwardLine(self: Env, n: i64) i64 {
+        return self.extractInteger(self.call1(self.intern("forward-line"), self.makeInteger(n)));
+    }
+
+    pub fn moveToColumn(self: Env, col: i64) void {
+        _ = self.call1(self.intern("move-to-column"), self.makeInteger(col));
+    }
+
+    pub fn eraseBuffer(self: Env) void {
+        _ = self.call0(self.intern("erase-buffer"));
+    }
+
+    pub fn lineEndPosition(self: Env) Value {
+        return self.call0(self.intern("line-end-position"));
+    }
+
+    pub fn pointMax(self: Env) Value {
+        return self.call0(self.intern("point-max"));
+    }
+
+    pub fn deleteRegion(self: Env, start: Value, end: Value) void {
+        _ = self.call2(self.intern("delete-region"), start, end);
+    }
+
+    pub fn putTextProperty(self: Env, start: Value, end: Value, prop: Value, value: Value) void {
+        _ = self.call4(self.intern("put-text-property"), start, end, prop, value);
+    }
+
     /// Signal an error with a message string.
     pub fn signalError(self: Env, msg: []const u8) void {
         self.nonLocalExitSignal(

src/ghostty.zig

@@ -106,3 +106,10 @@ pub const CURSOR_BLOCK_HOLLOW: c_int = c.GHOSTTY_RENDER_STATE_CURSOR_VISUAL_STYL
 pub const SCROLL_TOP: c_int = c.GHOSTTY_SCROLL_VIEWPORT_TOP;
 pub const SCROLL_BOTTOM: c_int = c.GHOSTTY_SCROLL_VIEWPORT_BOTTOM;
 pub const SCROLL_DELTA: c_int = c.GHOSTTY_SCROLL_VIEWPORT_DELTA;
+
+// Formatter types and constants
+pub const Formatter = c.GhosttyFormatter;
+pub const FormatterTerminalOptions = c.GhosttyFormatterTerminalOptions;
+pub const FormatterTerminalExtra = c.GhosttyFormatterTerminalExtra;
+pub const FormatterScreenExtra = c.GhosttyFormatterScreenExtra;
+pub const FORMATTER_FORMAT_HTML: c_int = c.GHOSTTY_FORMATTER_FORMAT_HTML;