Change all instances of DEVMODE to DEVMODEW since the program is unicode

Fix "C28251 Inconsistent annotation for function" compiler warning by correctly defining WinMain.

README.md

@@ -2,9 +2,9 @@
 
 A utility for switching the resolution of your laptop's display based on the current power state.
 
-Currently a work in progress. Not very useful yet since it doesn't save your preferences. It doesn't even have an icon.
+Currently a work in progress. It works reasonably well for a standard single display configuration, but other scenarios have not been extensively tested, and there are some edge cases that may need to be worked out.
 
-This is a simple C program written using Visual Studio 2022 that has no external dependencies. It should support Windows Vista or higher, but this hasn't been tested yet.
+This is a simple C program written using Visual Studio 2022 that has no external dependencies. It supports Windows Vista or higher.
 
 ## TODO
 - [x] Save preferences to the Windows registry.

WinPowerDMS/DisplayMode.c

@@ -0,0 +1,109 @@
+#include <stdio.h>
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+#include "DisplayMode.h"
+
+BOOL DisplayModeEquals(const DISPLAY_MODE* a, const DISPLAY_MODE* b) {
+    return a->width == b->width && a->height == b->height && a->refresh == b->refresh;
+}
+
+// I hate parsing the string here, but the alternative requires extra memory management.
+DISPLAY_MODE GetModeFromCB(HWND hComboBox) {
+    DISPLAY_MODE mode = { 0 };
+    LRESULT selectedIndex = SendMessage(hComboBox, CB_GETCURSEL, 0, 0);
+    if (selectedIndex != CB_ERR) {
+        LRESULT len = SendMessage(hComboBox, CB_GETLBTEXTLEN, selectedIndex, 0);
+        if (len != CB_ERR) {
+            LPWSTR text = HeapAlloc(GetProcessHeap(), 0, len * sizeof(*text));
+            if (text) {
+                SendMessage(hComboBox, CB_GETLBTEXT, selectedIndex, (LPARAM)text);
+                swscanf_s(text, L"%dx%d @ %d Hz", &mode.width, &mode.height, &mode.refresh);
+                HeapFree(GetProcessHeap(), 0, text);
+            }
+        }
+    }
+
+    return mode;
+}
+
+// returns the result of the ChangeDisplaySettings call that this results in.
+LONG ChangeDisplayMode(LPCWSTR displayName, const DISPLAY_MODE* mode, DWORD dwFlags) {
+    DEVMODEW devMode = {
+        .dmSize = sizeof(devMode),
+        .dmFields = DM_PELSWIDTH | DM_PELSHEIGHT | DM_DISPLAYFREQUENCY,
+        .dmPelsWidth = mode->width,
+        .dmPelsHeight = mode->height,
+        .dmDisplayFrequency = mode->refresh
+    };
+    if (displayName) wcscpy_s(devMode.dmDeviceName, sizeof(devMode.dmDeviceName) / sizeof(devMode.dmDeviceName[0]), displayName);
+
+    return ChangeDisplaySettings(&devMode, dwFlags);
+}
+
+struct MessageBoxParams {
+    HWND hWnd;
+    LPCWSTR lpText;
+    LPCWSTR lpCaption;
+    UINT uType;
+};
+
+static DWORD WINAPI MessageBoxAsync(LPVOID lpParam) {
+    struct MessageBoxParams* params = lpParam;
+    return MessageBox(params->hWnd, params->lpText, params->lpCaption, params->uType);
+}
+
+struct TestDisplayModeParams {
+    HWND hDlg;
+    WCHAR displayName[32];
+    DISPLAY_MODE mode;
+};
+
+static DWORD WINAPI TestDisplayModeThread(LPVOID lpParam) {
+    struct TestDisplayModeParams* params = lpParam;
+    DEVMODEW originalMode = { .dmSize = sizeof(originalMode) };
+    EnumDisplaySettings(params->displayName, ENUM_CURRENT_SETTINGS, &originalMode);
+    ChangeDisplayMode(params->displayName, &params->mode, CDS_FULLSCREEN);
+
+    // Create the message box about the resolution change
+    WCHAR msgText[96];
+    swprintf_s(msgText, sizeof(msgText) / sizeof(msgText[0]),
+        L"Testing %dx%d @ %d Hz\nThe display mode will reset back in 10 seconds.",
+        params->mode.width, params->mode.height, params->mode.refresh);
+    struct MessageBoxParams mbParams = {
+        .hWnd = params->hDlg,
+        .lpText = msgText,
+        .lpCaption = L"Resolution Test",
+        .uType = MB_OK | MB_ICONINFORMATION
+    };
+    HANDLE mbThread = CreateThread(NULL, 0, MessageBoxAsync, &mbParams, 0, NULL);
+    if (mbThread) {
+        CloseHandle(mbThread);
+        Sleep(10000);
+        ChangeDisplaySettings(&originalMode, 0);
+    }
+    else {
+        MessageBox(params->hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
+    }
+    HeapFree(GetProcessHeap(), 0, params);
+    return 0;
+}
+
+void TestDisplayMode(HWND hDlg, LPCWSTR displayName, DISPLAY_MODE* mode) {
+    struct TestDisplayModeParams* tdmParams = HeapAlloc(GetProcessHeap(), 0, sizeof(*tdmParams));
+    if (tdmParams) {
+        tdmParams->hDlg = hDlg;
+        if (tdmParams->displayName) wcscpy_s(tdmParams->displayName, sizeof(tdmParams->displayName) / sizeof(tdmParams->displayName[0]), displayName);
+        tdmParams->mode = *mode;
+        HANDLE tdmThread = CreateThread(NULL, 0, TestDisplayModeThread, tdmParams, 0, NULL);
+        if (tdmThread) CloseHandle(tdmThread);
+        else {
+            HeapFree(GetProcessHeap(), 0, tdmParams);
+            MessageBox(hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
+        }
+    }
+    else {
+        MessageBox(hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
+    }
+}

