Win32API窗口输出浮点数
使用TextOut()在窗口中输出数值时一般的方式是,先将数值存到字符数组,再打印出来:
wsprintf(szData, TEXT("Data = %d"), data); TextOut(hdc, x, y, szData, lstrlen(szData));
有一个问题是, wsprintf()这个函数无法处理浮点数。这里需要将其替换成sprintf():
sprintf(szData, "Data = %f",data);
替换后在本人使用平台(Visual C++ 2000 Express Chinese Simplified)出现乱码,发现需要改变字符集,修改方法为:
1.中文版:
项目-》设置属性-》配置属性-》常规-》项目默认值-》字符集
2.英文版:
Project-》Properties-》Configuration Properties-》General-》Project Defaults-》Character Set
参考
Real Loop in Win32 Program
To introduce real loop in Win32 program. “GetMessage()” need to be replaced by “PeekMessage()” The traditional GetMessage loop looks like:
while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0) { if (bRet == -1) { break; } else { TranslateMessage(&msg); DispatchMessage(&msg); }
The PeekMessage Program is like:
while(!Stop){ if(PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) { TranslateMessage(&msg); DispatchMessage(&msg); } DoCalculation(); }
Ref:
关于Windows中的系统消息循环占用CPU的疑问
GetMessage函数是一个阻塞型的函数,当消息队列中没有消息时,GetMessage会处于阻塞状态。一旦有消息到达,进程会被唤醒,GetMessage马上返回。实现时,使用了一个信号量, GetMessage函数在确定没有消息可读时,对这个信号量进行一个V操作,从而使线程阻塞。而PostMessage、SendNotifyMessage、SendSyncMessage等任何一个发送消息函数在发送完消息之后,都会读取这个信号量的值,当发现这个值等于零时,即表示读消息的线程当前已阻塞,这时就会作一次P操作,来唤醒睡眠的线程。
(Microsoft VC++ Express)LINK : fatal error LNK1123: failure during conversion to COFF: file invalid or corrupt
There are several "cvtres.exe" in C disk, maybe installed by .NET Framework. Replace the old one in VC/bin by the first one(new?) in C disk.
连接器LNK是通过调用cvtres.exe完成文件向coff格式的转换的,所以出现这种错误的原因就是cvtres.exe出现了问题。
在电脑里面搜索一下cvtres.exe,发现存在多个文件,使用最新的cvtres.exe替换老的文件即可,替换之前记得备份一下,如果不对,可以替换回来。
例如:我的电脑里面安装了vs2010,最近更新了系统,打了一些补丁,结果就出现这种错误了。在电脑里面搜索发现
C:\Program Files\Microsoft Visual Studio 10.0\VC\bin
C:\Windows\winsxs\x86_netfx-cvtres_for_vc_and_vb_b03f5f7f11d50a3a_6.1.7600.16385_none_ba476986f05abc65
C:\Windows\Microsoft.NET\Framework\v4.0.30319
这三个路径里面都有cvtres.exe文件,于是我尝试使用第二个路径里面的文件替换第一个路径的文件,问题解决。
参考资料如下:
マウスで円を描くコード
「猫でもわかるWindowsプログラミング」より
↓こんな感じ。
#include <windows.h> LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM); ATOM InitApp(HINSTANCE); BOOL InitInstance(HINSTANCE, int); void DrawRect(HWND, POINTS, POINTS); TCHAR szClassName[] = TEXT("Mouse1"); POINTS start, end, old_end; //Start and End point of Rectangle //windows prgram entry point int WINAPI WinMain(HINSTANCE hCurInst, HINSTANCE hPrevInst, LPSTR lpsCmdLine, int nCmdShow) { MSG msg; BOOL bRet; if(!InitApp(hCurInst)) return FALSE; if(!InitInstance(hCurInst, nCmdShow)) return FALSE; //Get Message while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0){ if (bRet == -1){ break; }else{ TranslateMessage(&msg); DispatchMessage(&msg); } } return (int)msg.wParam; } //register window class ATOM InitApp(HINSTANCE hInst) { WNDCLASSEX wc; wc.cbSize = sizeof(WNDCLASSEX); wc.style = CS_HREDRAW | CS_VREDRAW; wc.lpfnWndProc = WndProc; wc.cbClsExtra = 0; wc.cbWndExtra = 0; wc.hInstance = hInst; wc.hIcon = NULL; wc.hCursor = (HCURSOR)LoadImage( NULL, MAKEINTRESOURCE(IDC_ARROW), IMAGE_CURSOR, 0, 0, LR_DEFAULTSIZE | LR_SHARED); wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH); wc.lpszMenuName = NULL; wc.lpszClassName = szClassName; wc.hIconSm = NULL; return (RegisterClassEx(&wc)); } //Generage Window BOOL InitInstance(HINSTANCE hInst, int nCmdShow) { HWND hWnd; hWnd = CreateWindow(szClassName, //Class Name TEXT("Neko demo Mouse"), //Window Name WS_OVERLAPPEDWINDOW, //Window Style CW_USEDEFAULT, //x position CW_USEDEFAULT, //y position CW_USEDEFAULT, //Window Width CW_USEDEFAULT, //Window Height NULL, NULL, hInst, NULL, ); if (!hWnd) return FALSE; ShowWindow(hWnd, nCmdShow); UpdateWindow(hWnd); return TRUE; } //Window Procedure LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp) { TCHAR szBuf[32]; HDC hdc; HBRUSH hBrush; static BOOL bDraw; switch (msg){ case WM_LBUTTONDOWN: bDraw = TRUE; old_end = start = MAKEPOINTS(lp); DrawRect(hWnd, start, old_end); break; case WM_MOUSEMOVE: if(bDraw){ end = MAKEPOINTS(lp); DrawRect(hWnd, start, old_end); DrawRect(hWnd, start, end); old_end = end; }else{ return DefWindowProc(hWnd, msg, wp, lp); } break; case WM_LBUTTONUP: if(bDraw){ SetCursor(LoadCursor(NULL, IDC_ARROW)); DrawRect(hWnd, start, end); bDraw = FALSE; wsprintf(szBuf, TEXT("(%d, %d) - (%d, %d)"), start.x, start.y, end.x, end.y); SetWindowText(hWnd, szBuf); hdc = GetDC(hWnd); hBrush = (HBRUSH)GetStockObject(NULL_BRUSH); SelectObject(hdc, hBrush); Ellipse(hdc, start.x, start.y, end.x, end.y); ReleaseDC(hWnd, hdc); }else{ return DefWindowProc(hWnd, msg, wp, lp); } break; case WM_DESTROY: PostQuitMessage(0); break; default: return (DefWindowProc(hWnd, msg, wp, lp)); } return 0; } void DrawRect(HWND hWnd, POINTS beg, POINTS end) { HDC hdc; hdc = GetDC(hWnd); SetROP2(hdc, R2_NOT); MoveToEx(hdc, beg.x, beg.y, NULL); LineTo(hdc, end.x, beg.y); LineTo(hdc, end.x, end.y); LineTo(hdc, beg.x, end.y); LineTo(hdc, beg.x, beg.y); LineTo(hdc, end.x, end.y); ReleaseDC(hWnd, hdc); return; }
Use of Macro Definitions to Simplify MD Code
C supports the use of macro definitions that can simplify the code considerably.
#define Sqr(x) ((x)*(x)) #define Cube(x) ((x)*(x)*(x)) #define VSub(v1, v2, v3) (v1).x = (v2).x - (v3).x, (v1).y = (v2).y - (v3).y
The above definition will shorten the codes.
Win 32 API使ってみた。
一番簡単なやつを使ってみた。
#include "windows.h" void main(){ MessageBox(NULL,"Hello!","My First WinAPI",MB_YESNO); }