Win32 API自绘按钮

WinMain.c

#include <windows.h>

HINSTANCE hInst;
WNDPROC OldBtnProc;
BOOL bMouseHover;
HBRUSH hBrush1;
HBRUSH hBrush2;
HBRUSH hBrush3;

LRESULT CALLBACK WindowProc(HWND hwnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	);

LRESULT CALLBACK NewBtnProc(HWND hwnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	);

int WINAPI WinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	LPTSTR lpCmdLine,
	int nCmdShow
	)
{
	hInst = hInstance;
	bMouseHover = FALSE;

	WNDCLASS wndcls;
	wndcls.cbClsExtra = 0;
	wndcls.cbWndExtra = 0;
	wndcls.hbrBackground = GetStockObject(GRAY_BRUSH);
	wndcls.hCursor = LoadCursor(NULL,IDC_ARROW);
	wndcls.hIcon = LoadIcon(NULL,IDI_APPLICATION);
	wndcls.hInstance = hInstance;
	wndcls.lpfnWndProc = WindowProc;
	wndcls.lpszClassName = TEXT("MainWnd");
	wndcls.lpszMenuName = NULL;
	wndcls.style = CS_VREDRAW | CS_VREDRAW;
	RegisterClass(&wndcls);
	HWND hwnd = CreateWindow(TEXT("MainWnd"),TEXT("MainWnd"),WS_OVERLAPPEDWINDOW,CW_USEDEFAULT, CW_USEDEFAULT,
		CW_USEDEFAULT, CW_USEDEFAULT,NULL,NULL,hInstance,NULL);
	ShowWindow(hwnd, nCmdShow);
	UpdateWindow(hwnd);
	MSG msg;
	while (GetMessage(&msg,NULL,0,0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return 0;
}

LRESULT CALLBACK WindowProc(HWND hwnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	)
{
	static HWND hBtn;
	DRAWITEMSTRUCT* pdis;

	switch (uMsg)
	{
	case WM_CREATE:
		hBrush1 = CreateSolidBrush(RGB(0, 255, 0));
		hBrush2 = CreateSolidBrush(RGB(255, 0, 0));
		hBrush3 = CreateSolidBrush(RGB(0, 0, 255));
		hBtn = CreateWindow(TEXT("BUTTON"), TEXT("按钮1"), WS_CHILD |WS_VISIBLE| BS_OWNERDRAW, 50, 50, 200, 100, hwnd,
			123, hInst, NULL);
		OldBtnProc = SetWindowLong(hBtn,GWL_WNDPROC, NewBtnProc);
		SetFocus(hBtn);
		return 0;

	case WM_DRAWITEM:
		pdis = (LPDRAWITEMSTRUCT)lParam;
		if (GetCapture() == hBtn)
		{
			if (pdis->itemState & ODS_SELECTED)//如果鼠标选中按钮
			{
				FillRect(pdis->hDC, &pdis->rcItem, hBrush3);//蓝色
			}
			else
			{
				FillRect(pdis->hDC, &pdis->rcItem, hBrush2);//初始按钮样式：红色
			}
		}
		else
		{
			if (bMouseHover)//鼠标悬停
			{
				FillRect(pdis->hDC, &pdis->rcItem, hBrush1);//初始按钮样式：绿色
			}
			else
			{
				FillRect(pdis->hDC, &pdis->rcItem, hBrush2);//初始按钮样式：红色
			}
		}
		if (pdis->itemState & ODS_FOCUS)//如果按钮获得焦点
		{
			DrawFocusRect(pdis->hDC, &pdis->rcItem);
		}
		return 0;

	case WM_COMMAND:
		switch (LOWORD(wParam))
		{
		case 123:
			//MessageBox(hwnd,TEXT("按钮"),0,0);
			break;
		}
		return 0;
		 
	case WM_CLOSE:
		DestroyWindow(hwnd);
		return 0;

	case WM_DESTROY:
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hwnd,uMsg,wParam,lParam);
}


LRESULT CALLBACK NewBtnProc(HWND hwnd,
	UINT uMsg,
	WPARAM wParam,
	LPARAM lParam
	)
{
	switch (uMsg)
	{
	case WM_MOUSEMOVE://注意，只要当鼠标位于窗口内，即使没有移动，也会产生WM_MOUSEMOVE消息
	{
		if (!bMouseHover)
		{
			bMouseHover = TRUE;//特别注意：这条语句不能放在TrackMouseEvent函数调用之后
			InvalidateRect(hwnd, NULL, TRUE);
			UpdateWindow(hwnd);

			TRACKMOUSEEVENT tme;
			tme.cbSize = sizeof(tme);
			tme.hwndTrack = hwnd;
			tme.dwFlags = TME_LEAVE | TME_HOVER;
			tme.dwHoverTime = HOVER_DEFAULT;
			TrackMouseEvent(&tme);
		}
		break;
	}

	//可以用于显示ToolTip提示框
	case WM_MOUSEHOVER:
		break;

	case WM_MOUSELEAVE:
		bMouseHover = FALSE;
		InvalidateRect(hwnd, NULL, TRUE);
		UpdateWindow(hwnd);
		break;

	}
	return CallWindowProc(OldBtnProc,hwnd,uMsg,wParam,lParam);
}