WinPowerDMS/DisplayMode.h

@@ -0,0 +1,19 @@
+#pragma once
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+typedef struct {
+	DWORD width;
+	DWORD height;
+	DWORD refresh;
+} DISPLAY_MODE;
+
+BOOL DisplayModeEquals(const DISPLAY_MODE* a, const DISPLAY_MODE* b);
+
+DISPLAY_MODE GetModeFromCB(HWND hComboBox);
+
+// returns the result of the ChangeDisplaySettings call that this results in.
+LONG ChangeDisplayMode(LPCWSTR displayName, const DISPLAY_MODE* mode, DWORD dwFlags);
+
+void TestDisplayMode(HWND hDlg, LPCWSTR displayName,  DISPLAY_MODE* mode);

WinPowerDMS/WinPowerDMS.c

@@ -1,9 +1,14 @@
+#define WIN32_LEAN_AND_MEAN
+#define _WIN32_WINNT _WIN32_WINNT_VISTA
+#define NTDDI_VERSION NTDDI_VISTA
+
 #include <stdio.h>
 #include <windows.h>
 #include <shellapi.h>
 #include <commctrl.h>
 
 #include "resource.h"
+#include "DisplayMode.h"
 
 // Link Common Controls v6 for visual styling
 #pragma comment(linker,"\"/manifestdependency:type='win32' \
@@ -13,114 +18,6 @@ processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")
 #define WM_TRAYICON (WM_USER + 1)
 #define TRAY_ICON_ID 1001
 
