On Mon, 7 Aug 2000, clemensF wrote:
> many of you will not like to read this, as it is a set of newbie questions
> of the most repelling sort.
>
> some will hope to read the answers later...
That's why this list is here?
> 1. what is an alpha [channel]?
It's basically the transperence of the image. Usually this is implemented
as a grayscale layer (256 shades), where black is transparent, and white
is opaque, grey will therefore be translucent.
If you for example paint a filled circle on a completely transparent
layer, if you could see the alpha channel, it would get a full-white
circle.
Orinarily, gimp itself maintins the alpha channel, but using the tool "Add
Alpha channel", you can kindof "hardcode" it, on your own selecting which
parts of a layer should be transparent, opaque, or gradients thereof.
"Alpha", as I've read somewhere, is just because it in the beginning
symbolized a coefficent for how much of each pixel that should show...
> 2. what's the difference between layers, channels and paths?
Layers are the ordinary stuff you paint on.
Channels are 256-color grayscale layers which are used for masks, input to
filters, saving away selections etc. To give a 3d-effect to an shape, you
could for example put a copy of its alpha channel to a layer, blur it a
little, and then use this channel for a bump map.
Paths are mathematically stored bezier-shapes which can be conveniently
reshaped and converted to selections.
Each of these three have their own dialog, and what I'm now missing in
gimp is some way to quick-load stuff, for example have a shortcut for
"convert channel 4 to selection"...
> 3. is there a reasonable functional complement regarding vectors?
> reasonable is available on freebsd or some other unix, and functional
> complement means: if i want to specify objects and motion using
> vectors, can i make and render pretty surfaces in a jiffy with the
> gimp? or have it cooperate in 2d?
I don't really know, this is not my gebiet...Maybe would the simple
"sketch" do the job for you, maybe not...
> (4. how do i make use of histograms?
Is in the "levels"-dialog? There you can see how much there is of a
certain colour-value, and do stuff like "this gray is supposed to show as
black"...can be very useful instead of using the crude Contrast/Brightness
dialog...
> 5. is there anything one can /not/ do with adequately defined brushes?
> i'd like a broad, but memorable overview over defining and using brushes)
Sorry, can't help you on that one.
Hope I could help you some anyway.
Greets
/WoC
"...you look strong enough to pull the ears off a Gundark."
ICQ# 2357535
http://come.to/woc/
http://wlug.westbo.se/
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