From ae3c33ec8cb9ad8e08f1609def6653f85e7596c0 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Sat, 28 Jan 2023 13:01:21 +0530
Subject: [PATCH] Implement rate control

---
 src/calibre/utils/windows/winspeech.cpp | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/calibre/utils/windows/winspeech.cpp b/src/calibre/utils/windows/winspeech.cpp
index eea73795be..4dd7a1ddb2 100644
--- a/src/calibre/utils/windows/winspeech.cpp
+++ b/src/calibre/utils/windows/winspeech.cpp
@@ -442,12 +442,27 @@ class Synthesizer {
         }
     }
 
-    double volume() const { return synth.Options().AudioVolume(); }
+    double volume() const {
+        return synth.Options().AudioVolume();
+    }
+
     void volume(double val) {
         if (val < 0 || val > 1) throw std::out_of_range("Invalid volume value must be between 0 and 1");
+        std::scoped_lock sl(recursive_lock);
         synth.Options().AudioVolume(val);
     }
 
+    double rate() const {
+        return synth.Options().SpeakingRate();
+    }
+
+    void rate(double val) {
+        if (val < 0.5 || val > 6.0) throw std::out_of_range("Invalid rate value must be between 0.5 and 6");
+        std::scoped_lock sl(recursive_lock);
+        synth.Options().SpeakingRate(val);
+    }
+
+
 };
 
 static Synthesizer sx;
@@ -789,6 +804,13 @@ handle_stdin_message(winrt::hstring const &&msg) {
             }
             output(cmd_id, "volume", {{"value", sx.volume()}});
         }
+        else if (command == L"rate") {
+            if (parts.size()) {
+                auto rate = parse_double(parts[0].data());
+                sx.rate(rate);
+            }
+            output(cmd_id, "rate", {{"value", sx.rate()}});
+        }
         else if (command == L"save") {
             handle_save(cmd_id, parts);
         }