Clojurians Log v2
humbleui 2023-03-07
Looking for implementation advice from someone familiar with the internal workings of JWM <-> HumbleUI;
I'd like to "bring a window to top" in Windows, including stealing application focus if another application is on top. There is an existing implementation of window/set-visible, but it only works if the HumbleUI application already has toplevel OS focus.
src - https://github.com/HumbleUI/HumbleUI/blob/main/src/io/github/humbleui/window.clj#L128
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To get the behavior I want, I expect to add a function to humbleui.window.
It'll assumedly call into https://github.com/HumbleUI/JWM/blob/main/windows/cc/WindowWin32.cc ; probably jwm::WindowWin32::focus()
If ::focus() doesn't work, then I'll add a new method with some magic win API incantations (ref https://stackoverflow.com/questions/916259/win32-bring-a-window-to-top )
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Does the above plan track? Anything I should try or do differently?
Latest commit adds the feature on Windows via abuse of the AttachThreadInput. It ain't pretty but it works; lets my app popup from the background via alt+space trigger (think launcher program behavior)
Working snippet based off the latest commit --
(defn toggle-open!
[]
(let [$window @*window
foreground-hwnd (.getForegroundWindow $window)
app-in-foreground? (= (.getWindowThreadProcessId $window foreground-hwnd)
(.getCurrentThreadId $window))]
(log/debug (or (and app-in-foreground? "Toggling app to closed state")
"Toggling app to open state!"))
(window/set-visible $window (not app-in-foreground?))
(when-not app-in-foreground?
(window/steal-focus $window)
(window/restore $window)
(window/focus $window))))Tried some approaches but couldn't get .focus() to do OS level "steal focused app" behavior. I'm falling back to my second plan; update JWM with the magic SendMessage WinAPI calls that will produce the correct behavior. Now reading over JWM code to understand structure & how to compile a local .jar
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Some context: I'm building a 'native' desktop app in Clojure. I've written versions in ClojureFX and Membrane but the code / architecture felt complex & unpleasant.
HumbleUI has felt the best so far; responsibilities are decomplected in an understandable way. CljFX is comparatively a hot mess. Membrane has some really cool ideas but it's also immature with hard-to-understand src.
Given the pre-alpha release state of HumbleUI, I expect this will be a rocky path. Even then, it still seems the best option for a homegrown Clojure desktop app in 2023.
Took a while to grok JWM but some progress. https://github.com/HumbleUI/JWM/pull/266
I need to add another commit; though it's nasty, using AttachThreadInput of the JWM thread onto the Windows foreground thread is looking like the only way to correctly steal application focus
setVisible is only for hiding/unhiding window
As I understand it
I’m not sure if it’s working under Windows, but theoretically that’s where that code should go
.focus() is probably it -- I'll check this out until it's working on my local machine and raise a small PR if appropriate