c++ graphics 函数已经声明在
时间: 2023-12-06 14:02:59 浏览: 33
如果您想使用 GDI+ 绘图功能,需要在代码中包含 `gdiplus.h` 头文件,并链接 `gdiplus.lib` 库文件。以下是一个示例代码:
```c++
#include <windows.h>
#include <gdiplus.h>
#pragma comment (lib,"Gdiplus.lib")
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, PWSTR pCmdLine, int nCmdShow)
{
// 初始化 GDI+
Gdiplus::GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR gdiplusToken;
Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
// 创建窗口
HWND hWnd;
WNDCLASSEXW wcex = { sizeof(WNDCLASSEXW) };
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.hInstance = hInstance;
wcex.hCursor = LoadCursor(nullptr, IDC_ARROW);
wcex.lpszClassName = L"MyWindowClass";
RegisterClassExW(&wcex);
hWnd = CreateWindowW(wcex.lpszClassName, L"Window Title",
WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT,
800, 600, nullptr, nullptr, hInstance, nullptr);
if (!hWnd)
{
return FALSE;
}
// 显示窗口
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
// 消息循环
MSG msg = {};
while (GetMessage(&msg, nullptr, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
// 释放 GDI+
Gdiplus::GdiplusShutdown(gdiplusToken);
return (int)msg.wParam;
}
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch (message)
{
case WM_PAINT:
{
// 绘制图像
PAINTSTRUCT ps;
HDC hdc = BeginPaint(hWnd, &ps);
Gdiplus::Graphics graphics(hdc);
Gdiplus::Image image(L"path/to/image.jpg");
graphics.DrawImage(&image, 0, 0, 800, 600);
EndPaint(hWnd, &ps);
break;
}
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message, wParam, lParam);
}
return 0;
}
```
在该示例代码中,我们使用 `Gdiplus::Graphics` 类创建了一个绘图对象,使用 `Gdiplus::Image` 类加载了一张图像,并在窗口的 `WM_PAINT` 消息中使用 `graphics.DrawImage` 方法将图像绘制到窗口上。注意,需要在 `WM_DESTROY` 消息中释放 GDI+ 资源。