Constrain to aspect ratio when using select box?

[sabibo]

Hello - I just downloaded Affinity.  The very first thing I tried was to select an area of my image, but I want to constrain it to an aspect ratio.  This is something I have to do a lot.  But I don't see the setting for that.  Is there one?  I didn't see a similar question in the forums, sorry if I missed it.

Thanks

 

[thomaso]

Hi @sabibo, Welcome to the Affinity forums.

You could use the Crop Tool with various constraint/ratio options.

There are quite a few threads in the forum about cropping / aspect ratio / size. But the forum search engine requires and finds exact terms only, so if you enter your question in an internet search with the addition (site: …) to search in the Affinity forum only you may get more wanted results:

>> select an area of my image, but I want to constrain it to an aspect ratio  site:https://forum.affinity.serif.com <<

[walt.farrell]

Welcome to the Affinity forums, @sabibo.

First, which of the Affinity applications are you using? I'll assume Affinity Photo for the rest of this, pending your response.

Next, what will you want to do after you make the selection? That may help determine what is the best way to go. For example, if your intent is to Crop the image, then using the Crop Tool rather than making a pixel selection will offer the aspect ratio you're interested in, and is what I would normally use.

But it could be done using the Rectangular Marquee Tool. Make a selection approximately the size you want, then adjust it using the W and H fields in the Transform panel. If you click the chain icon to preserve aspect ration, when you adjust one of those values the other will adjust automatically.

[Carloes]

Sorry to necro this thread, but I think the question is quite valid using Affinity Photo.

But let me use a real-life example. Quite often I have to select parts of a photo for, say, a Pinterest post. If I would use Photoshop, I'd set 'Fixed Ratio' under Style in the Marquee Tool and then set Width to 10, Height to 15 so I have a perfect Pinterest post aspect ratio. Then I can just freely select parts, experiment a bit and find a good cutout for the end result.

As a tiny bonus question: does anyone know how to enable keyboard shortcuts in file save dialogs? I'm very used to be able to press D when prompted with a "do you want to save this document" dialog. EDIT: Command+Delete is "Don't Save"!

Edited September 10, 2024 by Carloes

[walt.farrell]

2 hours ago, Carloes said:

As a tiny bonus question: does anyone know how to enable keyboard shortcuts in file save dialogs? I'm very used to be able to press D when prompted with a "do you want to save this document" dialog. EDIT: Command+Delete is "Don't Save"!

Welcome to the Affinity forums.

What OS do you use, and what prompts are you getting? Screenshots would be nice.

[Carloes]

Hi Walt, thanks.

I'm using MacOS, and I've found out that Command+Delete is the way to press "Don't Save", so that part is solved.

[thomaso]

2 hours ago, Carloes said:

so that part is solved.

… wasn't the other part already solved before your post?

[Carloes]

No? Unless you can tell me how you can set an aspect ratio on the marquee tool?

[Old Bruce]

2 hours ago, Carloes said:

Unless you can tell me how you can set an aspect ratio on the marquee tool?

We cannot. You may have to change how you work. You can set a fixed aspect ratio with the crop tool, the problem is that you cannot see the area/image outside the cropped area. 

EDIT: fixed a mis-observation on my part and revealed by @walt.farrell.

[Carloes]

Just now, Old Bruce said:

We cannot. You may have to change how you work. You can set a fixed aspect ratio with the crop tool, the problem is that you cannot see the area/image outside the cropped area. 

Thank you for your answer! Too bad Affinity Photo cannot do that, hopefully the developers will implement it in the future.

[carl123]

Create a rectangle with the correct aspect ratio you want

Lower the opacity of that rectangle

When done turn that rectangle into a pixel marquee with Select > Selection from Layer & Delete

[walt.farrell]

2 hours ago, Old Bruce said:

You can set a fixed aspect ratio with the crop tool, the problem is that you cannot see the area/image outside the cropped area. 

Can you explain what you mean by that? I can see areas outside the crop box.

[Old Bruce]

11 minutes ago, walt.farrell said:

Can you explain what you mean by that? I can see areas outside the crop box.

Weird, when I checked earlier I couldn't. Now I can. Not sure what happened.

[thomaso]

3 hours ago, Carloes said:

No? Unless you can tell me how you can set an aspect ratio on the marquee tool?

As mentioned in Walt's first post, you can use the Transform Panel to set the size of the marquee with a desired aspect ratio.

