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Dot for Dot

View > Dot for Dot

what does it do?

0
8/9/2005 11:44:46 AM
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RicercatoreSbadato wrote:

> View > Dot for Dot
> 
> what does it do?

If you create a new image and set its dimensions to X by Y inches,
dot-for-dot will make your ruler indicate scale in inches. For millimeters
it will show millimeters/decimetres/centimetres depending on zooming state.
If dot-for-dot is unset, you will get a pixels ruler. That's what it does
as far as I can tell.

Roy

-- 
Roy S. Schestowitz
http://Schestowitz.com
0
Roy
8/9/2005 12:21:03 PM
I have found that 'dot for dot' is only to view the pixels of my image
like the pixels on my screen...
http://docs.gimp.org/en/ch06s05s02.html

0
RicercatoreSbadato
8/10/2005 7:58:05 AM
RicercatoreSbadato schrieb:

> I have found that 'dot for dot' is only to view the pixels of my image
> like the pixels on my screen...
> http://docs.gimp.org/en/ch06s05s02.html

IMO this description is rather bad - I doubt anyone can really
understand it, even if (or maybe because of) he knows what the setting
actually does...

Should be reported as a documentation bug.

Michael

0
Michael
8/10/2005 1:20:28 PM
Michael Schumacher wrote:

> RicercatoreSbadato schrieb:
> 
>> I have found that 'dot for dot' is only to view the pixels of my image
>> like the pixels on my screen...
>> http://docs.gimp.org/en/ch06s05s02.html
> 
> IMO this description is rather bad - I doubt anyone can really
> understand it, even if (or maybe because of) he knows what the setting
> actually does...
> 
> Should be reported as a documentation bug.

It needs context perhaps, but on its own, I agree that the explanation is
unhelpful. If anything, it is rather confusing.

In the GIMP 1.2.3 it only appears to change the rulers. I have played with
it for a few minutes, zooming in and out, trying to see the behaviour of
selections and snapping to pixel edges. I still don't understand...

I am not the only one who failed to grasp it...

http://lists.xcf.berkeley.edu/lists/gimp-user/2003-April/005676.html

Roy
0
Roy
8/10/2005 2:46:27 PM
Michael Schumacher wrote:

> 
> RicercatoreSbadato schrieb:
> 
>> I have found that 'dot for dot' is only to view the pixels of my image
>> like the pixels on my screen...
>> http://docs.gimp.org/en/ch06s05s02.html
> 
> IMO this description is rather bad - I doubt anyone can really
> understand it, even if (or maybe because of) he knows what the setting
> actually does...
> 
> Should be reported as a documentation bug.
> 
> Michael

I think I've got it..

The key to understanding dot for dot is the comment in the 
link below:

http://docs.gimp.org/en/ch06s05s02.html

----
"When turned on, every pixel in the image is shown as one pixel 
on the screen, on condition that the zoom ratio is 1:1".
----

In other words:

When you have 'dot for dot' selected, *AND* you zoom to 100%
then one pixel in the image (one dot) will equal one pixel
on your screen (another dot).  This is dot-for-dot.

For example:

My monitor image is 15.05 inches across.

My screen resolution is set to 1280x1024 which means 
this 15 inches of monitor width is filled with exactly 
1280 pixels.

Therefore, my horizontal monitor resolution must be:

 1280 pixels / 15.05 inches = 85 DPI

To check and see if my understanding of dot-for-dot was
true, I used GIMP to create an image that was 425 pixels
wide.  

When displayed at 100% zoom on my monitor with dot for 
dot selected, this image should be exactly 5 inches wide  
since 425 pixels / 85 DPI = 5 inches.

I measured it.  It was exactly 5 inches across because
one pixel in the image was equal to one pixel on my
screen. (dot for dot).

If it turned dot-for-dot OFF, then I could not get the image 
to appear 5 inches wide on the monitor at any zoom setting.  
This was because the image pixels were no longer tied to my 
screen pixels.  This only occurs when dot for dot is 
checked and the image is zoomed to 100%.


(It's commonly held that monitors are 72 DPI, but nowadays
this is untrue.  With modern monitor sizes and screen
resolutions, you'd be hard pressed to find one that actually
dispayed images at 72 DPI).







0
Jim
8/10/2005 4:27:50 PM
Jim Townsend <jwt@xescape.ca> writes:

> I measured it.  It was exactly 5 inches across because
> one pixel in the image was equal to one pixel on my
> screen. (dot for dot).
> 
> If it turned dot-for-dot OFF, then I could not get the image 
> to appear 5 inches wide on the monitor at any zoom setting.  
> This was because the image pixels were no longer tied to my 
> screen pixels.  This only occurs when dot for dot is 
> checked and the image is zoomed to 100%.

Um, actually it is supposed to work this way:

With dot for dot activated, your image size should not change when you
change the ppi setting for it. A 600px wide image will appear 600px
wide on your monitor at a zoom setting of 100%.

With dot for dot deactivated, and the correct screen reolution set in
the GIMP preferences, your image should be displayed in in't actual,
real world size. A 600px wide image, which has its pixel per inch set
to 600, will be displayed 1 inch wide at 100% zoom.

So, you described the opposite of what should happen, which makes me
think that your didn't set the display ppi in GIMP's preferences
correctly.


HTH,
Michael

-- 
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0
Michael
8/10/2005 5:36:57 PM
In <ddd40m$j9o$1@godfrey.mcc.ac.uk>, Roy Schestowitz wrote:

> In the GIMP 1.2.3 it only appears to change the rulers. I have played with
> it for a few minutes, zooming in and out, trying to see the behaviour of
> selections and snapping to pixel edges. I still don't understand...

If "dot for dot" is active then 100% means "show all pixels".  If "dot for
dot" is not active then 100% means "show the image at a size calculated by
a) size in pixels, b) monitor resolution and c) image resolution".

No matter how you call the menu item, many people will have problems to
understand the latter.

Ciao,
	Marc 'BlackJack' Rintsch
0
Marc
8/10/2005 7:50:51 PM
Marc 'BlackJack' Rintsch wrote:

> In <ddd40m$j9o$1@godfrey.mcc.ac.uk>, Roy Schestowitz wrote:
> 
>> In the GIMP 1.2.3 it only appears to change the rulers. I have played
>> with it for a few minutes, zooming in and out, trying to see the
>> behaviour of selections and snapping to pixel edges. I still don't
>> understand...
> 
> If "dot for dot" is active then 100% means "show all pixels".  If "dot for
> dot" is not active then 100% means "show the image at a size calculated by
> a) size in pixels, b) monitor resolution and c) image resolution".
> 
> No matter how you call the menu item, many people will have problems to
> understand the latter.

I see what you mean now. The change in the grid scale (rulers) was the only
things that caught my sight. I suppose it would have a distracting effect
to whoever attempts to figure out the impact of Dot for Dot.

Then again, one will need to have a clue about rendering to understand the
meaning of the technical phrase, which is probably day-to-day jargon to an
expert. This is definitely deceiving to an average user (unless there are
tooltips), much like the offering of different types of smoothing filters
(there is usually a default one for rookies).

Thanks for the answer,

Roy

-- 
Roy S. Schestowitz
http://Schestowitz.com
0
Roy
8/11/2005 2:32:38 AM
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