-typedef struct {
-    DWORD width;
-    DWORD height;
-    DWORD refresh;
-} DISPLAY_MODE;
-
-BOOL DisplayModeEquals(const DISPLAY_MODE* a, const DISPLAY_MODE* b) {
-    return a->width == b->width && a->height == b->height && a->refresh == b->refresh;
-}
-
-#define MODE_SELECTED(mode) (!DisplayModeEquals(&mode, &(DISPLAY_MODE) { 0 }))
-
-// I hate parsing the string here, but the alternative requires extra memory management.
-static DISPLAY_MODE GetModeFromCB(HWND hComboBox) {
-    DISPLAY_MODE mode = { 0 };
-    LRESULT selectedIndex = SendMessage(hComboBox, CB_GETCURSEL, 0, 0);
-    if (selectedIndex != CB_ERR) {
-        LRESULT len = SendMessage(hComboBox, CB_GETLBTEXTLEN, selectedIndex, 0);
-        if (len != CB_ERR) {
-            LPWSTR text = HeapAlloc(GetProcessHeap(), 0, len * sizeof(*text));
-            if (text) {
-                SendMessage(hComboBox, CB_GETLBTEXT, selectedIndex, (LPARAM) text);
-                swscanf_s(text, L"%dx%d @ %d Hz", &mode.width, &mode.height, &mode.refresh);
-                HeapFree(GetProcessHeap(), 0, text);
-            }
-        }
-    }
-
-    return mode;
-}
-
-// returns the result of the ChangeDisplaySettings call that this results in.
-static LONG ChangeDisplayMode(const DISPLAY_MODE* mode, DWORD dwFlags) {
-    DEVMODE devMode = {
-        .dmSize = sizeof(devMode),
-        .dmFields = DM_PELSWIDTH | DM_PELSHEIGHT | DM_DISPLAYFREQUENCY,
-        .dmPelsWidth = mode->width,
-        .dmPelsHeight = mode->height,
-        .dmDisplayFrequency = mode->refresh
-    };
-
-    return ChangeDisplaySettings(&devMode, dwFlags);
-}
-
-struct MessageBoxParams {
-    HWND hWnd;
-    LPCWSTR lpText;
-    LPCWSTR lpCaption;
-    UINT uType;
-};
-
-static DWORD WINAPI MessageBoxAsync(LPVOID lpParam) {
-    struct MessageBoxParams* params = lpParam;
-    return MessageBox(params->hWnd, params->lpText, params->lpCaption, params->uType);
-}
-
-struct TestDisplayModeParams {
-    HWND hDlg;
-    DISPLAY_MODE mode;
-};
-
-static DWORD WINAPI TestDisplayModeThread(LPVOID lpParam) {
-    struct TestDisplayModeParams* params = lpParam;
-    DEVMODE originalMode = { .dmSize = sizeof(originalMode) };
-    EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &originalMode);
-    ChangeDisplayMode(&params->mode, CDS_FULLSCREEN);
-
-    // Create the message box about the resolution change
-    WCHAR msgText[96];
-    swprintf_s(msgText, sizeof(msgText) / sizeof(msgText[0]),
-        L"Testing %dx%d @ %d Hz\nThe display mode will reset back in 10 seconds.",
-        params->mode.width, params->mode.height, params->mode.refresh);
-    struct MessageBoxParams mbParams = {
-        .hWnd = params->hDlg,
-        .lpText = msgText,
-        .lpCaption = L"Resolution Test",
-        .uType = MB_OK | MB_ICONINFORMATION
-    };
-    HANDLE mbThread = CreateThread(NULL, 0, MessageBoxAsync, &mbParams, 0, NULL);
-    if (mbThread) {
-        CloseHandle(mbThread);
-        Sleep(10000);
-        ChangeDisplaySettings(&originalMode, 0);
-    }
-    else {
-        MessageBox(params->hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
-    }
-    HeapFree(GetProcessHeap(), 0, params);
-    return 0;
-}
-
-static void TestDisplayMode(HWND hDlg, DISPLAY_MODE* mode) {
-    struct TestDisplayModeParams* tdmParams = HeapAlloc(GetProcessHeap(), 0, sizeof(*tdmParams));
-    if (tdmParams) {
-        tdmParams->hDlg = hDlg;
-        tdmParams->mode = *mode;
-        HANDLE tdmThread = CreateThread(NULL, 0, TestDisplayModeThread, tdmParams, 0, NULL);
-        if (tdmThread) CloseHandle(tdmThread);
-        else {
-            HeapFree(GetProcessHeap(), 0, tdmParams);
-            MessageBox(hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
-        }
-    }
-    else {
-        MessageBox(hDlg, L"Failed to test resolution.", L"Error", MB_OK | MB_ICONERROR);
-    }
-}
-
 typedef struct {
     DISPLAY_MODE modeBatt;
     DISPLAY_MODE modeAC;
@@ -190,7 +87,7 @@ static BOOL LoadPrefs(void) {
 }
 
 static DISPLAY_MODE GetCurrentDisplayMode(void) {
-    DEVMODE currentMode = { .dmSize = sizeof(currentMode) };
+    DEVMODEW currentMode = { .dmSize = sizeof(currentMode) };
     EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &currentMode);
     return (DISPLAY_MODE) {
         .width = currentMode.dmPelsWidth,
@@ -207,7 +104,7 @@ static INT_PTR CALLBACK PrefsDialogProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPA
     switch (uMsg) {
     case WM_INITDIALOG: {
         // devMode object that will be enumerated
-        DEVMODE devMode;
+        DEVMODEW devMode;
         ZeroMemory(&devMode, sizeof(devMode));
         devMode.dmSize = sizeof(devMode);
 
