GDI绘图之画图

1. 创建画笔
  HPEN CreateOen(
  int fdPenStyle,  // 画笔的样式
  int nWidth,  // 画笔的粗细
  COLORREF crColor // 画笔的颜色
  
  );
  
  PS_SOLID - 实线笔 可以多个像素
  PS_DASH  - 虚线笔,只能一个像素宽,否则不起作用
 
2. 将画笔应用到DC中


  HGDIOBJ SelectObject(
  HDC hdc, // 绘图设备句柄
  HGDIOBJ hgdiobj, // GDI绘图对象句柄,画笔句柄
  
  );
3.画图
4.替换为原来的画笔.
  SelectObject(...);
5.释放句柄
  BOOL DeleteObject(
  HGDIOBJ 
  )
  
  #include <Windows.h>


// 窗口处理函数
HINSTANCE g_hInstance = 0;
LRESULT CALLBACK WndProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
HDC dc;
PAINTSTRUCT ps;
switch (uMsg)
{
case WM_PAINT:
{
dc = BeginPaint(hwnd, &ps);
HPEN pen = CreatePen(PS_DASHDOT, 1,RGB(0, 255, 0));
HGDIOBJ oldPen = SelectObject(dc, pen);
RoundRect(dc, 10, 10, 200, 200, 50, 50);


SelectObject(dc, oldPen);
EndPaint(hwnd, &ps);
}
break;
case WM_DESTROY:
PostQuitMessage(0);
default:
break;
}
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
// 窗口注册函数
void Register(LPCWSTR lpClassName, WNDPROC wndproc)
{
WNDCLASSEX wcx = { 0 };


wcx.cbClsExtra = 0;
wcx.cbSize = sizeof(wcx);
wcx.cbWndExtra = 0;
wcx.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wcx.hCursor = LoadCursor(g_hInstance, IDC_ARROW);
wcx.hIcon = NULL;
wcx.hIconSm = NULL;
wcx.hInstance = g_hInstance;
wcx.lpfnWndProc = wndproc;
wcx.lpszClassName = lpClassName;
wcx.lpszMenuName = NULL;
wcx.style = CS_HREDRAW | CS_VREDRAW;


RegisterClassEx(&wcx);
}


HWND CreateMain(LPCWSTR lpClassName)
{
HWND hwnd = CreateWindowEx(0, lpClassName, L"LEARN", WS_OVERLAPPEDWINDOW, 100, 100, 700, 500, NULL, NULL, g_hInstance, NULL);
ShowWindow(hwnd, SW_SHOW);
UpdateWindow(hwnd);
return hwnd;
}


int exec()
{
MSG msg = { 0 };
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
int WINAPI WinMain(
HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow
)
{
g_hInstance = hInstance;
UNREFERENCED_PARAMETER(hPrevInstance);
UNREFERENCED_PARAMETER(lpCmdLine);
UNREFERENCED_PARAMETER(nCmdShow);
TCHAR szAppName[] = L"MAIN";
Register(szAppName, WndProc);
CreateMain(szAppName);
return exec();
}