Make JACK Standalone more useful on windows

Signed-off-by: falkTX <falktx@falktx.com>

distrho/src/DistrhoPluginJACK.cpp

@@ -907,6 +907,36 @@ int main(int argc, char* argv[])
         return runSelfTests() ? 0 : 1;
 #endif
 
+#if defined(DISTRHO_OS_WINDOWS) && DISTRHO_PLUGIN_HAS_UI
+    /* the code below is based on
+     * https://www.tillett.info/2013/05/13/how-to-create-a-windows-program-that-works-as-both-as-a-gui-and-console-application/
+     */
+    bool hasConsole = false;
+
+    HANDLE consoleHandleOut, consoleHandleError;
+
+    if (AttachConsole(ATTACH_PARENT_PROCESS))
+    {
+        // Redirect unbuffered STDOUT to the console
+        consoleHandleOut = GetStdHandle(STD_OUTPUT_HANDLE);
+        if (consoleHandleOut != INVALID_HANDLE_VALUE)
+        {
+            freopen("CONOUT$", "w", stdout);
+            setvbuf(stdout, NULL, _IONBF, 0);
+        }
+
+        // Redirect unbuffered STDERR to the console
+        consoleHandleError = GetStdHandle(STD_ERROR_HANDLE);
+        if (consoleHandleError != INVALID_HANDLE_VALUE)
+        {
+            freopen("CONOUT$", "w", stderr);
+            setvbuf(stderr, NULL, _IONBF, 0);
+        }
+
+        hasConsole = true;
+    }
+#endif
+
     jack_status_t  status = jack_status_t(0x0);
     jack_client_t* client = jackbridge_client_open(DISTRHO_PLUGIN_NAME, JackNoStartServer, &status);
 
@@ -950,9 +980,19 @@ int main(int argc, char* argv[])
             d_stderr("Failed to create the JACK client, cannot continue!");
 
        #if defined(DISTRHO_OS_WINDOWS) && DISTRHO_PLUGIN_HAS_UI
+        // make sure message box is high-dpi aware
+        if (const HMODULE user32 = LoadLibrary("user32.dll"))
+        {
+            typedef BOOL(WINAPI* SPDA)(void);
+            if (const SPDA SetProcessDPIAware = (SPDA)GetProcAddress(user32, "SetProcessDPIAware"))
+                SetProcessDPIAware();
+            FreeLibrary(user32);
+        }
+
         const String win32error = "Failed to create JACK client, reason was:\n" + errorString;
         MessageBoxA(nullptr, win32error.buffer(), "", MB_ICONERROR);
        #endif
+
         return 1;
     }
 
@@ -992,6 +1032,34 @@ int main(int argc, char* argv[])
 
     const PluginJack p(client);
 
+#if defined(DISTRHO_OS_WINDOWS) && DISTRHO_PLUGIN_HAS_UI
+    /* the code below is based on
+     * https://www.tillett.info/2013/05/13/how-to-create-a-windows-program-that-works-as-both-as-a-gui-and-console-application/
+     */
+
+    // Send "enter" to release application from the console
+    // This is a hack, but if not used the console doesn't know the application has
+    // returned. The "enter" key only sent if the console window is in focus.
+    if (hasConsole && (GetConsoleWindow() == GetForegroundWindow() || SetFocus(GetConsoleWindow()) != nullptr))
+    {
+        INPUT ip;
+        // Set up a generic keyboard event.
+        ip.type = INPUT_KEYBOARD;
+        ip.ki.wScan = 0; // hardware scan code for key
+        ip.ki.time = 0;
+        ip.ki.dwExtraInfo = 0;
+
+        // Send the "Enter" key
+        ip.ki.wVk = 0x0D; // virtual-key code for the "Enter" key
+        ip.ki.dwFlags = 0; // 0 for key press
+        SendInput(1, &ip, sizeof(INPUT));
+
+        // Release the "Enter" key
+        ip.ki.dwFlags = KEYEVENTF_KEYUP; // KEYEVENTF_KEYUP for key release
+        SendInput(1, &ip, sizeof(INPUT));
+    }
+#endif
+
     return 0;
 
 #ifndef DPF_RUNTIME_TESTING