D2D坐标与屏幕坐标不匹配

Question

我正在将D2D与D3D11一起使用。我有一些使用Windows API中的GetCursorpos（）的代码，然后将其转换为客户端坐标，然后使用D2D FillEllipse（）在此位置绘制一个小圆圈。屏幕到客户端的坐标可以正常工作，但是由于某些原因，D2D会将圆与期望位置（数十个像素）相距一小段距离，就好像坐标已被小比例缩放一样，随着圆的进一步绘制，误差会变大从（0，0）开始。我注意到更改D2D1_RENDER_TARGET_PROPERTIES的dpi会影响此“缩放”，因此我怀疑问题与dpi有关。这是从我在D3D11代码中从交换链获得的DXGI曲面创建D2D渲染目标的代码。

    // Create render target
    float dpiX, dpiY;
    this->factory->GetDesktopDpi(&dpiX, &dpiY);
    D2D1_RENDER_TARGET_PROPERTIES rtDesc = D2D1::RenderTargetProperties(
        D2D1_RENDER_TARGET_TYPE_HARDWARE,
        D2D1::PixelFormat(DXGI_FORMAT_UNKNOWN, D2D1_ALPHA_MODE_PREMULTIPLIED),
        dpiX,
        dpiY
    );
    AssertHResult(this->factory->CreateDxgiSurfaceRenderTarget(
        surface.Get(),
        &rtDesc,
        &this->renderTarget
    ), "Failed to create D2D render target");

这里，dpiX和dpiY变为96，​​我注意到这也是Windows API的GetDpiForWindow（）在不识别dpi时返回的常数。

我想知道如何修复我的代码，以便它将在GetCursorPos（）给定的位置绘制圆。

更多相关代码：

驱动程序代码

    Vector3f cursPos = input.GetCursorPos();
    DrawCircle(Colour::Green, cursPos.x, cursPos.y, 3/*radius*/);

输入

    POINT pt{};
    ::GetCursorPos(&pt);
    // Convert from screen pixels to client pixels
    return ConvertPixelSpace(this->hWnd, (float)pt.x, (float)pt.x, PixelSpace::Screen, PixelSpace::Client);

Direct2D

void DrawCircle(const Colour& c, float centreX, float centreY, float radius, PixelSpace ps)
{
    Vector3f centre = ConvertPixelSpace(this->gfx.hWnd, centreX, centreY, ps, PixelSpace::Client);
    centreX = centre.x;
    centreY = centre.y;
    D2D1_ELLIPSE el{};
    el.point.x = centreX;
    el.point.y = centreY;
    el.radiusX = radius;
    el.radiusY = radius;
    auto brush = this->CreateBrush(c);
    this->renderTarget->FillEllipse(
        &el,
        brush.Get()
    );
}

PixelSpace转换

Vector3f ConvertPixelSpace(HWND hWnd, float x, float y, PixelSpace curSpace, PixelSpace newSpace)
{
    RECT rc = GetClientRectOfWindow(hWnd);
    struct
    {
        float top, left, width, height;
    } rectf;
    rectf.top = static_cast<float>(rc.top);
    rectf.left = static_cast<float>(rc.left);
    rectf.width = static_cast<float>(rc.right - rc.left);
    rectf.height = static_cast<float>(rc.bottom - rc.top);

    // Convert to client space
    if (curSpace == PixelSpace::Screen)
    {
        x -= rectf.left;
        y -= rectf.top;
    }

    // Convert to new space
    if (newSpace == PixelSpace::Screen)
    {
        x += rectf.left;
        y += rectf.top;
    }

    return Vector3f(x, y);
}

RECT GetClientRectOfWindow(HWND hWnd)
{
    RECT rc;
    ::GetClientRect(hWnd, &rc);
    // Pretty sure these are valid casts.
    // rc.top is stored directly after rc.left and this forms a POINT struct
    ClientToScreen(hWnd, reinterpret_cast<POINT*>(&rc.left));
    ClientToScreen(hWnd, reinterpret_cast<POINT*>(&rc.right));
    return rc;
}

Answer 1

问题是我正在使用窗口区域而不是客户区域来创建D3D11交换链。

    RECT rect{};
    GetWindowRect(hWnd, &rect); // !!! This should be GetClientRect()
    this->width = rect.right - rect.left;
    this->height = rect.bottom - rect.top;

    DXGI_SWAP_CHAIN_DESC scDesc{};
    scDesc.BufferDesc.Width = width;
    scDesc.BufferDesc.Height = height;
    //...