哇~~又更新啦.纯手工编写C++画图，有注释.-优快云博客

再次感谢Ttcofee提的问题

本次更新内容：

新增输入，切换密码模式和提交（两个按钮）
提前申明：如果运行不了，请到主页查看RedpandaDevc++下载，若还是不行就卸了重装。
errors
#include <windows.h>
#include <gdiplus.h>
#include <string>

#define IDC_EDIT_PWD   1001
#define IDC_BTN_TOGGLE 1002
#define IDC_EDIT1        1003
#define IDC_BUTTON_SUBMIT 1004

using namespace std;
HWND hEdit;
HWND hButton,hButton2;
POINT g_startPos, g_endPos;
RECT g_originalRect;
LONG_PTR g_originalStyle;
bool g_isFullscreen = false;
HBITMAP g_hMemBitmap = NULL;
HDC g_hMemDC = NULL;
int g_width = 0, g_height = 0;
bool g_isPasswordMode = true; // 初始为密码模式

// 初始化双缓冲
void InitDoubleBuffer(HWND hwnd) {
	RECT rc;
	GetClientRect(hwnd, &rc);
	g_width = rc.right - rc.left;
	g_height = rc.bottom - rc.top;
	HDC hdc = GetDC(hwnd);
	g_hMemDC = CreateCompatibleDC(hdc);
	g_hMemBitmap = CreateCompatibleBitmap(hdc, g_width, g_height);
	SelectObject(g_hMemDC, g_hMemBitmap);
	ReleaseDC(hwnd, hdc);
	// 初始清屏（可选）
	FillRect(g_hMemDC, &rc, (HBRUSH)GetStockObject(WHITE_BRUSH));
}
// 切换全屏函数
void ToggleFullscreen(HWND hwnd) {
	if (!g_isFullscreen) {
		// 进入全屏
		GetWindowRect(hwnd, &g_originalRect);
		g_originalStyle = GetWindowLongPtr(hwnd, GWL_STYLE);
		int screenWidth = GetSystemMetrics(SM_CXSCREEN);
		int screenHeight = GetSystemMetrics(SM_CYSCREEN);

		SetWindowLongPtr(hwnd, GWL_STYLE, WS_POPUP);
		SetWindowPos(hwnd, HWND_TOP,
		             0, 0, screenWidth, screenHeight,
		             SWP_FRAMECHANGED | SWP_SHOWWINDOW
		            );
	} else {
		// 退出全屏
		SetWindowLongPtr(hwnd, GWL_STYLE, g_originalStyle);
		SetWindowPos(hwnd, NULL,
		             g_originalRect.left,
		             g_originalRect.top,
		             g_originalRect.right - g_originalRect.left,
		             g_originalRect.bottom - g_originalRect.top,
		             SWP_FRAMECHANGED | SWP_NOZORDER
		            );
	}
	g_isFullscreen = !g_isFullscreen;
}

// 切换密码显示模式
void TogglePasswordMode(HWND hwnd) {
    // 保存当前文本
    wchar_t szText[256] = {0};
    GetWindowTextW(hEdit, szText, 256);

    // 获取当前窗口位置
    RECT rc;
    GetWindowRect(hEdit, &rc);
    MapWindowPoints(HWND_DESKTOP, GetParent(hEdit), (LPPOINT)&rc, 2);

    // 销毁旧编辑框
    DestroyWindow(hEdit);

    // 创建新编辑框（切换样式）
    DWORD style = WS_CHILD | WS_VISIBLE | WS_BORDER | ES_AUTOHSCROLL;
    if (g_isPasswordMode) {
        style |= ES_PASSWORD;
    }

    hEdit = CreateWindowW(
        L"EDIT", szText,
        style,
        rc.left, rc.top,
        rc.right - rc.left,
        rc.bottom - rc.top,
        hwnd, (HMENU)IDC_EDIT_PWD,
        NULL,
        NULL
    );

    // 更新模式状态
    g_isPasswordMode = !g_isPasswordMode;

    // 更新按钮文本
    SetWindowTextW(GetDlgItem(hwnd, IDC_BTN_TOGGLE),
        g_isPasswordMode ? L"隐藏密码" : L"显示明文");
}

// 窗口过程函数
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
	switch (msg) {
		case WM_SIZE:
			// 窗口大小变化时重置缓冲
			if (g_hMemDC) {
				DeleteDC(g_hMemDC);
				DeleteObject(g_hMemBitmap);
			}
			InitDoubleBuffer(hwnd);
			break;
		case WM_KEYDOWN:
			if (wParam == VK_BACK) { // 按Backspace切换全屏
				ToggleFullscreen(hwnd);
			} else if (wParam == VK_CONTROL) {
				DestroyWindow(hwnd);
				HWND hwnwd;
				hwnwd = FindWindow("ConsoleWindowClass", NULL);
				if (hwnwd) {
					ShowOwnedPopups(hwnwd, SW_SHOW);
					ShowWindow(hwnwd, SW_SHOW);
				}
			}
			return 0;
		case WM_PAINT: { // 窗口需要绘制时触发
			PAINTSTRUCT ps;
			HDC hdc = BeginPaint(hwnd, &ps);  // 获取设备上下文
			// 设置背景模式为透明
			BitBlt(hdc, 0, 0, g_width, g_height, g_hMemDC, 0, 0, SRCCOPY);
			SetBkMode(hdc, TRANSPARENT);
			HPEN hDashPen = CreatePen(PS_DASH, 1, RGB(256, 256, 256));
			SelectObject(hdc, hDashPen);
			MoveToEx(hdc, g_startPos.x, g_startPos.y, NULL);
			LineTo(hdc, g_endPos.x, g_endPos.y);
			return 0;
		}
		case WM_CLOSE:
			break;
		case WM_DESTROY:
			break;
		// 处理鼠标消息
		case WM_LBUTTONDOWN:
			g_startPos.x = LOWORD(lParam);
			g_startPos.y = HIWORD(lParam);
			return 0;

