Fix input method bugs on macos.

There are a lot of problems about input methods and we will definitely
spend more on this. And the bug made me awkward on today's interview
when showing the demo.

1 files changed, 19 insertions, 8 deletions

diff --git a/include/cru/platform/gui/InputMethod.h b/include/cru/platform/gui/InputMethod.h
index 45e11c06..90d6b15a 100644
--- a/include/cru/platform/gui/InputMethod.h
+++ b/include/cru/platform/gui/InputMethod.h
@@ -21,6 +21,24 @@ struct CompositionText {
   TextRange selection;
 };
 
+/**
+ * \remarks I think it's time to standatdize this. The most important thing is
+ * the events.
+ *
+ * The events hould be triggered in this way.
+ * 1. Any time the IME begins to work, CompositionStartEvent is fired. Only
+ * once. Not triggerred again until CompositionEndEvent is fired.
+ * 2. Any time composition state changed, maybe user typed more characters, or
+ * user commit part of composition, CompositionEvent is fired.
+ * 3. TextEvent is fired when user commit part or whole of the composition. And
+ * you can use the args to get what characters are committed. So it is where you
+ * get the real text user want to give you.
+ * 4. Whenever a commit happens, TextEvent first, followed by CompositionEvent.
+ * Each for once. So use the TextEvent to get real input and use
+ * CompositionEvent to update UI.
+ * 5. When composition stops, a final CompositionEndEvent is fired. Also only
+ * once.
+ */
 struct IInputMethodContext : virtual IPlatformResource {
   // Return true if you should draw composition text manually. Return false if
   // system will take care of that for you.
@@ -36,20 +54,13 @@ struct IInputMethodContext : virtual IPlatformResource {
 
   virtual CompositionText GetCompositionText() = 0;
 
-  // Set the candidate window lefttop. Relative to window lefttop. Use this
+  // Set the candidate window left-top. Relative to window left-top. Use this
   // method to prepare typing.
   virtual void SetCandidateWindowPosition(const Point& point) = 0;
 
-  // Triggered when user starts composition.
   virtual IEvent<std::nullptr_t>* CompositionStartEvent() = 0;
-
-  // Triggered when user stops composition.
   virtual IEvent<std::nullptr_t>* CompositionEndEvent() = 0;
-
-  // Triggered every time composition text changes.
   virtual IEvent<std::nullptr_t>* CompositionEvent() = 0;
-
   virtual IEvent<StringView>* TextEvent() = 0;
 };
 }  // namespace cru::platform::gui
-