simplify - only need DispatchMessageW and WM_CHAR actually - no need for vsync - handle surrogate pairs

build.bat

@@ -1,6 +1,6 @@
 @echo off
 
-set libs=User32.lib Dwmapi.lib Gdi32.lib
+set libs=User32.lib Gdi32.lib
 
 set opts=-FC -GR- -EHa- -nologo -Zi
 set code=%cd%

win32_typing_test.c

@@ -1,6 +1,6 @@
 /*
 ** Win32 Typing Test Program
-**  v1.0.0 - Jan 19th 2024
+**  v1.1.0 - Jan 19th 2024
 **  by Allen Webster allenw@mr4th.com
 **
 ** public domain example program
@@ -8,7 +8,7 @@
 **
 **
 ** Tested on:
-**  Windows 10 English
+**  Windows 10 (English, Latvian, Emojis)
 **
 ** This is an example and a tool for gathering information about
 ** Win32 text input APIs.
@@ -25,9 +25,6 @@
 
 #include <Windows.h>
 
-// only for vsync in GDI
-#include <dwmapi.h>
-
 typedef LONG S32;
 typedef USHORT U16;
 typedef ULONG U32;
@@ -47,6 +44,9 @@ static void AppTypeCodepoint(U32 cp);
 
 static BOOL keep_running = 1;
 
+static WCHAR lo_surrogate = 0;
+static WCHAR hi_surrogate = 0;
+
 static LRESULT
 WindowProc(HWND   wnd,
            UINT   msg,
@@ -55,51 +55,53 @@ WindowProc(HWND   wnd,
   LRESULT result = 0;
   
   switch (msg){
-    case WM_PAINT:
-    {
-      PAINTSTRUCT ps;
-      BeginPaint(wnd, &ps);
-      AppRender(wnd);
-      EndPaint(wnd, &ps);
-    }break;
-    
     case WM_CHAR:
     {
-      //  When a user uses IME, their input is handled by
+      // When a WM_CHAR generally represents text input that
-      // WM_IME_CHAR messages, but additional WM_CHAR messages
+      //  should be inserted, but there are a few twists.
-      // get generated in the process.
       //
-      //  I'm not entirely sure what the best thing is to do with
+      // Sometimes WM_CHAR is triggered by controls that are
-      // them - but they appear to always be messages I want to ignore.
+      //  not text input, like Ctrl + Letter. To filter out
+      //  these cases we ignore values less than ' ' (0x20)
+      //  and the value 0x7F. See WM_KEYDOWN for a little
+      //  more on this issue.
       //
-      //  They also appear to be the only case where a WM_CHAR 
+      // When the user types a character that does not fit
-      // message has a scan code of zero.
+      //  in a single U16, a pair of WM_CHAR messages are sent.
+      //  Each WM_CHAR message in the pair contains a
+      //  "surrogate" (defined by UTF16) one "high" surrogate
+      //  followed by a "low" surrogate. A pair of surrogates
+      //  translates into a single typed codepoint.
       //
-      //  Therefore my best solution so far is to filter out WM_CHAR
+      // (Actually the docs don't clearly say one order
-      // messages that have a zero scan code.
+      //  or the other - I just support both)
       
-      U32 scan_code = ((lparam >> 16) & 0xFF);
+      U32 c = (wparam & 0xFFFF);
-      if (scan_code != 0){
+      if (c >= ' ' && c != 0x7F){
-        U32 cp16 = (wparam & 0xFFFF);
+        
-        if (cp16 >= ' ' && cp16 != 0x7F){
+        if (IS_LOW_SURROGATE(c)){
-          AppTypeCodepoint(cp16);
+          lo_surrogate = c;
+        }
+        else if (IS_HIGH_SURROGATE(c)){
+          hi_surrogate = c;
+        }
+        else{
+          AppTypeCodepoint(c);
+          lo_surrogate = 0;
+          hi_surrogate = 0;
         }
-      }
-    }break;
         
-    case WM_IME_CHAR:
+        if (hi_surrogate != 0 && lo_surrogate != 0){
-    {
+          if (IS_SURROGATE_PAIR(hi_surrogate, lo_surrogate)){
-      U32 cp16 = (wparam & 0xFFFF);
+            U32 cp = (0x10000 +
-      if (cp16 >= ' ' && cp16 != 0x7F){
+                      ((hi_surrogate & 0x3FF) << 10) +
-        AppTypeCodepoint(cp16);
+                      (lo_surrogate & 0x3FF) );
-      }
+            AppTypeCodepoint(cp);
-    }break;
+          }
+          hi_surrogate = 0;
+          lo_surrogate = 0;
+        }
         
-    case WM_UNICHAR:
-    {
-      U32 cp32 = wparam;
-      if (cp32 >= ' ' && cp32 != 0x7F){
-        AppTypeCodepoint(cp32);
       }
     }break;
     
@@ -143,6 +145,14 @@ WindowProc(HWND   wnd,
       }
     }break;
     
