Windows StretchBlt API performance

Question

I timed a DDB drawing operation which uses multiple StretchBlt and StretchDIBits calls.

And I found that, time to complete is increase/decr

Answer 1

I've implemented D2D + WIC routine today. Test results are really good.

With my previous GDI StretchDIBits version, it took 20 ~ 60ms time for drawing 1280x640 DDB into a 1920x1080 window. After switching to Direct2D + WIC, it usually takes under 5ms, also picture quality looks better.

I used ID2D1HwndRenderTarget with WicBitmapRenderTarget, because I need to read/write raw pixel data.

HWndRenderTarget is only used for screen painting (WM_PAINT).
The main advantage of HWndRenderTarget is that the destination window size doesn't affect drawing performance.

WicBitmapRenderTarget is used as a temporary drawing canvas (as Memory DC in GDI drawing). We can create WicBitmapRenderTarget with a WIC bitmap object (like GDI DIBSection). We can read/write raw pixel data from/to this WIC bitmap at any time. Also it's very fast. For side note, somewhat similar D3D GetFrontBufferData call is really slow.

Actual pixel I/O is done through IWICBitmap and IWICBitmapLock interface.

Writing:

IWICBitmapPtr m_wicRemote;
...
const uint8* image = ...;
...
WICRect rcLock = { 0, 0, width, height };
IWICBitmapLockPtr wicLock;
hr = m_wicRemote->Lock(&rcLock, WICBitmapLockWrite, &wicLock);
if (SUCCEEDED(hr))
{
    UINT cbBufferSize = 0;
    BYTE *pv = NULL;
    hr = wicLock->GetDataPointer(&cbBufferSize, &pv);
    if (SUCCEEDED(hr))
    {
        memcpy(pv, image, cbBufferSize);
    }
}

m_wicRenderTarget->BeginDraw();
m_wicRenderTarget->SetTransform(D2D1::Matrix3x2F::Identity());
ID2D1BitmapPtr d2dBitmap;
hr = m_wicRenderTarget->CreateBitmapFromWicBitmap(m_wicRemote, &d2dBitmap.GetInterfacePtr());
if (SUCCEEDED(hr))
{
    float cw = (renderTargetSize.width / 2);
    float ch = renderTargetSize.height;
    float x, y, w, h;
    FitFrameToCenter(cw, ch, (float)width, (float)height, x, y, w, h);
    m_wicRenderTarget->DrawBitmap(d2dBitmap, D2D1::RectF(x, y, x + w, y + h));
}
m_wicRenderTarget->EndDraw();

Reading:

IWICBitmapPtr m_wicCanvas;
IWICBitmapLockPtr m_wicLockedData;
...
UINT width, height;
HRESULT hr = m_wicCanvas->GetSize(&width, &height);
if (SUCCEEDED(hr))
{
    WICRect rcLock = { 0, 0, width, height };
    hr = m_wicCanvas->Lock(&rcLock, WICBitmapLockRead, &m_wicLockedData);
    if (SUCCEEDED(hr))
    {
        UINT cbBufferSize = 0;
        BYTE *pv = NULL;
        hr = m_wicLockedData->GetDataPointer(&cbBufferSize, &pv);
        if (SUCCEEDED(hr))
        {
            return pv; // return data pointer
            // need to Release m_wicLockedData after reading is done
        }
    }
}

Drawing:

ID2D1HwndRenderTargetPtr m_renderTarget;
....

D2D1_SIZE_F renderTargetSize = m_renderTarget->GetSize();
m_renderTarget->BeginDraw();
m_renderTarget->SetTransform(D2D1::Matrix3x2F::Identity());
m_renderTarget->Clear(D2D1::ColorF(D2D1::ColorF::Black));

ID2D1BitmapPtr d2dBitmap;
hr = m_renderTarget->CreateBitmapFromWicBitmap(m_wicCanvas, &d2dBitmap.GetInterfacePtr());
if (SUCCEEDED(hr))
{
    UINT width, height;
    hr = m_wicCanvas->GetSize(&width, &height);
    if (SUCCEEDED(hr))
    {
        float x, y, w, h;
        FitFrameToCenter(renderTargetSize.width, renderTargetSize.height, (float)width, (float)height, x, y, w, h);

        m_renderTarget->DrawBitmap(d2dBitmap, D2D1::RectF(x, y, x + w, y + h));
    }
}
m_renderTarget->EndDraw();

In my opinion, GDI Stretch.. APIs are totally useless in Windows 7+ setup (for performance sensitive applications).

Also note that, unlike Direct3D, basic graphics operations such as text drawing, ling drawing are really simple in Direct2D.