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Counting pixels of one color


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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!

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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!

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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!

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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!

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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!

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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!

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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!

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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!

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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!

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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!

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