Is there no way to center an elliptical selection?

[Stokestack]

I was trying to create a circular selection in Photo, on Mac, from a center point; but no combination of modifier keys caused the circle to expand symmetrically from the starting point. Is this not possible?

Another problem was that when the selection overflowed the the document window, that side of it was simply cut off (flattened). This is not only undesirable, but profoundly inconsistent with other behavior in the app; for example, crop, which doesn't actually crop but leaves the surrounding image data intact. So if even the canvas edges don't trim image data, why on earth would the viewing window?

In the attached video, I've had to set up guidelines at the edges of the record label to address the first problem (no hotkey to make the selection emanate from the center). But then the selection isn't round anymore.

 

[Alfred]

3 minutes ago, Stokestack said:

In the attached video, I've had to set up guidelines at the edges of the record label to address the first problem (no hotkey to make the selection emanate from the center). But then the selection isn't round anymore.

The left and right guidelines make sense, but why isn’t the top guideline at the top of the label?

At present the only way to create a selection from the centre is to create a shape from the centre and then convert that shape into a selection.

[Stokestack]

2 hours ago, Alfred said:

The left and right guidelines make sense, but why isn’t the top guideline at the top of the label?

Because it's a circle; I only need to know its diameter.

Ah, you're asking simply because there's a horizontal guideline in the screen grab. That doesn't have anything to do with the circle; I only put it there so I could rotate the image by hand and make the text perfectly horizontal.

Thanks for your answer. I guess this is another basic function missing from the application.

[StuartRc]

You can draw a vector Shape (ellipse/circle in this case) and use it for the selection in Pixel Persona

1. Draw shape

2. Switch to Pixel Persona

3. Control Click the object layer in layers panel

4. Works with any shape and you can multi select Add combine and negate

[Stokestack]

Thanks for that. I forgot that the forum doesn't distinguish between products (?), so I needed to specify that this is in Photo.

Right-clicking on the shape layer doesn't seem to offer any option to convert the shape into a selection, nor do I see that option elsewhere.

It's nice to know that the shape-drawing feature lets you start at the center, but it makes the absence of that ability for selections all the more baffling.

[StuartRc]

3 minutes ago, Stokestack said:

Thanks for that. I forgot that the forum doesn't distinguish between products (?), so I needed to specify that this is in Photo.

Right-clicking on the layer doesn't seem to offer any option to convert the shape into a selection.

Hi,
It is ok I assumed it was designer but... 

It is CONTROL+Click...just tried it with the donut tool....in photo!

[Stokestack]

Thanks again! But... now I have to add that this is on Mac, so Ctrl-click is the same as right-click. I tried clicking with the other modifier keys, but nothing happened.

[R C-R]

At least for me it is far from intuitive or obvious but you can use AP's Quick Mask function to move, resize, or skew a marching ants pixel selection. This also works with snapping options, Transform panel entries, etc., all in the usual way.

The trick is to make the initial marching ants selection, click on the Quick Mask button in the toolbar, & then change to the Move Tool.

[R C-R]

19 minutes ago, Stokestack said:

Thanks again! But... now I have to add that this is on Mac, so Ctrl-click is the same as right-click. I tried clicking with the other modifier keys, but nothing happened.

On a Mac, CMD + clicking on the shape's thumbnail in the Layers panel will add a marching ants selection to the document but you probably won't see it unless you hide or delete the shape because the marching ants follow the outline of the shape.

An easier way to convert the shape to a marching ants selection in one step is to select the shape & from the AP Select menu choose "Selection From Layer and Delete." If you need to do this frequently, you can assign a keyboard shortcut to that menu item.

It is also possible to make that a step in a macro but I can't think of any good reason to do so.

[Stokestack]

Oh yeah, you just reminded me about the lack of a "transform selection" function, which I haven't gotten around to filing a bug report on.

Sometimes I wonder if I'm being too harsh on the UI gaffes in this app, but that is beyond non-intuitive. It may as well not even exist.

However... as it turns out, the same state is invoked by choosing "edit selection as layer" from the Select menu, which is indeed where I would look for this transformation function. So... the function is where it belongs; it just has an unnecessarily obscure name.

Thanks for taking the time to point it out!

Update, now that you added the additional info: No; I'm not being too harsh. That last tidbit is even more obscure: Command-clicking on the layer does nothing, because it only works if you click on the thumbnail. Really?

29 minutes ago, R C-R said:

An easier way to convert the shape to a marching ants selection in one step is to select the shape & from the AP Select menu choose "Selection From Layer and Delete." If you need to do this frequently, you can assign a keyboard shortcut to that menu item.

Thanks. However, I can't find any way to transform the selection after that; transformations distort the selected area of the image, not the selection marquee itself.

[R C-R]

12 minutes ago, Stokestack said:

However... as it turns out, the same state is invoked by choosing "edit selection as layer" from the Select menu, which is indeed where I would look for this transformation function. So... the function is where it belongs; it just has an unnecessarily obscure name.

I think this is the result of the word "selection" having different meanings depending on the context. That's why I usually write "marching ants pixel selection" or just "marching ants selection" or some such so it (hopefully) won't be confused with a layer or node or whatever selection.

If you use the "edit selection as layer" or Quick Mask methods, the context toolbar shows "Selection Raster." So maybe the Select menu could be renamed "Raster Select" or the like to make this more obvious, but long menu names are usually best avoided so maybe not.

[Stokestack]

I don't know what "selection raster" or "raster select" mean here (because what other kind would there be?)...

