Scrolling to change brush feather size on MacOS not working with non-Apple mouse

[tylerhenthorn]

Describe the bug
This may be related to #1977. Scrolling the mouse wheel in either direction to change the mask brush feather size will decrease the size of the feather. The issue happens when using a non-Apple USB mouse, but is not present when using the Macbook's trackpad, or when using the Apple Magic Mouse.

To Reproduce

1. Open a CR2 file in darktable
2. Create a new mask and select the brush tool
3. Hold shift and scroll the mouse wheel in either direction

Expected behavior
Scrolling the mouse wheel in one direction should increase the brush feather size, and scrolling in the other direction should decrease it.

Platform (please complete the following information):

• MacOS Sierra 10.12.6 (16G2016)
• MacOS Mojave 10.14.1 (18B75)
• darktable 2.6.2
• non-Apple USB mouse

Additional context
darktable_all.log

[dartemisia]

@tylerhenthorn >>> Are you saying that Shift + scroll only decreases the feather size, regardless of which direction you scroll? I'm just checking because most people seem to report the inverse: that Shift+scroll only increases feather size (as in #1977).

[tylerhenthorn]

@dartemisia the inner circle grows to meet the boundary of the outer circle.

[dartemisia]

@tylerhenthorn I'm a bit puzzled by your description, as it seems to say that the mask increases in size, but the feather doesn't change. That's very odd.

So please forgive me if I try to say what I see as clearly as I can. Let's say I'm using the exposure module, and I select 'drawn mask' from the blend options. And let's say I then select a circular mask, and click on the picture where I want to apply this, to set the mask position.

When I then hover the mouse over the mask, I see two concentric circles: one displayed as a thick line, which is the mask itself; the other shown as a dotted line, outside the thick line, which indicates how far the feather region extends beyond the mask. Now, lets just talk about increasing sizes...

If I place the mouse on the mask and just scroll, the diameters of both circles increase in unison, so the distance from the thick line to the dotted line remains constant as both the circles increase in size together at the same rate. In other words, the mask gets bigger, but the distance over which the feathering occurs does not - it stays the same distance from the mask.

But if I hover the mouse over the mask, press the shift key and then scroll, the thick line doesn't move, but the dotted line moves away from it, as the dotted circle gets bigger. In other words, the mask stays the same size, but the feathering distance increases.

However, if I scrolled in the opposite direction, both of these procedures should produce a decrease in size: the simple scroll should decrease the size of the mask, and keep the feather the same distance from it as both get smaller together; but shift + scroll should keep the mask's thick-lined circle the same size, while the dotted line moves towards it — and if I were to keep on scrolling, the dotted circle should meet and merge with the thick line of the mask circle, so that there's no feather at all, and the mask would have a hard edge.

On my Mac, the problem is that Shift+scroll only makes the dotted line move away from the solid line, regardless of the direction I rotate the scroll wheel. So the feather always just gets bigger.

Apologies if my description comes across as very pedantic, but it's hard to describe time-based motion in writing! I hope I've described clearly what I see happening. Is it what you see?

[tylerhenthorn]

@dartemisia the behavior with the circle tool is exactly as you describe. The behavior with the brush tool is as I described above.

[dartemisia]

I'm intrigued that you find you can only decrease the size of the feather for the brush tool. On my system, scrolling in either direction only increases it. Strange!

(I'm in discussion over on issue #1977 with @edgardoh about scrolling with and without key modifiers. You might be interested in taking a look, and perhaps contributing your observations. )

[dartemisia]

@tylerhenthorn >>> BTW, did you manage to try your Apple USB mouse? I think that information on how that works for scroll, Shift+scroll and Ctrl+scroll with Masks, Brushes, Tone Curve nodes and Zooming would be very enlightening.

If you have the time, please see my observations here:
#1977 (comment)

[tylerhenthorn]

I do not have an Apple USB mouse. I have tested on these devices:

non-Apple USB mouse: broken
Apple Magic Mouse (Bluetooth): working
2016 15-inch Macbook Pro integrated trackpad: working

The logs attached in this ticket are with the non-Apple USB mouse.

[dartemisia]

I do not have an Apple USB mouse. I have tested on these devices:

Sorry, I don't know how I got the idea that you had. Anyway, no worries, as a couple of devs (including the OS X maintainer) have been investigating the issue over on #1977. They seem to have worked out what's going on, and how to fix it. Let's hope someone volunteers to build it, so it can be incorporated into the 2.7 release. :)

[github-actions]

This issue did not get any activity in the past 30 days and will be closed in 7 days if no update occurs. Please check if the master branch has fixed it since then.