Re: About AutoCAD, BMPs and TIFFs (WAS: Bitmap to .wmf conversion )

[George Mena <George -dot- Mena -at- ESSTECH -dot- COM>]

It does indeed work.   It has worked since 1996, which is when I saw
AutoCAD Rel. 14 do this for the first time.  And just to make sure I saw
it right, I actually saved a TIF graphic in AutoCAD under its *.dwg
format.  The drawing was in fact completely editable in AutoCAD Rel.14
as a vector drawing.  And I was able to export a *.wmf version of the
drawing to diskette. :D

What the folks at Autodesk did was develop a translation algorithm that
makes bitmap-to-vector conversion possible.  As this was one of the
biggest new features of Rel 14, this algorithm is one of Autodesk's most
closely guarded trade secrets after the DXF engine.

I speculate that what Autodesk did was to base their algorithm on what
Adobe's Streamline program could do (or something like it) and then took
it quite a few steps further.  Either way, though, remember that all
image data is binary in nature. Creating a translation algorithm that
can turn imported bitmaps into vectors had to be possible.  It had to be
possible because export filters already use algorithms to export bitmap
versions of vector drawings.

Earlier versions of AutoCAD not only have this ability, but so do
current versions of Adobe Illustrator, CorelDraw and God only knows how
many other software drawing packages.  Go to http://www.adobe.com if
you've never heard of Adobe Streamline.  It's usually bundled with
Illustrator.  :D

The patterns and colors mentioned in the post are based on the raw
binary data required to generate the image in the first place.  Without
the raw binary data being used by a processor via the machine language
routines, a video card doesn't know how to draw the image to the
monitor.  Without knowing how to draw the image on the monitor screen,
the data is never transferred over the address/data lines between the
CPU and the video chip.  And data I/O transfer is something that MUST
happen, regardless of whether you're writing a chapter or working up a
block diagram in the graphics editor du jour.  :D

Hope this helps.  :D

George Mena

> -----Original Message-----
> From: Tim Altom [SMTP:taltom -at- simplywritten -dot- com]
> Sent: Wednesday, September 09, 1998 11:10 AM
> To:   George Mena
> Subject:      Re: Bitmap to .wmf conversion
>
> Thanks for the note. I can't imagine how that would work, unless the
> bitmap
> is essentially a pattern of lines and blank spaces. Most bitmaps
> aren't, and
> I can't imagine that even the vaunted and venerable AutoCad could
> distinguish between patterns of 25 million colors and derive a useful
> vector
> drawing from it.
>
> Does this work, in your personal experience?
>
        [George Mena]  snip

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