Selection is not pixel perfect

[Orico]

Hi,

I need to create a perfect pixel sized image. I make a perfect sized selection from my source, then: Edit->Copy Merged, then I create a new file with File->New From Clipboard.

However, my new image is always different in size by a pixel or two in the width or length.

What am I doing wrong?

Thanks!

 

For reference for example: 

1. My selection

2. My new image (one extra pixel in the width):

Edited November 13, 2024 by Orico

[GarryP]

Welcome to the forums @Orico

Have a look in Settings / User Interface and make sure the “Decimal Places for Unit Types” for Pixels is set to more than zero (I have it set to 3).

Then look at your selection position and dimensions in the Transform Panel to see if there are digits after the decimal point.

If there are then you need to fix that first.

[Orico]

2 hours ago, GarryP said:

Welcome to the forums @Orico

Have a look in Settings / User Interface and make sure the “Decimal Places for Unit Types” for Pixels is set to more than zero (I have it set to 3).

Then look at your selection position and dimensions in the Transform Panel to see if there are digits after the decimal point.

If there are then you need to fix that first.

Thanks Garry,

In the Settings / User Interface  the value was 1. I changed it to 3 to test. And this is what happened:

My selection:

And after repeating the steps in my original post:

Now it increased the width by 3 pixels....

 

What just happend? maybe it needs to be zero?

Edited November 13, 2024 by Orico

[Old Bruce]

5 hours ago, Orico said:

I need to create a perfect pixel sized image. I make a perfect sized selection from my source, then: Edit->Copy Merged, then I create a new file with File->New From Clipboard.

However, my new image is always different in size by a pixel or two in the width or length.

What am I doing wrong?

Which of the three applications are you using; Designer, Photo, or Publisher? How are you making your selection?

[Orico]

Just now, Old Bruce said:

Which of the three applications are you using; Designer, Photo, or Publisher? How are you making your selection?

1. Affinity Photo 2

2. I use the Rectangular Marquee Square tool and then adjust the exact size that I need, using the Transform panel. 

[David in Яuislip]

4 minutes ago, Orico said:

adjust the exact size that I need, using the Transform panel.

Sadly that leads to disaster. I suggest making a white rectangle shape of the final size, no stroke, set blend mode to darken
Position over the image and do Select/ Selection from layer and delete
That should produce marching ants properly sized

[Old Bruce]

11 minutes ago, Orico said:

2. I use the Rectangular Marquee Square tool and then adjust the exact size that I need, using the Transform panel. 

Before you adjust the size, make a new (empty) pixel layer so the marquee's size adjustment is happening in a vacuum, so to speak. If you are on a layer with stuff in it then you will see this sort of problem. 

I would suggest you use the Rectangle shape tool to make your selection, set its fill opacity to 50% or 20% or whatever. Then once you are satisfied with the selection use the Select > Selection from Layer and Delete. Just make sure the Force Pixel alignment is on in the snapping.

 

[Orico]

2 hours ago, Old Bruce said:

Before you adjust the size, make a new (empty) pixel layer so the marquee's size adjustment is happening in a vacuum, so to speak. If you are on a layer with stuff in it then you will see this sort of problem. 

I would suggest you use the Rectangle shape tool to make your selection, set its fill opacity to 50% or 20% or whatever. Then once you are satisfied with the selection use the Select > Selection from Layer and Delete. Just make sure the Force Pixel alignment is on in the snapping.

 

Thank you very much, I'll try it

[Orico]

3 hours ago, David in Яuislip said:

Sadly that leads to disaster. I suggest making a white rectangle shape of the final size, no stroke, set blend mode to darken
Position over the image and do Select/ Selection from layer and delete
That should produce marching ants properly sized

Thanks! I will try it.