WinCE下IImage图像旋转和缩放

图像旋转和缩放总结：
根据《WinCE中用IImage如何旋转JPG图片》http://topic.youkuaiyun.com/u/20091118/15/97b5a6d0-f9aa-456d-b26e-f91286df8a97.html?seed=1545030343&r=61272118#r_61272118

和《WinCE下的IImage问题》http://topic.youkuaiyun.com/u/20100511/01/76b08366-7573-49c6-8a29-9b3617396e19.html
旋转图像需要通过IBasicBitmapOps的Rotate函数和Resize函数

 

看代码：

HRESULT CIImageExt::OnRotate() { HRESULT hr ; //retrun result IBasicBitmapOps * pbmpOp = NULL; //旋转操作 IBitmapImage *m_pbmpImg= NULL; //bmp图像 IBitmapImage * pNewbmpImg = NULL; //旋转后的bmp图像 ImageInfo info , Newinfo;//旋转前后的图像信息 if(m_pImage != NULL) { m_pImage->GetImageInfo( &info ); } PixelFormatID dstFormat = info.PixelFormat; //hr = m_pImageFactory->CreateNewBitmap(m_nWidth, m_nHeight, dstFormat, &m_pbmpImg); hr = m_pImageFactory->CreateBitmapFromImage(m_pImage, 0, 0, PixelFormatDontCare, InterpolationHintDefault, &m_pbmpImg); if(m_pbmpImg != NULL) { hr = m_pbmpImg->QueryInterface(IID_IBasicBitmapOps,(void **)&pbmpOp); //hr = pbmpOp->Resize(200,187,dstFormat, InterpolationHintDefault,&pNewbmpImg);//第一个和第二个参数是缩放的宽高，Draw的时候也要有与之对应的Rect if (m_pbmpImg != NULL) { m_pbmpImg->Release(); m_pbmpImg = NULL; } if(pbmpOp != NULL) { if (pNewbmpImg != NULL) { pNewbmpImg->Release(); pNewbmpImg = NULL; } hr = pbmpOp->Rotate(90,InterpolationHintDefault,&pNewbmpImg); if (pbmpOp != NULL) { pbmpOp->Release(); pbmpOp = NULL; } if(pNewbmpImg != NULL) { if(m_pImage != NULL) { m_pImage->Release(); m_pImage = NULL; } hr = pNewbmpImg->QueryInterface(IID_IImage,(void **)&m_pImage); if (pNewbmpImg != NULL) { pNewbmpImg->Release(); pNewbmpImg = NULL; } if(m_pImage != NULL) { m_pImage->GetImageInfo( &Newinfo ); m_nWidth = Newinfo.Width; m_nHeight= Newinfo.Height; } } } } return hr; }

IImage图像旋转成功后需要一个与之对应的Rect来Draw，我们以旋转90度为例，旋转后的区域为DestRect,则DestRect计算方法如下：

void CRotateView::GetRotateRect() { POINT center; //计算图像中心点 //m_rcImage是原来图像的区域 center.x = (m_rcImage.right - m_rcImage.left + 1)/2 + m_rcImage.left; center.y = (m_rcImage.bottom - m_rcImage.top + 1)/2 + m_rcImage.top; POINT SrcLeftTop, SrcRightBottom; //旧的左上和右下点 SrcLeftTop.x = m_rcImage.left; SrcLeftTop.y = m_rcImage.top; SrcRightBottom.x= m_rcImage.right; SrcRightBottom.y= m_rcImage.bottom; POINT DestLeftTop, DestRightBottom; //新的左上和右下点 DestLeftTop.x = center.x - center.y + SrcLeftTop.y; DestLeftTop.y = center.x + center.y - SrcLeftTop.x; DestRightBottom.x= center.x - center.y + SrcRightBottom.y ; DestRightBottom.y= center.y + center.x - SrcRightBottom.x; m_rcImage.left = DestLeftTop.x; m_rcImage.top = DestRightBottom.y; m_rcImage.right= DestRightBottom.x; m_rcImage.bottom = DestLeftTop.y; }

图像的显示：

void CRotateView::OnDraw(HDC hdc) { ... //m_hDC是create mem dc //GetRotateRect();//获取旋转后的DestRect //CopyRect( &m_pImageObj->m_position, &m_rcImage);//将DestRect拷贝给IImage对象 m_pImageObj->Draw( m_hDC, true, true ); BitBlt(hdc, 0, 0, rcWidth, rcHeight, m_hDC, 0, 0, SRCCOPY); ... }  

为了防止图像转了而上次的Draw没完成，最好将GetRotateRect()和CopyRect放在旋转图像之后。

 

感谢yuji我的帮助 !