Taking measurements

[asking]

Hi,

I'm new. I am trying to measure:

(1) Area and Perimeter of a selection (any kind of selection). I've managed to measure the area only.

(2) Length of a free drawn or a straight line.

(3) It would be nice to be able to:

(i) Set a Scale and get the result in cm2.

(ii) automatically write the results by a right click or any other way.

THANK YOU

[Sarkut]

At the bottom of the Paint.NET UI is the status bar,

where many of these measurements will show.

Length of a straight Line/Curve tool line will show until mouse button is released.

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At the far right of the toolbar (top header),

Units can be set to Pixels, Inches, or Centimeters.

automatically write the results by a right click or any other way.

So far as I know, not possible.

Edited May 21, 2010 by Sarkut

[asking]

Thanks!

What about:

(1) AFTER mouse button released, when selecting an object?

(2) Perimeter of a Lasso or other selection?

(3) Length of a free line?

THANKS AGAIN

At the bottom of the Paint.NET UI is the status bar,

where many of these measurements will show.

Length of a straight Line/Curve tool line will show until mouse button is released.

---------------------------------------------------------------------------

At the far right of the toolbar (top header),

Units can be set to Pixels, Inches, or Centimeters.

So far as I know, not possible.

[Sarkut]

What about:

(1) AFTER mouse button released, when selecting an object?

Area, and Bounding Rectangle dimensions only.

(2) Perimeter of a Lasso or other selection?

Area, and Bounding Rectangle dimensions only.

(3) Length of a free line?

No.

[pyrochild]

It sounds like you're wanting to use Paint.NET for some sort of CAD work, which is really not what it's designed for.

[asking]

Hi,

Not CAD.

I'm analyzing pictures acquired by a microscope for a medical study.

You will be amazed to know there are not to many tools or easy ways to do the things I asked.

THANK YOU

It sounds like you're wanting to use Paint.NET for some sort of CAD work, which is really not what it's designed for.

[Rick Brewster]

If you want physical dimensions, be sure to set the Resolution from Image->Resize. You will need to know the physical resolution of the image precisely. (By resolution I'm referring to DPI -- dots per inch, aka pixels per real-world-unit-of-measurement).

I'm not sure if the resolution can scale down to what you need; typical resolution is 96 dpi (dots aka pixels per inch) or 37.80 dots per centimeter. WIth microsocopic images you're probably looking for pixels per micrometer or less. You might just need to mentally multiply and divide by 10,000 in that case (substitute µm for cm and vice-versa).

[asking]

Thanks.

All is OK. I have no problem with the scale.

I'm still looking for a tool that gives:

(1) Perimeter of a Lasso or other selection, Length of a free line

(2) Preferable also AFTER mouse button released, when selecting an object (the software recognizes the object so it seems an easy task)

(3) It would be nice to be able to automatically write the results by a right click or any other way.

Once again, thank you all for all the help.

If you want physical dimensions, be sure to set the Resolution from Image->Resize. You will need to know the physical resolution of the image precisely. (By resolution I'm referring to DPI -- dots per inch, aka pixels per real-world-unit-of-measurement).

I'm not sure if the resolution can scale down to what you need; typical resolution is 96 dpi (dots aka pixels per inch) or 37.80 dots per centimeter. WIth microsocopic images you're probably looking for pixels per micrometer or less. You might just need to mentally multiply and divide by 10,000 in that case (substitute µm for cm and vice-versa).

[pyrochild]

I'm still looking for a tool that gives:

(1) Perimeter of a Lasso or other selection

Any perimeter measurement for a non-rectangular shape would be very ambiguous and probably not what you're looking for.

For example, you would expect a circular selection with a radius 50px to have a circumference/perimeter of 100ᴨpx, but in actuality it would be something very different, since Paint.NET uses hard selections. Instead of following the contour of the circle, it would follow the contour of the pixels that lie on the circle, inflating this "perimeter."

Maybe that's what you want, maybe not. Either way, it's going to be very confusing for people who are expecting the opposite.

[Sarkut]

Here's an idea for getting a Lasso Select perimeter approximation.

Make the selection, then, on a new layer use Outline Selection at 1 pixel width, primary color.

Deselect, run Color Count , set to Primary Color.

That should give a perimeter in pixels.

You might want to average the results of two layers, one with inverted selection.

Be sure to put a check in the box for "Preserve canvas edges" in Outline Selection.

Outline Selection

Color Count

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This doesn't negate any of the concerns detailed by pyrochild in the previous post.