Implement dynamic window size change

3 files changed, 35 insertions, 3 deletions

diff --git a/vterm-module.c b/vterm-module.c
index 6f169c2..465fa27 100644
--- a/vterm-module.c
+++ b/vterm-module.c
@@ -173,7 +173,7 @@ static void vterm_redraw(VTerm *vt, emacs_env *env) {
 
   erase_buffer(env);
 
-  char buffer[rows * cols];
+  char buffer[(rows + 1) * cols];
   int length = 0;
   VTermScreenCell cell;
   VTermScreenCell lastCell;
@@ -208,7 +208,7 @@ static void vterm_redraw(VTerm *vt, emacs_env *env) {
 
   // row * (width + 1) because of newline character
   // col + 1 because (goto-char 1) sets point to first position
-  int point = (pos.row * 81) + pos.col + 1;
+  int point = (pos.row * (cols + 1)) + pos.col + 1;
   goto_char(env, point);
 }
 
@@ -358,6 +358,24 @@ static emacs_value Fvterm_kill(emacs_env *env, ptrdiff_t nargs,
   return env->intern(env, "nil");
 }
 
+static emacs_value Fvterm_set_size(emacs_env *env, ptrdiff_t nargs,
+                                   emacs_value args[], void *data) {
+  struct Term *term = env->get_user_ptr(env, args[0]);
+  int rows = env->extract_integer(env, args[1]);
+  int cols = env->extract_integer(env, args[2]);
+
+  int old_rows, old_cols;
+  vterm_get_size(term->vt, &old_rows, &old_cols);
+
+  if (cols != old_cols || rows != old_rows) {
+    struct winsize size = {rows, cols, 0, 0};
+    ioctl(term->masterfd, TIOCSWINSZ, &size);
+    vterm_set_size(term->vt, rows, cols);
+  }
+
+  return env->intern(env, "nil");
+}
+
 int emacs_module_init(struct emacs_runtime *ert) {
   emacs_env *env = ert->get_environment(ert);
   emacs_value fun;
@@ -374,6 +392,10 @@ int emacs_module_init(struct emacs_runtime *ert) {
                            "Kill the the shell process.", NULL);
   bind_function(env, "vterm-kill", fun);
 
+  fun = env->make_function(env, 3, 3, Fvterm_set_size,
+                           "Sets the size of the terminal.", NULL);
+  bind_function(env, "vterm-set-size", fun);
+
   provide(env, "vterm-module");
 
   return 0;
diff --git a/vterm-module.h b/vterm-module.h
index 2af8d47..57a2381 100644
--- a/vterm-module.h
+++ b/vterm-module.h
@@ -36,4 +36,6 @@ static emacs_value Fvterm_update(emacs_env *env, ptrdiff_t nargs,
                                  emacs_value args[], void *data);
 static emacs_value Fvterm_kill(emacs_env *env, ptrdiff_t nargs,
                                emacs_value args[], void *data);
+static emacs_value Fvterm_set_size(emacs_env *env, ptrdiff_t nargs,
+                                   emacs_value args[], void *data);
 int emacs_module_init(struct emacs_runtime *ert);
diff --git a/vterm.el b/vterm.el
index 8381f0b..e109560 100644
--- a/vterm.el
+++ b/vterm.el
@@ -23,7 +23,8 @@ be send to the terminal.")
         buffer-read-only t)
   (setq-local scroll-conservatively 101)
   (setq-local scroll-margin 0)
-  (add-hook 'kill-buffer-hook #'vterm-kill-buffer-hook t t))
+  (add-hook 'kill-buffer-hook #'vterm-kill-buffer-hook t t)
+  (add-hook 'window-size-change-functions #'vterm-window-size-change t t))
 
 ;; Keybindings
 (define-key vterm-mode-map [t] #'vterm-self-insert)
@@ -71,4 +72,11 @@ be send to the terminal.")
     (cancel-timer vterm-timer)
     (vterm-kill vterm-term)))
 
+(defun vterm-window-size-change (frame)
+  (dolist (window (window-list frame 1))
+    (let ((buffer (window-buffer window)))
+      (with-current-buffer buffer
+        (when (eq major-mode 'vterm-mode)
+          (vterm-set-size vterm-term (window-height) (window-width)))))))
+
 (provide 'vterm)