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ID2D1RenderTarget::Clear methods

Clears the drawing area to the specified color.

Overload list

MethodDescription
Clear(D2D1_COLOR_F*)

Clears the drawing area to the specified color.

Clear(D2D1_COLOR_F&)

Clears the drawing area to the specified color.

Remarks

Direct2D interprets the clearColor as straight alpha (not premultiplied). If the render target's alpha mode is D2D1_ALPHA_MODE_IGNORE, the alpha channel of clearColor is ignored and replaced with 1.0f (fully opaque).

If the render target has an active clip (specified by PushAxisAlignedClip), the clear command is only applied to the area within the clip region.

Examples

The following example uses the Clear method to create a white background before rendering other content. (For the complete example, see the "Hello, World" Sample Application.)


//  Called whenever the application needs to display the client
//  window. This method writes "Hello, World"
//
//  Note that this function will automatically discard device-specific
//  resources if the Direct3D device disappears during function
//  invocation, and will recreate the resources the next time it's
//  invoked.
//
HRESULT DemoApp::OnRender()
{
    HRESULT hr;

    hr = CreateDeviceResources();

    if (SUCCEEDED(hr))
    {
        static const WCHAR sc_helloWorld[] = L"Hello, World!";

        // Retrieve the size of the render target.
        D2D1_SIZE_F renderTargetSize = m_pRenderTarget->GetSize();

        m_pRenderTarget->BeginDraw();

        m_pRenderTarget->SetTransform(D2D1::Matrix3x2F::Identity());

        m_pRenderTarget->Clear(D2D1::ColorF(D2D1::ColorF::White));

        m_pRenderTarget->DrawText(
            sc_helloWorld,
            ARRAYSIZE(sc_helloWorld) - 1,
            m_pTextFormat,
            D2D1::RectF(0, 0, renderTargetSize.width, renderTargetSize.height),
            m_pBlackBrush
            );

        hr = m_pRenderTarget->EndDraw();

        if (hr == D2DERR_RECREATE_TARGET)
        {
            hr = S_OK;
            DiscardDeviceResources();
        }
    }

    return hr;
}


Requirements

Library

D2d1.lib

DLL

D2d1.dll

See also

ID2D1RenderTarget

 

 

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