		case WM_MOUSEMOVE:
			if (wParam & MK_LBUTTON) {
				g_endPos.x = LOWORD(lParam);
				g_endPos.y = HIWORD(lParam);
				InvalidateRect(hwnd, NULL, TRUE);
			}
			return 0;
		case WM_ERASEBKGND:
			return 1; // 禁用背景擦除
		default:
			return DefWindowProc(hwnd, msg, wParam, lParam);
        case WM_CREATE: {
            // 创建按钮
            hButton = CreateWindow(
                "BUTTON",                     // 窗口类（按钮）
                "点击我关闭",                     // 按钮文本
                WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, // 样式
                50, 50,                       // 位置 (x, y)
                100, 30,                       // 大小 (宽度, 高度)
                hwnd,                         // 父窗口句柄
                (HMENU)1,                     // 控件ID
                ((LPCREATESTRUCT)lParam)->hInstance, // 实例句柄
                NULL                          // 附加数据
            ); 
            hButton2 = CreateWindow(
                "BUTTON",                     // 窗口类（按钮）
                "点击我切换全屏",                     // 按钮文本
                WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON, // 样式
                850, 50,                       // 位置 (x, y)
                100, 30,                       // 大小 (宽度, 高度)
                hwnd,                         // 父窗口句柄
                (HMENU)2,                     // 控件ID
                ((LPCREATESTRUCT)lParam)->hInstance, // 实例句柄
                NULL                          // 附加数据
            ); 	
            // 创建切换按钮
            CreateWindowW(
                L"BUTTON", L"隐藏密码",
                WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
                100, 300, 80, 30,
                hwnd, (HMENU)IDC_BTN_TOGGLE,
                NULL, NULL
            );	
            hEdit = CreateWindowW(L"EDIT", L"", 
                WS_CHILD | WS_VISIBLE | WS_BORDER | ES_AUTOHSCROLL,
                20, 250, 200, 25, hwnd,  (HMENU)IDC_EDIT1, NULL, NULL);
            
            CreateWindowW(L"BUTTON", L"示例输入",
                WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
                20, 300, 80, 30, hwnd, (HMENU)IDC_BUTTON_SUBMIT, NULL, NULL);	         
            return 0;
        }
        case WM_COMMAND: {
            if (LOWORD(wParam) == IDC_BUTTON_SUBMIT) {
                wchar_t buffer[256];
                GetWindowTextW(hEdit, buffer, 256);
                
                if (wcslen(buffer) == 0) {
                    MessageBoxW(hwnd, L"输入不能为空！", L"错误", MB_ICONERROR);
                } else {
                    MessageBoxW(hwnd, buffer, L"输入内容", MB_OK);
                }
            }
            if (LOWORD(wParam) == IDC_BTN_TOGGLE) {
                TogglePasswordMode(hwnd);
            }
            int ButtonID=LOWORD(wParam);
            switch(ButtonID){
				case 1:
					DestroyWindow(hwnd);
					HWND hwnwd;
					hwnwd = FindWindow("ConsoleWindowClass", NULL);
					if (hwnwd) {
						ShowOwnedPopups(hwnwd, SW_SHOW);
						ShowWindow(hwnwd, SW_SHOW);
					}
					break;
				case 2:
					ToggleFullscreen(hwnd);
					break;				
			}
            return 0;
        }        
	}
	return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR pCmdLine, int nCmdShow) {
	HWND hwnwd;
	hwnwd = FindWindow("ConsoleWindowClass", NULL);
	if (hwnwd) {
		ShowOwnedPopups(hwnwd, SW_HIDE);
		ShowWindow(hwnwd, SW_HIDE);
	}
	const char* CLASS_NAME = "CustomWindowClass";

	WNDCLASS wc = {};
	wc.lpfnWndProc = WndProc;
	wc.hInstance = hInstance;
	wc.lpszClassName = TEXT(CLASS_NAME);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);

	if (!RegisterClass(&wc)) return 0;

	// 创建窗口
	HWND hwnd = CreateWindowEx(
	                0,                              // 扩展样式
	                TEXT(CLASS_NAME),                     // 窗口类
	                " 绘画",                   // 窗口标题
	                WS_OVERLAPPEDWINDOW | WS_VISIBLE, // 窗口样式
	                CW_USEDEFAULT, CW_USEDEFAULT,   // 位置
	                1000, 1000,                       // 大小
	                NULL,                           // 父窗口
	                NULL,                           // 菜单
	                hInstance,                      // 实例句柄
	                NULL                            // 附加数据
	            );

	if (!hwnd) return 0;

	// 消息循环
	MSG msg = {};
	while (GetMessage(&msg, NULL, 0, 0)) {
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return 0;
}