I’m using the rectangle select tool and overall I like it as I’m able to “subtract” parts from it using option-click. Very slick. There is a use case however where I find this extra power gets in the way of doing something super simple: setting the origin and dimensions of the selection. I’m often zoomed in 300% or more trying to get the perfect selection box and need to make it a bit wider. As far as I’ve found so far that’s not possible. Something similar to the Crop tool where I can edit the (x,y) and width&height is what I’m looking for.
I see I can use the arrow keys to move the selection. That is very good and super helpful so I gotta imagine you have a hidden trick for the width and height tucked away somewhere.
Related question: often I want to move the selection on the X or Y plane and nothing else. Is this possible? I only found how to do this with the mouse (while holding ⌘) but my dexterity is shit so I’m hoping there’s a way to do so with the arrow keys.
Sorry for the late reply - this didn’t show up in my inbox till now!
At any rate, there’s no easy way to change the width / height of a selection once it’s been added. Bonus answer below for the reason why.
As far as moving the selection with the arrow keys, it’s possible! Just click on the canvas so it has focus (clicking once inside a selection should do it), and you can use the arrow keys to move it around. Holding the shift key will move it 10 pixels at a time. You will need to have a selection tool already active, but that’s usually the case if you just made a selection.
You can also hold down the option key to have it expand in a direction.
Bonus answer:
So why can’t you resize the selection bounds?
Acorn’s selections are written to a bitmap, which essentially acts as a mask when you do something with that selection. So when you press delete to remove pixels from a layer, the selection mask is applied to that area which filters out all the pixels and then Acorn sets those new pixels to the layer bitmap. Applying a filter to a selection, or filling it goes through the same process.
“Why can’t a selection be just like regular shape layers?” you might ask. Well, in theory this is possible - but the magic wand tool, which is super popular, works on pixels and not shapes. So the selection mask needs to be in a format that can cross both boundaries (so you can add a magic wand selection to an existing oval selection).
One workaround for this is for the selection mask to be a composite of two types of masks - bitmap masks and vector masks (much like Acorn has vector and bitmap layers). And obviously the bitmap wouldn’t come into play if you didn’t use both magic wand and rect selections on the canvas.
At any rate- it’s something I’m certainly considering for a future release, as it’s often requested.
