How to make layer size equal the document size?

[Charles Jenkins]

This is one of those trivial things that seems impossible to find in AP.

Last night I needed to recolor an image based on a color found in one small part. Recognizing that the color I perceived and liked was probably an area with minute variations, instead of using an eyedropper, I wanted to get an average of just that spot. I used a circle selection to copy the desired area, then pasted it into a new layer that was supposed to be blended with the entire image. I ran the Average filter and got my first surprise: instead of the average color filling the layer, all it did was turn my small circle into a small square containing the average color! My theory was that the layer size was small--just large enough to contain the circle--and I needed to resize it to become the full size of the image, then run the Average filter again.

At this point I wasted my time trying to find a menu option for fitting the layer size to the image or otherwise expanding it, but eventually I had to give up. I realized that the eyedropper would work fine if I used it on the averaged square, so my workaround was to pick that color and fill it into a new empty later that I did not make via copy/paste. So eventually I got where I needed to be on this project, but for future reference I would still like to know how to control and adjust layer sizes.

[gdenby]

A "layer" in the Affinity suite is a generic term for what might also be called an object. When one creates a blank layer, it defaults to the whole work space size. Once can do anything within that space. But if you make a selection, as you saw, the new layer from it is just that selection. This is also true of a single vector arc, which is only the single mark residing within a bounding box.  You can modify that selection by activating the layer, and using the "move" tool to access the selections bounding box, and resize the selection.

For what you were trying to do, your working solution was a much better option. If up sizing the selection and moving it to cover the whole image, any irreguarities in the original selection would have been spread out, but still there.

I don't us AP enough to say for sure, but I'm supposing using an adjustment layer that affected the whole canvas would have been a more appropriate method.

[toltec]

2 hours ago, Charles Jenkins said:

This is one of those trivial things that seems impossible to find in AP.

Last night I needed to recolor an image based on a color found in one small part. Recognizing that the color I perceived and liked was probably an area with minute variations, instead of using an eyedropper, I wanted to get an average of just that spot. I used a circle selection to copy the desired area, then pasted it into a new layer that was supposed to be blended with the entire image. I ran the Average filter and got my first surprise: instead of the average color filling the layer, all it did was turn my small circle into a small square containing the average color! My theory was that the layer size was small--just large enough to contain the circle--and I needed to resize it to become the full size of the image, then run the Average filter again.

At this point I wasted my time trying to find a menu option for fitting the layer size to the image or otherwise expanding it, but eventually I had to give up. I realized that the eyedropper would work fine if I used it on the averaged square, so my workaround was to pick that color and fill it into a new empty later that I did not make via copy/paste. So eventually I got where I needed to be on this project, but for future reference I would still like to know how to control and adjust layer sizes.

You would probably be better to pick a colour using the Eyedropper. You can set the Eyedropper to use an average reading. See various options available from the context menu.

Then add a new fill layer, Layer > New Fill Layer. That will fill the entire document with a layer in the colour you picked.

 

If you press Alt and drag slightly, you get a magnified picker which gives you a better sense of what colour is in that area.

[Charles Jenkins]

Thank you both! I swear, I don't know why Serif makes things so difficult, but at least there is a good workaround for this one.