问题
I need to free the bitpointer
, because this function is executed multiple times and memory usage is growing for a reason I don't understand and it crashes after reaching 22mb of ram usage.. If I try to delete the bitpointer
like this delete []bitpointer
or free(bitpointer)
I get access violation error. But I don't understand why, because the function shouldn't use the pointer any more and the new red blue green values are set..
void Get_Color(int x,int y,int w,int h,int &red,int &green,int &blue,int action)
{
HDC hdc, hdcTemp;
RECT rect;
BYTE*bitPointer=new BYTE[4*h*w];
HWND Desktop = GetDesktopWindow();
hdc = GetDC(Desktop);
GetWindowRect(Desktop, &rect);
hdcTemp = CreateCompatibleDC(hdc);
BITMAPINFO bitmap;
bitmap.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bitmap.bmiHeader.biWidth = w;
bitmap.bmiHeader.biHeight = h;
bitmap.bmiHeader.biPlanes = 1;
bitmap.bmiHeader.biBitCount = 32;
bitmap.bmiHeader.biCompression = BI_RGB;
bitmap.bmiHeader.biSizeImage = 0;
bitmap.bmiHeader.biClrUsed = 0;
bitmap.bmiHeader.biClrImportant = 0;
HBITMAP hBitmap2 = CreateDIBSection(hdcTemp, &bitmap, DIB_RGB_COLORS, (void**)(&bitPointer), NULL, NULL);
SelectObject(hdcTemp, hBitmap2);
BitBlt(hdcTemp, 0, 0, w, h, hdc, x, y, SRCCOPY);
if(action==1)
{
for(int j=0;j<=w*h*4;j+=4)
{
red = bitPointer[j+2];
green = bitPointer[j+1];
blue = bitPointer[j];
if(red<30 && green>190 && blue>190)
{
break;
}
}
}
else
{
for(int j=0;j<=w*h*4;j+=4)
{
red = bitPointer[j+2];
green = bitPointer[j+1];
blue = bitPointer[j];
break;
}
}
///RELEASE
ReleaseDC(NULL,hdc);
ReleaseDC(NULL,hdcTemp);
delete []bitPointer; ///Error
}
回答1:
If you read the documentation you'll see that you shouldn't be allocating memory for bitPointer
, CreateDIBSection
does that for you. You need to use DeleteObject
to free hBitmap2
.
The crash occurs because the value of bitPointer
youi are freeing is not the one that you allocated. (And the memory you allocated is leaked.)
回答2:
In SelectObject, save the returned value: HGDIOBJ save = SelectObject(hdcTemp, hBitmap2);
Then before ReleaseDC, delete the DIB DeleteObject( SelectObject(hdcTemp, save) );
Otherwise, you create bitmaps and don't delete them.
来源:https://stackoverflow.com/questions/27568783/freeing-memory-error