windows下控制台程序实现窗口显示
windows下实现窗口显示,如果限定是C/C++语言,并且是原生Windows支持,需要使用GDI或GDI+。一般是在Visual Studio里新建Win32应用程序,而不是Win32 console application(控制台程序),然后使用GDI的一些API,例如CreateWindow、CreateWindowEx来实现窗口的创建、显示等。
实际上MSDN官方并没有说只能是Win32应用程序,控制台程序完全可以。个人并不习惯WinMain()函数,更习惯main(int argc, char** argv)。例如OpenCV的highgui模块,它里面的cvNamedWindow(), cvShowImage(), cvWaitKey()这几个函数,在windows下的实现,如果不考虑其opengl版本的话,它是基于GDI实现的;而作为一个广泛使用的图像处理库,OpenCV源码中并没有WinMain函数。
第1种实现
下面是用纯C实现的“调用GDI的API接口,实现控制台类型程序中显示窗口”的样例程序,改编自How do you create a Win32 window from Console Application?
#include <stdio.h>
#include <windows.h>
LRESULT __stdcall WindowProcedure(HWND window, unsigned int msg, WPARAM wp, LPARAM lp)
{
switch(msg)
{
case WM_DESTROY:
printf("\ndestroying window\n");
PostQuitMessage(0) ;
return 0L ;
case WM_LBUTTONDOWN:
printf("\nmouse left button down at (%d, %d)\n", LOWORD(lp), HIWORD(lp));
// fall thru
default:
printf(".");
return DefWindowProc( window, msg, wp, lp ) ;
}
}
typedef struct MyRect{
int x, y, width, height;
} MyRect;
int main()
{
printf("hello world!\n");
const char* const myclass = "myclass" ;
WNDCLASSEX wc;
wc.cbSize = sizeof(WNDCLASSEX);
/* Win 3.x */
wc.style = CS_DBLCLKS;
wc.lpfnWndProc = WindowProcedure;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = GetModuleHandle(0);
wc.hIcon = LoadIcon(0, IDI_APPLICATION);
wc.hCursor = LoadCursor(0, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = 0;
wc.lpszClassName = myclass;
/* Win 4.0 */
wc.hIconSm = LoadIcon(0, IDI_APPLICATION);
if(RegisterClassEx(&wc))
{
MyRect rect;
rect.x = 300;
rect.y = 300;
rect.width = 640;
rect.height = 480;
HWND window = CreateWindowEx( 0, myclass, "title",
WS_OVERLAPPEDWINDOW, rect.x, rect.y,
rect.width, rect.height, 0, 0, GetModuleHandle(0), 0 ) ;
if(window)
{
ShowWindow( window, SW_SHOWDEFAULT ) ;
MSG msg ;
while( GetMessage( &msg, 0, 0, 0 ) ) DispatchMessage(&msg);
}
}
}
第2种实现
实际上,在Visual Studio中通过“菜单栏”->"文件"->“新建项目”->"Win32项目"(或"Win32控制台项目"进入后再选“Windows应用程序”),创建的“Hello World”工程提供的代码也仅仅是“显示一个窗口”,只不过入口函数是WinMain,其内容如下:
// gdi_show_png.cpp : 定义应用程序的入口点。
//
#include "stdafx.h"
#include "gdi_show_png.h"
#define MAX_LOADSTRING 100
// 全局变量:
HINSTANCE hInst; // 当前实例
WCHAR szTitle[MAX_LOADSTRING]; // 标题栏文本
WCHAR szWindowClass[MAX_LOADSTRING]; // 主窗口类名
// 此代码模块中包含的函数的前向声明:
ATOM MyRegisterClass(HINSTANCE hInstance);
BOOL InitInstance(HINSTANCE, int);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK About(HWND, UINT, WPARAM, LPARAM);
int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
_In_opt_ HINSTANCE hPrevInstance,
_In_ LPWSTR lpCmdLine,
_In_ int nCmdShow)
{
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
// TODO: 在此放置代码。
// 初始化全局字符串
LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
LoadStringW(hInstance, IDC_GDI_SHOW_PNG, szWindowClass, MAX_LOADSTRING);
MyRegisterClass(hInstance);
// 执行应用程序初始化:
if (!InitInstance (hInstance, nCmdShow))
{
return FALSE;
}
HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_GDI_SHOW_PNG));
MSG msg;
// 主消息循环:
while (GetMessage(&msg, nullptr, 0, 0))
{
if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
return (int) msg.wParam;
}
//
// 函数: MyRegisterClass()
//
// 目的: 注册窗口类。
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEXW wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_GDI_SHOW_PNG));
