Hi, yes, this requirement is not as easy as it looks like.
I just listed all the methods that most useful, by reading their docs, you
can easily find your algorithm to compute the correct location.
I mentioned you snip% does not have its own mouse event object,
therefore, you cannot obtain the enter and leave event stats of a snip.
Sometimes it works, because your mouse happens to leaving the listbox and
entering the editor-canvas%. Here is my solution:
(define &hover (box #false)) ; the last hovered snip
(define/override (on-event mouse)
(super on-event mouse)
(define &editor-x (box (send mouse get-x)))
(define &editor-y (box (send mouse get-y)))
(global-to-local &editor-x &editor-y)
(define maybe-snip (find-snip (unbox &editor-x) (unbox &editor-y)))
(let ([hovered (unbox &hover)])
(when (and hovered (not (eq? hovered maybe-snip)))
'(on-leaving))
(set-box! &hover maybe-snip)
(when (and maybe-snip (send mouse moving?) (not (send mouse
get-left-down)))
'(on-hover))))
On Thu, May 25, 2017 at 12:59 AM, Erich Rast <er...@snafu.de> wrote:
> Hi,
>
> Thanks a lot for your answer! The methods you mention for A3 do not
> give the right results, though. Here is my current callback with your
> method, where show-info really just opens a window at the x and y
> coordinate:
>
> (lambda (snip evt dc show?)
> (and-let* ((admin (send snip get-admin))
> (editor (send admin get-editor))
> (editorx (box 0))
> (editory (box 0))
> (win (get-top-level-edit-target-window)))
> (send admin get-view x y w h snip)
> (send editor get-snip-location snip editorx editory)
> (send editor local-to-global editorx editory)
> (let*-values (((tx ty) (send win client->screen (inexact->exact
> (unbox editorx)) (inexact->exact (unbox editory)))))
> (displayln (format "position x=~s y=~s" tx ty))
> (send snip show-info
> (inexact->exact (+ tx (unbox w)))
> (inexact->exact (+ ty (unbox h)))
> show?))))
>
> In this case, I'd like to have the window left below the snip, but it
> shows up in a completely different place. (The x coordinate seems
> roughly close, but skewed, the y-coordinate is far too small.)
>
> The closest I got to a solution so far is this clumsy callback:
>
> (lambda (snip evt dc show?)
> (and-let* ((admin (send snip get-admin))
> (canvas (get-canvas))
> (editor (send admin get-editor))
> (editor-canvas (send editor get-canvas))
> (panel (send editor-canvas get-parent))
> (p2 (send panel get-parent))
> (x (box 0))
> (y (box 0))
> (w (box 0))
> (h (box 0))
> (editorx (box 0))
> (editory (box 0))
> (win (get-top-level-edit-target-window)))
> (send admin get-view x y w h snip)
> (send editor get-snip-location snip editorx editory)
> (send editor local-to-global editorx editory)
> (let-values (((tx ty)
> (send win client->screen
> (inexact->exact (unbox editorx))
> (inexact->exact (unbox editory)))))
> (send snip show-info
> (inexact->exact (+ (send p2 get-x) tx (unbox w)))
> (inexact->exact (+ (send panel get-y) ty (unbox h)))
> show?))))
>
> (Please ignore any unused variables, I've experimented with many
> different approaches.)
>
> This nearly gives the right result, so it seems as if I have to
> traverse the nested hierarchy of controls in order to find the 'right'
> control that doesn't have a 0 x- and y-coordinates because it is just
> locally embedded. This unfortunately means that if I change the layout
> geometry, the approach will fail. Not very good.
>
> In any case, the window location is still off, a little bit too much to
> the left and about the size of the tab panel heading to the top of
> where it ought to be. See the @"Notes":26 test window as a popup for
> the purple snip in the attached screenshot.
>
> Is there any way to fix this or a more general, easier way to get the
> coordinates?
>
> Best,
>
> Erich
>
> p.s. Another, more serious issue is that hovering the mouse over the
> snip and leaving it only works sometimes (e.g. when I hover from the
> listbox directly to the snip) and fails most of the time. But one thing
> at a time.
>
> On Wed, 24 May 2017 07:03:45 +0800
> WarGrey Gyoudmon Ju <juzhenli...@gmail.com> wrote:
>
> > Hi Rast
> >
> > the mouse event object of editor% and snip% is always the one passed
> > to the on-event method of editor-canvas% (that's why event handlers
> > of snip% have lots of extra arguments to provide you the location
> > information, racket/snip do the computing for you). When it is used
> > with a snip% instance directly, you have to check the docs to see the
> > proper way to use it correctly. Another thing you should take care is
> > that, the event object itself is not able to tell you the snip%s'
> > enter and leave stats.
> >
> > A1 & A2: You have get-top-level-windows and get-current-mouse-state.
> > (But the Question 1 is not necessary for your requirements here).
> > A3: You have get-snip-location, local-to-global, and client->screen.
> >
> >
> > On Tue, May 23, 2017 at 10:24 PM, Erich Rast <er...@snafu.de> wrote:
> >
> > > Hi,
> > >
> > > For me personally, coordinates are probably the most unintuitive
> > > aspect of Racket's GUI management. The problem comes up again and
> > > again, and I never get it right, so maybe someone can clarify this
> > > once and for all.
> > >
> > > I have a mouse-event% in on-event of a snip% and would like to
> > > display a floating frame% just below the mouse.
> > >
> > > Question 1: What is the right way to obtain the window in a
> > > potentially nested hierarchy of editors? I'm currently using:
> > >
> > > (define top-window (and-let* ((canvas (get-canvas))
> > > (top (send canvas
> > > get-top-level-window))) top))
> > >
> > > is that correct?
> > >
> > > Question 2: How do I obtain the right coordinates for the frame%
> > > that I would like to show below the mouse?
> > >
> > > I assume it has something to do with top-window above, but how do I
> > > convert from the coordinates of the mouse-event to the 'right'
> > > coordinates? Currently, the frame% appears offset about 20 to 20
> > > pixels below the top-window's top-left corner and not at all where
> > > the mouse is located.
> > >
> > > Are the mouse-event coordinates relative to the editor? Or relative
> > > to the snip within the editor? How do I convert them?
> > >
> > > Question 3: Suppose I want to do the same with a snip% displayed in
> > > a text% with one editor-canvas%, i.e., show a floating window just
> > > below the snip%. Use cases: tooltips, spell corrections, etc.
> > >
> > > How do I do that?
> > >
> > > Thanks a lot in advance!
> > >
> > > Best,
> > >
> > > Erich
> > >
> > >
> > >
> > > --
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> > >
> >
>
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