Fix window_range expansion

It relied on the buffer first char being visible, and could trigger
segfaults when that was not the case.

2 files changed, 4 insertions, 7 deletions

diff --git a/src/main.cc b/src/main.cc
index 16b4a1a9..84c88012 100644
--- a/src/main.cc
+++ b/src/main.cc
@@ -305,12 +305,9 @@ static const EnvVarDesc builtin_env_vars[] = { {
         "window_range", false,
         [](StringView name, const Context& context, Quoting quoting) -> String
         {
-            const auto top_left = context.window().display_position({0, 0});
-            const auto window_dim = context.window().dimensions();
-
-            return format("{} {} {} {}", top_left->line, top_left->column,
-                                         window_dim.line - top_left->line,
-                                         window_dim.column - top_left->column);
+            auto setup = context.window().compute_display_setup(context);
+            return format("{} {} {} {}", setup.window_pos.line, setup.window_pos.column,
+                                         setup.window_range.line, setup.window_range.column);
         }
     }
 };
diff --git a/src/window.hh b/src/window.hh
index ad754568..dd7a325b 100644
--- a/src/window.hh
+++ b/src/window.hh
@@ -50,11 +50,11 @@ public:
     void clear_display_buffer();
     void run_resize_hook_ifn();
 
+    DisplaySetup compute_display_setup(const Context& context) const;
 private:
     Window(const Window&) = delete;
 
     void on_option_changed(const Option& option) override;
-    DisplaySetup compute_display_setup(const Context& context) const;
 
     friend class ClientManager;
     void run_hook_in_own_context(Hook hook, StringView param,