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = MAKEINTRESOURCEW(IDC_GDI_SHOW_PNG);
wcex.lpszClassName = szWindowClass;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));
return RegisterClassExW(&wcex);
}
//
// 函数: InitInstance(HINSTANCE, int)
//
// 目的: 保存实例句柄并创建主窗口
//
// 注释:
//
// 在此函数中,我们在全局变量中保存实例句柄并
// 创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
hInst = hInstance; // 将实例句柄存储在全局变量中
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);
if (!hWnd)
{
return FALSE;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}
//
// 函数: WndProc(HWND, UINT, WPARAM, LPARAM)
//
// 目的: 处理主窗口的消息。
//
// WM_COMMAND - 处理应用程序菜单
// WM_PAINT - 绘制主窗口
// WM_DESTROY - 发送退出消息并返回
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_COMMAND:
{
int wmId = LOWORD(wParam);
// 分析菜单选择:
switch (wmId)
{
case IDM_ABOUT:
DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
break;
case IDM_EXIT:
DestroyWindow(hWnd);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
}
break;
case WM_PAINT:
{
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
// TODO: 在此处添加使用 hdc 的任何绘图代码...
EndPaint(hWnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
// “关于”框的消息处理程序。
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
UNREFERENCED_PARAMETER(lParam);
switch (message)
{
case WM_INITDIALOG:
return (INT_PTR)TRUE;
case WM_COMMAND:
if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
{
EndDialog(hDlg, LOWORD(wParam));
return (INT_PTR)TRUE;
}
break;
}
return (INT_PTR)FALSE;
}
而如果忽略WinProc函数(各种事件处理代码),不妨把前面从gamedev上的帖子中的例子进行改造,把各种步骤都拆分到函数中,在主函数中调用,就得到如下代码:
#include <stdio.h>
#include <windows.h>
LRESULT __stdcall WindowProcedure(HWND window, unsigned int msg, WPARAM wp, LPARAM lp)
{
switch (msg)
{
case WM_DESTROY:
printf("\ndestroying window\n");
PostQuitMessage(0);
return 0L;
case WM_LBUTTONDOWN:
printf("\nmouse left button down at (%d, %d)\n", LOWORD(lp), HIWORD(lp));
// fall thru
default:
printf(".");
return DefWindowProc(window, msg, wp, lp);
}
}
const char* szWindowClass = "myclass";
typedef struct MyRect {
int x, y, width, height;
} MyRect;
ATOM MyRegisterClass(HINSTANCE hInstance)
{
WNDCLASSEX wc;
wc.cbSize = sizeof(WNDCLASSEX);
/* Win 3.x */
wc.style = CS_DBLCLKS;
wc.lpfnWndProc = WindowProcedure;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(0, IDI_APPLICATION);
wc.hCursor = LoadCursor(0, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = 0;
wc.lpszClassName = szWindowClass;
/* Win 4.0 */
wc.hIconSm = LoadIcon(0, IDI_APPLICATION);
return RegisterClassEx(&wc);
}
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
MyRect rect;
rect.x = 300;
rect.y = 300;
rect.width = 640;
rect.height = 480;
HWND hwnd = CreateWindowEx(0, szWindowClass, "title",
WS_OVERLAPPEDWINDOW, rect.x, rect.y,
rect.width, rect.height, 0, 0, GetModuleHandle(0), 0);
if (!hwnd)
{
return FALSE;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
return TRUE;
}
int main()
{
printf("hello world!\n");
HINSTANCE hInstance = GetModuleHandle(0);
int nCmdShow = SW_SHOWDEFAULT;
MyRegisterClass(hInstance);
if (!InitInstance(hInstance, nCmdShow))
{
return FALSE;
}
MSG msg;
while (GetMessage(&msg, 0, 0, 0))
{
DispatchMessage(&msg);
}
}
对比一下发现,其实main()
和WinMain()
分别作为入口的差别,仅仅在于hInstance
函数和nCmdShow
参数有所不同:WinMain()函数中是这两个参数作为参数传入,而main()函数中则手动赋予这两个参数初值:
HINSTANCE hInstance = GetModuleHandle(0);
int nCmdShow = SW_SHOWDEFAULT;