Re: Graphic converter query - transparency

Chris Ridd <chrisridd@[EMAIL PROTECTED]
> wrote:

> (Rowland McDonnell) said:
> 
> > Woody <usenet@[EMAIL PROTECTED]
> wrote:
> > 
> >> Rowland McDonnell <real-address-in-sig@[EMAIL PROTECTED]
> wrote:
> >> 
> >>> Woody <usenet@[EMAIL PROTECTED]
> wrote:
> >>> 
> >>>> Rowland McDonnell <real-address-in-sig@[EMAIL PROTECTED]
> wrote:
> >>>> 
> >>>>> It's a question I would have thought the manual would help me
with, but
> >>>>> it seems not.
> >>>>> 
> >>>>> Can anyone tell me how to make a (currently white) area around the
> >>>>> outside of an image into a transparent region using Graphic
Converter?
> >>>> 
> >>>> Although not a user of graphic converter, assuming it works in a
> >>>> similarish way to other things, you can only change an area to
> >>>> transparent if you want to make a gif, which I assume you don't if
you
> >>>> are making an icon.
> >>> 
> >>> I dunno - I recall icons with transparent (missing, more like) bits
> >>> under < OS X, so why can't I have 'em with OS X?
> >> 
> >> Well, you can, but that isn't what the finder uses for transparent
> >> images (I don't think).
> > 
> > Well, with ResEdit, you could define a mask to blank off regions of
the
> > icon square that you didn't want to count as `part of the icon'.
> > 
> > Sometimes, this mask was used in an annoying fa****on so that the icon
> > had holes in it thus making it hard to click.
> > 
> > Sounds like `equivalent to transparency' to me - and one would assume,
> > in a sensible world, that the Finder would interpret transparent parts
> > of an image given to it to use as an icon as `masked off bits' in that
> > fa****on.
> 
> Finder still does, but not in general.
> 
> What you're describing is an image with a 1-bit mask, and that's either
> done by providing a 1-bit image as part of the icon file or by 
> indicating which colour in the full icon is to be the mask.

Yep - I had assumed that the Finder would do the sensible thing on
meeting transparency, bearing the above in mind, when meeting a `paste
into icon', sort of thing.

> Finder and OS X still use icon with 1-bit masks, but in general you 
> need to provide icons with 8-bit masks because they're needed by the 
> Dock. The mask is treated as grey-scale, where black is equivalent to
> "don't show" or "transparent", white is "show" or "100% opaque", and 
> the other values give a smooth change between the two.

Ah!

> Another name for the mask is alpha channel.

Ah!!!!!!!!!!!!

So it's all a bit more `special' these days, which is why I didn't get
behaviour that looked sensible to me.

> Good luck with getting transparency working in any sane way with 
> Graphic Converter. Last time I tried it was quite hard to make GC do 
> anything approaching the right thing, or what I wanted.

It's been a bit like that the whole time I've had it.  On the other
hand, given that I couldn't possibly justify the expense of
Photoshop[1], what else could I use?

Rowland.

[1]  The price only makes sense to professional people who use it to
make money, or maybe to a /very/ keen amateur photographer.

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