png图片加载问题?

[mirroatl215]

m_image2 = Image::FromFile(L"res/10.png");
Graphics graphics(dc.m_hDC);
graphics.DrawImage(m_image,10,10);
//显示正常

但是，我有一个Png按钮类，只把背景图片拷贝出来与png按钮的不同状态png图片放一个HDC里，然后，把HDC的拷贝到OnEraseBkgnd(CDC *pDC)的pDC里。
//不把背景拷贝到按钮类的CopyFrom里，半透明效果出不来呢。是哪一步造成的；去掉就好了。

void GdipButton::DrawItem(LPDRAWITEMSTRUCT lpDIS)
{
	int i = 0;
	if(lpDIS->itemState & ODS_DISABLED) i = 3;
	else if (lpDIS->itemState & ODS_SELECTED) i = 2;
	else if (hovering) i = 1;
	//else index = 0;
	
	CRect rect;
	if(gdipDraw[i] == NULL && image[i] != NULL)
	{
		GetWindowRect(rect);
		GetParent()->ScreenToClient(rect);
		gdipDraw[i] = new GdipDraw(lpDIS->hDC,rect.Width(),rect.Height());
		gdipDraw[i]->CopyFrom(hBackDC,rect.left,rect.top);//拷入背景图片的HDC hBackDC//加载是在对话框程序里通过按钮类接口函数进行加载的 代码就不复制了
		gdipDraw[i]->DrawImage(image[i]);
		CString text;
		GetWindowText(text);
		if(!text.IsEmpty())
		{
			rect.left = lpDIS->rcItem.left + textRect.left;
			rect.right = lpDIS->rcItem.right - textRect.right/*-rect.left*/;
			rect.top = lpDIS->rcItem.top + textRect.top;
			rect.bottom = lpDIS->rcItem.bottom - textRect.bottom/*-rect.top*/;
			gdipDraw[i]->DrawText(text,rect,textFont,textColor,textFormat);
		}
	}
	if(gdipDraw[i] != NULL)
	{
		::GetClipBox(lpDIS->hDC,rect);
		gdipDraw[i]->CopyTo(lpDIS->hDC,rect);//把Png图片画到lpDIS->hdc里
          }
}

bool GdipDraw::CopyFrom(HDC hDC,int x /*= 0*/,int y /*= 0*/)
{
	if(hDC == 0 || hMemDC == 0) 
		return false;

	return ::BitBlt(hMemDC,0,0,width,height,hDC,x,y,SRCCOPY) == TRUE;
}


bool GdipDraw::DrawImage( Image *image )
{
	if(image == 0 || hMemDC == 0) 
		return false;

	Gdiplus::Graphics graphics(hMemDC);
	return graphics.DrawImage(image,0,0,width,height) == Gdiplus::Ok;
}

BOOL CGButtonTestDlg::OnEraseBkgnd(CDC* pDC)
{
	CRect rect;
	pDC->GetClipBox(rect);
	gd.CopyTo(pDC->m_hDC,rect);//对话框类的把按钮类把背景图片与png按钮的不同状态png图片处理完成一张图片之后，拷贝到CDC*pDC里
	return TRUE;        
//是这个步的问题?????
}



bool GdipDraw::CopyTo( HDC hDC,LPRECT rect )
{
	if(hDC == 0 || hMemDC == 0 || rect == 0) 
		return false;
	
	return ::BitBlt(hDC,
		rect->left,rect->top,
		rect->right - rect->left,
		rect->bottom - rect->top,
		hMemDC,rect->left,rect->top,SRCCOPY) == TRUE;
}

[mirro187_]

bool GdipImage::Load( UINT id,LPCSTR type)
{
	Clear();
	ASSERT(type != 0);

	HRSRC res = ::FindResource(NULL, MAKEINTRESOURCE(id), "PNG");
	if ( res == NULL) return false;

	DWORD size = ::SizeofResource(NULL, res);
	if (size == 0) return false;

	LPCVOID data = ::LockResource(::LoadResource(NULL, res));
	if (data == NULL) return false;

	hBuffer  = ::GlobalAlloc(GMEM_MOVEABLE, size);
	if(hBuffer == NULL) return false;

	void* buff = ::GlobalLock(hBuffer);
	if (buff != NULL)
	{
		CopyMemory(buff, data, size);
		IStream* pstream = NULL;
		if (::CreateStreamOnHGlobal(hBuffer, FALSE, &pstream) == S_OK)
		{
			image = Gdiplus::Bitmap::FromStream(pstream);
			pstream->Release();
			if (image != NULL)
			{ 
				if (image->GetLastStatus() == Gdiplus::Ok)
					return true;

				delete image;
				image = NULL;
			}
		}
		::GlobalUnlock(hBuffer);
	}
	::GlobalFree(hBuffer);
	hBuffer = NULL;

	return false;
}

//加载方式问题??????????????不是吧

[编程小白_大场]

什么东西，还用得着那样麻烦呀，你用cximage就不用那样麻烦了。 http://blog.csdn.net/sadasasdasd/article/details/8510691#comments

[jimette]

我有一个Png按钮类，只把背景图片拷贝出来与png按钮的不同状态png图片放一个HDC里，然后，把HDC的拷贝到OnEraseBkgnd(CDC *pDC)的pDC里。 是吧 png图片考到按钮上？ 按钮也不是透明的!

[mirro187_]

bool GdipDraw::DrawImage( Image *image ) { if(image == 0 || hMemDC == 0) return false; Gdiplus::Graphics graphics(hMemDC); return graphics.DrawImage(image,0,0,width,height) == Gdiplus::Ok; }

引用 5 楼 redui 的回复:

DrawImage时的工作模式是COPY还是OVER？只有OVER模式才执行混合，否则就是直接覆盖

[mirroatl215]

是呀！！！！！！！！

[redui]

DrawImage时的工作模式是COPY还是OVER？只有OVER模式才执行混合，否则就是直接覆盖

[mirro187_]

bool GdipDraw::DrawImage( Image *image ) { if(image == 0 || hMemDC == 0) return false; Gdiplus::Graphics graphics(hMemDC); return graphics.DrawImage(image,0,0,width,height) == Gdiplus::Ok; }

引用 5 楼 redui 的回复:

DrawImage时的工作模式是COPY还是OVER？只有OVER模式才执行混合，否则就是直接覆盖