D2D Solid Brush With Alpha

Question

DrawGeometry with solid brush with alpha color, when one stroke covers another, why some will add 2 alpha value, some will not?

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C++ DX11

Answer 1

Hello,

I draw a gird but can not reproduce this issue. Would you please provide us some codes to reproduce it?

// In head file
Microsoft::WRL::ComPtr<ID2D1PathGeometry> m_pathGeometry[6];

//void geomerty::CreateWindowSizeDependentResources() function
	for(int i=0;i<2;i++)
	{
	DX::ThrowIfFailed(
		m_d2dFactory->CreatePathGeometry(&m_pathGeometry[i])
		);
	ID2D1GeometrySink *pSink=NULL;
	DX::ThrowIfFailed(m_pathGeometry[i]->Open(&pSink));
	pSink->BeginFigure(D2D1::Point2F(100+i*50,200),D2D1_FIGURE_BEGIN_HOLLOW);
	pSink->AddLine(D2D1::Point2F(100+i*50,700));
		pSink->EndFigure(D2D1_FIGURE_END_CLOSED);
	pSink->Close();
	}
	for(int i=2;i<6;i++)
	{
	DX::ThrowIfFailed(
		m_d2dFactory->CreatePathGeometry(&m_pathGeometry[i])
		);
	ID2D1GeometrySink *pSink=NULL;
	DX::ThrowIfFailed(m_pathGeometry[i]->Open(&pSink));
	pSink->BeginFigure(D2D1::Point2F(100,200+(i-2)*50),D2D1_FIGURE_BEGIN_HOLLOW);
	pSink->AddLine(D2D1::Point2F(700,200+(i-2)*50));
	pSink->EndFigure(D2D1_FIGURE_END_CLOSED);
	pSink->Close();
	}


//void geomerty::Render() function
	for(int i=0;i<5;i++)
	{
		m_d2dContext->DrawGeometry(m_pathGeometry[i].Get(),m_solidBrush.Get(),30.f);
	}

Best regards,
Jesse

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Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 2

See the DWriteCustomTextRenderer sample.

DWriteCustomTextRenderer.cpp :  Change to alpha brush

        m_d2dContext->CreateSolidColorBrush(
            D2D1::ColorF(D2D1::ColorF::GreenYellow,0.5),
            &m_blackBrush
            )

CustomTextRenderer.cpp : Draw wide Outline

    D2DDeviceContext->DrawGeometry(
        transformedGeometry.Get(),
        outlineBrush.Get(),32
        );

Just because different fonts?  They are in ONE Draw command. Where can I set alpha operation mode. I DON'T want them added up.

Some Asian characters' outline with SAME font even cover each other when there are several Draws in the CustomTextRenderer::DrawGlyphRun

Why they are different?  Seems some characters are not drawn at one time.

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C++ DX11

Answer 3

 

Hi,

 

Sorry for delay replay, did you solve this problem? If so, would you please sharing the solution with us?

 

Best regards,

Jesse

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Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 4

Seems there will be several "DrawGlyphRun" calls in ONE "IDWriteTextLayout.Draw" command when using Asian fonts. (Is it a bug, or ?  ) A new DrawGlyphRun will cover the old one. So just do not draw in DrawGlyphRun .

D2D and DWrite seems not fast enough, and I will only use it in offline rendering.

Answer 5

Hello,

 

Would you please provide us the whole codes to reproduce this issue?

 

You can upload your project to skydriver

http://skydrive.live.com/

 

Best regards,

Jesse

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Jesse Jiang [MSFT]
MSDN Community Support | Feedback to us

Answer 6

Seems only have problem when fontname="", default font ?

https://skydrive.live.com/redir.aspx?cid=62c178358aee6cc2&resid=62C178358AEE6CC2!111&parid=62C178358AEE6CC2!109&authkey=!AC8I8fLXULhsnR0

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C++ DX11