如何清除MFC中以前的Png图像? [英] How to clear previous Png Image in mfc?

问题描述

void CPictureCtrl::FreeImage()
{
FreeData();
Graphics graphics( GetDC()->GetSafeHdc() );
graphics.Clear(Color::Transparent);
// or any other color ; see Gdiplus..
}

m_picCtrl.FreeImage();
	CFile picFile;
	if(picFile.Open(_T("acoustic grand piano_small.png"), CFile::modeReadWrite | CFile::typeBinary))
	{
		cout("opened");
		BYTE* pBuffer = new BYTE[(unsigned int)picFile.GetLength()];
		if(pBuffer != NULL)
		{
			picFile.Read(pBuffer, (UINT)picFile.GetLength());

			//Load the Image
			cout("displayed");
				m_picCtrl.Load(pBuffer, (size_t)picFile.GetLength());

			delete pBuffer;
		}
	}

当我释放应清除png并显示新图像的图像时，我将得到黑色背景.但是我需要透明的背景.


我的目标是显示png，当我显示新的png时，它应该清除上一张图片.

我已经使用CStatic控件显示png.

When I freeImage which should clear the png and display new i am getting black background. But I need transparent background.


My objective is display png and when I display new png it should clear the previous pic.

I have used CStatic control to display the png.

推荐答案

添加

Invalidate(true);

m_picCtrl.FreeImage();
    CFile picFile;
    if(picFile.Open(_T("acoustic grand piano_small.png"), CFile::modeReadWrite | CFile::typeBinary))
    {
        cout("opened");
        BYTE* pBuffer = new BYTE[(unsigned int)picFile.GetLength()];
        if(pBuffer != NULL)
        {
            picFile.Read(pBuffer, (UINT)picFile.GetLength());

            //Load the Image
            cout("displayed");
                m_picCtrl.Load(pBuffer, (size_t)picFile.GetLength());

            delete pBuffer;
        }
    }
Invalidate(true);

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