User talk:David D Allen

David D Allen (talk) 20:04, 30 April 2010 (UTC)

BMP File revision
On February 8 you revised the BMP File Format - DIB header (bitmap information header): Noted the variable size of the BITMAPCOREHEADER2/OS22XBITMAPHEADER.

Specifically you changed the BITMAPCOREHEADER2 / BITMAPCOREHEADER2 size from 64 to 12-64 making it indistinguishable from the following header types: BITMAPCOREHEADER / OS21XBITMAPHEADER - 12 bytes BITMAPINFOHEADER - 40 bytes BITMAPV2INFOHEADER - 52 bytes BITMAPV3INFOHEADER - 56 bytes ...because these header types are differentiated by their size, not by their contents.

Programs that would follo your revised documentation would be unable to distinguish between the above DIB Headers. This would generate serious bugs in implementations. Especially for DIBs in memory where the Bitmap File Header is absent.

As someone who created most of this article (and the main illustration), I am announcing my intent to revert this revision, if you are not going to provide a good argument for keeping the DIB header size ambiguity within a week.

Please, note that I will not accept an explanation in the style that "some program XYZ treats some BITMAPCOREHEADER2 fields as optional" as this does not prove anything and individual implementations do not constitute documentation. Even Adobe Photoshop makes serious implementation errors.

Verpies (talk)