ID2D1RenderTarget::PushLayer(constD2D1_LAYER_PARAMETERS&,ID2D1Layer*) method (d2d1.h)

Adds the specified layer to the render target so that it receives all subsequent drawing operations until PopLayer is called.

Syntax

void PushLayer(
  [ref] const D2D1_LAYER_PARAMETERS & layerParameters,
  [in]  ID2D1Layer                    *layer
);

Parameters

[ref] layerParameters

Type: const D2D1_LAYER_PARAMETERS

The content bounds, geometric mask, opacity, opacity mask, and antialiasing options for the layer.

[in] layer

Type: ID2D1Layer*

The layer that receives subsequent drawing operations.

Return value

None

Remarks

The PushLayer method allows a caller to begin redirecting rendering to a layer. All rendering operations are valid in a layer. The location of the layer is affected by the world transform set on the render target.

Each PushLayer must have a matching PopLayer call. If there are more PopLayer calls than PushLayer calls, the render target is placed into an error state. If Flush is called before all outstanding layers are popped, the render target is placed into an error state, and an error is returned. The error state can be cleared by a call to EndDraw.

A particular ID2D1Layer resource can be active only at one time. In other words, you cannot call a PushLayer method, and then immediately follow with another PushLayer method with the same layer resource. Instead, you must call the second PushLayer method with different layer resources.

This method doesn't return an error code if it fails. To determine whether a drawing operation (such as PushLayer) failed, check the result returned by the ID2D1RenderTarget::EndDraw or ID2D1RenderTarget::Flush methods.

Examples

The following example uses a layer to clip a bitmap 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

Layers Overview

PopLayer