c++ - WIC中调用CreateBitmapFromHIcon时指定HICON索引

Question

根据文档 ExtractIconEx返回指向 HICON 数组的指针。在传递给 CreateBitmapFromHICON 时，如何指定要使用此数组中的哪个项目？ .

#include <iostream>
        #include <Windows.h>
        #include <Wincodec.h>
        #pragma comment(lib,"Windowscodecs.lib")

HICON hiconLarge = NULL;
HICON hiconSmall = NULL;

int main()
{
    CoInitialize(NULL);
    double x, y;

    IWICImagingFactory* piFactory = NULL;
    IWICBitmap* piBitmap = NULL;

    //Create the COM imaging factory.
    HRESULT hr = CoCreateInstance(
        CLSID_WICImagingFactory,
        NULL,
        CLSCTX_INPROC_SERVER,
        IID_IWICImagingFactory,
        (LPVOID*)&piFactory);

    UINT nIcons;
    nIcons = ExtractIconEx(L"c:\\windows\\system32\\shell32.dll",
        -1,
        NULL,
        NULL,
        0);

        ExtractIconEx(L"c:\\windows\\system32\\shell32.dll",
        0,
        &hiconLarge,
        &hiconSmall,
        nIcons);

    std::cout << nIcons << " icons found." << std::endl;

    HRESULT hResult = piFactory->CreateBitmapFromHICON(hiconLarge, &piBitmap);
    if (hResult == S_OK)
    {
        piBitmap->GetResolution(&x, &y);
        std::cout << "Resolution x=" << x << " y=" << y << std::endl;
    }
}

Answer 1

在第二次调用 ExtractIconEx 之前，您需要为 nIcons HICON 值分配足够的空间，因此 hiconLarge和 hiconSmall 应该是指向 HICON 对象 (HICON *) 的指针。目前，您只有足够的空间容纳一个。然后，您可以像通常访问数组一样访问这些值。