ID2D1Layer interface (d2d1.h)

Represents the backing store required to render a layer.

Inheritance

The ID2D1Layer interface inherits from ID2D1Resource. ID2D1Layer also has these types of members:

• Methods

Methods

The ID2D1Layer interface has these methods.

Remarks

To create a layer, call the CreateLayer method of the render target where the layer will be used. To draw to a layer, push the layer to the render target stack by calling the PushLayer method. After you have finished drawing to the layer, call the PopLayer method.

Between PushLayer and PopLayer calls, the layer is in use and cannot be used by another render target.

If the size of the layer is not specified, the corresponding PushLayer call determines the minimum layer size, based on the layer content bounds and the geometric mask. The layer resource can be larger than the size required by PushLayer without any rendering artifacts.

If the size of a layer is specified, or if the layer has been used and the required backing store size as calculated during PushLayer is larger than the layer, then the layer resource is expanded on each axis monotonically to ensure that it is large enough. The layer resource never shrinks in size.

Creating ID2D1Layer Objects

A layer is a device-dependent resource: your application should create layers after it initializes the render target with which the layers will be used, and recreate the layers whenever the render target needs recreated. (For more information about resources, see Resources Overview.)

Examples

The following example uses a layer to clip a drawing to a geometric mask. For the complete example, see How to Clip to a Geometric Mask.

HRESULT DemoApp::RenderWithLayer(ID2D1RenderTarget *pRT)
{
    HRESULT hr = S_OK;

    // Create a layer.
    ID2D1Layer *pLayer = NULL;
    hr = pRT->CreateLayer(NULL, &pLayer);

    if (SUCCEEDED(hr))
    {
        pRT->SetTransform(D2D1::Matrix3x2F::Translation(350, 50));

        // Push the layer with the geometric mask.
        pRT->PushLayer(
            D2D1::LayerParameters(D2D1::InfiniteRect(), m_pPathGeometry),
            pLayer
            );
            
  
        pRT->DrawBitmap(m_pOrigBitmap, D2D1::RectF(0, 0, 200, 133));
        pRT->FillRectangle(D2D1::RectF(0.f, 0.f, 25.f, 25.f), m_pSolidColorBrush);  
        pRT->FillRectangle(D2D1::RectF(25.f, 25.f, 50.f, 50.f), m_pSolidColorBrush);
        pRT->FillRectangle(D2D1::RectF(50.f, 50.f, 75.f, 75.f), m_pSolidColorBrush); 
        pRT->FillRectangle(D2D1::RectF(75.f, 75.f, 100.f, 100.f), m_pSolidColorBrush);    
        pRT->FillRectangle(D2D1::RectF(100.f, 100.f, 125.f, 125.f), m_pSolidColorBrush); 
        pRT->FillRectangle(D2D1::RectF(125.f, 125.f, 150.f, 150.f), m_pSolidColorBrush);    
        

        pRT->PopLayer();
    }

    SafeRelease(&pLayer);

    return hr;
}

Requirements

See also

ID2D1RenderTarget

ID2D1Resource

Layers Overview