mengapa skia di windows memiliki efisiensi yang buruk

Saya membandingkan skia dengan lukisan gdi di jendela. keduanya menggambar 98.000 garis acak. yang mengejutkan saya bahwa skia memiliki efisiensi yang jauh lebih rendah daripada gdi (lukisan skia berharga 1600 md, sedangkan gdi berharga 0 md). kode pengujian saya tempel di bawah. ada saran?

bool PaintCompare() {
    //generate ramdon points
    std::default_random_engine e(std::chrono::high_resolution_clock::now().time_since_epoch().count());
    std::uniform_real_distribution<float> u(10, 500);
    SkPoint pts[100];
    for (int i = 0; i<100; i++)
        pts[i].set(u(e), u(e));
    SkPaint paint;
    paint.setColor(SkColorSetRGB(255, 0, 0));

    //create skia canvas
    sk_sp<SkSurface> rasterSurface(
        SkSurface::MakeRasterN32Premul(600, 600));
    SkCanvas* canvas = rasterSurface->getCanvas();

    //draw lines with skia
    auto start = std::chrono::high_resolution_clock::now();
    for (int i = 0; i<1000; i++)
    {
        for (int j = 1; j<99; j++)
        {
            canvas->drawLine(pts[j].fX, pts[j].fY, pts[j + 1].fX, pts[j + 1].fY, paint);
        }
    }
    auto cost = std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - start);
    sk_sp<SkImage> img(rasterSurface->makeImageSnapshot());
    if (!img) { return false; }
    SkBitmap skBmp;
    if (!img->asLegacyBitmap(&skBmp, SkImage::kRO_LegacyBitmapMode)) {
        return false;
    }

    //show bitmap on hdc
    BITMAPINFO bmi;
    memset(&bmi, 0, sizeof(bmi));
    bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
    bmi.bmiHeader.biWidth = 600;
    bmi.bmiHeader.biHeight = -600; // top-down image 
    bmi.bmiHeader.biPlanes = 1;
    bmi.bmiHeader.biBitCount = 32;
    bmi.bmiHeader.biCompression = BI_RGB;
    bmi.bmiHeader.biSizeImage = 0;

    HDC hdc = GetDC();
    LPVOID pBits = NULL;
    HBITMAP hBmp = CreateDIBSection(hdc, &bmi, DIB_RGB_COLORS, &pBits, 0, 0);
    skBmp.copyPixelsTo(pBits, skBmp.getSize());
    CDC memdc;
    memdc.CreateCompatibleDC(hdc);
    memdc.SelectBitmap(hBmp);
    BitBlt(hdc, 0, 0, 600, 600, memdc, 0, 0, SRCCOPY);
    memdc.DeleteDC();


    //draw with gdi
    CPen pen;
    pen.CreatePen(PS_SOLID, 1, RGB(0, 255, 0));
    RECT rc{ 0,0,600,600 };
    CBitmap bmp;
    bmp.CreateCompatibleBitmap(hdc, 600, 600);
    memdc.CreateCompatibleDC(hdc);
    memdc.SelectBitmap(bmp);
    memdc.FillSolidRect(&rc, RGB(0, 0, 0));
    memdc.SelectPen(pen);
    start = std::chrono::high_resolution_clock::now();
    for (int i = 0; i<1000; i++)
    {
        for (int j = 1; j<99; j++)
        {
            memdc.MoveTo(pts[j].fX, pts[j].fY);
            memdc.LineTo(pts[j + 1].fX, pts[j + 1].fY);
        }
    }
    auto cost2 = std::chrono::duration_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now() - start);

    //copy bitmap to window
    BitBlt(hdc, 700, 0, 600, 600, memdc, 0, 0, SRCCOPY);
    ReleaseDC(hdc);
    memdc.DeleteDC();

    //wchar_t buf[256];
    //wsprintf(buf, L"left cost=%I64d, right cost=%I64d", cost.count(), cost2.count());
    //GetParent().SetWindowText(buf);

    //cost == 1596615 microseconds
    //cost2 == 107253 microseconds
}