From Drawfiles to Sprites
Colin Johnson
the merits of both. Curiously, I find that whilst a Sprite can readily be
dragged to the Draw icon and saved as a DrawFile, the reverse operation via
Paint doesn't appear to be catered for.
Yet the solution is surprisingly simply, since the two data layouts are
almost identical. By stripping off the first 140 bytes of a Drawfile, and
making easily programmable chances to the next twelve, the result can then
be filed as a normal Sprite.
Why is this facility not already available? And what are the unique
advantages that only Draw can offer?
Regards to all,
Colin Johnson.
--
__ __ _ _ _ _ // Retired DP pioneer now using an Acorn 4000
| '| || | |\ | // Enjoys Railway Videos. Has offspring in USA
|__.|__||__ | | \| JOHNSON // Enthusiastic programmer adept in BBC Basic V
__________________________// cjoh...@argonet.co.uk ZFC from Lympne, Kent
Marko Lukat
[..]
> Yet the solution is surprisingly simply, since the two data layouts are
> almost identical. By stripping off the first 140 bytes of a Drawfile, and
> making easily programmable chances to the next twelve, the result can then
> be filed as a normal Sprite.
And then what? Why should I file vector data as pixel data (ie sprite)?
Apart from that, what if the first n bytes you're stripping off contain
vital information ;)
> Why is this facility not already available? And what are the unique
> advantages that only Draw can offer?
Apparently ...
Marko
Reuben Thomas
>I've recently been playing with Sprites and Drawfiles, trying to discover
>the merits of both. Curiously, I find that whilst a Sprite can readily be
>dragged to the Draw icon and saved as a DrawFile, the reverse operation via
>Paint doesn't appear to be catered for.
>
>almost identical. By stripping off the first 140 bytes of a Drawfile, and
>making easily programmable chances to the next twelve, the result can then
>be filed as a normal Sprite.
??? The mind boggles. Draw files contain vector graphics, Sprites bitmap
images. Draw files can have sprites embedded in them (in a non-editable,
black box way). You certainly can't do what you say above unless all the
Draw file contains is a sprite.
>Why is this facility not already available? And what are the unique
>advantages that only Draw can offer?
Vector graphics give you object-orientation (you can take a Draw file
apart according to how it was constructed) and resolution independence
(since it consists of objects the computer understands, they can be
rendered to the full resolution of the output device).
Am I missing something?
--
http://www.cl.cam.ac.uk/users/rrt1001/ | maxim, n. wisdom for fools
Liam Gretton
<URL:mailto:cjoh...@argonet.co.uk> wrote:
> Yet the solution is surprisingly simply, since the two data layouts are
> almost identical. By stripping off the first 140 bytes of a Drawfile, and
> making easily programmable chances to the next twelve, the result can then
> be filed as a normal Sprite.
???
A drawfile is very different to a sprite internally. Drawfiles describe
objects (curves, regions of text etc) in terms of their attributes
(co-ords, colour and so on), whereas bitmaps such as sprites just hold an
array of pixels.
Although a drawfile can contain a sprite, what you describe cannot work.
Even if a sprite is the only object in a drawfile, simply removing the first
140 bytes and retyping the file does not leave you with a valid sprite.
To make a sprite out of a drawfile, you can either grab draw's window with
!Paint, or much better, use a program such as Tony Houghton's ArtToSpr.
--
Liam Gretton l...@star.le.ac.uk
Space Research Centre, http://www.src.le.ac.uk/
Physics and Astronomy Dept, phone +44 (0) 116 223 1039
Leicester University, fax +44 (0) 116 252 2464
Leicester LE1 7RH, UK http://xmm4.xra.le.ac.uk/