@@ -261,12 +158,12 @@ static INT_PTR CALLBACK PrefsDialogProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPA
         }
         case IDC_BUTTON_TEST_BATT: {
             DISPLAY_MODE mode = GetModeFromCB(hComboBatt);
-            TestDisplayMode(hDlg, &mode);
+            TestDisplayMode(hDlg, NULL, &mode);
             return TRUE;
         }
         case IDC_BUTTON_TEST_AC: {
             DISPLAY_MODE mode = GetModeFromCB(hComboAC);
-            TestDisplayMode(hDlg, &mode);
+            TestDisplayMode(hDlg, NULL, &mode);
             return TRUE;
         }
         break;
@@ -325,7 +222,7 @@ static LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM l
             if (GetSystemPowerStatus(&powerStatus) &&
                 (DisplayModeEquals(&currentMode, &userPrefs.modeBatt) || DisplayModeEquals(&currentMode, &userPrefs.modeAC)))
             {
-                ChangeDisplayMode(powerStatus.ACLineStatus ? &userPrefs.modeAC : &userPrefs.modeBatt, CDS_UPDATEREGISTRY);
+                ChangeDisplayMode(NULL, powerStatus.ACLineStatus ? &userPrefs.modeAC : &userPrefs.modeBatt, CDS_UPDATEREGISTRY);
             }
         }
         break;
@@ -333,7 +230,7 @@ static LRESULT CALLBACK WindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM l
     return DefWindowProc(hWnd, uMsg, wParam, lParam);
 }
 
-int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
+int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nShowCmd) {
     if (!LoadPrefs()) { // set both battery and AC to current display mode if there are no preferences set
         DISPLAY_MODE currentMode = GetCurrentDisplayMode();
         userPrefs.modeAC = currentMode;

WinPowerDMS/WinPowerDMS.vcxproj

@@ -82,9 +82,10 @@
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalDependencies>ComCtl32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <MinimumRequiredVersion>6.0</MinimumRequiredVersion>
     </Link>
     <Manifest>
-      <EnableDpiAwareness>PerMonitorHighDPIAware</EnableDpiAwareness>
+      <EnableDpiAwareness>true</EnableDpiAwareness>
     </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
@@ -100,9 +101,10 @@
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalDependencies>ComCtl32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <MinimumRequiredVersion>6.0</MinimumRequiredVersion>
     </Link>
     <Manifest>
-      <EnableDpiAwareness>PerMonitorHighDPIAware</EnableDpiAwareness>
+      <EnableDpiAwareness>true</EnableDpiAwareness>
     </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
@@ -116,9 +118,10 @@
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalDependencies>ComCtl32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <MinimumRequiredVersion>6.0</MinimumRequiredVersion>
     </Link>
     <Manifest>
-      <EnableDpiAwareness>PerMonitorHighDPIAware</EnableDpiAwareness>
+      <EnableDpiAwareness>true</EnableDpiAwareness>
     </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
@@ -134,15 +137,18 @@
       <SubSystem>Windows</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalDependencies>ComCtl32.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <MinimumRequiredVersion>6.0</MinimumRequiredVersion>
     </Link>
     <Manifest>
-      <EnableDpiAwareness>PerMonitorHighDPIAware</EnableDpiAwareness>
+      <EnableDpiAwareness>true</EnableDpiAwareness>
     </Manifest>
   </ItemDefinitionGroup>
   <ItemGroup>
+    <ClCompile Include="DisplayMode.c" />
     <ClCompile Include="WinPowerDMS.c" />
   </ItemGroup>
   <ItemGroup>
+    <ClInclude Include="DisplayMode.h" />
     <ClInclude Include="resource.h" />
   </ItemGroup>
   <ItemGroup>

WinPowerDMS/WinPowerDMS.vcxproj.filters

@@ -18,11 +18,17 @@
     <ClCompile Include="WinPowerDMS.c">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="DisplayMode.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="resource.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="DisplayMode.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="WinPowerDMS.rc">

WinPowerDMS/resource.h

@@ -11,6 +11,9 @@
 #define IDC_BUTTON_APPLY                1005
 #define IDC_LIST1                       1006
 #define IDC_CHECK_STARTUP               1007
+#define IDC_COMBO_DISPLAY               1008
+#define IDC_CHECK_ENABLE_DISPLAY        1009
+#define IDC_CHECK_DISPLAY               1009
 
 // Next default values for new objects
 // 
@@ -18,7 +21,7 @@
 #ifndef APSTUDIO_READONLY_SYMBOLS
 #define _APS_NEXT_RESOURCE_VALUE        107
 #define _APS_NEXT_COMMAND_VALUE         40001
-#define _APS_NEXT_CONTROL_VALUE         1008
+#define _APS_NEXT_CONTROL_VALUE         1012
 #define _APS_NEXT_SYMED_VALUE           101
 #endif
 #endif