将调整大小的位图文件设置为 MFC 优化校准

Setting Resized bitmap file to an MFC Picture Control(将调整大小的位图文件设置为 MFC 优化校准)

问题描述

有没有比这更简单的方法，如果这是唯一的方法，这里是否有任何潜在的内存泄漏?

Is there an easier way to do it than this, and if this is the only way, are there any potential memory leaks here?

    CImage img1;
            int dimx = 100, dimy = 100;
    img1.Load(filename);
    //filename = path on local system to the bitmap

    CDC *screenDC = GetDC();
    CDC *pMDC = new CDC;
    pMDC->CreateCompatibleDC(screenDC);

    CBitmap *pb = new CBitmap;
    pb->CreateCompatibleBitmap(screenDC, dimx, dimy);

    CBitmap *pob = pMDC->SelectObject(pb);
    pMDC->SetStretchBltMode(HALFTONE);
    img1.StretchBlt(pMDC->m_hDC,0, 0, dimx, dimy, 0, 0, img1.GetWidth(), img1.GetHeight(), SRCCOPY);
    pMDC->SelectObject(pob);

    CImage new_image;
    new_image.Attach((HBITMAP)(*pb));
    //
    m_pictureCtrl.SetBitmap(new_image.Detach());
    ReleaseDC(screenDC);

推荐答案

我认为不需要 CImage new_image(因为 SetBitmap 需要一个您已经通过 pb 获得的 HBITMAP)并且必须删除 pb 和 pMDC(在分离 HBITMAP 之后)，但其余的似乎是正确的.

I see no need for the CImage new_image (as SetBitmap takes a HBITMAP which you already have through pb) and pb and pMDC must be deleted (after detaching the HBITMAP), but for the rest it seems correct.

CImage img1;
int dimx = 100, dimy = 100;
img1.Load(filename);
//filename = path on local system to the bitmap

CDC *screenDC = GetDC();
CDC mDC;
mDC.CreateCompatibleDC(screenDC);
CBitmap b;
b.CreateCompatibleBitmap(screenDC, dimx, dimy);

CBitmap *pob = mDC.SelectObject(&b);
mDC.SetStretchBltMode(HALFTONE);
img1.StretchBlt(mDC.m_hDC, 0, 0, dimx, dimy, 0, 0, img1.GetWidth(), img1.GetHeight(), SRCCOPY);
mDC.SelectObject(pob);

m_pictureCtrl.SetBitmap((HBITMAP)b.Detach());
ReleaseDC(screenDC);

当然，我会将 CImage/CBitmap 的缩放放入一个单独的函数中(使其可重用).

Of course I would put the scaling of the CImage/CBitmap into a separate function (make it reusable).

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