[gimp-web-devel/pat/bootstrap] Issue #5: adding a page for graphic tablets and touchscreen support.

[Jehan <jehanp src gnome org>]

commit 489a496da1d5b43a72889061dc85c6be49b49103
Author: Jehan <jehan girinstud io>
Date:   Sun Sep 11 17:43:38 2022 +0200

    Issue #5: adding a page for graphic tablets and touchscreen support.
    
    I was initially porting the associated old wiki page
    wiki/Graphic_tablets_support-20210622010105-edit.txt (see !3), though
    it's actually quite bare and not so useful. There was just a table for
    Windows with 3 tablets (and possibly wrong or outdated) and an empty
    table for macOS.
    
    I kept the Windows table (though not sure how useful it really is),
    added a few tablets we know work fine, but especially I wrote down the
    full situation of GIMP 2.10 and 2.99 regarding tablet and touchscreen
    support.

 content/core/graphic_tablets_support.md | 185 ++++++++++++++++++++++++++++++++
 1 file changed, 185 insertions(+)
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diff --git a/content/core/graphic_tablets_support.md b/content/core/graphic_tablets_support.md
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+---
+title: "Graphic tablets, pen displays and touch screen support"
+Author: "GIMP team"
+Date: 2022-09-11
+---
+
+## Stylus usage
+### GIMP 2.10
+
+#### Linux
+
+GIMP maintainers, Aryeom and Jehan, have worked with graphic tablets on
+GIMP since 2013. They used in turn an old Wacom Bamboo MTE 450, Intuos
+5, Intuos Pro M, Cintiq, Mobile Studio… On X11, there are no major
+problems to report.
+
+On Wayland, various issues, sometimes blocking ones, have been reported,
+and since then fixed for the most. We don't use Wayland for daily work
+so can't be sure, but support seems like it would be reasonable
+nowadays.
+
+#### Windows
+
+As a general rule, GIMP 2.\* on Windows supports every tablet with a
+`Wintab` driver. Nowadays some of the newest tablets don't come with the
+Wintab driver activated by default, but they often have one if you
+search on the constructor website, or as a switch in settings.
+
+The below table is legacy and kept here in case anyone wants to update
+it. Nevertheless it is very incomplete and possibly wrong.
+
+| Brand | Model | Version of GIMP | Version of OS | Status |
+| ----- | ----- | --------------- | ------------- | ------ |
+| Genius | MousePen 8x6   | 2.10.6  | ?           | Not supported |
+| Huion  | 1060P          | 2.10.8  | 7           | Not supported |
+| Wacom  | One (CTL-671)  | 2.10.8  | 7           | Supported     |
+| Wacom  | Mobile Studio  | 2.10.\* | 7           | Supported     |
+| Wacom  | Intuos Pro     | 2.10.\* | 7           | Supported     |
+| Wacom  | Cintiq Pro     | 2.10.\* | 7           | Supported     |
+| Wacom  | Bamboo MTE 450 | 2.10.\* | 7           | Supported     |
+
+#### macOS
+
+Though we do have bug reports at time, involving tablets, they are
+rarely about the tablet not working at all (see [bug reports involving
+macOS and graphic
+tablets](https://gitlab.gnome.org/GNOME/gimp/-/issues/?sort=updated_desc&state=all&label_name%5B%5D=OS%3A%20macOS%20%2F%20OSX&label_name%5B%5D=Environment%3ATablets&first_page_size=20)).
+
+GIMP contributors (Aryeom as teacher, and Jehan as assistant) have also
+been giving university classes with GIMP, for digital illustrations and
+retouching. Students all have graphic tablets. No specific issues were
+reported.
+
+As a consequence, we assume GIMP 2.10 has an acceptable graphic tablet
+support on macOS.
+
+### GIMP 2.99/3.0
+
+#### Linux
+
+GIMP maintainers, Aryeom and Jehan, have worked with graphic tablets on
+GIMP since 2013. They used in turn an old Wacom Bamboo MTE 450, Intuos
+5, Intuos Pro M, Cintiq, Mobile Studio… They moved to using development
+2.99 versions, a few years ago. On X11, there are no major problems to
+report.
+
+On Wayland, various issues, sometimes blocking ones, have been reported,
+and since then fixed for the most. We don't use Wayland for daily work
+so can't be sure, but support seems like it would be reasonable
+nowadays.
+
+#### Windows
+
+Whereas GTK had historically only support for Wintab drivers, this
+changed for [GTK
+3.24.30](https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/1563) which
+added support for Windows Pointer Input Stack, based on [Windows Ink
+backend](https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/1563#note_767239),
+which is why the names are often used interchangeably.
+
+Starting GIMP 2.99.8, GIMP detects API support and use Windows Ink
+(prefered) if available and Wintab as fallback.
+
+Since we know that the Windows Ink API has sometimes issues, we also
+added a settings in `Preferences > Input Devices`, allowing to manually
+choose the API you want, when several are available.
+
+As far as we understood, Windows Ink API should [work on Windows
+8+](https://gitlab.gnome.org/GNOME/gtk/-/issues/262#note_713393) and