+    case WM_PAINT:
+    {
+      PAINTSTRUCT ps;
+      BeginPaint(wnd, &ps);
+      AppRender(wnd);
+      EndPaint(wnd, &ps);
+    }break;
+    
     case WM_CLOSE:
     {
       keep_running = 0;
@@ -158,6 +168,63 @@ WindowProc(HWND   wnd,
 }
 
 
+////////////////////////////////
+// Main
+
+static BOOL composition_enabled = 0;
+
+int
+WinMain(HINSTANCE hInstance,
+        HINSTANCE hPrevInstance,
+        LPSTR     lpCmdLine,
+        int       nShowCmd){
+  WNDCLASSW window_class = {0};
+  window_class.style         = CS_HREDRAW|CS_VREDRAW;
+  window_class.lpfnWndProc   = WindowProc;
+  window_class.hInstance     = hInstance;
+  window_class.hCursor       = LoadCursorA(0, IDC_ARROW);
+  window_class.lpszClassName = L"WindowClass";
+  
+  ATOM atom = RegisterClassW(&window_class);
+  if (atom == 0){
+    MessageBoxW(0, (WCHAR*)L"RegisterClassW failed\n", (WCHAR*)L"Fatal", MB_OK);
+    ExitProcess(1);
+  }
+  
+  DWORD style = WS_OVERLAPPEDWINDOW;
+  HWND wnd = CreateWindowW(L"WindowClass", L"Type Test", style,
+                           CW_USEDEFAULT, CW_USEDEFAULT,
+                           CW_USEDEFAULT, CW_USEDEFAULT,
+                           0, 0, hInstance, 0);
+  
+  // init
+  AppInit(wnd);
+  
+  // main loop
+  ShowWindow(wnd, SW_SHOW);
+  
+  keep_running = 1;
+  for (;keep_running;){
+    
+    // Handle Message Queue
+    BOOL wait = 1;
+    MSG msg;
+    for (;(wait?GetMessageW(&msg, 0, 0, 0):
+           PeekMessageW(&msg, 0, 0, 0, PM_REMOVE));){
+      wait = 0;
+      TranslateMessage(&msg);
+      DispatchMessageW(&msg);
+    }
+    
+    // render
+    AppRender(wnd);
+    
+    // sleep
+    Sleep(33);
+  }
+}
+
+
 ////////////////////////////////
 // App Implementation
 
@@ -271,79 +338,4 @@ AppRender(HWND wnd){
 }
 
 
-////////////////////////////////
-// Main
-
-static BOOL composition_enabled = 0;
-
-int
-WinMain(HINSTANCE hInstance,
-        HINSTANCE hPrevInstance,
-        LPSTR     lpCmdLine,
-        int       nShowCmd){
-  // window setup
-#define WINDOW_CLASS L"InputWindowClass"
-  
-  WNDCLASSW window_class = {0};
-  window_class.style         = CS_HREDRAW|CS_VREDRAW;
-  window_class.lpfnWndProc   = WindowProc;
-  window_class.hInstance     = hInstance;
-  window_class.hCursor       = LoadCursorA(0, IDC_ARROW);
-  window_class.lpszClassName = WINDOW_CLASS;
-  
-  ATOM atom = RegisterClassW(&window_class);
-  if (atom == 0){
-    MessageBoxW(0, (WCHAR*)L"RegisterClassW failed\n", (WCHAR*)L"Fatal", MB_OK);
-    ExitProcess(1);
-  }
-  
-  DWORD style = WS_OVERLAPPEDWINDOW;
-  HWND wnd = CreateWindowW(WINDOW_CLASS, L"Type Test", style,
-                           CW_USEDEFAULT, CW_USEDEFAULT,
-                           CW_USEDEFAULT, CW_USEDEFAULT,
-                           0, 0, hInstance, 0);
-  
-  // setup vsync
-  if (DwmIsCompositionEnabled(&composition_enabled) != S_OK){
-    composition_enabled = 0;
-  }
-  if (!composition_enabled){
-    MessageBoxW(0, (WCHAR*)L"No Vsync\n", (WCHAR*)L"Issue", MB_OK);
-  }
-  
-  // init
-  AppInit(wnd);
-  
-  // main loop
-  ShowWindow(wnd, SW_SHOW);
-  
-  keep_running = 1;
-  for (;keep_running;){
-    
-    // flush message queue
-    {
-      BOOL wait_for_message = 1;
-      MSG msg;
-      for (;(wait_for_message?
-             GetMessageW(&msg, 0, 0, 0):
-             PeekMessageW(&msg, 0, 0, 0, PM_REMOVE));){
-        wait_for_message = 0;
-        TranslateMessage(&msg);
-        DispatchMessage(&msg);
-      }
-    }
-    
-    // render
-    AppRender(wnd);
-    
-    // vsync or sleep
-    if (composition_enabled){
-      DwmFlush();
-    }
-    else{
-      Sleep(33);
-    }
-  }
-}
-
 //$ graphical //