Merge pull request #187 from mitchellh/clear-at-prompt

clear_screen uses FF (0x0C) if cursor is at prompt

src/termio/Exec.zig

@@ -258,6 +258,7 @@ pub fn resize(
 
 /// Clear the screen.
 pub fn clearScreen(self: *Exec, history: bool) !void {
+    {
         self.renderer_state.mutex.lock();
         defer self.renderer_state.mutex.unlock();
 
@@ -270,8 +271,21 @@ pub fn clearScreen(self: *Exec, history: bool) !void {
         // Clear our scrollback
         if (history) try self.terminal.screen.clear(.history);
 
+        // If we're not at a prompt, we clear the screen manually using
+        // the terminal screen state. If we are at a prompt, we send
+        // form-feed so that the shell can repaint the entire screen.
+        if (!self.terminal.cursorIsAtPrompt()) {
             // Clear above the cursor
             try self.terminal.screen.clear(.above_cursor);
+
+            // Exit
+            return;
+        }
+    }
+
+    // If we reached here it means we're at a prompt, so we send a form-feed.
+    assert(self.terminal.cursorIsAtPrompt());
+    try self.queueWrite(&[_]u8{0x0C});
 }
 
 pub inline fn queueWrite(self: *Exec, data: []const u8) !void {