Start with any marquee, then enter the wanted ratio, here for instance Din A4 …

…then close the 'lock' + enter the wanted width to get the according height, or vice versa:

If you want to create a selection by dragging you need indeed a workaround: Create an empty Pixel layer and switch to the MoveTool which enables you to drag the handles together with the marquee…

… with or without Shift key pressed, according to your preference setting:

[R C-R]

7 hours ago, Old Bruce said:

Weird, when I checked earlier I couldn't. Now I can. Not sure what happened.

Not sure if this will explain it but if I crop an image with the Crop Tool then the cropped out part won't show after I hit Apply. But if I then reselect the Crop Tool & do not have "Reveal" checked, I can't see the cropped out area until I reenable that option.

[lucaben]

The solution highlighted by Tomaso works very nicely, but I wonder why there is no way to do this directly when the marque tool is selected… if I remember well, the previous version of Affinity Photo actually allowed to do it easily, same implementation as in the crop tool, not sure why this feature has been removed…

[Ldina]

@lucaben On my Mac, it gives me a perfectly square or round aspect ratio if I hold down the Cmd key while dragging when using the Marquis tool.

[R C-R]

10 minutes ago, Ldina said:

@lucaben On my Mac, it gives me a square or round aspect ratio if I hold down the Cmd key while using the Marquis tool.

Same for me, so I wonder if @lucaben is using Windows if holding down the Control key would do the same ... or if the status bar indicates that it will....

[Carloes]

@Ldina The goal is to have the Marquee tool open, then define a ratio (say 1:2 because you need to make Pinterest posts), and then being able to drag the marquee tool around to select a part of an image. You can do this in Photoshop if you open the Marquee tool and then select "Fixed Ratio". In Affinity Photo the option to crop a ratio exists, but you resize the crop area instead of being able to drag a marquee tool.

I still hope the team adds this functionality at some point, because it's what is keeping me from switching fully to Affinity.

[R C-R]

1 minute ago, Carloes said:

In Affinity Photo the option to crop a ratio exists, but you resize the crop area instead of being able to drag a marquee tool.

Not sure exactly what you mean by that but you can drag around the 'marching ants' marquee selection if the Mode: is set to New.

A less convenient way to do this is to click on Quick Mask in the toolbar (or use the Q keyboard shortcut) & switch to the Move tool. You can then drag or resize the marquee 

[R C-R]

On 9/10/2024 at 4:07 PM, thomaso said:

Start with any marquee, then enter the wanted ratio, here for instance Din A4 …

Maybe I am missing something obvious, but how do you set a ratio in the Transform panel for a 'marching ants' marquee selection?

Same question for what @Carloes said about an option to crop a ratio of a 'marching ants' marquee selection.

[Hangman]

1 minute ago, R C-R said:

Maybe I am missing something obvious, but how do you set a ratio in the Transform panel for a 'marching ants' marquee selection?

As @thomaso mentioned earlier in the thread, by adding the marquee selection to a blank pixel layer and then selecting the Move Tool... This will allow you to set width and height values for the selection...

[R C-R]

16 minutes ago, Hangman said:

As @thomaso mentioned earlier in the thread, by adding the marquee selection to a blank pixel layer and then selecting the Move Tool... This will allow you to set width and height values for the selection...

??? Blank (empty) or not, I can enter pixel numbers (document units like pixels or cm's) for w or h values but I am asking how to set a ratio (in the Transform panel or elsewhere).

EDIT: Say I want to set a marquee I dragged out to an arbitrary size, like 200 x 600 px. I want to change it so the ratio is 2:3 (like say 200 x 300 px). Obviously, I can easily do the math for something this simple & just manually change 600 to 300, but  there does not seem to be any way to set the ratio directly in the Transform panel.

Can someone please show me a step by step way to do this?

[Hangman]

59 minutes ago, R C-R said:

Say I want to set a marquee I dragged out to an arbitrary size, like 200 x 600 px. I want to change it so the ratio is 2:3 (like say 200 x 300 px). Obviously, I can easily do the math for something this simple & just manually change 600 to 300, but  there does not seem to be any way to set the ratio directly in the Transform panel.

Sorry, yes, it's a case of doing the math, I'm afraid, there is no other way to achieve this...

[R C-R]

3 minutes ago, Hangman said:

Sorry, yes, it's a case of doing the math, I'm afraid, there is no other way to achieve this...

What would be ideal is if the Transform panel would take expressions like H*3/2 for W or the like.