Oh... hold on, it actually means it's a pixel-based selection, so when you scale it up it degrades the edges of the selection marquee itself.

Welp, this is useless. Thus far I have to conclude that there's no way to transform a selection marquee competently in this application.

[R C-R]

27 minutes ago, Stokestack said:

Thanks. However, I can't find any way to transform the selection after that; transformations distort the selected area of the image, not the selection marquee itself.

Try the Quick Mask method after using the "Selection From Layer and Delete" option.

[Stokestack]

Thanks, but given the degradation that I mention above, I'll never use this method. I'll just have to draw vector shapes and apply them as a mask.

[Alfred]

6 hours ago, Stokestack said:

Ah, you're asking simply because there's a horizontal guideline in the screen grab.

No, I was asking because we can’t currently create them from the centre as you and I would like to be able to do! Given that we can only directly create selections from the corner, we need to resort to an alternative means of achieving the same result. A horizontal guideline at the top of the circle would intersect with the left-hand guideline at exactly the point where you need to start dragging out your circular selection, and ending the drag at the right-hand guideline would make the selection the required size.

[firstdefence]

I think a better way would be to use the Ellipse shape tool.

1. I would crop to the edge of the label instead of having the document as it is, you can even use the ellipse tool to make a clipping mask for visual neatness.
2. Select the ellipse shape tool and drag out an ellipse constrain the ellipse to a circle by holding down the shift key as you drag out the shape.
3. Go to the layers panel, select the layer and drop the layer opacity down to 70% so you can see through the ellipse.
4. Now position the ellipse as you want, if the label centre is centre of document you can use the align tools on the Arrange menu to centre to the document
5. Change the ellipse layers opacity back to 100%
6. Now use Select > Selection from layer this method gives you better control over select shape and selection position.

You can also retain the shape to modify selection if needed

An even simpler method is to use the Doughnut shape tool to create a clipping mask, this will automatically have the centre circle aligned, it also allows for resizing of the inner and outer edges. The white area’s are actually transparent.

 

[Stokestack]

Thanks, guys. Yes, I agree that drawing a vector shape is the best way to accomplish this kind of thing. The degradation of the "raster" selection outline when you transform it is just... ridiculous.

[R C-R]

15 minutes ago, Stokestack said:

Thanks, guys. Yes, I agree that drawing a vector shape is the best way to accomplish this kind of thing. The degradation of the "raster" selection outline when you transform it is just... ridiculous.

I am not sure what you mean by degradation here but please consider the following:

• A marching ants pixel selection just defines an area on the canvas.
• It does not belong to any layer or object -- it is an independent entity. In fact, you can make one even if the document has no layers.
• It may & usually does include along the edges of the selection only part of some of the pixels of the canvas.
• The marching ants outline encloses an area where at least ½ of a pixel is selected.
• The feathering & anti-aliasing options on the context toolbar can be used to soften & blend whatever is applied to a pixel layer within the selection.
• The Quick Mask mode will preview how partial pixel selections & softening/blending are going to affect the selected part of the layer.

Effective use of these properties of marching ants selections are often an important part of many retouching jobs, for example to sharpen or blur, burn or dodge, paint over, etc. selected parts of a photo without making it overly obvious or looking unnatural.

[lepr]

2 hours ago, Stokestack said:

The degradation of the "raster" selection outline when you transform it is just... ridiculous.

We've been told that the developers will be having a look at improving that situation. (Although that could be decades away, if ever.)

[Stokestack]

6 hours ago, anon2 said:

We've been told that the developers will be having a look at improving that situation. (Although that could be decades away, if ever.)

That's interesting news.

8 hours ago, R C-R said:

I am not sure what you mean by degradation

When you scale-up a selection marquee using the transform control, its edges smear and degrade as if you're blowing up a low-resolution bitmap. You can see this in the QuickMask mode.

[R C-R]

2 hours ago, Stokestack said:

When you scale-up a selection marquee using the transform control, its edges smear and degrade as if you're blowing up a low-resolution bitmap. You can see this in the QuickMask mode.

That depends on if the selection is feathered and/or anti-aliased or not.

[Stokestack]

Anti-aliasing shouldn't be necessary, because it should be a vector.

[R C-R]

36 minutes ago, Stokestack said:

Anti-aliasing shouldn't be necessary, because it should be a vector.

Please consider what I wrote in this earlier post. A marching ants pixel selection -- the moving dashed line created with the selection tools or by converting a shape to a selection -- is not a vector object. In fact, it isn't an object at all, vector or otherwise. It is simply a defined pixel area of the canvas.

It does not belong to any particular layer -- in fact, as this marching ants selection.afphoto example demonstrates, it can exist even when there are no layers in the document.

EDIT: Should you be wondering, that particular selection was made with the Elliptical Marquee Tool, with Feathering set to 61 px & antialiasing enabled. If you enable Quick Mask mode, you can see the extent of the feathering.

[thomaso]

On 9/5/2020 at 12:36 AM, Stokestack said:

Ctrl-click is the same as right-click. I tried clicking with the other modifier keys, but nothing happened.

On mac you CMD-click on a layer thumbnail to create a marquee selection from its content.

[firstdefence]

With regard to the “smearing” effect or that the edge looks fuzzier as it gets bigger, this is probably because the feather parameter is being scaled, so on a 100px diameter with a 10px feather, when scaled to 200px diameter the feather will likely be 20px approx so the feather is not maintaining it’s 10px parameter. 

Would be interesting to know if this is actually the case.