Reply To: Memory transfer mode: desuming the header

[sdavi]

Now, i can get the image data by a memory transfer, desume the hneeded headers (BITMAPFLILEHEADER and BITMAPINFOHEADER),
and i can save it into the filesystem, but when i open the image with a program (gimp for example) i note that the image is flipped vertically.
Why???
Anyone can say me why the source transfer image data in that way?

Post my code in relevants parts:

void doBufferedMemoryTransfer()

{

/*commented code, only explained for semplicity*/

//call DG_CONTROL,DAT_SETUPMEMXFER,MSG_GET so  i can setup twMemXFer that is of TW_SETUPMEMXFER type

// call getImageInfo(); and getImageLayout(); that wraps DG_IMAGE,DAT_IMAGEINFO,MSG_GET and DG_IMAGE,DAT_IMAGELAYOUT,MSG_GET respectively

// in a loop i call DG_IMAGE,DAT_IMAGEMEMXFER,MSG_GET until TWRC_XFERDONE is fired by last call to DG_IMAGE,DAT_IMAGEMEMXFER,MSG_GET

/*end commented code*/

...

case TWRC_SUCCESS:

fwrite((void*)buf,1,(UINT)twImageMemXFer.BytesWritten,pFile);

break;

case TWRC_XFERDONE:

//write last buffer into the file

fwrite((void*)buf,1,(UINT)twImageMemXFer.BytesWritten,pFile);

//call fseek to move the file pointer to begin of file in order to write

//image headers that needs to be placed in

fseek ( pFile , 0 , SEEK_SET );

bitmapFileHeader.bfSize = sizeof(BITMAPFILEHEADER) ;

bitmapFileHeader.bfType = 0x4D42;//BM

bitmapFileHeader.bfReserved1 = 0;

bitmapFileHeader.bfReserved2 = 0;

bitmapFileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) ;



bitmapInfoHeader.biSize = sizeof(BITMAPINFOHEADER) ;

bitmapInfoHeader.biPlanes = 1;

bitmapInfoHeader.biBitCount = imageInfo->getBitsPerPixel();

bitmapInfoHeader.biCompression = BI_RGB;//imageInfo->getCompression();

bitmapInfoHeader.biSizeImage = ((((imageInfo->getImageWidth() * imageInfo->getBitsPerPixel() + 31) / 32)*4) * abs(imageInfo->getImageLength()));



bitmapInfoHeader.biXPelsPerMeter = 0;

bitmapInfoHeader.biYPelsPerMeter = 0;

bitmapInfoHeader.biClrUsed = 0;

bitmapInfoHeader.biClrImportant = 0;

bitmapInfoHeader.biWidth = imageInfo->getImageWidth();

bitmapInfoHeader.biHeight = imageInfo->getImageLength();



fwrite(&bitmapFileHeader, 1, sizeof(BITMAPFILEHEADER), pFile);

fwrite(&bitmapInfoHeader, 1, sizeof(BITMAPINFOHEADER), pFile);

//other calls to free memory, close file handle and exit from the loop omitted.

break;







}

The imageInfo instance is a instance of a class that wraps TW_IMAGEINFO struct.

best regards