使用GetHBITMAP（）和MFC CStatic :: SetBitmap（）可能發生的內存泄漏

Question

我每100毫秒調用一次以下函數。 目的是從renderBuffer中獲取圖像，調整其大小，然后使用SetBitmap（）將其顯示在對話框的CStatic控件中。 問題是執行此功能時，我每秒觀察到相當大的內存使用高峰。 它在CStatis控件中顯示調整大小的圖像沒有問題，但是我在任務管理器中看到，每個第二個進程都會分配額外的4 MB內存，並且永遠不會停止，直到該進程用完內存為止。

這是代碼，如果您有任何想法，請告訴我。

void CAppDlg::UpdatePreview( const RenderBuffer* renderBuffer )
{
HBITMAP hbmReturn = NULL; 
Gdiplus::Bitmap  *bmPhoto  = NULL;
Gdiplus::Bitmap bmPhoto( THUMBNAIL_WIDTH, THUMBNAIL_HEIGHT );
CBitmap Bmp1;

Gdiplus::Bitmap image( 780, 780, 4*780, PixelFormat32bppARGB, renderBuffer->buffer );

int sourceWidth  = image.GetWidth();
int sourceHeight = image.GetHeight();

int destX = 0,
    destY = 0; 

float nPercent  = 0;
float nPercentW = ((float)THUMBNAIL_WIDTH/(float)sourceWidth);;
float nPercentH = ((float)THUMBNAIL_HEIGHT/(float)sourceHeight);

if(nPercentH < nPercentW)
{
    nPercent = nPercentH;
    destX    = (int)((THUMBNAIL_WIDTH - (sourceWidth * nPercent))/2);
}
else
{
    nPercent = nPercentW;
    destY    = (int)((THUMBNAIL_HEIGHT - (sourceHeight * nPercent))/2);
}

int destWidth  = (int)(sourceWidth * nPercent);
int destHeight = (int)(sourceHeight * nPercent);

bmPhoto.SetResolution( image.GetHorizontalResolution(), image.GetVerticalResolution() );

Gdiplus::Graphics *grPhoto = Gdiplus::Graphics::FromImage( &bmPhoto );
Gdiplus::Color colorW(255, 255, 255, 255);
grPhoto->Clear( colorW );
grPhoto->SetInterpolationMode( Gdiplus::InterpolationModeHighQualityBicubic );
grPhoto->DrawImage( &image, Gdiplus::Rect(destX, destY, destWidth, destHeight) );

bmPhoto.GetHBITMAP( colorW, &hbmReturn );

m_BitmapPreview.SetBitmap( hbmReturn ); // ---- without this line memory usage doesn't go up rapidly every second.

DeleteObject( hbmReturn ); // ---- returns non-zero which would point out that it was freed properly.
delete grPhoto;
}

謝謝你的幫助！

問候。

Answer 1

我猜你應該使用DeleteObject 。

我認為代碼如下所示：

// ..............
bmPhoto.GetHBITMAP( colorW, &hbmReturn );

HBITMAP prev = m_BitmapPreview.SetBitmap( hbmReturn ); // ---- without this line memory usage doesn't go up rapidly every second.
if (NULL != prev)
{
   DeleteObject(prev); // *** do not forget to delete the previously associated bitmap
}

DeleteObject( hbmReturn ); // ---- returns non-zero which would point out that it was freed properly.
// .........