Herd Software Development
DaVinci Graphics Library
DaVinci Documentation

Leonardo: The ConvertDIB function

Converts a 1, 4, 8, 16, 24, 32 or 48 bit DIB to a DIB of a new color depth. Optimized for generation of 32 bit DIBs.

BOOL API ConvertDIB(
HDIB FAR *	lphdib,
UINT	uNewBitCount,
DWORD	dwReserved);

lphdib HDIB FAR * Variable pointer to an HDIB. When passed to the function, it should contain the handle of the source dib. On completion, the handle is the handle of the output DIB.

uNewBitCount UINT Desired color depth for the new DIB (1, 4, 8, 16, 24, 32 or 48 bits)

dwReserved DWORD Reserved for future use. Should be specified as 0.

Returns

Returns TRUE if the function was successful, otherwise FALSE. Conversion failure is usually due to insufficient memory to complete the operation.

Remarks

The value of the DIB handle becomes the handle of the destination DIB on return. Since the conversion is executed "in-place", the original handle becomes invalid and cannot used after conversion any more. The source DIB's handle cannot and should not be deleted by the application.

In many cases, the returned handle will be identical to the source DIB's handle.

Requirements for source DIBs

• Image must have 1, 4, 16, 24, 32 or 48 bit color depth
  
  
• No RLE compression (biCompression=BI_RGB) can be used in the source image.
  
  
• Only Windows bitmap formats are permitted (i.e. no OS/2 bitmaps (biSize == sizeof(BITMAPINFOHEADER)) or "bottom-up" DIBs (biHeight>0))

Optimization

DaVinci Professional includes optimized routines for conversion to 32 bit DIBs. Code is optimized for speed and color depth adjustment occurs "in-place", meaning that no temporary storage is required during the operation.