+should not require specific drivers [for recent enough
+tablets](https://gitlab.gnome.org/GNOME/gimp/-/issues/7197#note_1259860),
+though it may require a "HID filter driver" for older hardware.
+
+Future possible work:
+
+* adding [RealTimeStylus
+API](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/458#note_1248705) support.
+It can be interesting for cases such as using GIMP on [Windows 7 without
+a Wintab driver installed](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/458#note_1255848).
+In this case, only the RealTimeStylus API is an option.
+
+#### macOS
+
+Though we do have bug reports at time, involving tablets, they are
+rarely about the tablet not working at all (see [bug reports involving
+macOS and graphic
+tablets](https://gitlab.gnome.org/GNOME/gimp/-/issues/?sort=updated_desc&state=all&label_name%5B%5D=OS%3A%20macOS%20%2F%20OSX&label_name%5B%5D=Environment%3ATablets&first_page_size=20)).
+
+GIMP contributors (Aryeom as teacher, and Jehan as assistant) have also
+been giving university classes with GIMP, for digital illustrations and
+retouching. Students all have graphic tablets. In the 2021-2022 school
+year, some students even worked with 2.99 development versions. No
+specific issues were reported.
+
+Our macOS build maintainer, Lukas Oberhuber, also reported proper
+support when testing a [Wacom Intuos on M1 Mac in emulated
+mode](https://gitlab.gnome.org/Infrastructure/gimp-macos-build/-/issues/40#note_1538829):
+
+> Can confirm that I am able to get pressure sensitivity with a Wacom
+> Intuos on M1 Mac in emulated mode.
+>
+> Performance is good and seems to work (I've not used tablets much so I
+> might be missing something).
+
+As a consequence, we assume GIMP 2.99 has an acceptable graphic tablet
+support on macOS.
+
+Future possible work:
+
+* [Sidecar support](https://gitlab.gnome.org/GNOME/gimp/-/issues/4971)
+
+## Gestures in GIMP 2.99
+
+The feature was not possible using GTK+2 so support only started with
+GIMP 2.99 (which will become GIMP 3.0 when stable).
+
+Povilas Kanapickas added [zooming
+gestures](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/401) for
+the canvas, with 2 fingers, in GIMP 2.99.6, then [rotation
+gesture](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/597) with
+2 fingers in GIMP 2.99.12.
+These 2 gestures are exclusive, depending on how the gesture was
+initially recognized. This is a choice on purpose because we thought
+that people may not want both rotation and zoom in the same time, but it
+can always be re-evaluated. Also it currently only works using touchpad.
+Not directly in canvas with a touchscreen.
+
+There is also gesture support for [zooming in
+`GimpContainerTreeView`](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/599)
+(e.g. Layers, Channels, Vectors dockable), to increase the preview size
+in the tree listing. Finally there is gesture support for [zooming in the
+gradient editor](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/615).
+
+Note that we don't have proper on-canvas gesture for touchscreens yet.
+I.e. that currently, fingers on touchscreens are their own input device
+and will simply apply the tool attached to the device (drawing, etc.).
+It has often been discussed, e.g. in this [MR
+thread](https://gitlab.gnome.org/GNOME/gimp/-/merge_requests/486#note_1286056)
+and with Aryeom. Basically good support could be:
+
+* There should be a way to disable touch altogether in the software.
+  Some hardware have physical switch for this, but not all of them. OSes
+  or desktops also usually have settings, but you might want to disable
+  it only for GIMP. Wandering fingers adding random pixels, or even
+  unexpected zooming or panning is annoying for some people who do
+  everything with their stylus.
+* What we really want is a switch to either use touch for tool actions,
+  or to switch it for canvas navigation: panning, rotating and zooming
+  in particular. What should be the specific gesture is to be discussed,
+  as I thought that the number of fingers could determine this (1
+  finger: panning; 2 fingers: zooming; 3 fingers: rotating). But
+  apparently some OSes want to reserve 3-finger touch for OS actions.
+  Currently, touchpad zoom and rotation are both handled with 2-finger
+  touch.
+* There was also the talk of having both painting/tool action and canvas
+  navigation active. In particular: 1-finger touch would be tool action,
+  whereas 2-finger touch would be canvas navigation. To be tested but I
+  believe that if we had this, it should be optional too. Some people
+  may want tool action or canvas navigation only.
+* Other actions may be interesting too: swipe (3-finger?) to move from
+  one opened image to another? Or to navigate through layers? And other
+  canvas navigation actions like quick canvas mirroring may be worth it
+  too.
+
+This is all in discussion and we welcome patches for this to happen.