Jump to content

Counting pixels of one color


Recommended Posts

Hi all-

I am trying to create stimuli for a research study and need to control for the amount of one color in a display. I am creating various-sized circles that are either red or yellow on a black background. Is there a way to count the number of pixels of one color on the screen? If I use the magic wand and the shift key, I can select all the circles of one color, but it only gives me dimensions for the bounding rectangle, right? Is there a way to do this?

THANK YOU!

Link to comment
Share on other sites

Hi all-

I am trying to create stimuli for a research study and need to control for the amount of one color in a display. I am creating various-sized circles that are either red or yellow on a black background. Is there a way to count the number of pixels of one color on the screen? If I use the magic wand and the shift key, I can select all the circles of one color, but it only gives me dimensions for the bounding rectangle, right? Is there a way to do this?

THANK YOU!

Link to comment
Share on other sites

Hi all-

I am trying to create stimuli for a research study and need to control for the amount of one color in a display. I am creating various-sized circles that are either red or yellow on a black background. Is there a way to count the number of pixels of one color on the screen? If I use the magic wand and the shift key, I can select all the circles of one color, but it only gives me dimensions for the bounding rectangle, right? Is there a way to do this?

THANK YOU!

Link to comment
Share on other sites

Hi all-

I am trying to create stimuli for a research study and need to control for the amount of one color in a display. I am creating various-sized circles that are either red or yellow on a black background. Is there a way to count the number of pixels of one color on the screen? If I use the magic wand and the shift key, I can select all the circles of one color, but it only gives me dimensions for the bounding rectangle, right? Is there a way to do this?

THANK YOU!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles. One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

THANKS!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles. One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

THANKS!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles. One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

THANKS!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles. One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

THANKS!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles.
I believe I had the same misconception at one point.
One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

Clarifying what Rick said, to create a circle of A = 6cm², you'd need a radius of 1.382cm, or .544". At the default image resolution of 96dpi, that's 52.232 pixels. Paint.NET does not support soft selections, so it can't have only a fraction of a pixel selected; it's either selected or it's not. So you can't get exactly 6cm² at 96dpi.

Also due to the lack of soft selections, the formula A=πr² doesn't really apply anyway.

xZYt6wl.png

ambigram signature by Kemaru

[i write plugins and stuff]

If you like a post, upvote it!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles.
I believe I had the same misconception at one point.
One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

Clarifying what Rick said, to create a circle of A = 6cm², you'd need a radius of 1.382cm, or .544". At the default image resolution of 96dpi, that's 52.232 pixels. Paint.NET does not support soft selections, so it can't have only a fraction of a pixel selected; it's either selected or it's not. So you can't get exactly 6cm² at 96dpi.

Also due to the lack of soft selections, the formula A=πr² doesn't really apply anyway.

xZYt6wl.png

ambigram signature by Kemaru

[i write plugins and stuff]

If you like a post, upvote it!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles.
I believe I had the same misconception at one point.
One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

Clarifying what Rick said, to create a circle of A = 6cm², you'd need a radius of 1.382cm, or .544". At the default image resolution of 96dpi, that's 52.232 pixels. Paint.NET does not support soft selections, so it can't have only a fraction of a pixel selected; it's either selected or it's not. So you can't get exactly 6cm² at 96dpi.

Also due to the lack of soft selections, the formula A=πr² doesn't really apply anyway.

xZYt6wl.png

ambigram signature by Kemaru

[i write plugins and stuff]

If you like a post, upvote it!

Link to comment
Share on other sites

Oh gosh - you are right. Thanks - I was thinking it was giving me the area of the bounding rectangle of the selected circles.
I believe I had the same misconception at one point.
One more quick question, is there a way to type in the dimensions of a desired circle? I need circles of various exact sizes and drawing the circles allows me to get close to the desired area but not exact (for instance, I need a circle with an area of 6 cm sq and I can get it to 6.05 or 5.97....) Any suggestions?

Clarifying what Rick said, to create a circle of A = 6cm², you'd need a radius of 1.382cm, or .544". At the default image resolution of 96dpi, that's 52.232 pixels. Paint.NET does not support soft selections, so it can't have only a fraction of a pixel selected; it's either selected or it's not. So you can't get exactly 6cm² at 96dpi.

Also due to the lack of soft selections, the formula A=πr² doesn't really apply anyway.

xZYt6wl.png

ambigram signature by Kemaru

[i write plugins and stuff]

If you like a post, upvote it!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...