Re: [Gimp-developer] Canvas size, background, and channels

2010-08-20 Thread Chris Mohler
On Thu, Aug 19, 2010 at 10:53 PM,
saulgo...@flashingtwelve.brickfilms.com wrote:
 Imagine you've made a selection around an object and then saved that
 selection to a channel for later use (for example, a model's face). If
 increasing the canvas size filled the edges of the canvas with
 anything but black, then your saved selection would no longer be
 limited to the original object (e.g., the model's face), but would
 also include the edges. It seems more reasonable to me that saved
 selections should not be changed if the canvas size changes.

(forgot to reply-all)

That's pretty much the same (and opposite) problem I'm facing.
Imagine you're storing image data for output in the channels.  100%
solid  = 100% output.  Now, increase the canvas size and there's a
solid border of output.  I must delete it to prevent it from printing.

IMO, storing selections is but a secondary function of spot channels -
their primary function is output to press.  But I'm coming from a
print background, so perhaps I'm biased ;)

Chris
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Re: [Gimp-developer] Canvas size, background, and channels

2010-08-20 Thread Chris Mohler
On Fri, Aug 20, 2010 at 12:29 AM, Martin Nordholts ense...@gmail.com wrote:
 I would expect it to be filled with what it was filled with when you
 created it, as if it would have no bounds but extend into infinity

Then I wish I could create channels with no fill ;)

(yes, color and opacity but zero fill/solidity - this is not currently
possible AFAICT)

Chris
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Re: [Gimp-developer] Canvas size, background, and channels

2010-08-20 Thread yahvuu
Hi,

On 20.08.2010 08:52, Chris Mohler wrote:
 On Thu, Aug 19, 2010 at 10:53 PM,
 saulgo...@flashingtwelve.brickfilms.com  wrote:
 Imagine you've made a selection around an object and then saved that
 selection to a channel for later use (for example, a model's face). If
 increasing the canvas size filled the edges of the canvas with
 anything but black, then your saved selection would no longer be
 limited to the original object (e.g., the model's face), but would
 also include the edges. It seems more reasonable to me that saved
 selections should not be changed if the canvas size changes.

 (forgot to reply-all)

 That's pretty much the same (and opposite) problem I'm facing.
 Imagine you're storing image data for output in the channels.  100%
 solid  = 100% output.  Now, increase the canvas size and there's a
 solid border of output.  I must delete it to prevent it from printing.

I think the 'infinite fill' behaviour as described by Martin will solve this
problem, too. If you start by filling with 0% (whithout an active selection),
then expanding the canvas will just reveal more of that 0%-filled infinite 
plane.



 IMO, storing selections is but a secondary function of spot channels -
 their primary function is output to press.  But I'm coming from a
 print background, so perhaps I'm biased ;)

IMO, the channels dialog in its traditional form is fundamentally broken
from a conceptual point of view: anything that can be stored as a grayscale
bitmap has been dumped in there, regardless of the corresponding concepts.


What is currently being called a 'channel'?

1) Color components, like R,G,B

These are what every pixel in every layer consists of.

Here, a 'channel' is a representation of one color component of a single 
layer's pixels.
For example, the red component of all pixels of a certain layer can be 
treated as a
grayscale bitmap.

Alpha is a color component in that sense, too.

(Multi-band images have additional color components. It has already been 
decided
that 'spot colors' will not be considered as such additional color 
components.)


2) Spot channels aka plates for the wet press

These are additional grayscale bitmaps which are unrelated to the rest of 
the image.
Interpretation is completely up to the user.

In contrast to 1), these 'channels' don't give a different view on the 
image's pixels
but provide new, 'other' pixels which allocate additional memory.


3) Stored selections

Since selections are defined as per-pixel values of 'membership', they can 
be
represented as grayscale bitmaps, too. Hence they get stored as 'channels'.

The conceptual difference to the 'channel' types 1) and 2) is that 
selections are inherently
multi-colored (to avoid the term multi-channel) -- they apply to all the 
R,G,B components
of a pixel. It would make perfect sense to have 'colored' selections which 
treat the pixel
components individually -- but they are simply not practical.

Following the concept of a fuzzy stencil, a selection could allow 50% tool 
action for red,
75% action for green and 0% for blue -- and all that within a circular 
area. If that sounds
strange, think of the R,G,B pixel layout on your TFT screen -- the 
described effect could
be achieved by proper rasterization of a physical stencil.

So a selection is conceptually a multi-color stencil which -- for practical 
reasons -- has
all R,G,B values bound to the same value for each pixel.



Now, it has been proven very beneficial to allow manipulation (and interaction) 
of all
these different entities via their grayscale representation. But that surely 
doesn't
imply to stuff everything into a single dialog -- which falsely suggests 
similarity
of quite different concepts.


rant finished,
yahvuu
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Re: [Gimp-developer] Canvas size, background, and channels

2010-08-20 Thread Martin Nordholts
On 08/20/2010 08:22 PM, Alexandre Prokoudine wrote:
 On 8/20/10, Martin Nordholts wrote:

 IMO that nicely fits into automatically managed layer (and channel)
 boundaries scheduled for GIMP 3.0.

 Will it also make layer mask move along with the layer it is attached to?

Hi Alexandre

No, automatically managed layer boundaries has nothing to do with that.

But it is still a change we should do.

  / Martin


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Re: [Gimp-developer] Canvas size, background, and channels

2010-08-19 Thread saulgoode
Quoting Chris Mohler cr33...@gmail.com:

 Is this a bug? (or a feature ;)

 1. Create new RGB image
 2. Add channel
 3. Increase canvas size
 4. Edges of channel are now filled 100% solid, regardless of BG color

 I expected:

 4. Edges of channel are now filled with % based on BG or possibly FG
 color (or 0% fill)

 Or am I missing something?

Imagine you've made a selection around an object and then saved that  
selection to a channel for later use (for example, a model's face). If  
increasing the canvas size filled the edges of the canvas with  
anything but black, then your saved selection would no longer be  
limited to the original object (e.g., the model's face), but would  
also include the edges. It seems more reasonable to me that saved  
selections should not be changed if the canvas size changes.



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Re: [Gimp-developer] Canvas size, background, and channels

2010-08-19 Thread Martin Nordholts
On 08/19/2010 11:12 PM, Chris Mohler wrote:
 Is this a bug? (or a feature ;)

 1. Create new RGB image
 2. Add channel
 3. Increase canvas size
 4. Edges of channel are now filled 100% solid, regardless of BG color

 I expected:

 4. Edges of channel are now filled with % based on BG or possibly FG
 color (or 0% fill)

I would expect it to be filled with what it was filled with when you 
created it, as if it would have no bounds but extend into infinity

IMO that nicely fits into automatically managed layer (and channel) 
boundaries scheduled for GIMP 3.0.

  / Martin


-- 

My GIMP Blog:
http://www.chromecode.com/
Automatic tab style and removed tab title bar
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